Hotwater in one bathroom very slow to warm and never reaches full temperature.

[cgilley]

Trying to gain some knowledge before calling a plumber. Back in 2001, I completed a major addition to my home - 2 bedrooms, 2 bathrooms, a laundry and a few other things. I also expanded my hot water supply by adding a 50 gallon gas water heater. Both water heaters are tied into the entire house, but the new water heater is closest to the two new bathrooms and laundry. One bathroom - furthest from the new tank, has always been slow to warm, and it never gets to the temp I have the water heater set at. It also getting worse. Just to be clear, the same behavior is in the bathroom sink. The shower and/or the sink are set to full hot. Water flow seems to be normal.

I'm curious as to possible reasons for this behavior. I cannot get my head around some issue with the shower valve when the sink does it as well. Further, since the water flow is okay, my thought is that there must be some restriction in the hot water feed. But then, if the water flow seems normal, this doesn't seem right to me as well.

Appreciate any thoughts on the matter.

note: I thought I had already posted this question, so if this is a duplicate, apologies.

 

[MicEd69]

How are the two water heaters tied into your hot water supply lines? I assume you do not have a circulating hot water system.

 

[CT18]

Trying to gain some knowledge before calling a plumber. Back in 2001, I completed a major addition to my home - 2 bedrooms, 2 bathrooms, a laundry and a few other things. I also expanded my hot water supply by adding a 50 gallon gas water heater. Both water heaters are tied into the entire house, but the new water heater is closest to the two new bathrooms and laundry. One bathroom - furthest from the new tank, has always been slow to warm, and it never gets to the temp I have the water heater set at. It also getting worse. Just to be clear, the same behavior is in the bathroom sink. The shower and/or the sink are set to full hot. Water flow seems to be normal.

I'm curious as to possible reasons for this behavior. I cannot get my head around some issue with the shower valve when the sink does it as well. Further, since the water flow is okay, my thought is that there must be some restriction in the hot water feed. But then, if the water flow seems normal, this doesn't seem right to me as well.

Appreciate any thoughts on the matter.

note: I thought I had already posted this question, so if this is a duplicate, apologies.

Is it piped where one heater feeds the addition and the other heater feeds the rest of the house. It may just be too far away and losing temp by the time it reaches the bathroom. You could try a recirc pump, or even a undercounter type

 

[cgilley]

How are the two water heaters tied into your hot water supply lines? I assume you do not have a circulating hot water system.

How are the two water heaters tied into your hot water supply lines? I assume you do not have a circulating hot water system.

I do not have a circulating hot water system.

As far as I know, both hot water heater hot lines join somewhere. I know that when replacing one of them, the other had to be isolated as well. My conclusion was that they are joined *somewhere* <--- homeowner should have paid attention, but the plumbers were already pissed at having to drive so far to do the job.

This smells like the plumber coming out is going to need to track the installed plumbing somehow. I honestly don't know, and it further smells like something stupid.

My original intent was that the additional water heater would be the closest feed to the laundry, new bathroom above (probably a 16' run) and the 2nd new bathroom - maybe twice that. The alternative was to open up existing walls to use the original water heater source.

 

[MicEd69]

Unless there is some type of a temperature control valve, your piping arrangement is likely your problem. Fluids flow based on pressure drop through the piping. With your cold-water source being the starting pressure, the flows through each water heater to a single hot water user will balance flows based on the piping and fittings between each water heater and the user. In other words, if you have two 50-gallon water heaters and no temperature controls to equally balance the flows, you will not have 100 gallons of hot water available to you.

You need a detailed layout of all the hot water piping to resolve your problem.

 

[Twowaxhack]

If both water heaters are full of hot water you should get hot water even if they piped it wrong, unless there’s a cross connection.

You could have a temp limited shower valve and the temp limiter is set too cool. Might Need to adjust it.

Post some pics of the shower valve.

 

[MicEd69]

You could have a temp limited shower valve and the temp limiter is set too cool. Might Need to adjust it.

One bathroom - furthest from the new tank, has always been slow to warm, and it never gets to the temp I have the water heater set at. It also getting worse. Just to be clear, the same behavior is in the bathroom sink. The shower and/or the sink are set to full hot. Water flow seems to be normal.

 

[Twowaxhack]

Probably improper parallel install. If that’s the case then you’ll need to find where the two water heater outlet supply lines connect together and disconnect them. If you want to combine the heaters it needs to be done in series. That means running the hot water outlet of one heater into the cold inlet of the second heater. This way you’ll have one hot pipe serving the entire house.

It still should work even if it’s a wrong parallel install if both heaters are hot until one of the heaters starts to run out of hot water.

Check for cross connection.



Or the water is cooling off before it gets to the far bath.

I would still check the hot water limiter on the shower if it has one.

 

[cgilley]

I suppose it's possible there is something in the shower valve, but what seems to contradict this is the sink 4' away, which is almost certainly running from the same hw supply has the same issue. I'll do some testing this weekend and verify flow rates and what I am being told.

I also have somewhere pictures of the open walls I took (before sheetrock) while the addition is being built. I would find it hard to believe they ran plumbing in the attic, but I would not put it past that plumbing team.

It's an interesting problem, and I appreciate your ideas.

 

[Geofd]

Do you have a single handle faucet in that bathroom??????.
Are you able to use your shower diverter to shut the shower valve on and off rather than using the shower valve itself????

 

[cgilley]

yes. and it's still slow. Sorry, my downstairs super smart washer is on the fritz and my upstairs laundry room won't cooperate. It's not just the shower. The adjacent sink is very slow as well - as reported by children yet to be confirmed by me.

Stay tuned.

 

[cgilley]

Okay, so the super intelligent washer is fixed, the upstairs laundry is working (damn dryer vent), and now its back to this issue. I did some additional testing because users, children and the public lie or are confused . Turns out the sink gets to water heater temperature within reason. It's a longer run but within 30 seconds it's warming and by 60 seconds it's hot. Cannot say the same for the shower - same timing but only gets luke-warm.

Pulled the Price Pfister valve and checked it's operation. Interestingly, when on full hot, the cold side was still open. Pretty obvious issue. Down to Lowes, buy new valve, and I now have "better" performance. It's still not as hot as the sink but it's at a usable temp. The concept is pretty simple how they are mixing the hot and cold. Maybe I need to replace the seals in the base?

 

[Geofd]

If your trying compare the temp of a hot faucet all the way open and an antiscald shower valve all the way one you will always be mixing a little cold on the shower, it's not supposed to be as hot as your sink

 

[cgilley]

Fair enough. Let me toss some more info. The shower in question is from a 2001 addition - figure that into your antiscald thoughts. I have a re-done shower in 2023 - it's peel the skin off your back.

How would I know if it's anti-scald?

 

[Rickyman]

Fair enough. Let me toss some more info. The shower in question is from a 2001 addition - figure that into your antiscald thoughts. I have a re-done shower in 2023 - it's peel the skin off your back.

How would I know if it's anti-scald?

You can post a picture of the valve and cartridge you replaced

 

[Geofd]

Yep, that s great idea rickyman

You can post a picture of the valve and cartridge you replaced

 

[cgilley]

https://www.amazon.com/Pfister-9740...xDy141xEtxyTAUt-MQ68NpCf6vhoC8uQQAvD_BwE&th=1
This is it. Sorry, not up to the challenge of figuring out how to get images to the forum tonight. It beds to a pretty generic valve receiver - hot and cold - brass or copper base with two O rings. I do know looking at the old one on full hot, the cold is still open. Other than that, they both look fine, the hardware in the wall looks fine, and it just begs the question maybe it's installed wrong. Looking hard at myself.