Hot water pipe with low pressure

[Kenuel80]

Hi, I have an Eco Smart 37KW inline water heater and I'm experiencing low hot water pressure only at the bathrooms shower heads. Cold water pressure probably comes out double to that of the hot pressure. I know this because I took off the shower heads. The kitchen faucet water pressure is equal on hot and cold and gets hotter than in the shower (it actually burns your hand. In the shower it doesn't get that hot). I opened up the water heater to have the heating elements cleaned and expected to find some type of calcium buildup or scaling but this wasn't the case. Only one of the elements had deposits but not something to worry about. I was also expecting buildup at the outlet restrictor of the water heater but that was also fine. Both of my bathrooms have individual valves for hot and cold. I took apart the hot water valve to see if there was a blockage but I didn't see anything. There is definitely a blockage somewhere but I don't know what else to do. Now that I'm thinking about it... I don't remember if I let the water run long enough after I took apart the valve to have any debris run out. I did this 3months ago, that's why I cant remember. My water pressure has decreased a bit more and I can shower by only opening the hot water valve (no need for cold like in the past). Any suggestions is appreciated. Thanks

 

[Jeff Handy]

Has your water heater been flushed and de-scaled on a regular basis, at least yearly?

Your shower valve cartridges also might be shot, and they might also have a second component that is going bad, the pressure balancing module.
Sometimes the pressure balancer and shower cartridge are all one big unit.

There might also be a high limit stop inside the handle trim of the shower valves, which stops the hot water from being turned up all the way.

Post pics of the trims and handles, and also pics of the exposed cartridges if you take off the trims.
If there is a brand name post that also.

 

[Jeff Handy]

Do you have 36kw or 27kw.
What is the model number?

 

[Kenuel80]

Its the 36kw model. Last December I opened it up and cleaned the elements. They all looked good, only one element had some scale build up. See pictures so you can understand what I mean with water pressure.

 

[Kenuel80]

Its the 36kw model. Last December I opened it up and cleaned the elements. They all looked good, only one element had some scale build up. See pictures so you can understand what I mean with water pressure.

Picture ending 26 is hot water full opened. Picture 40 is the cold water open. Picture 53 is hot water only opened, as you can see there's a blockage because it shoots out. Picture 32 is both opened (hot and cold).

 

[Kenuel80]

Has your water heater been flushed and de-scaled on a regular basis, at least yearly?

Your shower valve cartridges also might be shot, and they might also have a second component that is going bad, the pressure balancing module.
Sometimes the pressure balancer and shower cartridge are all one big unit.

There might also be a high limit stop inside the handle trim of the shower valves, which stops the hot water from being turned up all the way.

Post pics of the trims and handles, and also pics of the exposed cartridges if you take off the trims.
If there is a brand name post that also.

The water heater was not flushed yearly but I cleaned all elements. There isn't a problem at the kitchen faucet, only bathroom shower heads as pictured. It seems my valves don't have cartridges? No bran names. Also, when I took out the plastic thing (is that the cartridge?) the hot water coming out was not that hot. I have it set up to 140 degrees. The kitchen faucet will burn you.

 

[Jeff Handy]

You will always get less pressure from full hot, because it has to go through the guts of the water heater.
Cold just comes straight through house piping.

You can’t compare kitchen to shower pressure.
First of all, you are actually talking about flow rate, not pressure.
Volume of water flowing out.

The kitchen faucet head has a much tighter flow restricter, so hot and cold flow difference won’t be as obvious.

Bring that hot side white cartridge stem to a plumbing supply place and get a new one.
It looks ceramic, they tend to hold minerals.

Or go to HD, you might spot you ceramic cartridge stem there, but many types look almost alike.

Is that middle lever just a diverter for shower head or tub spout?

There might be another component still inside the wall, besides just that little cartridge.
A pressure balancing part.
I don’t know.

Meanwhile, someone on here might recognize your faucet or cartridge brand, to narrow down your search.

Your water heater might have more than one output line, and the one to the showers might have a clogged filter.

 

[Jeff Handy]

Find your heater manual, or find it online.

Look up troubleshooting for low hot pressure.
Look up flushing schedule and procedures.

 

[Jeff Handy]

Here is a link to your manual.
I did not see any info on cleaning or flushing, which seems very weird to me.

https://s3.amazonaws.com/rmc-cdn/site/ecosmart/downloads/manuals/ECO+8-ECO+36+English+Manual.pdf

 

[Kenuel80]

You will always get less pressure from full hot, because it has to go through the guts of the water heater.
Cold just comes straight through house piping.

You can’t compare kitchen to shower pressure.
First of all, you are actually talking about flow rate, not pressure.
Volume of water flowing out.

The kitchen faucet head has a much tighter flow restricter, so hot and cold flow difference won’t be as obvious.

Bring that hot side white cartridge stem to a plumbing supply place and get a new one.
It looks ceramic, they tend to hold minerals.

Or go to HD, you might spot you ceramic cartridge stem there, but many types look almost alike.

Is that middle lever just a diverter for shower head or tub spout?

There might be another component still inside the wall, besides just that little cartridge.
A pressure balancing part.
I don’t know.

Meanwhile, someone on here might recognize your faucet or cartridge brand, to narrow down your search.

Your water heater might have more than one output line, and the one to the showers might have a clogged filter.

Last year I had my water heater set up to 120 degrees and I would always have to open the cold water because it was too hot. Now I have it set up to 140 degrees and it doesn't get hot because the water flow is too low.

If you want to get technical we are talking about water exit velocity. The pressure at the exit of the pipe is actually zero (no pressure at all). Most people don't know that, and that's why I said pressure because that's how the majority of people refers to it.

I will take your advice and change those white cartridges. Yes, the middle lever is a diverter for shower head and tub spout.

Thanks you for your fast replies. Your time was appreciated.

 

[Jeff Handy]

No, we are talking about flow rate.
How much volume of water is being delivered at a given time.

Which can be altered by water pressure, diameter of pipes or valves, internal friction, and other factors.

It seems like there is a restriction somewhere, probably in or near the water heater, that is limiting the full flow that you used to have.

The link to the manual I sent has a number to call for troubleshooting info.
They might have a procedure to de-scale or flush that will open things up.

Most heaters I am familiar with need to be flushed with several gallons of vinegar (or another approved mineral cleaner) once or twice a year.

There might also be internal or external filters that need cleaning or replacing.

With some heaters, if you don’t flush and de-scale often enough, the flow rate and heat transfer rate drops permanently.

Also, some heaters have a sensor that will throttle back the flow rate, to help the heater keep the outflowing water hot enough.

 

[Kenuel80]

No, we are talking about flow rate.
How much volume of water is being delivered at a given time.

Which can be altered by water pressure, diameter of pipes or valves, internal friction, and other factors.

It seems like there is a restriction somewhere, probably in or near the water heater, that is limiting the full flow that you used to have.

The link to the manual I sent has a number to call for troubleshooting info.
They might have a procedure to de-scale or flush that will open things up.

Most heaters I am familiar with need to be flushed with several gallons of vinegar (or another approved mineral cleaner) once or twice a year.

There might also be internal or external filters that need cleaning or replacing.

With some heaters, if you don’t flush and de-scale often enough, the flow rate and heat transfer rate drops permanently.

Also, some heaters have a sensor that will throttle back the flow rate, to help the heater keep the outflowing water hot enough.

You are correct in everything you said about flow rate calculations. But I'm talking about once the water leaves the pipe we no longer talk about flow rate since flow rate calculations require the diameter of the pipe. You are correct by saying there is something restricting the flow rate because it deals internally within the system.

Going back to my problem I will call the manufacturer. The water heater has a flow rate sensor and maybe limiting the flow like you said. Once again thank you for all your tips.

 

[Kenuel80]

No, we are talking about flow rate.
How much volume of water is being delivered at a given time.

Which can be altered by water pressure, diameter of pipes or valves, internal friction, and other factors.

It seems like there is a restriction somewhere, probably in or near the water heater, that is limiting the full flow that you used to have.

The link to the manual I sent has a number to call for troubleshooting info.
They might have a procedure to de-scale or flush that will open things up.

Most heaters I am familiar with need to be flushed with several gallons of vinegar (or another approved mineral cleaner) once or twice a year.

There might also be internal or external filters that need cleaning or replacing.

With some heaters, if you don’t flush and de-scale often enough, the flow rate and heat transfer rate drops permanently.

Also, some heaters have a sensor that will throttle back the flow rate, to help the heater keep the outflowing water hot enough.

I just realized something. Both my bathroom faucets works perfectly. The faucet is a mixer just like the kitchen one. Now, the bathtub and shower bathrooms have individual valves. So I think the problem lies on how it mixes the water. I have access to the back of tub and looked up into the piping. Its a water manifold (just cold and hot inlets). Any idea on how to check for proper operation? I don't have access the bathroom that only has a shower, I would have to break the tile.

 

[Kenuel80]

No, we are talking about flow rate.
How much volume of water is being delivered at a given time.

Which can be altered by water pressure, diameter of pipes or valves, internal friction, and other factors.

It seems like there is a restriction somewhere, probably in or near the water heater, that is limiting the full flow that you used to have.

The link to the manual I sent has a number to call for troubleshooting info.
They might have a procedure to de-scale or flush that will open things up.

Most heaters I am familiar with need to be flushed with several gallons of vinegar (or another approved mineral cleaner) once or twice a year.

There might also be internal or external filters that need cleaning or replacing.

With some heaters, if you don’t flush and de-scale often enough, the flow rate and heat transfer rate drops permanently.

Also, some heaters have a sensor that will throttle back the flow rate, to help the heater keep the outflowing water hot enough.

Hi Jeff, I found out my problem. If I don't open the hot valve all the way the water comes out very hot. I remember I took out the flow restrictors from the shower heads. So I guess I need them flow restrictors.

 

[Jeff Handy]

Great news!

But it still seems like the heater is throttling back the flow rate of the fully hot water output, more than it used to before.

That heater should be able to run two showers at the same time.

So the heat transfer of the heater might be getting less efficient, or is somehow internally restricted.

I would still call the manufacturer to ask about flushing procedures or any other advice.

Maybe an element is burned out or the heat exchanger is coated in minerals.

Is there a diagnostic mode you can try?
I think it also should give error codes for problems.

 

[Kenuel80]

Great news!

But it still seems like the heater is throttling back the flow rate of the fully hot water output, more than it used to before.

That heater should be able to run two showers at the same time.

So the heat transfer of the heater might be getting less efficient, or is somehow internally restricted.

I would still call the manufacturer to ask about flushing procedures or any other advice.

Maybe an element is burned out or the heat exchanger is coated in minerals.

Is there a diagnostic mode you can try?
I think it also should give error codes for problems.

Update, I called the manufacturer and they had me test for voltages at the heating elements and found that one of the elements is not turning on. The women on the phone was telling me that the element is bad. I had to teach her that the element isn't bad if its not receiving power like in my case. How can it turn on if its not receiving power? Lol. She said that they will be contacting me soon to further troubleshoot the unit. I checked the triac and thermostat and they seem to work fine (they give power to the element), I compared to the other 3 since I have 4 elements set up the same way. I tested all elements and they all measures between 7-10 ohms. The only thing left is the controller. The controller is not sending power to that one element. Theres only one main fuse to power everything, so its not a fuse.

 

[Jeff Handy]

Is anything still under warranty?

Hopefully so.

Also ask about flushing and de-scaling procedures.
Ask if there is a pdf file, video, link to it, etc.

The last page or so of the manual said warranty does not cover problems related to minerals or scale from lack of maintenance, or words to that effect.
But no maintenance procedures were listed, that I could find.

 

[Jeff Handy]

That must be a big frigging fuse, like 240 volt 80 amps?
Or is this all 120 volt?

 

[Jeff Handy]

Looks like your heater is fed by four separate breakers in the breaker panel.

Unless they are tied together with a handle bar, they can trip separately.

So turn each one fully off, then back to on.
In case one has tripped.

 

[Kenuel80]

That must be a big frigging fuse, like 240 volt 80 amps?
Or is this all 120 volt?

Its actually a small fuse that powers the controller. When I opened it up I saw it and tested it. The controller is low voltage but the unit itself is 240V. The unit is not under warranty they told me. Ive had it for 4 years now. For de scaling I will just have to install two valves at the in/out inlets to hook up a hose. I will ask, but I'm guessing they will just tell me what I already did. Just take out all elements and soak in vinegar for 6 hours, she actually said that. But I took them out and scrubbed them with baking soda. It will be a lot easier if I install 2 valves and hook up a hose to a pump to flush it out.