what is this called?

[havasu]

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]

Originally Posted by CHRISM

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]

"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.

[CHRISM]

"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]

Originally Posted by CHRISM;
[I

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]

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.

[havasu]

[QUOTE=Reedwalker;4095]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!.........../QUOTE]

There, I fixed it for you!

[Mr_David]

--------------------------------------------------------------------------------

Originally Posted by Reedwalker

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]

Originally Posted by Reedwalker

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.