drippy hot water

[lbmaples]

I have had sporadic issues with drippy hot water. I have tried to figure out the problem and i'm stuck. The hot water connection on the kitchen faucet drips only when the water is hot, but only when the water is heated from being cold. Once the water is hot, it doesn't leak any more. I have replaced the fittings, the faucet, and the pex pipes. It's as if the pressure is too high, but, where would the pressure be coming from? And, why does it quit leaking once the water is hot?

[dward51]

Expansion of the water as it heats would be my thinking. Water expands about 4% in volume when heated from room temp to boiling for example. Once the pressure on your lines and faucets equalize, no more dripping.

No big deal, but you could ad and expansion tank if it really bothers you. The expansion tank would also let you pull a little water without the pump kicking on or pulsing. Although if your water pump is a variable speed pump (VSP) they do not recommend using an expansion tank. If you add a expansion tank, there are RV specific models made that are small, but if you have the space for it, there is no reason not to use a "regular" expansion tank from HD or Lowes, etc.... The larger tank will go longer between pump runs as it stores more water in the tank.

[Bama Rambler]

It's possible that you've lost the air space in the water heater tank. When the water heats it expands and if it doesn't have an air space to compress it forces it way out of the weakest point.

It's easy to re-establish it. turn off the water heater and the water coming into the RV, then open a hot water faucet. Once the water is cool go out to the water heater and open the lever on the T&P (Pop-off) valve. Let the water run out until it stops and then close the T&P valve. Turn the water back on and let all the air purge out of the hot water faucet that you opened and then shut it off. Then turn the water heater back on and see if that fixes your problem.