Hot water on demand

[Aquah0lic]

Since this is my first boat with a hot water heater, I'm confused about mine. I know its not electric, but I thought the engine running heats the water and then its available until it cools off. I tried it (engine off) the other day after motoring a couple miles and a short spurt of warm winterized water came out and then nothing. The pressure pump was on and the cold worked fine. So, do you get your hot water pressure only when engine is actually running (what develops this pressure) or is there something wrong with my system?

[David M]

Boat hot water heaters generally use engine coolant, electricity or both to warm the water.

Trace out your potable water system on paper.

Normally the hot and cold water come from the same source pressurized by the same pump. The only difference is at the "Y" or "T" fitting, one hose goes directly to your faucets and the other hose goes to a heat source and then to your faucets.

It may be something like a valve along the hot water line that is turned off. If so, be careful, it may have been turned off because it is leaking or because of some other problem.

[Aquah0lic]

David thanks for the reply and good call on the valve. I'll bet that's exactly the problem. I've been so busy on other boat systems, I haven't had a chance to chase the plumbing runs yet.