Community Forums

Peterd503 · 12-03-2014, 12:40 PM

I have a drinking water faucet on my kitchen sink that is hooked up to a filter under the sink. Everything works fine until I turn on the water heater and as the water heats up, the drinking faucet starts to drip. It will drip as long as the water in hot water tank is hot. It drips cold water. It takes about 20 minutes to drip a cupful. It never drips otherwise. I have tracked the lines and see no connection in the lines that could cause this. I am at a loss to figure this out. Anyone have a similar experience?

BFlinn181 · 12-03-2014, 01:08 PM

As the water in the tank heats up, it expands. There should be a cushion of air in the tank to absorb the expansion. Perhaps your tank has lost the air pocket. You could test by making sure pump and city water valves are closed and open the WH relief valve. Also, why not just get a new cartridge or replace the washer in the faucet?

thunderjet · 12-03-2014, 01:17 PM

The water heater has a small amount of air that is compressed when filled with water the first time after charging system. This does two things a) after pump pressurizes system you can some draw water without pump restarting or if system had a small leak the pump would not short cycle. and b) when water is heated it expands ie pressure goes up. sometimes over 150 psi. that is the why we need a relief valve. your faucet maybe a spring loaded shutoff unable to handle the increased water pressure. I think the problem could be solved by shutting down pump and city water, open drain on water heater and lifting handle on relief valve. Then restore service

thunderjet · 12-03-2014, 01:20 PM

see post above mine as he types much faster then I LOL

TJ

Ray,IN · 12-04-2014, 09:59 AM

Sometimes when the water heater overpressure valve has not been exercised regularly, when you do open it corrosion buildup will prevent it from seating properly and will drip constantly.
I merely drain some water out to restore the air cushion in the tank. The reason for losing the air cushion is, water absorbs air over time.
Our filtered water outlet will drip sometimes. When it does I open the twist valve handle and let it snap shut, which usually stops the drip. Once again, corrosion/buildup in the valve.

gemini5362 · 12-04-2014, 10:55 AM

I am not doubting what you guys say. Just trying to make sense of it. I drain my system for winter. When I get ready to use the system again I hook the freshwater hose to a faucet and turn on the water. I take the heater out of bypass. I open up both the cold and hot water faucets until the air stops coming out and I have water. How does that get air pressure in the hot water heater. The air is going to go into the faucet as the water pushes it out ?

In a well pump tank you have two ways of getting air into it. One is there is an enclosed bladder that stores air and keeps pressure on the sytem. The other is a valve that as water is pulled out of the tank it sucks air back in. Not sure I understand how you keep air in the hot water heater

BFlinn181 · 12-04-2014, 11:01 AM

The water heater tank is designed to keep an air pocket in the top of the tank. As water fills it, air is pushed out the hot water line. The inlet and outlet points of the tank ensure that an air cushion forms in the top of the tank. Over time that air can be absorbed by the water.

Gordon Dewald · 12-04-2014, 11:07 AM

Is the pressure relief valve on your water heater dripping or showing moisture? If so the expansion in the water heater is gone. Since water is not compressible any expansion due to the water heating will have to be vented some where. Better a tap drips than a line or connection breaks.

Jupiter · 12-04-2014, 08:25 PM

another perspective...
I would suggest that the solution is to address the problem at the faucet. My suspicion is that you have faulty washer and/or seat in the filtered water fixture. All faucets should readily seal the small amount of residual water pressure (hot or cold) from the pump cycle. Most RV water systems have very little static pressure and rely primarily on the energized pump for water pressure.

I'm thinking the weak link may be the faucet.

cheers,
Joopy

98FPA · 12-05-2014, 01:39 PM

I agree with Jupiter, I think you need to take a look at your faucet. They are not designed to drip but to keep water from dripping. A faucet in your stick home keeps water from dripping at anywhere between 60-90 psi, an RV faucet should be able to withstand any normal pressures that is provided. I'd say you a have a defective washer or seat too.

twinboat · 12-05-2014, 02:07 PM

One cure is to install a one way ( Check ) valve in the "water heater" supply line. Any excess pressure will then have to go out the relief valve and not back up into the cold water pipes.

Peterd503 · 12-09-2014, 12:26 PM

TwinBoat, you may have a good point here. In any city water hook up, it never drips, regardless of pressure, until I turn the water heater on. I have it winterized now, but will try this when I bring it out of storage. Thanks all.

Jupiter · 12-09-2014, 09:12 PM

Peter,
Respectfully, I'm not sure that adding a check valve is a "cure". I think it is treating a symptom as opposed to treating the root cause. The problem that you describe is frankly unusual in terms of an RV hot water heater creating a dripping faucet problem. Basically, (but not in all cases) check valves for the most part are designed to restrict flow and not necessarily to restrict pressure.

Again, in my humble opinion, I would begin the process by rebuilding the faucet washer and/or seat since it's fairly simple and easy to do and it then eliminates the most obvious cause of the drip.

Good luck and do let us curious folks know the outcome.

cheers,
Joopy