Dual Water Heaters

[Nmnunna32]

I have two water heaters connected in series (one acts as pre-heater and sends warm water to the second one which in turn is connected to hot supply pipe of the house).

Whenever a hot faucet is open else where in the house, a bath room in particular side of the house loses hot water (in the middle of someone taking shower!).

I am thinking of getting this reconfigured where one heater supplies water to one side of the house and the send one to the rest of the house. Is there there anything I need to be concerned about this configuration?

 

[WorthFlorida]

Where are you located? Why are there two water heaters? Is the plumbing accessible from below?
What size water heaters do you have? On cold well water or city water? How many bathrooms, tubs? showers, and people. Do you know your water pressure? Asking that it may be beneficial to change to one water heater, perhaps a tank less system.

With two water heaters you’ll need to add check valves, etc. I’ll let other plumbers comment on this.

 

[Sponsor]

 

[FullySprinklered]

Sounds like a crossover situation. You may have a bad or nonexistent check valve in a hot water recirculation system. That would give you a place to start.

 

[Brian Codding]

I have a problem with a dual water heater setup. I have had issues since day 1 of owning my house. Think I have a line crossed or something. Every year I have had a water leak just above the heaters on the hot line where they connect. I believe they are in a series because I have turned off the left water heater and now water is luke warm. I also have to constantly clean the sink traps because they fill up with debris. On the dual heater setup, there is a line coming off the bottom of the left heater also. Not sure why this would be needed if properly configured.

To answer questions from above: 2 water heaters because house is 4,000 SF, plumbing accessible from basement, 2 people, 4 bathrooms, city water, no idea on the water pressure.

 

[Brian Codding]

Pictures of the configuration

 

[Reach4]

I have a problem with a dual water heater setup. I have had issues since day 1 of owning my house. Think I have a line crossed or something. Every year I have had a water leak just above the heaters on the hot line where they connect.

I see the water drops at that SharkBite tee. It could be that the pipe was damaged there if the leak happens all of the time. It could be that leaks only when the water pressure gets above 140. I don't see a thermal expansion tank, so it would not be surprising to get 150 PSI water pressure at times. Pressure gauges are cheap. Buy one. A garden hose thread pressure gauge can go on an outside faucet, a laundry tap, or the drain on a water heater.

I believe they are in a series because I have turned off the left water heater and now water is luke warm.

They are in parallel for sure. If you want to keep them in parallel, you will have to add check valves. And the check valves must not be after the new thermal expansion tank.

I suggest you get this re-plumbed to add a thermal expansion tank -- a big one due to the large WH volume. Then connect the two WHs in series. If you add check valves, it still could be that most of the water goes through one tank only. In series, you could turn off the first tank until you need more hot water due to visitors or whatever.

I am not a plumber.

I also have to constantly clean the sink traps because they fill up with debris.

What the heck? What kind of debris? You don't suspect that is related to the water heaters, do you?

 

[WorthFlorida]

I posted this before the pictures were posted.

I...now water is luke warm. I also have to constantly clean the sink traps because they fill up with debris. On the dual heater setup, there is a line coming off the bottom of the left heater also. Not sure why this would be needed if properly configured.

Where does it leak? Fitting, a valve, a pipe leak? Leaks at both water heaters? Are they gas or electric water heaters? Pictures would help.

Generally, at the picture below two water heaters in series would be "B" of one water heater would be connected to "A" of the other. and "B" of the other would feed the house. Parallel connection both "B's" would be connected together to feed the house. But your statement that a pipe comes from the bottom. Where does it go? "J" are your drain valves.

Since you mentioned debri in the sink traps tell me that both water heaters are filled with sediment and if you have hard water it always will be prevalent. Turning off one heater and end up with warm water also suggest one heater is not working 100%. If they are electric one electric element is burned out. if gas there's a heavy coating of minerals deposits on the heat exchanger.

Sound like the best solution is to hire a plumber. Install only one 50 gal water heater with temperature mixing valve and an expansion tank (required now in most area's). Set the temperature to 140 degrees and the mixing valve would need to be adjust to no more than 120 degrees or less. If you have small kids in the home set it to 110 and if the water temp seems too low adjust the temperature at the mixing valve a few degrees at a time.

Another option is to install a tankless system. If you have electric the cost to rewire for the proper load requirement can get expensive or your electric panel would not be able to add the additional load. A large enough tankless you may never run out of hot water during use.

A choice would be up to you by the cost difference between one conventional water heater vs the additional cost of a tankless. If your more concerned about meeting your home hot water demand tankless is the way to go but if your budget is tight, a conventional water heater would be the choice.

 

[WorthFlorida]

Pictures of the configuration

The major concern here is the drain valve connection. Do you have a solar panel or a heat recovery unit on your AC? Any water recirculation pumps at sinks for faster hot water delivery? Both tanks looks very new and if the PEX connection leak every year you need an expansion tank. I assume you have very coldwater and as it expands when heated to really ups the pressure. Get one of these gauges with the tattletale (red) needle. The gauge will push the red needle to the highest pressure and it remains there until you reset it.

If the temperature pressure relief valve on the water heaters are set to 150 PSI max pressure. Above that these will open. If your not getting any water on the floor your pressure is remaining below 150, but 145 psi it is still too high.


https://www.homedepot.com/p/Winters...Pointer-and-0-160-psi-kPa-PETM213LF/305046977

 

[Brian Codding]

After further research, it is a parallel setup. Sorry about that, not a plumber, but thanks for all your responses. Yes, hard/cold water in Castle Rock, CO. I could do an expansion tank, but since we only have 2 people in the house, what do you think about attempting the setup in the attached picture? I have a friend that is a plumber and I can get him to do the work. I have drained sediment out of heaters once but maybe it is time to do it again. I think previous plumbers may have messed with the parallel system setup as the lines are no longer equal on the hot side. Not sure why the right side does not get as hot (or maybe it's uneven draw since lines are not equal length)? Thinking the picture would be a better setup to save $ and just turn up the 2nd one when expecting heavy flow.

 

[Brian Codding]

Also, leak is always on the hot Pex line just above the T. Usually a pinhole leak that sprays out. Had a plumber out last week and he replaced the Pex above the T with a 2' copper line. I'm guessing this will only raise where the issue occurs the next time (which will be in a wall).

Will I still need an expansion tank if I go with the setup posted above?

Thanks!

 

[Reach4]

Will I still need an expansion tank if I go with the setup posted above?

Yes, very probably. The pressure gauge will illustrate it to you. Take a hot shower or draw a hot bath. Stop all water usage, including getting ice or water from fridge. Go check the pressure gauge an monitor the minutes while the WH is recovering.

 

[Brian Codding]

Where do I put the pressure gauge? Also, I measured, I have 36" on the left & 24" on the right going into the hot water T.

 

[Brian Codding]

The major concern here is the drain valve connection. Do you have a solar panel or a heat recovery unit on your AC? Any water recirculation pumps at sinks for faster hot water delivery? Both tanks looks very new and if the PEX connection leak every year you need an expansion tank. I assume you have very coldwater and as it expands when heated to really ups the pressure. Get one of these gauges with the tattletale (red) needle. The gauge will push the red needle to the highest pressure and it remains there until you reset it.

If the temperature pressure relief valve on the water heaters are set to 150 PSI max pressure. Above that these will open. If your not getting any water on the floor your pressure is remaining below 150, but 145 psi it is still too high.


https://www.homedepot.com/p/Winters...Pointer-and-0-160-psi-kPa-PETM213LF/305046977

I agree regarding the drain valve connection, that does not seem correct to me especially since it is supplying the entire second floor of the house. If I change the configuration, I will have both of the HW supply coming out of the top with an expansion tank.

 

[Reach4]

Where do I put the pressure gauge?

Pretty much anywhere, as long as there is not a closed valve or check valve between there and the WH. The pressure equalizes in all of your pipes very quickly when you are not using water.

A garden hose thread pressure gauge can go on an outside faucet, a laundry tap, or the drain on a water heater.

Some pressure gauges have a lazy/tattletale hand that records the peak pressure. Vibration can move the lazy hand. Sudden pressure spikes can make the lazy hand overshoot. Usually it is a useful feature.

 

[Brian Codding]

Pretty much anywhere, as long as there is not a closed valve or check valve between there and the WH. The pressure equalizes in all of your pipes very quickly when you are not using water.

A garden hose thread pressure gauge can go on an outside faucet, a laundry tap, or the drain on a water heater.

Some pressure gauges have a lazy/tattletale hand that records the peak pressure. Vibration can move the lazy hand. Sudden pressure spikes can make the lazy hand overshoot. Usually it is a useful feature.

Thank you. I'm going to grab one and test the pressure.

 

[WorthFlorida]

I agree regarding the drain valve connection, that does not seem correct to me especially since it is supplying the entire second floor of the house.....

It tells that it was not a plumber who installed this dual setup. The cold water is dumped at the bottom if the water heater buy along tube from the top cold water connection.

You stated you get a lot of debris in some of the sink traps. If it all coming from the water heater the screens at the faucet aerators should be clogging up. Remove the aerators and clean them. Soaking them in vinegar would help.

 

[Brian Codding]

It tells that it was not a plumber who installed this dual setup. The cold water is dumped at the bottom if the water heater buy along tube from the top cold water connection.

You stated you get a lot of debris in some of the sink traps. If it all coming from the water heater the screens at the faucet aerators should be clogging up. Remove the aerators and clean them. Soaking them in vinegar would help.

Potentially not a qualified plumber, but it was a brand new house, so it was a plumbing company. I have cleaned the traps several times per year. Just dealing with it for now and evaluating solutions but hoping to have a legit plumber come out soon and recommend a permanent solution. Hoping to do the following: install expansion tank, re-do parallel system, re-work supply for second story to remove supply from water heater base, OR re-configure dual heater setup.

 

[Reach4]

What is this stuff that you clean from the traps? If it were solids from the WH, I would think that would get caught by the aerator screens.

 

[Brian Codding]

What is this stuff that you clean from the traps? If it were solids from the WH, I would think that would get caught by the aerator screens.

I believe that it is solids from the water heater. Maybe it is not being caught by the screens because the line is coming off the bottom of the water heater? Thanks

 

[Reach4]

I believe that it is solids from the water heater. Maybe it is not being caught by the screens because the line is coming off the bottom of the water heater? Thanks

I think that would be a hot water recirculation line. I think that usually there is a check valve and pump that moves water to the bottom connection, and not out of the bottom connection.