Shower hot water supply pipe

[Tikay74]

I installed a new shower valve in my upstairs bathroom. It has been working great for months, then one day the hot water stopped working. Luckily I have access to the hot water supply pipe and found that it is not producing hot water.(can tell just by feeling the pipe) I have hot water in my upstairs bathroom sink faucet, as well as, the rest of the house. Why would the upstairs shower hot water supply pipe stop working? And how do I fix it? No leaks or broken pipe that I know of.

 

[phishfood]

If the water doesn't flow through the hot side of the shower valve, than the pipe will not heat up, since hot water is not flowing through it.

Shut the water off to the house, remove the cartridge from the valve, and see if there is any debris clogging it. Chances are the balancing spool is stuck.

 

[Tikay74]

The hot water supply pipe going to the valve does not heat up. So it is a problem with the pipe before getting to valve. I can't figure out why it would just stop randomly but all other supply pipes provide hot water to all fixtures.

 

[steve60513]

Read what Phishfood wrote again. The pipe going to the valve will only heat up if hot water is flowing. Since the problem is that the water doesn't flow, the pipe going into the shower will not heat up.

The problem is 99.9% likely to be in the shower valve.