old hot water heater problem

[crieders]

2 seasons ago put in new Atwood hot water heater. No hot water! Any suggestions to diagnose? I did check the antifreeze level and a little more was added. I do not think the pipes at the heater end are heating up even when I run the engine for half an hour or more. Could the water be circulating everywhere else and not through the hot water heater?

[sailaway]

Cliff On my boat when I am at anchor. The water never gets very hot when I run the engine at  1000 rpm for an hour. But when I am motoring under way the water gets very hot. Lots of other reasons. Air lock in the line. pluged line.  Charlie

[Stu Jackson]

If there was an air lock in the line his engine would overheat big time.

There could be a block in the line.

Have you checked your thermostat operation recently?

I agree, running the engine at essentially idle speed will NOT provide hot water.  sailaway is right.

[Ken Juul]

They way the system is designed to work.  Once the thermostat opens, flow begins to the HW heater.  The water flows through the HW heater and returns to the belt driven coolant pump.  Once the thermostat opens at 160/180 depending which you have you should be able to feel the hose from the thermostat housing to the HW heater begin to heat up.  Then depending on the water temp in the HW Heater, 15-20 minutes will be needed to heat the water.

[crieders]

Thanks for the help. I was running the engine from Manhasset Bay to Great Neck, about 1/2 to 45 minute run. Engine ran at 160 or so according to the not very accurate temp guage. "Hot" was was tank temperature. No heating!! I forgot to check the hoses with my hand but I think they were not hot going into the heater. I believe I replaced the thermostat about 2 seasons ago.

[MarkT]

It doesn't sound like a thermostat issue since the engine otherwise maintains a steady temperature.

I think I would disconnect both hoses to the heater at the engine and see if you can get anti freeze to drain out by pumping or blowing into one of the lines. If so then you don't have a blockage. Then perhaps try draining the anti freeze from the heater and filling the hoses with a funnel and bucket before reconnecting.  My $0.02

Mark Tamblyn

[Ron Hill]

Cliff : Try Mark's suggestion.  Also just blow thru the liquid heater lines to make sure they are clear.  

[Stu Jackson]

2 seasons ago put in new Atwood hot water heater. No hot water!

Cliff, maybe an obvious question, but when you installed it did you NEVER get hot water, or has it been two years since you put it in and it worked for a while and then quit?

Just playin' detective...

[crieders]

never got hot water!