water heater problem when on electric heat

[Syversens]

ok... we have a weird thing happening with out hot water tank. Its always been like this but we only use it while on power. When I turn the water on electric after about 20 minutes the water pump start going off intermittent... I found that water is just flowing right from the pressure relief valve thru the host to the bilge and its a steady stream. the weird thing is this happen only on electric, when running the enginge we get hot water, never hear the pump go off (will keep an eye on the discharge hose from now on). Anyone know why this is happening ? do I need a new pressure relief or valve ?when I turn the waterheater off and let it cool down the system goes back to normal and it doesnt set off the pump from time to time...regardsGaute

 

[Mike]

Pressure relief valve

Gaute, replace the pressure relief valve. I suspect when your on electric the water is heated to a higher temperature then when you run the engine. Higher temperature will create more pressure and if your valve is weak it will leak. Think of a coffee maker. Once it get's good and hot it starts to pass the water and steam through it. Once your water heater get's good and hot the water expands and then leaks through the valve.Mike

 

[Syversens]

relief valve or thermostat...

Hey Mike, I was thinking the same thing. I got all details about the unit and I'll be calling the people that make it tomorrow to see what parts they have. they might be able to share trouble shooting too.... I was thinking its either the valve or the thermostat. Do you or anyone else know the temp on the hot water when heating it electrically ? I can measure mine and if its considerably higher then its the thermostat. I think replacing the valve might be the easiest and most accessible so I hope your right )thanks again Mike !Gaute

 

[Mike]

Thermostat

Gaute, I didn't think about the thermostat so yes I'd check that too. If it's allowing the water to get too hot then you'd also get the same symptoms. That would also explain why it only happens when your on shore power as the engine temp is not thrmostatically controlled by the water heater. Try the thermostat first. Also in case you've not found the steaming light info, it's a 12 volt, 10 watt, .8 amp, Series 25 bulb. I bought mine at a local marine store and they're made by Aqua Signal.Mike