Hot water tank issues

[svchances]

The water in my hot water tank is hardly even warm after a couple of hours motoring. Motor is a Universal M35 and runs at 160 - 180 F. Never overheats.
Water tank heats up to boiling in 5 minutes on shore power. Is this a thermostat problem in the engine or in the water heater? No leaks visible in the coolant.
Water heater is 3 years old and worked perfect when first installed. Slowly it has run out of steam. No pun intended.

[neilpride]

Most likely in your engine, since the AC in your water heater have a thermostat, the intake and out from your cooling system is a separated circuit, the internal resistance in your wáter heater work with your AC , it have a small thermostat , i dont know where is pluged your coolant lines in the engine to fed the wáter heater.. engine thermostat housing? header tank?

[GILow]

Had the same problem on a Halvorsen cruiser we hired in the last days of the hire business, when they had stopped maintaining the boats.

I tracked it down to a water flow problem on the heat exchanger circuit, and easily fixed it by disconnecting the circuit from the engine then blowing water backwards in the circuit to flush out the crud that had most likely built up somewhere on a lip in the circuit. Big wad of rusty brown flakes came out into the bucket.

Reconnected everything and we had hot water for the rest of the hire period.

Decided not to give them my bill.

Matt

[rwidman]

Originally Posted by GILow

Had the same problem on a Halvorsen cruiser we hired in the last days of the hire business, when they had stopped maintaining the boats.

I tracked it down to a water flow problem on the heat exchanger circuit, and easily fixed it by disconnecting the circuit from the engine then blowing water backwards in the circuit to flush out the crud that had most likely built up somewhere on a lip in the circuit. Big wad of rusty brown flakes came out into the bucket.

Reconnected everything and we had hot water for the rest of the hire period.

Decided not to give them my bill.

Matt

I would think that would be the problem, no coolant flow through the water heater since the engine seems to be operating at the correct temperature.

On my boat there are valves to isolate the water heater so that's the first thing to check. If there are no valves or if they are open, flushing the line would seem to be the next step.