Sorry….this got a bit long but I wanted to supply all of the information. The T&P valve on the water heater keeps popping. The valve is supposed to prevent the water heater from exploding from too much pressure or too high a temperature. It is set to trip at 210F or 125 psi. The valve is tripping on high temperature. I know because I have been sailing with the pressure water off and the hot water faucet open. As soon as I turn the pressure water on the T&P valve trips. The water is definitely HOT...but I don't know if it exceeds the 210F trip point. I'll bring a thermometer next time if I think of it. I replaced the water heater on my boat last winter. The water heater can work using either electricity or heat from the engine. There is a check valve installed in the domestic cold water supplied to the water heater per the original design. That keeps hot water from backing up into my water tank. There isn't an expansion tank. (There wasn't one in the original design) The coolant connections from the engine are connected directly to the water heater without any valves or temperature controls. That's how the one I took out was connected. The engine is running fine. Raw water strainer isn't plugged and there is plenty of water shooting out the back. So I don't believe the engine is overheating. What's your hot water setup look like? What is the operating temperature of the coolant in my Yanmar? I plan to do the following: Any other suggestions? 1. I plan on replacing the T&P valve. They are only about $10. Maybe mine is set a little too low. I'll also pipe the overflow to the bilge. It makes a real mess when it pops inside my storage locker. 2. If that doesn't work I'll try adding some kind of temperature control valve. I haven't found a good source for the valve yet. The first water heater I tried to install came with one, unfortunately that model didn't fit. Has anyone retro-fitted a temperature control valve? 3. The only other piece I can think to add is an expansion tank. I don't know where I would put it. Does anyone have one?
Water Heater - Overheating
- Thread starter Dan L
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T&P Valve
It is not unusual for the T&P valve to go bad. When it does it will open at around 140 degrees. The engine water is 160 to 190 degrees so the valve will open if you motor for a long period. Replacing the valve is easy. I put a hose on the valve and ran it to the shower sump discharge thruhull to keep the bilge dry. Since I replaced the valve of course it has not opened again.
It is not unusual for the T&P valve to go bad. When it does it will open at around 140 degrees. The engine water is 160 to 190 degrees so the valve will open if you motor for a long period. Replacing the valve is easy. I put a hose on the valve and ran it to the shower sump discharge thruhull to keep the bilge dry. Since I replaced the valve of course it has not opened again.
T&P Valve
It is not unusual for the T&P valve to go bad. When it does it will open at around 140 degrees. The engine water is 160 to 190 degrees so the valve will open if you motor for a long period. Replacing the valve is easy. I put a hose on the valve and ran it to the shower sump discharge thruhull to keep the bilge dry. Since I replaced the valve of course it has not opened again.
It is not unusual for the T&P valve to go bad. When it does it will open at around 140 degrees. The engine water is 160 to 190 degrees so the valve will open if you motor for a long period. Replacing the valve is easy. I put a hose on the valve and ran it to the shower sump discharge thruhull to keep the bilge dry. Since I replaced the valve of course it has not opened again.
T&P Valve
It is not unusual for the T&P valve to go bad. When it does it will open at around 140 degrees. The engine water is 160 to 190 degrees so the valve will open if you motor for a long period. Replacing the valve is easy. I put a hose on the valve and ran it to the shower sump discharge thruhull to keep the bilge dry. Since I replaced the valve of course it has not opened again.
It is not unusual for the T&P valve to go bad. When it does it will open at around 140 degrees. The engine water is 160 to 190 degrees so the valve will open if you motor for a long period. Replacing the valve is easy. I put a hose on the valve and ran it to the shower sump discharge thruhull to keep the bilge dry. Since I replaced the valve of course it has not opened again.
T&P Valve
It is not unusual for the T&P valve to go bad. When it does it will open at around 140 degrees. The engine water is 160 to 190 degrees so the valve will open if you motor for a long period. Replacing the valve is easy. I put a hose on the valve and ran it to the shower sump discharge thruhull to keep the bilge dry. Since I replaced the valve of course it has not opened again.
It is not unusual for the T&P valve to go bad. When it does it will open at around 140 degrees. The engine water is 160 to 190 degrees so the valve will open if you motor for a long period. Replacing the valve is easy. I put a hose on the valve and ran it to the shower sump discharge thruhull to keep the bilge dry. Since I replaced the valve of course it has not opened again.
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