It is a Valley single handle shower valve. A similar Valley model (with possibly the same internals) is shown at https://www.youtube.com/watch?v=caZnXs42Zo4 .

How likely is it that replacing only the cartridge will fix the low hot water flow problem?

How likely is it that the entire assembly needs replacement (requiring soldering et cetera)?

Hot water flow in the two other faucets in the house (kitchen and bathroom basin) seems fine.

In alt.home.repair, on Wed, 4 Sep 2019 08:59:27 -0700 (PDT),
wrote:

It is a Valley single handle shower valve. A similar Valley model (with possibly the same internals) is shown at https://www.youtube.com/watch?v=caZnXs42Zo4 .

How likely is it that replacing only the cartridge will fix the low hot water flow problem?

How likely is it that the entire assembly needs replacement (requiring soldering et cetera)?

Hot water flow in the two other faucets in the house (kitchen and bathroom basin) seems fine.

How is the cold water flow at that shower?

On Wednesday, September 4, 2019 at 11:59:33 AM UTC-4, wrote:
It is a Valley single handle shower valve. A similar Valley model (with possibly the same internals) is shown at https://www.youtube.com/watch?v=caZnXs42Zo4 .

How likely is it that replacing only the cartridge will fix the low hot water flow problem?

How likely is it that the entire assembly needs replacement (requiring soldering et cetera)?

Hot water flow in the two other faucets in the house (kitchen and bathroom basin) seems fine.

IDK, good question. Cartridges can cause leaks, but I don't see a failure
mechanism where they result in low flow. It seems more likely there is
some debris lodged in there. Taking it apart, flowing some water, might
fix it. Or if you have an air compressor, rigging that up to blow air
backwards can work. Had a low flow problem here and that did it.
I blew it backwards, from shower to bathtub. Nothing visible came out,
no debris, but it fixed it.

On Wed, 4 Sep 2019 08:59:27 -0700 (PDT), wrote:

It is a Valley single handle shower valve. A similar Valley model (with possibly the same internals) is shown at https://www.youtube.com/watch?v=caZnXs42Zo4 .

How likely is it that replacing only the cartridge will fix the low hot water flow problem?

How likely is it that the entire assembly needs replacement (requiring soldering et cetera)?

Hot water flow in the two other faucets in the house (kitchen and bathroom basin) seems fine.

I once replaced a 20-year-old shower valve (Harcroft) for that same reason. Once the new valve
was in use and working well, I got the old one on the bench and found a rubber washer jammed in
the hot water circuit. If I could have seen that before ripping it out, I could have saved a
lot of $ and sweat!

--
croy

On Wed, 04 Sep 2019 20:24:30 -0700, croy
wrote:

On Wed, 4 Sep 2019 08:59:27 -0700 (PDT), wrote:

It is a Valley single handle shower valve. A similar Valley model (with possibly the same internals) is shown at https://www.youtube.com/watch?v=caZnXs42Zo4 .

How likely is it that replacing only the cartridge will fix the low hot water flow problem?

How likely is it that the entire assembly needs replacement (requiring soldering et cetera)?

Hot water flow in the two other faucets in the house (kitchen and bathroom basin) seems fine.

I once replaced a 20-year-old shower valve (Harcroft) for that same reason. Once the new valve
was in use and working well, I got the old one on the bench and found a rubber washer jammed in
the hot water circuit. If I could have seen that before ripping it out, I could have saved a
lot of $ and sweat!

99% of the time this is a stuck balancing valve and you can fix it by
replacing the cartridge. I have taken the cartridge apart and fixed
them but it is a pain in the ass and it might end up leaking
afterwards.

Thank you for the input Micky, trader_4, croy and grfe. The cold water flow is fine. My condo requires a licensed plumber to do this repair (else the condo association will not shut off the water to do the repair). Today the plumber found the cartridge's hot water side clogged with debris. A new cartridge fixed the low flow.

In alt.home.repair, on Fri, 6 Sep 2019 21:05:31 -0700 (PDT),
wrote:

Thank you for the input Micky, trader_4, croy and grfe. The cold water flow is fine. My condo requires a licensed plumber to do this repair (else the condo association will not shut off the water to do the repair). Today the plumber found the cartridge's hot water side clogged with debris. A new cartridge fixed the low flow.

A decent resolution.

Thanks for getting back to us.

On Saturday, September 7, 2019 at 12:05:37 AM UTC-4, wrote:
Thank you for the input Micky, trader_4, croy and grfe. The cold water flow is fine. My condo requires a licensed plumber to do this repair (else the condo association will not shut off the water to do the repair). Today the plumber found the cartridge's hot water side clogged with debris. A new cartridge fixed the low flow.


I wonder if an air compressor would have saved a plumber's bill.