Hi, I would much appreciate if someone could help me with this.

I have noticed that if my kitchen sink hot water is running for a given time (with good pressure) the pressure will suddenly drop to about half of its original force. It does this when there is only hot water and when there is both hot and cold turned on. It does not drop when there is only cold water running. Also I was messing around with it and had the cold water full throttle and turned the sprayer on (which worked fine) but after the sprayer was disengaged the cold water ran at half pressure?

A few other things that might help I don't know.

Old gas water heater with leaking pressure relief valve
I think I have noticed the hot water pressure drop in the washing machine during the fill cycle after a given amount of time with full pressure.

Thanks in advance.

How long since you drained and flushed you water heater?

Hey Fountain;

I am never happy to hear about leaking pressure relief valves... I will assume yours is old... but it can also indicate excessive temperatures and excessive pressures (people can get hurt/die when water heater safety devices fail)... so please be aware of that and replace the T&P valve ASAP.

Other then that... HKSTROUD seems to have a good question.. answer him and we will all see what we can do. You take care... ;)

Thanks for the quick replies folks, I inherited the water heater when I purchased the home and I have not drained and flushed it since (11 months). Any good order to replacing the valve and draining/flushing. I really know nothing of this. Thanks,

Attach a hose to the drain valve at the bottom of the tank, point it into a sink or floor drain and open the drain valve. Let water run until clear. Hopefully you will flush out all the mineral deposits that have settled in the bottom of the tank. Close drain valve and remove hose. The drain valve may have a slight leak . This would be because debris is caught up in the valve and it cannot seal properly. Get a hose cap and put on it. If this solves you pressure problems , replace you T&P valve. If it doesn't solve the problem come on back, we will muddle through it together.

You don't have to drain the water heater. Just open the drain valve until it runs clear as much as once per month. Find an interval, but definitely no less than 1/year. A couple of gotcha though:It's possible that it will pass a large piece and the valve won't seal again. Heater manufacturer's put rinky dink plastic valves on the drain.

The T&P replacing could be hard, could be easy depending on how it's plumbed and what material.

Example (a moderately difficult example): Plumbed in copper. Replace with CPVC
1. Get T & P, fittings, primer and glue
2. Have a method to cut the CPVC (hacksaw or special cutter)
3. Cut copper pipe. Hacksaw or close-quarter tubing cutter
4. Unscrew valve
5. Tape all threads with two layers of teflon tape
6. Finger tight plus at least two additional turns.
7. Check for leaks (fill water heater). Fix if necessary.
8. Dry fit CPVC
9. Glue
10. Turn on water heater: Gas to on, breaker to on if electric,


Oh, you have to shut off the cold inlet to the hot water heater and power or if gas, set to pilot and drain the water heater below the T&P valve first. The male adapter for the T&P requires teflon tape too.




Post a pic under "go advanced" if you like.