Automotive-type heater (bus heater) on sea water cooled engine

[chasfgr]

Originally Posted by esarratt

I figure this has already been figured out. I have a Volvo MD7A. It is sea water cooled.



Is there a way to make an automotive-type heater/fan work with this system or is it just too much hassle?


Thanks!

No.
I've tried.


Buy a truck diesel heater such as Webasto.
Mine was fitted in the cockpit locker, feeding into main saloon and forecabin.
It worked well but the pump ticking kept some awake.

[Mike Banks]

I used them with a separate diesel fresh water heater with anti-corrosive added, but it was outside the hull in the wheel house and only the hot water got inside cabins through lagged piping. That way you stay warm when the engine is not running.


I will always keel-cool any future engines. They are so efficient that you can also cool the exhaust manifold with them, using a completely dry exhaust. I have had it with salt water cooling and impellers, and I hate wet exhausts. No commercial operators use wet exhausts in any of the fishing vessels--just so much extra trouble.

[Cadence]

I would be concerned about corrosion.

[captlloyd]

Originally Posted by Mike Banks

I used them with a separate diesel fresh water heater with anti-corrosive added, but it was outside the hull in the wheel house and only the hot water got inside cabins through lagged piping. That way you stay warm when the engine is not running.


I will always keel-cool any future engines. They are so efficient that you can also cool the exhaust manifold with them, using a completely dry exhaust. I have had it with salt water cooling and impellers, and I hate wet exhausts. No commercial operators use wet exhausts in any of the fishing vessels--just so much extra trouble.

I have been advocating that for a long time.

[Char99]

Originally Posted by sailingabe41ds

Just a thought....if you have a water heater that uses the engine to heat water why not tap into the water heater thus running a lesser risk of corrosion? Only thing is that is going to be more hoses and things that can break in addition to more fans. Your system will also only work when the engine is running.
Personally I think installing a diesel heater is the best way to go.

Abe

I am sitting near my Mr. Heater Buddy. I have come to talk to him and tell him how much I love him. I am warm here in the North west in the salon of my Cal 2-46. I use a 20lb tank on deck and leave lots of ventilation and sure make this week nice up here. I have the buss heaters but the diesel unit has gone down. Since I have used this 9000 btu unit I will not be replacing the diesel unit. Draws no electric power.

[alaskanviking]

Originally Posted by esarratt

I figure this has already been figured out. I have a Volvo MD7A. It is sea water cooled. Is there a way to make an automotive-type heater/fan work with this system or is it just too much hassle? Thanks!

Absolutely not with a raw water cooled system! The heater matrix/radiators are aluminum or copper. Your introducing dissimilar metals in the system and it will eat them out. Secondly hot saltwater will precipate calcium and other minerals and deposite the inside the hoses and small tubes inside the heater. Like the hoses in the head or a clogged artery. The heat makes this process rather quick. The heaters lose their ability to pass heat over time as they clog up, while the metal is being eaten. Frequent flushing and acid cleaning will reduce/remove the deposits. It is POSSIBLE if you found a heater made from cupronickel or stainless tubes but I haven’t seen many of those. Even the REAL hydronic heaters from sure marine are only made from copper. You probably would have to have a custom one made, and there are cheaper options to heat your boat.

You realistically have two options
Install a small 2-3 gallon water heater with an engine coil OR a heat exchanger for a separate freshwater heater system. Unfortunately you have the same issue with this plan the exchanger coil or plates will clog and get eaten. Stainless materials will last longer but eventually the hot water and metal corrosion will be too much. Hot salt water makes corrosion faster also. I do not recommend this plan.
Forced air diesel heaters - Get a cheap Chinese diesel air heater off of ebay. There are big facebook groups all about these heaters, alternative control software (afterburner) it’s probably the cheapest option and the easiest to install. ~$150 for the heater. There is a Russian version of this heater that’s supposed to be good but not horribly expensive, than there is Wallas, Webasto, and espar name brands the Chinese heaters copy, they run ~$1000-1500. Espar or webasto also have gasoline fueled heaters. I have been seeing a lot lately on the cheap Chinese heaters and it looks like they may be worth looking into and reading the group posts.

Get a diesel or propane bulkhead or floor mount heater. The diesel is safer and doesn’t add moisture into the boat. Most expensive route. Install costs more. Sometimes you can get these used if you’re lucky. These are more economical on diesel than the forced air heaters, and don’t use electricity. You can get one with a water coil to provide hot water to the sink or hydronic heater.

Originally Posted by CarinaPDX

I have my doubts that this is worth the effort. The water temps are fairy low on a raw water cooled engine (no steam pressure as in a closed system) and with a small engine there isn't a lot of heat to work with. I share the other concerns with corrosion - automotive grade heat exchangers are not likely to last very long. I suppose you could use cupro-nickel tubing and a 12V computer case fan to make your own heat exchanger to take a bit of chill out of the boat but I doubt it could heat even a 24' boat on a cold day.
Greg

True the coolant on a raw water cooled engine will be cooler the general rule in a raw water cooled motor running in salt water is you should run the 140-145* thermostat. With closed cooling the thermostat is usually the 165*. Actual temps are a little higher about 170-180 for closed cooling system, and 150-170 for raw water cooled. Even 140 is much higher than 70-80 degrees, and you should have no issue with heat based on temperatures. With one heater it’s the same heat system as a car and when working well should provide plenty of heat for a 24ft boat. The main problem here is mineral deposits from the hot seawater insulating the exchanger.

[NorthCoastJoe]

One thing nobody mentioned: Friction loss in the hoses and heat exchangers will slow down the flow. This in turn may cause engine overheating. I would not try this without using an electric booster pump. But I would not waste my time trying to do this, though I have thought about it.

To be realistic, My Yanmar 3gm30f heats the whole boat just from the heat radiating off the engine itself no heaters are needed. Open up some venting around the engine and get all the heat you could use.

[canyonbat]

Our friend ran a Red Dot Heater in his Willard 30 on several trips to Alaska. It worked well.

https://www.fisheriessupply.com/red-dot

[ColIn Ferguson]

I have fitted a calorifier to a Volvo 2002 that is raw water cooled. The main problem has been getting air locks on the circuit.
The problem is that as the engine cools water falls down out of the manifold so when starting up again and reaching operating temperature, as the thermostat opens, air is pumped through the piping. This the
N causes the engine to overheat as coolant flow is stopped.
The solution has been to put in a second direct circuit to run the coolant as normal until operating temperature is reached before opening the circuit to the calorifier. You then need to shut off the calorifier circuit before stopping the engine so the circuit remains primed before restarting from cold.
I have incorprated electric valves wired to a switch in the cockpit to open and close the circuits.
A complex problem but i think you will have the same issues with an air heater installation.

[Colin Stone]

I fitted a Bowman marine oil cooler from a boat jumble. The engine calorifier connections feed it with hot water. It is plumbed into the oil boiler central heating supply pipe.
14 radiators and 2 calorifiers are heated by engine. Water temp is a 85-90C and calorifiers have enough hot water capacity to last 2 days after engine switch off.

http://www.luxe-motor-kei.co.uk/inte.../image179.html

When I run generator, that heats one calorifier by keel cooling water and the other by immersion heater.

[CarinaPDX]

Originally Posted by ColIn Ferguson

I have fitted a calorifier to a Volvo 2002 that is raw water cooled. The main problem has been getting air locks on the circuit. ...

I'm not clear why this should happen as long as there is an expansion tank that is mounted higher than the engine and water heater (calorifier). Volvo is very clear for their D1 and D2 engines that the expansion tank should be removed from the engine and mounted higher, if needed to keep it above the rest of the system. (Well clear, if you can get a copy of the Installation Manual. PM me if needed.)

Greg

[Shaneesprit]

I have this already installed in my boat
25ft CAT 25hp Beta
It’s coolant side, so only working like a vehicle heater matrix, although it’s some sort of marine version, anyway still the thermostat will regulate the coolant flow.
My opinion is it’s fairy unless, you would have to be under power not just charging batteries, well I prefer to sail. But even when I have to motor it doesn’t help that much.
I fitted a cheap diesel air heater, but probably going to replace it with a more expensive model, I want hot air and hot water from it as well as reliable operation

[laird]

I've fitted a Chinese diesel heater to my rv , it's great for those cold mornings especially it comes with a remote control and I switch it on and wait until the hab areas warm

When I get my yacht ,I'll fit one but with a few modifications , it's easy to do , you need marine grade stainless steel exhaust pipe and a through hull fitting , connect the fuel pipes to the main tank of run a separate tank , the fuel pump gets a bit noisy like an old parlour clock ,but if you suspend it it is a lot quieter ,there's also.a guy in England who makes pumps for the heaters they are very quiet and use less diesel

There's lots of info on you tube about them ,don't forget to.fit a.monoxide alarm near the unit as a precaution ,they draw around 8.5 amps on start up for the glow plugs and then draw less than 1a depending on how warm you like it

[Shaneesprit]

How have you found the Chinese heater
My first one didn’t start, Fan issue I never had the time to fix it so sold it and bought another, it was ok only ran it a couple of times, probably never long enough to be sure but seemed a bit toxic.
I have a working monoxide alarm,
Then this year I tried to start the heater abs it failed to start, it’s a real pain to access on the boat, so I will probably buy another that heats water as well as air.
Seems to me better to buy a decent one? Not sure if the others have the air and water option.
Then if it works well I intend to remove the off engine heater completely

[steffan]

I just finished installing a Russian heater. It took one cycle to prime then fired right up. I've only run it for a couple of hours so far but it uses less power and produces more heat than I was expecting. Smells a bit 'new' in the locker, but no other fumes or smoke I can detect.