I'm running on internal water (not city water). I don't leave the water heater turned on all the time (too wasteful to do so) and when I turn it on it raises the pressure in the whole plumbing system way too high, and I get water leaking from the toilet onto the bathroom floor. The only way I've found to deal with this is to shut off the pump and briefly open a faucet every 10 minutes to relieve the pressure, until the heater gets hot and the pressure stabilizes, which gets pretty annoying.There is a pressure relief valve on the water heater, but apparently it's only intended to protect the heater tank, and opens at too high a pressure to do anything for the plastic plumbing.Is there some kind of relief valve that opens at a lower pressure, which I could install somewhere in the system and have it drain overboard?

I have the same issue. I turn off the pump and leave a HW tap open. When the tap starts to drip I turn off the heater.

Intresting problum, maybe try to turn down the tempature of the water heater. Less heat , less expansion , less pressure, maybe.....just an idea.

Sounds like a faulty check valve on the cold water line at the water heater.

I like installing a small bladder type pressure tank. It makes the whole water system work nicer.

Drain the water heater and refill it, that will re-establish the air pocket in the tank and allow for expansion. See your water heater owners manual for more information.

Plumbing pressure relief | Good Sam Community

2oldman
Explorer II
Jan 11, 2021
I have the same issue. I turn off the pump and leave a HW tap open. When the tap starts to drip I turn off the heater.
Sjm9911
Explorer
Jan 11, 2021
Intresting problum, maybe try to turn down the tempature of the water heater. Less heat , less expansion , less pressure, maybe.....just an idea.
Boon_Docker
Explorer III
Jan 11, 2021
Sounds like a faulty check valve on the cold water line at the water heater.
Dusty_R
Explorer
Jan 11, 2021
I like installing a small bladder type pressure tank. It makes the whole water system work nicer.
Lynnmor
Explorer
Jan 11, 2021
Drain the water heater and refill it, that will re-establish the air pocket in the tank and allow for expansion. See your water heater owners manual for more information.
schlep1967
Nomad
Jan 11, 2021
Lynnmor wrote:
Drain the water heater and refill it, that will re-establish the air pocket in the tank and allow for expansion. See your water heater owners manual for more information.

Or just turn off the pump and drain a small amount out. Then turn the pump back on without using 6-10 gallons of water.
time2roll
Nomad
Jan 11, 2021
A small accumulator will solve the issue. Yes I had the same problem.

Amazon - Shurflo 181-201 Accumulator Tank $38

This creates a permanent air pocket.

Mine was in the RV shop twice for several weeks for a mystery water leak. Never found. I had to dig for this myself while camping. I guess the dealer did not think to cycle the water heater to find a leak.
4x4van
Explorer III
Jan 11, 2021
Lynnmor wrote:
Drain the water heater and refill it, that will re-establish the air pocket in the tank and allow for expansion. See your water heater owners manual for more information.

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Lynnmor
Explorer
Jan 11, 2021
schlep1967 wrote:
Lynnmor wrote:
Drain the water heater and refill it, that will re-establish the air pocket in the tank and allow for expansion. See your water heater owners manual for more information.

Or just turn off the pump and drain a small amount out. Then turn the pump back on without using 6-10 gallons of water.

I didn't want to get onto it, but since the air dissolved into the water tells me that draining and flushing is way overdue.
2oldman
Explorer II
Jan 11, 2021
Lynnmor wrote:
I didn't want to get onto it, but since the air dissolved into the water tells me that draining and flushing is way overdue.
I drained and flushed mine 6 months ago and it does it.