Leaky Tub Faucet + Low Shower Head Hot Water Pressure

[django5]

I hope this finds you all doing well. I am in need of some sage advice. In my downstairs bathroom the hot water pressure is a mere trickle out of the shower arm but is stronger coming out of the faucet, conversely the cold water pressure is strong out of both. Our sinks on this level work fine, including hotwater. This is irrespective of the shower head being on so that’s not the issue. . I have a single handle system (can not find the brand name to look up specs) and when turned to only hot the faucet leaks tremendously but it doesn’t leak nearly as much when turned to the cold settings. Do you all think this points towards a blockage within the valve system—specifically the hot water inlet? Do you all have any suggestions as what to do from a DIY perspective---Honestly I am a total plumbing newb and I am somewhat intimidated about taking the valve apart. Do you think the faucet needs replaced? Thanks again

[jadnashua]

All newer shower valves have a means to set the maximum water temperature. This could be a cam, a screw stop, or possibly some other means. This results in limiting the amount of hot water that can get to the showerhead. Then, there's also in many a spool valve that is the guts of a pressure balance antiscald feature. This spool valve could be stuck so it is restricting the hot inlet. You may need to take it out and clean, or replace to free it up (if you had it out and shook it, you'd feel and probably hear the spool move from one end to the other). Without knowing the brand and model, it's impossible to say for certain.

[django5]

Thanks for your insight.. I have identified the brand/model to be an American Standard Hampton with a single handle. Here's a link to the schematics for your review.

http://common.csnstores.com/common/m...5438_Parts.pdf

I believe an obstruction with debris might be the culprit---When my wife and I first moved in 1 year ago we replaced our hot water heater--this process dispersed small bits of calcification that clogged up my kitchen faucet, eventually which I had to disassemble to get them out---do you think that the same could be happening here? Right now I am doing the old 'capping the tub spout and instilling vinegar to soak' trick. Any other beginner type suggestions? Thanks again

[jadnashua]

It could be crud, I'd probably take it apart and check.

[bulldog plumbing]

I just the other day peeled an american standard apart, they have inside of them some tiny little check valves all the way inside. that's where my problem was.... long needle nose pliers, and pay lots of attention those damn american standards have a ton of parts that like to fall. tip.. slide a paper plate under the valve body and above the tile wall opening so nothing can fall back into the wall.

[Redwood]

Sounds like the pressure balancing spool may be stuck...

I see it quite often on them... Not the best brand to stick in a wall...
About equal to Glacier Bay IMHO....