Lukewarm water after installing a New Gas heater

Old 12-15-08, 08:55 AM
Thread Starter
Join Date: Dec 2008
Location: Ohio
Posts: 5
Upvotes: 0
Received 0 Upvotes on 0 Posts
Lukewarm water after installing a New Gas heater

Hi there.

I just moved into a house. Since it was a foreclosure home, the first thing I did was replace the old electric heater with a 40 gal reliance gas heater. The old electric heater was already disconnected from the breaker box and was old and rusted.

The gas supply was already there. This was installed about one month ago now. My problem is that I get luke warm water from the upstairs tub and sink and the pressure is not bad but definetly not as strong as the cold water supply up there. No matter what the thermostat setting the temp does'nt change.

The heater is in the basement and is plumbing is mostly copper but there is some long galvanized that the hot water has to go through. I did insulate all the hot water plumbing in the basement and this made no difference in the water temp. Also it is winter but it does not get that cold in the basement. I called the manufacturer to troubleshoot. Their tech had me check the temp of the water at the tpv came out hot and steaming. So, they said its not the heater but an issue with the plumbing and to call a plumber.
Part II
When I installed the heater I let it filll up bled one of two faucets downstairs and then the sink, tub and shower upstairs. Then lit the heater. It functions fine but the water is just not hot enough upstairs. Now the downstairs kitchen sink I have shut off at the supply because the hot water side of the faucet is so rusted no water comes out of the faucet but it leaks under the sink so I have it shut off there. Same exact situation with the downstairs bath sink. I was able to bleed the downstairs bathroom but not the kitchen when installing. so the two sinks hot water have been shut off and the upstairs shower has'nt been ran much b/c of tile work. But the upstairs sink and tub have been run everyday but still a consistent lukewarm temp. I am having contractors out soon prob after Xmas now so I'am not bothering with fixing the two sinks hot water downstairs b/c i'll have all new. I am wondering if I had all of these being used (upstairs shower and downstairs sinks) that the water would be flowing better or something and coming out hot throughout the house. Since its all running off of the same copper configuration.

Thanks for reading this message and Let me know if you have any thoughts.
Old 12-15-08, 04:35 PM
Join Date: Sep 2008
Location: Long Island
Posts: 695
Upvotes: 0
Received 0 Upvotes on 0 Posts
2 places you might have a restriction is just out of the tank into the copper(steel to copper)the the other (copper to galvinized)do you remember opening up the faucets during the first time inot the was the hot water side pressures on everything.running all the faucets at one time is the same as flushing the toilet when somebody is taking a shower the pipe off the top of the tank is the start of the hot water for the house and is one size and stays that way up to the wall shut offs.when you open all of the hots you defusing the pressure too many times coming off the might have a mineral build up at the top of the tank or at that galv/copper connection on the hot line.hows the pressure at the bottom of the tank when you run it with a hose should be the same as the cold water
Old 02-27-09, 10:43 AM
Join Date: Feb 2009
Location: Littleton, CO
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
I have a very similar issue, 1959 brick ranch, screaming hot water in the basement and lukewarm upstairs. I have just redone the bathroom and kitchen upstairs and the only way I can take a shower is to turn all of the faucets upstairs on at the same time to hot. Otherwise I am at tepid/cool with just the shower on and at best just warm with everything turned on anyway. In the laundry room in the basement I turn it on hot and it is screaming hot! I don't get it, all new Moen faucets, new water heater, copper looks okay and pressure is fine... Why me?

P.S> I've already tried adjusting the posi-temp things on the Moen faucets and it didn't do anything.. Any help is appreciated..


Old 02-27-09, 06:35 PM
SeattlePioneer's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2007
Location: Seattle, Wa
Posts: 4,469
Upvotes: 0
Received 1 Upvote on 1 Post
One thing I'd check with both these complaints is the possibility of a defective mixing valve.

A mixing valve is one that mixes cold and hot water to allow varying water temperatures to be supplied, especially single handle valves on sinks, showers and even washing machines.

If the valve is defective it allows cold water to flow onto the hot water supply, diluting the hot water, often in only a portion of the hot water supply system.

To check this, simply turn off the cold water supply to the water heater. Then turn on any hot water tap. If water continues to flow out from that valve, especially cold water, you have a bad mixing valve somewhere that you need to track down by shutting off the cold water supply to various valves until you find the problem.
Old 02-28-09, 02:54 PM
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 7,826
Upvotes: 0
Received 1 Upvote on 1 Post
I wonder if debris got in your Moen posi's balancing valve inside the cartridge.

Since you did all that plumbing renovation, I bet some chunk broke loose somewhere, or even solder got up in there.

That temp-balancing slide pin in that cartridge is most likely not able to get in the right position, under a normal hot/cold water pressure situation.

We've had this happen to us more than once. I used to be involved in LOTS of bathroom remodels, in old homes, til I learned I could do easier work and work on furnaces instead.

A pain, since you have to take out the cartridge and dismantle it, or get another one, and also flush the lines out with the cartridge out. Kind of a waste of money when someone has to pay for this.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: