Is it necessary to replace the whole system?

[Cagle]

Do a plumber who repairs pipes and leaks at home can resolve the issues of a houseboat? Hello, friends, I am Cagle. I own a houseboat at Calgary. Normally I use to call a plumber for the house plumbing issues. Can those plumbers solve the problem within my houseboat? In my point of view, boat plumbing is a lot easier for the do it yourself than plumbing at home, mainly because it doesn't involve rigid pipes running inside solid walls. In fact, pipes are rarely used at all on boats, replaced by easier-to-handle flexible hose or tubing.
Let me point out my problem. My boat's hot water takes hours to heat.We would normally expect an average of 70 litre calorifier to take no more than an hour of engine time to heat. But it takes more than that. I think there are some kinds of problem. How can I solve it? Is it necessary to replace the whole system? Is there any simple technique to sort out the real problem with of the heater?

 

[Davidasailor26]

Marine plumbing has some notable
differences from a land based house. As an example rigid pipe is avoided not just because it's easier to handle but also because the motion and vibration of a boat is unfriendly to inflexible joints. Having said that none of it is especially complicated and doing it yourself can be a good learning experience.

With regard to your water heater - it sounds like your problem is limited to the heater itself or the coolant lines that bring heat to it. You say you run the engine to generate the hot water; does the heater have an additional capability to heat water from shore power, to help narrow down the problem? When you are running your engine do you have a coolant temperature indicator on it, to see if your engine is getting up to operating temperature? When the sea water is cold it may be hard for an idling engine to really warm up, which would add to the time it takes to heat the water tank. If your engine thermostat is stuck that would worsen that problem as well. Beyond that there could be a blockage or bubble in your coolant lines but I'd check the other things first.

 

[Cagle]

Thank you for the reply. Yes , It has. The whole system is working. But takes a long period of time.

 

[Kermit]

Welcome to the forum. I had never heard the word calorifier so I figured it was just Canadian for water heater. I also was going to suggest you talk to @Meriachee since he speaks fluent Canadian. But then Google set me straight. Thanks for giving us the opportunity to learn a new word!

 

[Cagle]

A calorifier is an indirect-fired water heater to provide hot water. Thank you for your reply.

 

[Kermit]

I have an actual suggestion. You could ask your plumber if he could help you. He might know something about boat plumbing.

 

[Kermit]

A calorifier is an indirect-fired water heater to provide hot water. Thank you for your reply.

I honestly had never heard that word. Seriously, thanks for using it. And as far as the whole Canadian dig, well, I just can’t help it sometimes, eh.

 

[dlochner]

When you are running your engine do you have a coolant temperature indicator on it, to see if your engine is getting up to operating temperature? When the sea water is cold it may be hard for an idling engine to really warm up, which would add to the time it takes to heat the water tank. If your engine thermostat is stuck that would worsen that problem as well. Beyond that there could be a blockage or bubble in your coolant lines but I'd check the other things first.

What @davidsailor26 said.

My first thought was a failed thermostat. How long does it take to reach operating temperature? Is the engine freshwater cooled (i.e. does it have a heat exchanger) or is it seawater cooled (takes the cooling water directly from the sea or lake)? A thermostat that is stuck open on a seawater cooled engine will take a long time to reach operating temperature.

Do you have enough coolant in the engine? If the boat is seawater cooled are there obstructions in the coolant hoses, like zebra mussels or some other crud.

 

[Peggie Hall HeadMistress]

You say you run the engine to generate the hot water; does the heater have an additional capability to heat water from shore power, to help narrow down the problem?

Good morning Cagle...welcome aboard! It would be very helpful to know whether you've tried heating water from shore power--and whether it takes just as long...and also whether the engine is sea water cooled and how cold the water is. Plus...
Yours is a pontoon houseboat, which means it doesn't have a bilge So there's a lot of cold air under the boat with little insulation, under the flooring...so depending on how the builder ran the heat exchanger piping, it may be close to the same temperature as the outside air, which--this time of year anyway--would cool off the water going through it, thus explaining why it's taking so long to heat your water. If it takes as long for the heating element--which requires shore power--to heat it, the problem may be in the water heater. What's the make/model/age and SIZE (gals) of the water heater?
Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein

 

[NYSail]

You may also have air in the line leading from engine to water heater...... may want to burp the lines and make sure coolant fills with no air. Good luck!

Greg

 

[Skipper]

Some systems, including mine, have a partial bypass for the heater. This is to actually prevent the water heater from reaching engine temperature during short runs in and out of the harbor, so that you don't have scalding water in the heater. I can open a valve that allows coolant to flow to the heater AND around it to the heat exchanger. Check your plumbing. One can close the valve to force coolant only through the heater, to produce hot water faster.
BTW many instead have a mixer valve at the hot water outlet to prevent scalding.
The coolant on mine runs from the exhaust manifold, which is the last heat generating item on the engine and is after the thermostat, then to the heater, then the exchanger. So the heater gets the full volume of hot coolant first (above 165, the thermostat rating). Some systems run the coolant from the water pump bypass relief hole to the heater and back to the thermostat housing, with a smaller hose with only partial volume, already-cooled coolant, and without the added heat of the exhaust manifold. This is the slowest system for heating domestic water.

Also an engine will generate substantially more heat under load instead of in neutral.

Example: my motor is a little 577 cc 2-cylinder Universal 14hp. With the partial bypass valve mentioned above closed, I can heat the 6 gallon HTP water heater to 120 degrees in 30 minutes of cruising at 2300 rpm. 120 is about at what a home hot water heater is set.
At 1 hour, it's up to 160 degrees. Which is why I always leave that valve open. Then it takes over 2 hours to get that hot.

 

[MitchM]

1/ get the manual for your calorifier aka hot water heater (HWH ) and call their tech service. 2/ change the thermostat on your engine block and make sure you put in a new thermostat wit the correct temperature rating. 3/ how long has it been since you flushed and refilled your engine coolant ? 4/ does your HWH take a very long time to get to suitable temperature when you run it on electric instead of heating the water with hot engine coolant engine coolant ? 5/ is your temperature mixing valve set to produce the hottest possible h 2 0 ?