Diesel Heater questions

[Sofa King Fishy]

Hola~ Installing a Chinese Diesel heater with an Espar exhaust- my questions:

Is it ok to T into the fresh air intake for my GenSet? Both are simply ‘inhaling’ outside air, and will most likely never be running at the same time. This would save drilling one more hole into the boat.

Barring the exterior air intake, is it acceptable to direct the fresh air intake for the heater into the main Saloon?

Is an air filter needed on the fresh air intake?

Would you use a Racor, or a simple inline fuel filter?

Finally, is installing a H20 drainage elbow in the exhaust a good idea?

[Manateeman]

We have a Hydronic 12 (and a spare Hydronic 12 ready to go )and an Air Top 5 and no air filter on either. No special air intakes. I’d pass on the connection to the genset but I don’t know what your layout looks like. Both heaters are separated from living quarters and are in lazarettes for fire prevention. I’m very careful about carbon monoxide as well. CO monitor for every cabin.
We use the tiny Espar fuel filters which are overpriced. Lot of better ways to filter. Someday I may improve the fuel filtering. The heater fuel tanks are seperate so I can strip any water out but this has not been an issue. Just make sure your voltage at the heater is good and don’t forget to run them in the summer once a month. I run ultra low sulfur diesel. Some people run a little Kerosene to clean out the carbon.
The Air Top burner self destructed after years. Our old Hydronic 10 died but these heaters had known problems so I’ll probably sell it for parts.
The air heater is nice and great for days you just want to dry out the boat.
Please be careful about CO. Enjoy the toasty toes.
Happy trails to you.
Mark and his hot coffee, toast and jam in bed manatee crew

[Dockhead]

Originally Posted by Manateeman

We have a Hydronic 12 (and a spare Hydronic 12 ready to go ). . .

Smart man! This is a highly recommended approach for anyone cruising in waters cold enough to make heat mission-critical.


I crossed the Arctic Ocean with a brand new Hydronic 12, and a box of three old non-functional Hydronic 10 basket cases, and a plan that I could cobble together one working unit out of the parts if push came to shove. Fortunately the Hydronic 12 didn't miss a beat and this was not necessary.



Next time I do that, I will have tossed the box and will adopt Mark's approach


The reason for this is that these devices, however wonderful they are when they work, are operated by a fussy computer which will shut them down and lock them out for any one of a long list of failure conditions or imagined failure conditions. Without a computer and diagnostic software and special connector and a room full of spare parts, good luck bringing it back to life. This is a huge disadvantage compared to a simple pot heater like a Dickenson or Sig etc.

[sailingabe41ds]

Hi..

I have a Wallas heater and had the same question about the fresh air intake. My concern of tapping into the air intake from GenSet is that you may be backwashing air from the GenSet in addition to the fresh air.
Second, I used a Racor filter the first time (overkill) and forgot to change it for 14 years. Nothing happened but that filter could have dissolved into little pieces causing problems. The volume used by these heaters is minute compared to the diesel engine, so this time I am using the small in line filter and change it yearly.

Abe

[goboatingnow]

There is a open source ( code on request ) Chinese diesel heater controller project called “ The Afterburner” , the basic heating unit is very simple and reliable , so if you are into your electronics , it’s easy to remove the dependency on custom closed controllers

I agree the Eperspacher one is way over the top

[wingssail]

Originally Posted by Sofa King Fishy

Hola~ Installing a Chinese Diesel heater with an Espar exhaust- my questions:

Is it ok to T into the fresh air intake for my GenSet? Both are simply ‘inhaling’ outside air, and will most likely never be running at the same time. This would save drilling one more hole into the boat.

Barring the exterior air intake, is it acceptable to direct the fresh air intake for the heater into the main Saloon?

Is an air filter needed on the fresh air intake?

Would you use a Racor, or a simple inline fuel filter?

Finally, is installing a H20 drainage elbow in the exhaust a good idea?

We have seen in recent threads that there are differences of opinion on the subject of which air to burn and which air to heat.

However my opinion is that you should burn inside air (being very careful that you don't use it all up) and heat outside air, for some benefits of reducing moisture in the boat.

I also like to reduce the number of holes I cut in the boat.

So in that case use the air supply provided for the gen set to heat for dry inside warmth and use inside air to supply the burner.

I used a small filter for the fuel supply (to an espar)

H2O drainage if your exhaust line has a low point.

[DefinitelyMe]

Originally Posted by Sofa King Fishy

Hola~ Installing a Chinese Diesel heater with an Espar exhaust- my questions:

Is it ok to T into the fresh air intake for my GenSet? Both are simply ‘inhaling’ outside air, and will most likely never be running at the same time. This would save drilling one more hole into the boat.

Barring the exterior air intake, is it acceptable to direct the fresh air intake for the heater into the main Saloon?

Is an air filter needed on the fresh air intake?

Would you use a Racor, or a simple inline fuel filter?

Finally, is installing a H20 drainage elbow in the exhaust a good idea?

I'm new to this myself but am perhaps a little further ahead of you on the install/research.

There seems to be some debate about where to draw the air from to be heated. Consensus is that drawing from the cabin (a closed system) is more thermally efficient but less good for ventilation and moisture control. I am not in a super-cold area so opted to take a hit on efficiency for the sake of better ventilation (i.e. draw the air to be heated from outside). But either will work.

Inline fuel filter, but a good one with high element surface area is best.

Yes you definitely need a drainage elbow if there is a low point in the exhaust.

Your other questions I can't answer with 100% confidence, but I hope these are of some use.

Take a look at the YouTube video series titled 'Chinese Diesel Air Heaters' in several parts done by an Aussie guy. They are a bit long-winded and repetetive but there is a huge amount of useful/interesting info. on there. Sorry I don't know how to do links to things on here.

[goboatingnow]

I’ve installed 5 such heaters over the years , ie installed them myself

In general they are very simple , quite forgiving devices.

Use an appropriate small flow filter , some pumps have a tiny integral gauze filter ( which inevitable varnishes blocked )

I’ve always drawn both combustion air and heating air from within the boat volume , I don’t bother with silencers . But I do accept there is a debate on exactly where to draw air from. The general trend these days is to pipe both combustion intake ( and obviously combustion exhaust ) to the outside , as this prevents intake blowback getting into the interior spaces , but I’ve , in 30 years , never seen it happen

I don’t see much point in drawing heating air from outside

And do remember to regularly run them flat out from time to time

I installed all eberspacher airtronics , never had one fail in 30 years over 5 boats , all still using the same igniter/ glow unit etc

Having dismantled several eberspachers , there’s is really nothing complicated , which is why the Chinese can knock them out for peanuts

YMMV of course applies

[Dockhead]

Originally Posted by goboatingnow

. . . I installed all eberspacher airtronics , never had one fail in 30 years over 5 boats , all still using the same igniter/ glow unit etc . . .

YMMV of course applies

Boy, you've been lucky. My old Hydronic 10 would fail like clockwork every other year, requiring a £500 to £1500 repair every time. Circuit board. Burner tube. Decarbonization and glow plug. Flame sensor. Blah blah blah. After the second circuit board failure (the achille's heel of those damned things) it was declared Beyond Economical Repair, and I bought a new Hydronic 12 (just before sailing to the Arctic).

That one has been flawless so far -- knock on wood. Will be 3 years old in April.

You've reminded me that I need to install a fuel filter. I've put it on my list. Thanks!

And I think I'm going to sell off the big box of broken/basket case Hydronic 10's and buy a spare Hydronic 12. Where I sail, I need heat year round and I don't want to spoil a cruise by futzing with the furnace if it goes down. As the years go by I concentrate more and more on trying to prevent those cruise-spoiling technical failures. The second best weapon against that is a really good set of spares.

The BEST weapon against that is a pro engineer in your crew!

Oh, and the other thing I'm doing over the winter is installing a bus heater so I can heat with engine waste heat. This is highly recommended for cruising in cold latitudes.


P.S. And by the way, the second generation of Eberspacher hydronic furnaces display the failure codes on the ordinary control unit, and allow you to clear them. This is a big leap forward in case you need to be able to fix it yourself in the field. The first generation of hydronic ones required a diagnostic wiring harness and special software, which I eventually acquired, but it's a real PITA to use. Without that, even if you can fix the unit, you can't clear the code and make it run again I don't know about the Airtronics.

[Dockhead]

Originally Posted by Manateeman

. . . The heater fuel tanks are seperate so I can strip any water out but this has not been an issue. . . . Some people run a little Kerosene to clean out the carbon. . .

If I were building a new boat, I would definitely have a separate fuel tank for the heater. In some countries, like the UK, kerosene (or jet fuel, or light heating oil, which are all more or less the same things) are much cheaper than diesel. And burns much better in these devices, eliminating carbonization as far as I understand. And even if you don't burn kerosene all the time, having a separate fuel tank allows you to burn a tank of kero once a year or so to keep the furnace clean.

[rbk]

If you draw your combustion air from the exterior you will need a separate means to manage moisture (breathing, cooking, hull condensation etc) as there is little to no exchange of air within the boat. If you draw combustion air from the boat is takes the warm moist air away through combustion and out the chimney and is replaced by cold air coming into the boat through various means (dorados, companionway etc) Cold air is denser and has less capacity to ‘hold’ water therefore generally had a high relative humidity. When you take that high humidity cold air and warm it, it expands, the water vapour in that volume of air stays the same so in turn the relative humidity drops substantially. The warmer it gets the drier it gets, so it sucks up more of the water vapour you are producing within the boat and again gets sucked up the combustion intake and expelled out the chimney. The greater the temperature difference from cold the warm the greater the drop in RH.

[Sofa King Fishy]

Originally Posted by rbk

If you draw your combustion air from the exterior you will need a separate means to manage moisture (breathing, cooking, hull condensation etc) as there is little to no exchange of air within the boat. If you draw combustion air from the boat is takes the warm moist air away through combustion and out the chimney and is replaced by cold air coming into the boat through various means (dorados, companionway etc) Cold air is denser and has less capacity to ‘hold’ water therefore generally had a high relative humidity. When you take that high humidity cold air and warm it, it expands, the water vapour in that volume of air stays the same so in turn the relative humidity drops substantially. The warmer it gets the drier it gets, so it sucks up more of the water vapour you are producing within the boat and again gets sucked up the combustion intake and expelled out the chimney. The greater the temperature difference from cold the warm the greater the drop in RH.

Wow! Thank you for the thorough response- I sincerely appreciate the effort- great information!

[pcmm]

Originally Posted by Sofa King Fishy

Hola~ Installing a Chinese Diesel heater with an Espar exhaust- my questions:

Is it ok to T into the fresh air intake for my GenSet? Both are simply ‘inhaling’ outside air, and will most likely never be running at the same time. This would save drilling one more hole into the boat.

Barring the exterior air intake, is it acceptable to direct the fresh air intake for the heater into the main Saloon?

Is an air filter needed on the fresh air intake?

Would you use a Racor, or a simple inline fuel filter?

Finally, is installing a H20 drainage elbow in the exhaust a good idea?

I've installed one of those CDH's in my OI 41. ha it for 2 years now and mostly use it when visiting the boat in the winter to work on it. for the combustion air intake I see no reason why you can't T into the air intake for the genset, but if there is a chance both might be running at the same time I'd give it it's own air supply. No filter is needed on the combustion air intake. for the fuel filter I just used a simple inline filter from a small engine shop.

The drip loop for the exhaust is important. it helps prevent condensation from rotting out the exhaust tubing. Most important though, most of the parts that come with the CDH's are garbage quality and you need to source better parts. The muffler is dangerous o a boat as its not sealed! the exhaust tubing and clamps are junk.

To do a quality install will cost a fair bit, in my case close to $400 in parts to install a $200 heater!

You'll need:

transom fitting ($75ish)
good quality espar type exhaust tubing ($40-100 depending on the length)
Muffler (optional but makes them almost silent) ($75)
elbow with drip loop ($70-100)
T-bolt clamps for the exhaust
hose clamps for the ductwork
you might need a different mounting plate
exhaust lagging
quality fuel filter
etc.