what is this called?

Help Support Plumbing Forums:

Emo113

New Member
Joined
May 27, 2010
Messages
2
Reaction score
0
Location
,
Hello,

my water heater started spewing out water from the pipe that is connected from the T&P relieve valve so I thought it needed to be changed. I did change it but the water kept going. (By going I mean it will fill up a 8oz glass in less than a minute). I went back to my W/H and I noticed that the HOT water pipe going back to the house has a samller 1/2 inch pipe connected to that pipe that is going outside the house.

so at this point I think I have to replace that brass part that is in the middle of the connections but I have no idea what's it called or where to get it... Lowes or HomeDepot do not carry this.

I noticed I can turn a knob on the top of it left and right but that did not help the water flow to go down.

At this point I dont know what else to do! Please help!

Thank you!

WhatIsThis.jpg
 

Emo113

New Member
Joined
May 27, 2010
Messages
2
Reaction score
0
Location
,
To give you a better view of the whole setup that I was talking about here is another pic that might help

thanks!

2010-05-27 11.14.06.jpg
 

phishfood

Professional
Professional
Lifetime Supporter
Joined
Jan 17, 2010
Messages
5,775
Reaction score
996
Location
Orlando, FL
HATE, HATE, HATE! I hate my internet connection!

I had a nice reply all typed up, with a big explanation of what a thermal expansion valve is, how it works, why it is needed, etc. And then, as I clicked the post reply button, my connection died. Aaaarrrgggghhhhh!

Anyway, a thermal expansion valve relieves excess pressure that is built up when cold water is added to the water heater and expands when it is heated. It is a valve that is held closed by a strong spring. When the pressure gets high enough to push back on the spring, the pressure is relieved. Normally, you can adjust the pressure setting by turning the knob on top. Since you can't, your best bet is to replace the valve. Any plumbing supply house should stock them. If none in your area will sell to you, I found one on Grainger's website, here
 

Mr_David

Easily Amused
Professional
Joined
Jan 11, 2010
Messages
4,170
Reaction score
1,059
Location
Santee,Ca,
Must be an east coast thing. I have never seen one of those used here in southern Calif. We are required to use expansion tanks to deal with thermal expansion.
 

phishfood

Professional
Professional
Lifetime Supporter
Joined
Jan 17, 2010
Messages
5,775
Reaction score
996
Location
Orlando, FL
An expansion tank is the best option, no argument there. I even had something about that in my original post that got eaten by the big mean web monster.
 

CHRISM

BUILDING SERVICES ENG MSc
Professional
Joined
Mar 18, 2010
Messages
208
Reaction score
6
Location
LONDON ENGAND, LONDON UNITED KINGDOM
As it is IMPOSSIBLE to heat water to a temperature suitable for `Household Use` WITHOUT EXPANSION - is it being suggested here that the Hot Water Cylinder / Tank is just `Holding` the pressure of the Expanded Water because it is `Strong Enough` - ?? - AND that the resulting increase in Pressure is always BELOW the Pressure that would normally `activate` the `spring loaded` Pressure Relief Valve ??

I am assuming that THIS Hot Water Cylinder / Tank is `Mains Fed` [Water] - So has to `withstand` the Pressure of the `Incoming Water Main` [regulated ?] - AND `Thermal Expansion`[?]
These are called `Unvented Cylinders`- in the U.K. - and have `Expansion Vessels` - often built into the Unit - within the casing.
Because of the `Dangers` of the incorrect installation of this type of Hot Water Cylinder - especially when heated by connection to a `Gas [or other] `Boiler` [Furnace] - by Flow and Return Pipework - We have to pass assessments [exams] on these appliances - AND be `registered` to be able to LEGALLY install - maintain or service them.
This is to ENSURE knowlege of the `Safety Controls`- Thermostatically controlled Zone [2 Port] Valve - Pressure AND Temperature Relief Valves - plus a `safely run` and `correctly sized` Discharge Pipework [can be `Scalding Hot Water] - etc.


I have `come across` Hot Water Cylinders in the Mediterranean Countries of Europe where the Water is primarily heated by a Solar Panel connected to the Hot water Cylinder - where the Thermal Expansion is `Allowed` to just `run off` - discharging via a spring loaded valve - Wasting water every time the Cylinder is heated - EVERY DAY.
This also applies when an Immersion Heater is used - Autumn / Winter / Early Spring.

BUT - I KNOW that is NOT allowed in the U.S.A. - !!! - OR even the `possibility` of that happening [as a norm.] ??

In the U.K. and most of `Mainland Europe` - There are Hot Water Cylinders which are Insulated and `Clad` [Casing] - as in the Photo for this original `Post` - which HAVE an Expansion Vessel - Built into the Unit - WITHIN THE `CASING`. [ Unvented Cylinders ]

This MUST be the case HERE [?] - IF it is - then the Expansion Vessel has `lost` its `charge` - cannot take up the Thermal Expansion - and the `Pressure Valve` is doing `its job`.
If there is an Expansion Vessel that EITHER needs `Recharging` or Replacing [?] - replacing the spring loaded `Pressure Valve` would do NO GOOD AT ALL !! - although IF I were `Recharging` [ pumping-up] or Replacing the Expansion Vessel [ there must be one ?] - I would replace the `Pressure Relief Valve` [inexpensive].

Can my `American Colleagues`inform me IF it is possible that THIS / OTHER Hot Water Cylinders are installed WITHOUT any `Expansion Vessel` ??
IF that were the case - The Cylinders / Tanks would have to be of a `Very Strong` Construction - to `Hold` the Pressure of the Water Main and EXPANDED WATER - Also a spring loaded `Pressure Relief Valve` would be `Suspect` as a design - because of the Substantial difference in the VOLUME of EXPANSION depending on the `SET TEMPERATURE`.
Although stored water should always be `Set` at a minimum of 60 Degrees Centigrade - [140 Fahrenheit] - to prevent `Legionella`- People `set` their Hot Water at `all sorts` of Temperatures - AND therefor - `all sorts` of `Thermal Expansion` has to be `allowed for` in the Design / Safety parameters of Hot Water Cylinders / Tanks.

I cannot imagine that a `Primitive Design` such as is being suggested - is `ALLOWED` - in ANY State of the U.S.A. ?? - For `SAFETY REASONS - IF nothing else !!

ANY idea of allowing Expansion of Heated / Stored Water to be `taken-up` within the Water MAIN - should not be `applicable` in this `Day and Age` - regarding `protecting` the `Potable`[Drinking Quality] Water to the Building, and also the `configuration` of Pressure Reducing Valves - `Non-Return` [check] Valves and `Isolating Valves` - that are installed at `most` properties - would stop that being an `option`.

I look forward to reading responses on this, Your `Fellow Professional` from the U.K. [ England].

"Regards", CHRISM.
 
Last edited:

phishfood

Professional
Professional
Lifetime Supporter
Joined
Jan 17, 2010
Messages
5,775
Reaction score
996
Location
Orlando, FL
In my experience, it is not the norm for water heaters to have a built in expansion tank. Expansion is relieved either through a relief valve, or through means of an externally mounted expansion tank.

In all new construction cases that I see, check valve arrangments HAVE to be installed between the dwelling and the water main, so obviously, the water main cannot be counted upon to absorb the expansion.

The thermal expansion valve that is at issue in this thread is meant to be the primary expansion relief system. If it were to fail, the backup would be the Temperature and Pressure Relief valve that is also required. It is designed to discharge at a much higher pressure than the thermal expansion valve, and is also designed to release in cases of excessive temperature.

As I noted above, expansion tanks are the best option, but in some areas expansion valves are allowable by code.
 

CHRISM

BUILDING SERVICES ENG MSc
Professional
Joined
Mar 18, 2010
Messages
208
Reaction score
6
Location
LONDON ENGAND, LONDON UNITED KINGDOM
As it is IMPOSSIBLE to COMPRESS WATER - regarding the pressures found in Domestic Hot Water supply - where are you saying that the Increased VOLUME of the Stored Water is `Accommodated` ??

The example in the Photo`s is a `Mains Fed`[Water] Hot Water `Cylinder`[Tank] - `UNVENTED` - WHERE are you suggesting that the `Expanded Volume` is `Taken - up`/ `Accommodated` ??

In my `extremely long` original Post I was suggesting that an `Expansion Vessel` might be Built - into the Hot Water Unit - IF that is NOT the case - I ask the `QUESTIONER` IF there IS such a `VESSEL` perhaps adjacent to the Unit - OR elsewhere [not recommended] on the Hot Water System ??

Thermal Expansion of Water HAS TO be `Accommodated` [extra VOLUME] somewhere - OR `Discharged`- note my comments in my original `Post` on this matter - regarding - IF no expansion vessel exists - parts of Europe ALLOW the Expanded Water to be `Discharged`- via a PIPE - usually not required to go to Drainage - just onto a Roof or onto the Ground ! !

I `fully understand` the operation of the `Pressure Relief Valve` AND the `Temperature Relief Valve` - As WE KNOW that - NO U.S. State would allow the Expanded Water to be `Discharged` / Wasted.

Without an `Open Vent` Pipe :
- The `Increased Volume` - even though small in percentage terms [of `cool` volume] - HAS TO be accommodated.

In my original `Post` about this - I suggested that the Expansion Vessel [must be one ?] `Charge` had dissipated - and the vessel was no longer `accepting` the Expanded VOLUME - of Heated Water - SO - the `Pressure Relief Valve` was `doing its job` and relieving the Pressure when the Expanded Water PRESSURISED THE UNIT, So - NOT ALLOWING THE UNIT TO `BECOME` `PRESSURISED` ! !

A Point to `note` is that the Hot Water `Cylinder`/ `Tank` is already `under pressure` from the `Incoming Water Main` - and although these `Units` are manufactured to be able to withstand fairly `high pressures`- `STATIC` and `WORKING`- they are NOT made to withstand the INCREASE in VOLUME - when `Thermal Expansion` occurs - in a `SEALED SYSTEM`.

When reading the paragraph above - you might think - WHAT is the `difference` between the Unit being pressurised by the Water Main - at various pressures - differing in various `States` and `Areas`- eg. 55psi in one State/Area and perhaps 70psi in another.
AND the Unit pressure on the Water Main [incoming pressure] here being perhaps 55psi - and INCREASING to 70psi when the Water is Heated ???

The DIFFERENCE is THIS: We can FILL the Unit / Hot Water System to EITHER of the `example pressures`- and the VOLUME of the Unit and System is the SAME on either `Incoming Main Pressure` - BUT when that Water is HEATED - the VOLUME INCREASES - THERE is the `DIFFERENCE` ! !
THAT increased VOLUME has to have `somewhere` to be `Accommodated`- `EXPAND TO`.

I THOUGHT that my Original `Post` FULLY EXPLAINED this - BUT as I have had to `REITTERATE` it - "Perhaps not" ???

I MUST `explain better` - perhaps `GOING INTO MORE DETAIL` - in future `Posts` - what do my `Professional Colleagues` think ???

As usual - I am `delighted` to be able to explain this to my `colleagues` - `Hydrodynamics` is a subject which very few people - including `Plumbers` understand - THAT is one of the `reasons` that some `seemingly` simple problems are `misdiagnosed` [not necessarily this post subject]

When systems are `Sealed` - by Design OR `inadvertently` by incorrect use of Valves etc. - the `Dynamics` of the system are COMPLETELY CHANGED - including for One example - the Boiling Point of Water - within a sealed system.

In a Sealed - `Unvented` Hot Water Cylinder - IF the Pressure Relief Valve and the Temperature Relief Valve were NOT fitted - NOT completely `unheard of` [in U.K. - by Unskilled Idiots] - AND the Thermostat of the Unit `FAILED` to turn off at Temperature setting - THAT UNIT would keep heating the Water - UNTIL the Unit OR another part of the Hot Water System Failed - under pressure.
IF the Water Temperature had risen to above boiling point - remembering the Water is NOT at `Atmospheric pressure` - which could happen - when the Unit `Failed` - BURST - the Contents / Water - NOW released at OVER BOILING POINT - would IMMEDIATLY EXPAND to approximately 1600 TIMES the Unit original Volume - of SCALDING STEAM ! !
Imagine for example even 50 GALLONS of Water X 1600 = 80.000 Gallons [Volume] of `INSTANTLY EXPANDING` VAPOUR = An `EXPLOSION` ! !

My Example assumes that the Pipework in the Hot Water System is Copper or Iron - Stronger than the Hot Water Unit itself.

That `DANGER` of `Incorrect Installation` is WHY we - in the U.K. have to pass EXAMS on this kind of `Installation` AND be `Registered` and `Licenced` to Install - Maintain or Service these `UnVented` Hot Water Units.
AND WHY `knowledge` is required to comment `on all aspects` about them,
- MORE KNOWLEDGE than - JUST `Installation techniques`! !

"Regards` to all my U.S. Colleagues - I would `welcome` ANY `informed` comments about ANY of my `Posts` - I don`t get any - WHY would that be ???

CHRISM.
 
Last edited:

havasu

Administrator
Staff member
Admin
Joined
Jan 5, 2010
Messages
10,360
Reaction score
2,008
Location
Southern California,
I'll give a shot on answering some questions from Chrism. You advised in England, your water heaters heat water to a minimum of 140 degrees, but the recommended temperature setting for the US is between 120 and 140 degrees, and if children are present, 120 degrees should be the maximum. Much of this is due to the stringent water standards and lack of bacteria in city water supplies.

The steel tanks sold in the US are capable of handling 300 PSI, and there is space built into the tops of these tanks for thermal expansion. In addition to the fail safe thermostats, the water heaters must be supplied with a temperature and pressure relief (TPR) valve, and per code, must not be connected to a drain line, because this is an early warning sign of a failure.

Also, with normal boiling point being 212 degrees farenheit (give or take with altitude variances) or 100 degrees celcius, these water heaters fall way short of vaporizing, which reduces the dangers substantially. There are expansion tanks used sometimes, but for the most part, in normal residential usage, and normal temperatures, are deemed unnecessary.

Every hardware store in the United States sell water heaters, primarily for installation by homeowners themselves. I myself have installed in excess of 100 water heaters, and using only common sense, have yet to have a failure or defective installation.
 

CHRISM

BUILDING SERVICES ENG MSc
Professional
Joined
Mar 18, 2010
Messages
208
Reaction score
6
Location
LONDON ENGAND, LONDON UNITED KINGDOM
"Thank You Havasu" - Good answers - Just a few `comments` on what you said - Regarding the Hot Water Temperature - ANY Temperature below 60 degrees Centigrade - 140 f - WILL allow bacterial growth - and U.K. Drinking Water - `Mains` is recognised as the `Purest` in Europe - by a `long way` - I would also expect that U.S. Drinking Water - `Mains` - would be `on a par` with ours - So the U.S. being able to heat water to a lower temperature BECAUSE of your `Water Quality` - is not a `Scientific` reason.

Regarding the Temperature of the Hot Water - To protect Children, the Blind or `Infirm` - We heat the Water to 60c - approx. 140f - THEN a Thermostatic Mixing Valve is installed to prevent the Hot Water being above between 40c and 44c - depending upon what Sanitary Fixture is being supplied.

I can `make sense` of your explanation regarding the Steel Water Heaters having a Design `Maximum Pressure` of 300 psi - AND the `Space` inside to accommodate `Thermal Expansion` - Acting like an Expansion Vessel - although I have `come across` this kind of design in the U.K. - they were `short lived` - I am intrigued as to WHY that Design would prevail in the U.S. - yet be consigned to `Obsolete` here in the U.K. ??

I would think that as our `Average` Water Mains Pressure in the U.K. is probably no more than 40psi - the Manufacturers have decided that `Medium Pressure` Unvented Hot Water Cylinders - WITH a `Built On` Expansion Vessel - is the `Best` Design ??
These Units have a MAXIMUM inlet pressure of 3 Bar - approx. = 44 psi.
and the `Thermal Expansion` is `Accommodated` by the Expansion Vessel - which has a `Membrane`inside - behind which the Vessel is Pressurised - when the Expansion of Water occurs - the Membrane `dilates` - to `take - up the extra VOLUME of water.

That explanation is Not directed at Havasu - who I am sure knows those details about an `Expansion Vessel`.


On your point about the `Boiling Point` of the Hot Water - What I stated in my example IS Correct for the `Extreme Scenario` that I described.
It is obviously RARE that an `Unvented Hot Water Heater` is installed in the way that I described - BUT - NOT `impossible`- I have been told of examples where this has been done - No Disaster occurred because the Hot Water Thermostat DID NOT FAIL to `ON`!

I would like to ask you - is it `Normal` for a Hot Water Heater to be `supplied` with heat from a Gas Boiler / Furnace - via `Flow and Return` primary pipework - HEATING a COIL/ ELEMENT within the Hot Water Heater ??

Obviously THIS type of Hot Water heater is MUCH more Dangerous if installed incorrectly - than a `DIRECT`- Electrically Heated Unit, because of the Control of the Heat Source when the Water Heater has `reached temperature`, We have `a lot` of this type of `Unvented Hot Water` Installation.

"Thank you" for responding - please have a look at some of my other `Posts`
I am particularly interested in `informed comments` on a Post the I did about the `SAFETY` of a Water Heater [Gas] Installation.

"Regards", CHRISM.
 
Last edited:

havasu

Administrator
Staff member
Admin
Joined
Jan 5, 2010
Messages
10,360
Reaction score
2,008
Location
Southern California,
Yes, we as well utilize mixing valves, but they are relatively new, expensive, and seldom used. They are used primarily in shower/bath stalls, and in high end homes, but most other faucets fail to have them installed. For this reason, when children and elderly are involved, the recommendation is to keep the hot water at no more than 120 degrees.

I hope you understand I was not insinuating that Europe has poor water quality. I'm sure some areas are as pure as water can get, but in my region, and in the city I just retired from, our well water was tested minimally twice a day, and chlorine is added to retard bacteria growth. My specific area was targeted as one of the worst areas for percolate poisons, and for this reason we were included in the Nationwide Superfund Clean Up, which was subsidized by the nasty companies who let their heavy metals soak into the groundwater. They have done a great job reducing and or eliminating polluted wells to a point that they could be reopened for general water consumption.

On the West Coast of California, where we are in a somewhat desert region, gas boilers and furnaces are virtually non-existant in residential usage, and since I have no knowledge on industrial or commercial applications, I will not attempt to answer, and leave it for the true commercial professionals.

Yes, I have read some of your comments on the dangers of carbon monoxide, and I concur completely. This is one of the reasons for codes prohibiting water heaters in living spaces, unless it is in a well ventilated area, with proper venting with true, positive air draw.

I know you have probably asked more questions then I have answered, but since I am retired, it is time to take a nap. ;) Feel free to again ask any questions I have forgotten to answer, and I will gladly reply.
 

phishfood

Professional
Professional
Lifetime Supporter
Joined
Jan 17, 2010
Messages
5,775
Reaction score
996
Location
Orlando, FL
As it is IMPOSSIBLE to COMPRESS WATER - where are you saying that the Increased VOLUME of the Stored Water is `Accommodated` ??

The example in the Photo`s is a `Mains Fed`[Water] Hot Water `Cylinder`[Tank] - `UNVENTED` - WHERE are you suggesting that the `Expanded Volume` is `Taken - up`/ `Accommodated` ??

In my `extremely long` original Post I was suggesting that an `Expansion Vessel` might be Built - into the Hot Water Unit - IF that is NOT the case - I ask the `QUESTIONER` IF there IS such a `VESSEL` perhaps adjacent to the Unit - OR elsewhere [not recommended] on the Hot Water System ??

Thermal Expansion of Water HAS TO be `Accommodated` [extra VOLUME] somewhere - OR `Discharged`- note my comments in my original `Post` on this matter - regarding - IF no expansion vessel exists - parts of Europe ALLOW the Expanded Water to be `Discharged`- via a PIPE - usually not required to go to Drainage - just onto a Roof or onto the Ground ! !

I `fully understand` the operation of the `Pressure Relief Valve` AND the `Temperature Relief Valve` - As WE KNOW that - NO U.S. State would allow the Expanded Water to be `Discharged` / Wasted.
Incorrect. In many areas of the US, thermal expansion is allowed to be accommodated by discharging it. As I have noted, this is not the best method, but it is the method that is being used in the picture that is being referenced.

Without an `Open Vent` Pipe :
- The `Increased Volume` - even though small in percentage terms [of `cool` volume] - HAS TO be accommodated.

In my original `Post` about this - I suggested that the Expansion Vessel [must be one ?] `Charge` had dissipated - and the vessel was no longer `accepting` the Expanded VOLUME - of Heated Water - SO - the `Pressure Relief Valve` was `doing its job` and relieving the Pressure when the Expanded Water PRESSURISED THE UNIT, So - NOT ALLOWING THE UNIT TO `BECOME` `PRESSURISED` ! !

A Point to `note` is that the Hot Water `Cylinder`/ `Tank` is already `under pressure` from the `Incoming Water Main` - and although these `Units` are manufactured to be able to withstand fairly `high pressures`- `STATIC` and `WORKING`- they are NOT made to withstand the INCREASE in VOLUME - when `Thermal Expansion` occurs - in a `SEALED SYSTEM`.

When reading the paragraph above - you might think - WHAT is the `difference` between the Unit being pressurised by the Water Main - at various pressures - differing in various `States` and `Areas`- eg. 55psi in one State/Area and perhaps 70psi in another.
AND the Unit pressure on the Water Main [incoming pressure] here being perhaps 55psi - and INCREASING to 70psi when the Water is Heated ???

The DIFFERENCE is THIS: We can FILL the Unit / Hot Water System to EITHER of the `example pressures`- and the VOLUME of the Unit and System is the SAME on either `Incoming Main Pressure` - BUT when that Water is HEATED - the VOLUME INCREASES - THERE is the `DIFFERENCE` ! !
THAT increased VOLUME has to have `somewhere` to be `Accommodated`- `EXPAND TO`.

I THOUGHT that my Original `Post` FULLY EXPLAINED this - BUT as I have had to `REITTERATE` it - "Perhaps not" ???
I fully understand what thermal expansion is, and the causes of it. Reiteration was not necessary, though appreciated.
I MUST `explain better` - perhaps `GOING INTO MORE DETAIL` - in future `Posts` - what do my `Professional Colleagues` think ???

As usual - I am `delighted` to be able to explain this to my `colleagues` - `Hydrodynamics` is a subject which very few people - including `Plumbers` understand - THAT is one of the `reasons` that some `seemingly` simple problems are `misdiagnosed` [not necessarily this post subject]

When systems are `Sealed` - by Design OR `inadvertently` by incorrect use of Valves etc. - the `Dynamics` of the system are COMPLETELY CHANGED - including for One example - the Boiling Point of Water - within a sealed system.

In a Sealed - `Unvented` Hot Water Cylinder - IF the Pressure Relief Valve and the Temperature Relief Valve were NOT fitted - NOT completely `unheard of` [in U.K. - by Unskilled Idiots] - AND the Thermostat of the Unit `FAILED` to turn off at Temperature setting - THAT UNIT would keep heating the Water - UNTIL the Unit OR another part of the Hot Water System Failed - under pressure.
IF the Water Temperature had risen to above boiling point - remembering the Water is NOT at `Atmospheric pressure` - which could happen - when the Unit `Failed` - BURST - the Contents / Water - NOW released at OVER BOILING POINT - would IMMEDIATLY EXPAND to approximately 1600 TIMES the Unit original Volume - of SCALDING STEAM ! !
Imagine for example even 50 GALLONS of Water X 1600 = 80.000 Gallons [Volume] of `INSTANTLY EXPANDING` VAPOUR = An `EXPLOSION` ! !

My Example assumes that the Pipework in the Hot Water System is Copper or Iron - Stronger than the Hot Water Unit itself.
In the situation that we are discussing, the piping is CPVC, a plastic piping material that is in common use in the US.

That `DANGER` of `Incorrect Installation` is WHY we - in the U.K. have to pass EXAMS on this kind of `Installation` AND be `Registered` and `Licenced` to Install - Maintain or Service these `UnVented` Hot Water Units.
AND WHY `knowledge` is required to comment `on all aspects` about them,
- MORE KNOWLEDGE than - JUST `Installation techniques`! !

"Regards` to all my U.S. Colleagues - I would `welcome` ANY `informed` comments about ANY of my `Posts` - I don`t get any - WHY would that be ???

CHRISM.
Hopefully, my further comments have helped you to better understand this situation.

Regards.
 

CHRISM

BUILDING SERVICES ENG MSc
Professional
Joined
Mar 18, 2010
Messages
208
Reaction score
6
Location
LONDON ENGAND, LONDON UNITED KINGDOM
"Hi Phishfood", In the EXAMPLE that I detailed - I described a `situation` of a `VERY DANGEROUS` installation - THIS was to show HOW a Hot Water Heater - installed incorrectly - and with the `Failure` of the Controls governing the `Heat Source` of the Unit - COULD BECOME A `BOMB` - in the consequences of what I described.
My EXAMPLE specified Copper or Iron Pipe - a `weaker` pipe material would obviously `FAIL` before the Hot Water unit - I was NOT talking about the Unit in the Original Questioner`s `Post` - re. the CPVC pipework.

I was TRYING to `scale - up` from the installation that WE started off writing about - to SHOW WHAT CAN happen IF a `Similar Type` of Hot Water heater - `Unvented` - Mains Fed Unit was installed `Completely Incorrectly`.

I have since been informed by `Havasu` of the `Construction` of the `Typical` - Steel Hot Water Heater - Max. Pressure Specification 300 psi - WITH an `area` within the `Cylinder` / `Tank` to accommodate the Thermal Expansion Volume - These Units - I assume are `Direct Heated` by an Electrical Immersion [or 2] Heater.


`Havasu` also told me that the Type of Installation that I was describing - an `Unvented Hot Water Heater` - PRIMARILY HEATED by `Flow` and `Return`pipework from a Gas `Boiler`/ `Furnace`- is not `normally` installed in His and other `Warm Weather` areas of the U.S. - which makes perfect sense - I was writing under the `assumption` that the type of Unit that I was describing - was a `Normal Installation` - throughout the U.S. - AND because of that - I did NOT give enough description of WHAT the HEAT SOURCE was - in my EXAMPLE.
That must be a `First` for me - `Not Enough Description` ! !

I am `surprised` that some areas of the U.S. allow the Thermal Expansion extra Volume to be `Discharged` - you do mean that the Water is `Discharged` every time that the Hot Water heater is `Fully Heated` ??
The Water going to a `Drain` ??
This is being a waste of Water - X however many Units are installed like that.

I think that - `in light` of Havasu`s information - that I may be `misunderstanding` YOU this time ??
You probably mean that `Excessive Thermal Expansion - Volume` would be `Discharged` ?? - as opposed to
Water being `Discharged` every time the Water Is Heated ?? - As Havasu explained - there is an `Expansion Area` within the Hot Water Cylinder / Tank itself.

My `comment` about having to `reiterate` the Facts in my `Post` was NOT directed at you - I SHOULD have written - as I was [then] explaining a simple area of `Hydrodynamics` - that while `explaining again` - "I have added the `additional information`" - no `offence was meant to you.

While I feel sure that You and Havasu would understand fully what I described about `Pressure` - `Static` - `Working` - AND `Increasing` - being DIFFERENT from VOLUME/Pressure increasing through `Thermal Expansion` - I GUARANTEE you that MOST Plumbers and Heating Fitters DO NOT - until the details are EXPLAINED to them.
MOST do not give any thought to the `Volume` increase - thinking that a `Pressure Increase` due to a rise in the `Mains Pressure` - is the SAME as a `Pressure Increase` due to `Heating the Water`.

That comment is NOT a `put down` to Plumbers - I am `Proud` to be called a Plumber - which is what my `Job Title` was for a long period of my life.

I look forward to reading your and Havasu`s `Posts` - I can `tell` from what you both write that you are `Knowledgeable` - and `Experienced` Plumbers.

"Thank you for your comments and information", - although I think that you `slightly misunderstood` my comments in my EXAMPLE - THAT May have been MY FAULT - as I was `Deviating` from answering the ORIGINAL QUESTIONER`S `POST`- and `offering` a `hypothetical scenario`.


"Regards", CHRISM.
 
Last edited:

CHRISM

BUILDING SERVICES ENG MSc
Professional
Joined
Mar 18, 2010
Messages
208
Reaction score
6
Location
LONDON ENGAND, LONDON UNITED KINGDOM
"Thank you very Much Havasu" for your comments and information - the Details about the Construction and Specification for the `Typical` Hot Water Heater have been helpful - although I am `surprised` about the Design and Installation procedures.

Your information that these Units are designed to be a `DIY Install` is also `surprising` - in the U.K. - that would definitely NOT be the case - BUT for Design and Installation `Differences` - and because We have to pass Exams and be Registered to `Install` - `Maintain` - `Service` etc.

Our Plumbing, Heating, Gas, Electrical and Ventilation Industries are `Severely` Controlled - with ONLY `Qualified` and `Registered` Operatives allowed to work on items within those `Trades`

I know that you did not mean to denigrate the U.K. Water Quality - sorry if my reply `came across` like that - I was just saying that our Mains - Drinking Water - which is of Very High purity - would be at least `on a par` with `Drinking Water` in the U.S. [or anywhere else in the World] - SO we don`t have to Heat it to a `Higher` temperature to `kill` bacteria - We heat it to a minimum of 60 Degrees Celsius - to ENSURE no formation of `Legionella` - which as you know - can KILL - rather than give one a `stomach upset` - as `other` bacteria can .

Thank you for letting me know that the `Example` Unvented Hot Water Heater that I described as being Heated by connection to a Gas `Boiler` / `Furnace` - IS NOT as `Normal` / `Prevelent` an installation as I had expected - throughout the U.S. - but `of course` your comment about the `Climate` in some parts - makes complete sense that NO BOILER / Furnace would be `required`.

I would be interested to find out how much of the U.S. - NEVER needs Heating ?? - OR is it the case where a `Hot Air System`/ Air Conditioning System WOULD be used in `Winter` - in the `Warmer Climes` of the States ??

Also thanks for your comment about `leaving commenting on that `scenario` to the `Professionals` - too many people in life have `comments` about stuff that they do not know about - It is `good to see` a person who `sticks` to commenting on matters where they have `EXPERTISE` [as you obviously do in Plumbing etc.]

I count myself as `Professional` - in matters of Plumbing, Heating [wet] and Gas - Domestic Gas Utilisation [Our Industrial / Commercial Gas Utilisation is Seperate] .
As well as having the `Highest Qualifications in each of those [associated] Trades - I have a `Master of Science Degree` in `Building Services Engineering`.
My Degree was obtained - in `part` thanks to my `experience` in working in those `Trades`- for most of my `working life`.

I have `mentioned` that - to show where my `comments` and `information` comes from - what I write is not `guessing` or from a `small amount` of knowledge, I have 40 Years in these `Industries`.

You mentioned that you are retired - "Have a Great Retirement" - I`m sure that you have `earned it` - and Plenty of people will `benefit` from your Knowledge and Experience on your `Posts`.

I am sure also that we will `correspond` here again, "Regards", CHRISM.
 

havasu

Administrator
Staff member
Admin
Joined
Jan 5, 2010
Messages
10,360
Reaction score
2,008
Location
Southern California,
I would be interested to find out how much of the U.S. - NEVER needs Heating ?? - OR is it the case where a `Hot Air System`/ Air Conditioning System WOULD be used in `Winter` - in the `Warmer Climes` of the States ??[/I]

In the desert climate where I reside, our "average temperature" ranges from 40 degrees to 100 degrees. Many residents do not, or can not afford the high costs of air conditioning, but most everyone has some type of heating system. Some are full forced air, and others only have vented wall heaters.

You mentioned that you are retired - "Have a Great Retirement" - I`m sure that you have `earned it` - and Plenty of people will `benefit` from your Knowledge and Experience on your `Posts`.
.
Yes, I am officially retired, but helping others is my passion. I understand many here are professional plumbers, and I certainly do not want to step on any toes, and if I feel it is best to hire a professional, I will tell users this exactly. When I began home repairs at the age of 17 years old, some 37 years ago (if my math is correct), there was not a service to help others, and either you had to pay big bucks, or learn by trial and error. Yes, I errored many times, and some were costly. I just want the readers to understand that some repairs can be done easily, and to not be afraid to learn something new.
 

Reedwalker

Expert Turd Herder
Professional
Joined
Jan 13, 2010
Messages
165
Reaction score
1
Location
Detroit, MI
Wow!

Havasu I love looking at your avatar. Please replace your leg with your wifes. Or a college aged girl...........

As for the rest............Wow!

I can't believe you guys actually made it that far through ChrisM's posts. I have rarely if ever made it over the wall of text that is ChrisM.


Sorry. It had to be said.
 

Mr_David

Easily Amused
Professional
Joined
Jan 11, 2010
Messages
4,170
Reaction score
1,059
Location
Santee,Ca,
--------------------------------------------------------------------------------

Wow!

Reedwalker I don't love looking at your avatar. Please replace your picture with your wife's butt. Or a college aged girl's butt would even be better!...........
Well done.

As far as ChrisM long worded post, I did find it to be interesting.
The physical dynamics of heated water are the same but how they are dealt with in different parts of the world is interesting.
 

CHRISM

BUILDING SERVICES ENG MSc
Professional
Joined
Mar 18, 2010
Messages
208
Reaction score
6
Location
LONDON ENGAND, LONDON UNITED KINGDOM
Wow!

Havasu I love looking at your avatar. Please replace your leg with your wifes. Or a college aged girl...........

As for the rest............Wow!

I can't believe you guys actually made it that far through ChrisM's posts. I have rarely if ever made it over the wall of text that is ChrisM.


Sorry. It had to be said.
CHRISM writes from Knowledge and the `Detail` that I put into my `Posts` is to TRY to ensure that people do not `misunderstand` any Technical explanation - even with all the detail that I `put in` - some misunderstanding still occurs.

I am sure that my Posts ARE viewed as TOO LONG by most - BUT I know from `Training` others - that IF one does NOT give enough detail - you WILL be `misunderstood`.

Hopefully this `Post` is brief enough - "Regards to All", CHRISM.
 
Top