Why is water not hot coming out of the faucet on the far side of the house?

[Jeff H Young]

David R didnt notice you are a new problem. hope its solved . sometimes confusing when its several people with same or similar issues

 

[WorthFlorida]

...........Following this post: when I closed one of the cold lines to a single handle faucet nearest the troubled shower, the troubled shower got very hot for a minute, and then went back to lukewarm.
I systematically closed each of the other cold faucet lines upstairs and downstairs, and with each new closure there was no improvement to the shower water temperature.

Should I disconnect the circulation lines to see if they are the issue?

David

The thermostatic valve within the shower cartridge could be faulty. Remove the trim plate and see if the shower valve body has stop valves. If yes close off the cold water. Depending on brand where the cartridge can be removed without destroying it, give it a cleaning and rinse with a little vinegar or replace it.

A little confusion on my part, the diagnostic reading is 95 degrees leaving the tankless? Is that before the circulator pump? When the shower has little hot water, open other hot water faucets to increase the water flow. The tankless may not be detecting enough water flow to the furthest faucet to fire up.

As others have stated, the symptoms appear to be a bad crossover (check) valve. It would be my first item. However, where the water did get hot after closing the cold water at a sink then cold, the problem could be elsewhere. The shower cartridge or the tankless.

 

[Sponsor]

 

[Fitter30]

Valve crossovers off ,unplug pump. Takes them out of the picture for a test. Then turn them on one at a time.

 

[David R]

David R didnt notice you are a new problem. hope its solved . sometimes confusing when its several people with same or similar issues

Jeff,
I noticed that when I turned off the cold supply to a nearby single handle faucet (not a crossover) the shower got very hot for a minute and then the temp went back down. After shutting off all of the cold supplies I did not see any improvement. There is a nearby shower upstairs that is doing very well, which leads me to believe that the crossover in that other bathroom is probably the first one to be looked at.
David

 

[David R]

Valve crossovers off ,unplug pump. Takes them out of the picture for a test. Then turn them on one at a time.

Great idea I will try this.

 

[David R]

Valve crossovers off ,unplug pump. Takes them out of the picture for a test. Then turn them on one at a time.

With both crossovers closed and the circulation pump unplugged, the water heater output temp was 100 degrees.

With only the crossover nearest the shower open and the circulation pump running for about 5 minutes, the output temp rose to 105 degrees - still far below the output temps for the downstairs faucets .

With only the crossover farthest from the shower open and the circulation pump running, the output temp was 100 degrees. I noticed that the cold water valve would not completely shut off on this faucet.

There are 2 separate shower heads in that shower and both have the same issue. I replaced both 10 year old cartridges about 2 years ago and there wasn't much buildup at that time.

Seems like the smallest next step is to get someone to add a check valve.
Since there is no return line, would that be done at the crossovers?

 

[JustWantHotWater]

So just to clarify.

1. BOTH cross over valves are "disconnected" in both locations with the hot and cold connected back directly to their fixtures.
2. Recirculation pump is turned off.

It may take a minute or two now for the hot water to get to the shower so let it run for a bit.

Are you are saying that the shower on pure hot under this scenario still does NOT get to temp? If this is the case, then it would be the shower fixture as other locations do get to temp.

If the shower does get to temp, then your cross over valve would be the culprit.

 

[Fitter30]

Shower might have temp setting adjustment on cartridge. Pull handle and escutcheon plate take a look.

 

[David R]

Thank you to everyone who offered advice. Here is an update in case you are interested:
I watched the tankless operate a few mornings, noticing that it had difficulty lighting a fire and staying lit when it was called to heat. Often the unit would error out in the morning, and I would have to restart it. Afterwards, the tankless would fire a few times and eventually stay lit.

In addition, it did not light when the circulation pump turned on.

Since I had already replaced the igniter a few months ago (parts are expensive as it is far out of warranty and the company went bankrupt), and I knew the cost of replacing the water sensor was high, I went ahead and looked at a new tankless vs a tank to replace it.

We installed a new tankless and even without the circ pump there is more than adequate hot water to all faucets. The new tankless is currently set to 120 and it is hotter than the old one which was turned up to 135 to accommodate a dying unit.

Thank you
David