Price Pfister Shower Issue

[Cavalier]

About ten years ago I had a Price-Pfister single handle shower unit installed. After this installation the shower never got extremely hot. It gets very warm, but not hot. I have replaced the cartridge several times over the past ten years and it seems to work for a while (although it could be my imagination). The hot water service for this bathroom, another full bathroom and the laundry is by a single 3/4 inch copper pipe. I few week ago I noticed the water in the shower in question was very hot when the washing machine was cycling through a hot water load. I thought this was unusual. The next day when I turn on this shower in question I turned on the hot water in the faucet in this bathroom and the shower was hot again. It seems if I turn on the hot water on the washing machine, the other faucet or bath, or the faucet in the same bath the water in this shower gets very hot (as it should be normally). Any ideas what the issue is?

 

[Terry]

Normally I would think it's the Temperature Limit Stop, but since it can get hot that makes me wonder what's going on.

 

[Sponsor]

 

[Cavalier]

Normally I would think it's the Temperature Limit Stop, but since it can get hot that makes me wonder what's going on.

Actually when it was first installed and never got really hot I removed the temp stop. We have extremely hard water, could this cause an issue?

 

[Jadnashua]

Could you be getting some cross-flow from the washing machine feeds? Do you have shutoff valves at the WM? If so, try closing them (not a bad idea every time you're not using the WM!). See if that helps, and let us know.

 

[Cavalier]

Could you be getting some cross-flow from the washing machine feeds? Do you have shutoff valves at the WM? If so, try closing them (not a bad idea every time you're not using the WM!). See if that helps, and let us know.

I will try that tomorrow. Can you explain what cross-flow is?

 

[hj]

You are describing the classic problem when a hot water circulation system is not working properly.

Terry, you need a new parts diagram. The new stems have the PB unit intergral with them.

 

[Cavalier]

You are describing the classic problem when a hot water circulation system is not working properly.

Terry, you need a new parts diagram. The new stems have the PB unit intergral with them.

Could you expand on that?

 

[hj]

The new prt #974-042 has the stem 971-350 and PBU 070-201 combined into a single piece.

 

[Jadnashua]

Normally, there is no easy path between the hot and cold supplies that is open when you are not using any water (it obviously must be in a faucet to get warm - some hot and some cold). Some faucets when they wear out, can allow the hot and cold to mix - cr0ss-over, even when you are not using water. Some people put adapters on their washing machine feeds to either mix hot and cold or to feed some other device. If you aren't careful, that can allow mixed hot-cold to then become the inlet water to some other valves.

A hot water recycling system typically has a cross-over built into it and usually a check valve to prevent backflow of the cooler water into the hot line. If you have one of those, as HJ said, that could cause your symptoms.

 

[Cavalier]

Normally, there is no easy path between the hot and cold supplies that is open when you are not using any water (it obviously must be in a faucet to get warm - some hot and some cold). Some faucets when they wear out, can allow the hot and cold to mix - cr0ss-over, even when you are not using water. Some people put adapters on their washing machine feeds to either mix hot and cold or to feed some other device. If you aren't careful, that can allow mixed hot-cold to then become the inlet water to some other valves.

A hot water recycling system typically has a cross-over built into it and usually a check valve to prevent backflow of the cooler water into the hot line. If you have one of those, as HJ said, that could cause your symptoms.

I am familiar with a check valve to prevent residential water from backflowing into the public system, but have never heard of one used for the purpose you describe. I also am not familiar with a "hot water recycling system". If I had this, where might it be located in the system? My specific situation is as follows; The water comes from a well and then into the water softener. I assume at this point the water is split into hot and cold, with the hot going to the water heater. But the question remains, if this is a system wide issue why does it only effect one shower? Admittedly I know very little about this, but it would seem to me the issue must be after the shower supply comes off the main hot water supply. Could there be a restriction in this shower's hot water supply line causing low water pressure? Could the increased hot water demand when another faucet is turned on cause the pressure to increase to the shower in question? Just grasping at straws here.

 

[Jadnashua]

Water will take the path of least resistance...if that is because the hot and cold are interconnected (cross-over) because of a device or failed valve, then instead of hot water into that shower, it might be receiving cold water on that path via the cross-over.

A hot water recirculation system is a system that moves hot water through the supply pipes (while returning it to the water heater) so that when you open a valve, instead of having to purge the water that has cooled off sitting there, that water is actually hot. It can both save energy, water, and sewer charges, if it is designed properly while adding significant convenience. As said, it can be the source of a cross-over, but there are some valve designs that can do that when they wear out.

 

[hj]

I am not going to go into the physics of it, but IF you have a hot water circulation system, and there is a problem with it, it WOULD cause the problem at a single fixture, usually a tub or shower.

 

[Cavalier]

I am not going to go into the physics of it, but IF you have a hot water circulation system, and there is a problem with it, it WOULD cause the problem at a single fixture, usually a tub or shower.

I understand, but where do look for this issue? There has been a mention of a cross-over that may be causing the issue. Except for the cross-over at the shower valve, is there another cross-over I should be looking for? If so, typically where are these located in the system? There also has been mention of a check valve. Typically, where would this be located and is there a way to verify it is working correctly?

 

[MACPLUMB]

The problem is most likely caused because
The shower valve does not flow enough
Hot water though the 3/4" copper pipe
That is why when something else is running
It gets hot

Just had the same problem where I used
To live left lav sink running at small flow
And plenty of hot water at shower

 

[Cavalier]

The problem is most likely caused because
The shower valve does not flow enough
Hot water though the 3/4" copper pipe
That is why when something else is running
It gets hot

Just had the same problem where I used
To live left lav sink running at small flow
And plenty of hot water at shower

How can I fix the issue? Should I replace the existing cartridge (which I have done a few time)? Or can the cartridge by altered to allow more hot water flow?

 

[hj]

First, we need a photo of your water heater, particularly any piping at the bottom of it, before we can rule out the most obvious possibility.

 

[Cavalier]

First, we need a photo of your water heater, particularly any piping at the bottom of it, before we can rule out the most obvious possibility.

Here is a pic of my water heater. There is a supply from the well pump in crawl space,(that is the what is to the right of the heater). There doesn't appear to be any piping around the bottom of the heater.

 

[Smooky]

It looks like a water meter over the top of the water treatment system. Are you sure there is a well pump? Could it be a recirulating pump instead of a well pump? Why is the water meter there?

 

[Cavalier]

It looks like a water meter over the top of the water treatment system. Are you sure there is a well pump? Could it be a recirulating pump instead of a well pump? Why is the water meter there?

We are on a well, but pay for wastewater. There is a well pump in the crawl space and a well head in the back yard. They monitor the amount of wastewater by metering the water coming in from the well. They assume all the water coming in from the well passes into the wastewater system. Since we do not use the outside spigots much, it is probably pretty close. If we wanted we could get separate meters on the outside spigots that would deduct that water from the wastewater charge.

I noticed something else tonight. I don't know if this is relevant, but when I turned on the hot water at the sink to make the shower water hotter I noticed the sink water never really got warm.

 

[hj]

The pipes all "merge" together because of the black insulation so we cannot tell where they are going or hooking together.