I just installed a new LP Gas 50 gallon hot water tank. It was a very simple install, I bleed the air out of the system, let it heat up until the gas turned off and turned on the recirculating pump (its on a timer) and got hot water almost instantly. Then the pump turned off and shortly after, about 3 minutes, the water turned ice cold. I have double checked everything and even pulled the drip tube and everything appeared to be fine. The only reason we replaced the tank was that it was old, but it was working fine.

So the water is ice cold until I hit the recirculating pump, then it gets hot until the pump turns off. The reason for the pump is that the tank is in a heated garage about 15 feet from the house.

The pump is on pipe that replaces the drain on the bottom of the tank, then runs into the house at the furthest point of plumbing. Not sure exactly where, but this is what the homeowner tells me. Also, there is a ball valve at the pump to stop water from going back into the bottom of the tank. I shut this valve and still no hot water coming from any faucet.

Thanks in advance

From what you have said I am going to assume that you have a hot water circulating system. So what I am going to tell you applies to that only.

I assume that you have a lin going into the heater at the bottom where the drain valve is and this is the line that feeds the cold water heater. I also assume that you pump is connected to this pipe. It sounds like that you also have a stop in that line, you should also have a check valve that keeps cold water from backing up into the hot water return line.

How I would check this is to let the pump run for a while until the return line is hot, then turn the pump off and turn on a hot water faucet in the house, as you are doing this check to see if the return line gets cold immediately.

Let me know what you find out.

I do have a recirculating system and it does have a line going into the bottom of the tank where the drain is. But I also have the regular cold water in at the top of the tank. The recirculating line goes into the house and is connected to the furthest point of hot water plumbing.

It worked fine with the old tank and basically sped up the time that hot water reached the house, otherwise if the pump was not on, hot water would still get to the faucets in the house, but it took a few minutes. Now, there is no hot water going to the house at all unless the pump is running.

The only difference between this new tank and the old one is that this new one has a drip tube where the old one did not. Don't know if this matters.

Thanks for the reply

See if the pump is installed in the correct direction: pointer pointed towards the heater.

Yes, I never took the pump off the line from the previous install, everything is put back together the same way. Could it be possible that this tank will not work with a pump attached? It is an American Water Heater - 50Gal LP Gas model.

Thanks

I am little skeptical about connecting pump to the bottom of the heater. Some heaters have various interior passages. But I may be wrong, here... We always attach pump to the top of the heater and to cold water side...

Question: when you turn pump off: do you get cold water from hot water side immediatelly ? Do you have to wait some time ? Where does the hot water pipe travels between garage and main house ? Underground ?

When the pump shuts off, hot water continues for about 3 minutes then turns ice cold. The pipes do travel through ground from garage to the house. There was no problem for the past 15 years with previous tank installed the same way. I haven't changed a thing.

Do you have a check valve on the recirculating line, I think that when the pump turns off you start getting cold water out of the bottom of the heater through the recirculating line.

There is not a check valve anywhere that I can tell, that does make sense, where should one be installed? Somewhere to stop water from going back into the bottom of the tank?

Thanks

Check valve should be installed between the Pump and where pipe from pump enters water heater. If your pump is connected on the bottom of the heater, then I would suggest 2nd check valve - this one on incoming cold water line, right above the top of the heater.

LetMeTellYou: very good question..

When the pump shuts off, hot water continues for about 3 minutes then turns ice cold. The pipes do travel through ground from garage to the house. There was no problem for the past 15 years with previous tank installed the exact same way. I havent changed a thing.


I have one more question: With pump turned off - how long does it take for hot water to arrive in your shower ?

I understand the check valve at the bottom of the tank, but the one at the cold water inlet on top confuses me... which way do I want to stop the water from going?

Lolhank: Try this: go to your water heater and turn thermostat to maximum setting. Use it at this setting for a day. See if you notice any changes...

I don't get any hot water to the shower or any other faucet in the house unless I turn the pump on, then after the pump stops, the hot water stops a few mintues later.

I did try the max setting on thermostat and still get no hot water ever... unless I turn on the pump and again its only while the pump is on

And you had no problem with the old heater, correct ?
Was anything done to your plumbing system with the installation - or was it only a simple w/h swap ?
Do you have Solar ?

This is my folks house, they have lived there for 15 years and they never had .a problem with the old tank until it rusted out. I put the new one in Sat and yes it was a simple swap-out. The only difference that I can tell is the old tank did not have a drip tube... or it was gone from corrosion... no solar, it is LP (Propane) gas.

Would you know how many Btu's was the old heater and how many Btu's is the new heater ?

I can find that out tomorrow, I appreciate all your help, I am going to install the check valve tomorrow and see what happens. The valve at the bottom of the tank makes a lot of sense to me, but the one at the top confuses me, Im not sure which way to install that one on the cold water inlet?

The check valve on the top of the heater will disallow hot water to enter cold water side.

Would you know what kind of plumbing you have? Copper, galvanized, or CPVC ?

Come back tomorrow and let us know how you did...

All of the plumbing is copper. Thanks again for all the help, will let you know how it goes.

Please, check for me if the underground section of pipe is insulated. Hot and Cold.
Also, do you live in area where it gets very cold ?

There is not a check valve anywhere that I can tell, that does make sense, where should one be installed? Somewhere to stop water from going back into the bottom of the tank?

Thanks You don't want to keep the recirculating water from going into the bottom of the tank you want just the opposite, you want the cold water to not come out of the heater and back into the circulating line.


Milo will you explain why you would put a check on the cold water line at the top of the heater.

Well, today we were able to figure out the problem, we traced all the plumbing and found the one set of lines (hot and cold) went to an old shower that used to be in service in one of the garage bays (the garage used to be a workshop). The plumbing was set up where it was a cold line feed and a hot line went into it at the end, basically you could add some hot water to the cold when you took a shower but not with your traditional type faucet, just some valves sweated into the lines. Anyway, the valve on the hot water was partially open therefore allowing the water to mix hot and cold, for whatever reason, as soon as we shut off the hot valve, hot water was restored to the entire system in the house. I hope this makes sense, it was a really dumb way to have a shower set up but with a lot of patience and help from you guys, we narrowed down the problem.

Thanks for everything!

Indeed, very unusual installation... Glad you were able to solve the problem yourself. Swing by if you need help with your plumbing projects in the future ! Milo