Recently we have found that the water pressure for the hot tap is very low. It takes for ever to run a bath and it is not easy to get a hot shower, the shower head is clean so that it not the problem. The cold water pressure is good. In the last year we have replaced the air conditioner and the furnace.

In the last year we have replaced the air conditioner and the furnace. But have you flushed your water out on a regular monthly maintenance schedule? If not let me show you how. For long life and fewer troubles you should keep your heater clear of mineral build-up by FLUSHING NOT DRAINING on a regular schedule. Attach a hose to the boiler drain at the bottom of the tank. With the pressure on, open the boiler drain and let it run until the water runs clear. You will see a spurt of red,(rust) followed by white or yellow grains,(lime or calcium carbonate). This shouldn't take more then a few minutes. Do this monthly to keep it clear. Now flush out your hot water lines on ALL fixtures that are affected . Now pull each aerator and clean the screens. Be sure you put them back together the same way you took them out. Don't forget to flush it out every month. Your heater will thank you for it.
Now, on to the valve with the problem.I think what has happened is that some minerals built up on the pipe walls came loose and is now clogging your valve. Is it just the bath tap? If so I'll need the brand name and the type, one handle or two knobs? Is it a older valve? Let me know, Tom

But have you flushed your water out on a regular monthly maintenance schedule? If not let me show you how. For long life and fewer troubles you should keep your heater clear of mineral build-up by FLUSHING NOT DRAINING on a regular schedule. Attach a hose to the boiler drain at the bottom of the tank. With the pressure on, open the boiler drain and let it run untill the water runs clear. You will see a spurt of red,(rust) followed by white or yellow grains,(lime or calcium carbonate). This shouldn't take more then a few minutes. Do this monthly to keep it clear. Now flush out your hot water lines on ALL fixtures that are affected . Now pull each aerator and clean the screens. Be sure you put them back together the same way you took them out. Don't forget to flush it out every month. Your heater will thank you for it.
Now, on to the valve with the problem.I think what has happened is that some minerals built up on the pipe walls came loose and is now clogging your valve. Is it just the bath tap? If so I'll need the brand name and the type, one handle or two knobs? Is it a older valve? Let me know, Tom

Hi thanks for the advice, It is the bath tap that is the worst. I could not see a brand name on them, the house is 25-30 years old and it is a two tap. I checked a showerdown stairs that I think has still the original taps and they say delta. The pressure down stairs is OK but not great especially the hot for the washing machine.
Does this help any
Sandy

Hi, I don't know if I did something wrong but I do not seem to have the answer to the question about the very low pressure of our hot water tap in th upstairs bathroom, I got the message about flushing the hot water tank and then you asked about the plumbing, I think the taps are Delta, two taps that are separate flow for hot and cold. I would appreciate your help as it drives you crazy waiting for a bath to run
Tahnks, sandy

I do not think Speedball1 is here today but I'm sure he will be around tomorrow.

Is hot water pressure lower in every fixture. If so, you may have plugged inlet or outlet on water heater. Let me know if hot water pressure is lower than cold in every fixture.

Is hot water pressure lower in every fixture. If so, you may have plugged inlet or outlet on water heater. Let me know if hot water pressure is lower than cold in every fixture.

Yes the hot water is lower on all the fictures and if I run the washing machine on hot.
It seems worse in the upstairs ones;
I would love some ideas on this if you have any
Thanks,
Sandy

Hi sandy,

First please respond to Tom's question about flushing the water tank.

Second like Mygirlsdad say you may have the inlet or the outlet on the heater plugged.

I would shut off the cold shut off valve to the water heater open a faucet inside the house to drain some water, disconnect the hot supply line from the water heater have a bucket ready and be very care full have some one open the cold shut off valve for a second and see how does the water flows Be care full not to burn yourself with hot water, once you do this check and come back and some one help you with next step, I may help from 8000 miles distance away, also can you tell us how old is you water heater, Thanks.

John

Ok, now that we know you have lower pressure in all hots, I'm betting that you have partially plugged inlets and or outlets of tank. If you can take a picture of the incoming and outgoing water connections on the water heater, we will be able to tell you your best step for fixing this problem. Most likely you have dialectric unions on top of the water heater. If you do, you should be able to break the union. Once the union is unhooked, you will be able to look inside the top and bottom portion, you will most likely see buildup of junk in there. If there is a build up, replace both union(or at least the one that is plugged, most likely both will be partially plugged). Please let us know what you find.