single handle shower faucet-not enough hot water (Home Depot, Lowes, sinks)

[plumberNOT]

I am renting a house with a tub that has a single handle faucet. There has never been enough water pressure, but it is slowly getting less and less. In the last week or so I am having trouble getting enough hot water. There has always been more pressure on the cold 'side'. The last time I used the shower I had to set it all the way to hot, and it never got hotter, didn't even steam up the mirror. The bathroom sink is plenty hot, as well as the kitchen and basement sink. Whatcha think? Please help.

[Ultrarunner]

I'm 100% certain there is a partial flow blockage on the Hot Water side.

I just re-piped a house from galvanized to copper last weekend due to lack of Hot Water Flow in the Kitchen and Bath.

The Bath had been upgraded to a single handle pressure balancing valve that made the problem go from annoying to acute. Taking the valve out of the wall to clean out little rust particles every other month was becoming old... so I just decided to make it my next available weekend project.

Many of the new water saver valve assemblies have reduced or restricted internal orifices that will clog easily from the slightest bit of sediment.

Shut your water off, remove, disassemble and flush and clean the line.

[SunnyKayak]

also
If the shower head appears new it setup to be low flow as the feds regulated the amount of water on the heads. It also may have anti scald device on it and that could be part of the problem.

[Poltracker]

The mixing valve in the faucet may also be out of whack. Had a similar frustrating problem and that is what it turned out to be.

[sean98125]

If you are getting plenty of hot water and plenty of water pressure out of the faucet in the bathroom sink, then the valve in your tub faucet is failing. It's a pretty easy job to replace the valve cartridge, and not expensive unless you have to buy the tools to do it.

Video:**How to Repair a Tub-and-Shower Valve | eHow.com

The hardest part of the job will be finding someone at Home Depot or Lowes that can help you identify the right replacement! If you have a plumbing supply store nearby or a smaller hardware store, try there first.

[Coldjensens]

You probably have galvanized pipes. Hot water silts up those pipes faster than cold water. Every old house that I have owned or rented had that problem initially. Cold water - ok pressure; hot water - bad or no pressure. Sometimes you can get better pressure by only replacing the horizontal pipe that connects to the sink/shower or whatever. Usually that is only a temporary repair. If you do have galvanized pipes, they probably need to be replaced.

If your pipes are all copper or plastic then you can be pretty certain that the problem is in the valve itself. However even if it apears that you have copper pipe, check the terminations. It is not unusually for a landlord or even a homeowner to leave the terminations when they re-plumb with copper in order to save money. It is really stupid, but I have seen that twice.

If it needs re-plumbing suggest to your landlord that they use PEX. PEX can be threaded in like wire and minimizes the destruction to walls and the disruption of your life.

[sean98125]

Don't forget that the OP said that there isn't a hot water problem at the other sinks, just at the tub. That points to the cartridge valve as the most likely problem.

[K'ledgeBldr]

Would it be too much to ask why you're asking?
Since you're renting- call your landlord to have it fixed.
If the landlord is unwilling to fix it, or have it fixed.
Call a plumber and have it fixed yourself and deduct the cost from next month's rent.

[Coldjensens]

Originally Posted by sean98125

Don't forget that the OP said that there isn't a hot water problem at the other sinks, just at the tub. That points to the cartridge valve as the most likely problem.

It could. However one of our houses had the hot water problem only in the upstairs bathrooms. The downstairs bath and the kitchen had no problem. I do not know whether parts of the system were already replaced, or perhaps there was some reason for the upstairs pipes to gunk up more than downstairs.

[plumberNOT]

WOW! Thanks for all the great input! As to the question regarding calling the landlord, I guess I'm one of those 'low maintenance' tenants that likes to try to handle things myself. I already had a friend who does maintenance look at the thing, and he had some trouble with the valve, and since he was unfamiliar with that type of faucet I thought I'd try and see if there was someone who could help with the trouble shooting. I am firmly convinced that either the thing is simply SET wrong or the hot water 'side' of the mixing part has gummed up. My landlord isn't a bad guy, but this kind of repair could turn into a big mess, and I wanted to avoid that if I could. Any input regarding the best way to get the valve out would be greatly appreciated, although I know that without seeing it or knowing who made it (it has not got any kind of identification anywhere that I can find) will probably make that difficult. THANKS AGAIN to all who responded!