Water on side of house not hot enough: crossed pipes?

[mistagenki]

Have a 3000 sq ft home, wide 1 story. One side of house gets nearly instant hot water (one bath, two sinks, laundry), while other side of house further from tank water heater (2 baths, 3 faucets) only gets about 65% as hot. Just moved in earlier this year, and would love to take a hot shower in the master bath!

I have gone through the steps I find online to detect crossed pipes, but have not had much success. There is no valve to turn off only hot water after water heater to troubleshoot easily. There is a valve on the cold to the whole house after the water heater, that I turned off to see if the cold side on any faucets would run, showing some crossover. While I did not get any flow out of the cold side on any faucets, I did find the water pressure from the hot side now to be much lower, almost a trickle from single-handle tub faucets throughout the house. The pressure increased if I turned on a cold water valve (even though no cold water was present). Not sure what that means.

I am not excited about having to excavate the slab where the pipes are laid, so hoping there is something else I can do. Any advice would be much appreciated!

 

[Terry]

With a pressure balanced faucet, turning off pressure to one side (you turned off the cold) reduces pressure to the other side to keep it even. You need full pressure on both sides.
Also, most pressure balanced faucets come with a temperature limit that can be adjusted behind the handle. Remove the handle that setting. It's normally a matter of rotating the stop a bit to allow the rotation of the handle to swing that direction further.

 

[Sponsor]

 

[hj]

If ANYONE suggests excavating the slab, throw them out of the house and get someone competent.

 

[LLigetfa]

My guess is the loss of temperature is due to the long run and not to any "cross". What you can do is to raise the temperature on the water heater and then add tempering valves near the fixtures to prevent scalding. Depending on how the lines branch, you might be able to put one tempering valve for the shorter runs near the water heater and one at the far end for the distant one.

 

[mistagenki]

None of my cheap older Moen faucets have the pressure balance behind the handle. Could it be on the cartridge instead? I'd have to get a puller to remove cartridges...

 

[mistagenki]

LLigetfa: I tried that a couple of weeks ago, turned the water heater is up to about 130F - scalding on the good side of the house and still lukewarm on the other side

 

[Jadnashua]

The first thing to do is as Terry indicated...adjust the max temperature limit on the tub/shower valve.

Question...if you let the hot run at say a sink, how hot does it get? My guess is that after a delay to warm up the pipes, it will get about the same temperature as those closer to the WH.

To overcome the long delay to get hot at the further end of the house, this is what a hot water recirculation system is specifically designed to do.

I put an article in the tutorial section and it has links to three brands of tub/shower valves with a video that shows how to adjust them to allow hotter water. This is one reason why I like thermostatically controlled valves...once calibrated, they will adjust themselves to get the set temperature, in the summer when the cold is likely warm, and even in the winter, when the cold is frigid.

 

[mistagenki]

jadnashua - Unfortunately, the water on one side of the house never warms up to match the other side. It is a long run, but there is definitely something more happening. I haven't taken a definite measurement with a thermometer, but there is no way to scald yourself on that side of the house with the 130F water coming from the water heater. To get the shower closest to the WH to a similar temp as the other side of the house, the handle is just past half way (around 65%).

The tub furthest from the WH takes about 90 seconds before the water gets any warmth, with handle all the way counterclockwise, max GPM possible in the house. The shower right next to that tub takes nearly 4 minutes to reach warm temps. But neither ever gets to the temp that I would consider a fulfilling shower, not enough to need to adjust the mix back down towards the cold side.

I definitely want to go with a re-circulator in the near future, but need to make sure whatever is causing the current issue is solved first.

 

[LLigetfa]

Assuming there is a lavatory with a faucet that does not use anti-scald technology, how hot is it? I think you should use a thermometer to get accurate measurements.

I would not use the relative position of a single hand control as a comparison.

 

[Obama the Plumber]

So I take it you "have" pulled the handles and check the hot temperature limits? Because, being the careful man I am, that's the first thing I would have done. Seriously, the first thing. Not the second, why are you even thinking it would be the second thing, no way man, the first!
Okay, do us this giant favor. Did I say a giant favor? Yes, I believe I did. Pull the handles and check to see if they can fully rotate.

 

[mistagenki]

No temp limiters behind any handles. One cartridge on one bath is upside down, but it works as it should.

Alright, I'll get a thermometer to report back shortly actual temps for purely technical reasons, since its impossible to convince without it the problem is as I have said. The 3 baths are the same valve/faucets, and 4 lav faucets are the same, so the results should be convincing.

 

[MACPLUMB]

You were right the Cartridges are your problem, they have a cross over effect when they get old, you need to change them out one at a time or just change them all some where in there your problem will be solved
all the old Plumbers know this

 

[hj]

Turn ALL the Moen faucets to HOT, then turn off the water to the heater. Open a lavatory faucet hot water. You will probably have cold water coming out out of it. Then listen at the Moen valves. You can usually heat the water flowing through the bad one(s).

 

[Jadnashua]

The question was...how hot can you get it at a lavatory faucet?

Many of the tub/shower valves have some way to limit how hot things get...it could be a screw, it could be a disk, a cam, or some other thing. If there's anything that limits how far the handle can turn...that may be the issue.

Second question...did that shower EVER get as hot as you wanted and now doesn't get as warm? From what you've said, it doesn't get as warm as you'd like NOW, but did it ever?

It could be a worn out cartridge, excessive losses in the run (but that usually warms up if run long enough), or the more common one, the valve needs to be adjusted to achieve a higher temperature.

A recirc system will alieve the 90+ second wait for hot water at that end.