Is it time for a new hot water heater?

[Geek_Guy]

I was flushing the engine freshwater cooling system. I tried to blow through the lines to the hot water heater. I could barely get the water through and out.

I've not been out to use only hot water from the engine. But had run the engine some 20 minutes the other day and didn't get hot water. Wondering if the water should flow easier than it is. The heater is old so needing replacement probably not a shock.

Could it even be rusted connections?

Thanks

Dave

[Pete7]

Try the dinghy pump first.

could be one of the connections, but ours was a hose going around a sharp corner had caused the hose to collapse inside, which you could feel as it was soft.

Take the calorfier out and use kettle descaler perhaps?

Pete

[Rapanui]

Assuming the engine is freshwater cooled using a closed loop system with seawater heat exchanger, then it seems unlikely to be corrosion especially if you are using corrosion inhibitor/antifreeze recommended by the manufacturer. If it is corrosion, then you likely have bigger problems with corrosion in the engine circuit. Sounds like a simple blockage such as kinking or collapsed hose.

[Rapanui]

Of course it could just be an airlock as you have been flushing the system.

[a64pilot]

Hook a garden hose to it and use that pressure.
You should get a lot of flow. A real easy way to do that and a way to flush your cooling system is to buy a Prestone radiator flush kit and install it into the water heater line. In a car it goes into the heater hose, but a water heater line is the same thing.

[rwidman]

I'm assuming you are talking about the lines that direct engine coolant to the water heater and not the potable water lines.


If I suspected a blockage, I would disconnect both hoses from the engine, then hook a garden hose up in the reverse direction of the normal flow and turn the water on and see what comes out. Remember that city water pressure will be far more than what comes from the engine so if you apply too much pressure, you could rupture the tubing inside the water heater. Be gentle at first.


The flushing stuff from the auto parts store as mentioned above would be my next step but if you are successful, be sure to rinse it all out of the system before reconnecting it to your engine. You don't want to risk contaminating your engine's coolant.

[Valmika]

Check your hoses for kinks and try using a hose to flush the system backwards. Sometimes if you had enough crud built up in engine cooling systems it could block I have been able to clear on some boats using the 60-80 psi from a shore hose going backwards through the heater.

Sorry Rwidman just saw your post. We agree

[Stu Jackson]

How old is the heater and what brand?

20 minutes engine run doesn't always make HW. I have to run 30 minutes at cruising speed to get HW. Were you just idling at the dock?

[Geek_Guy]

The heater is ancient. But my first question is:

Should the lines from the engine to the water heater be really difficult to blow through. I don't think the engine would be able to produce that kind of pressure to run water through.

Have enjoyed the input though. I can try to blow the lines out.

Dave

[Sailmonkey]

The lines should be quite easy to. Low through, unless the heater is quite a ways above the engine....then your trying to lift a Colum of fluid.

[buzzstar]

Originally Posted by Geek_Guy

I was flushing the engine freshwater cooling system. I tried to blow through the lines to the hot water heater. I could barely get the water through and out.

I've not been out to use only hot water from the engine. But had run the engine some 20 minutes the other day and didn't get hot water. Wondering if the water should flow easier than it is. The heater is old so needing replacement probably not a shock.

Could it even be rusted connections?

Thanks

Dave

You have received several reasonable ideas, so it is now time to ask, why do you need to heat hot water?

[rwidman]

Originally Posted by buzzstar

.............. why do you need to heat hot water?

A friend of mine was a plumber by trade. He asked me this one time when I asked about a "hot water heater". He made sense. I don't say that any more. It's a "water heater". Sometimes it's a "domestic water heater". It depends on who you are talking to.

[Geek_Guy]

Thanks for all the help. Finally got around to trying them out.

Not sure if I missed a point or two......but I took my air compressor. Whew did that work EXTREMELY well. Shot liquid and debris everywhere. Think the hose flapped so hard it put a bruise on my cheek.

I then put it all back together and ran the engine. The engine ran hotter than normal. Thinking that I should have filled the hoses from engine to water heater first. Yes??