diesel heater ducting

[boomerang]

I appreciate all of the knowledge regarding Wallas & Scan Marine I've gotten from this thread.
I would've loved to had been offered the option of them selling me a pump in hopes of getting lucky and the heater would run in some kind of fashion to get us down the ICW with auxiliary heat and then ship it to them for fine tuning when we had time but in the end, the fault lies with me. I should've tested everything earlier and allowed adequate time for repairs but I was kind of occupied with replacing the propeller shaft & cutlass bearing while the boat was on the hard, in addition to seacock maintenance, so the heater wasn't on my mind. Especially since it was working fine when we last used it in the early spring.
Oh well. I've learned a lot about Wallas maintenance and we'll appreciate the heater even more when it gets back to us.

[DW1979OA]

I have a 50’ boat and installed a Wallas. I only wanted to heat the salon which it does adequately. I do have also a 3 unit reverse cycle heat and air but it requires running the genny. At anchor I just want the salon heated without running the genny. I went with the Wallas because of the smaller duct size made for easier install running the ducting.
So my advice is not to necessarily size by boat length. Think what you want to heat

[paulga]

Originally Posted by DW1979OA

I have a 50’ boat and installed a Wallas. I only wanted to heat the salon which it does adequately. I do have also a 3 unit reverse cycle heat and air but it requires running the genny. At anchor I just want the salon heated without running the genny. I went with the Wallas because of the smaller duct size made for easier install running the ducting.
So my advice is not to necessarily size by boat length. Think what you want to heat

If the heater is installed in the cabin or bilge, how do you arrange the air ducts to the aft cabin and the bow area? Does the passage hide behind the wood panels so you have to open them to lay the ducts?

[DW1979OA]

I was able to run duct work in hidden areas. Every boat is different. I was able to locate the heater in a lazerette just aft of the salon and so duct work was partial under duct and then up in to the salon where I had three outlets and one return

[paulga]

Originally Posted by TJM

Paul: As you can see there are lot of options. Insulating the exhaust pipe is an easyish task. My tube-in-tube exhaust hose touches fiberglass and wood with NO issues. Where the hose touched the boat I have wrapped high temp cloth to act as a heat shield. Fuel can be extracted thru a manifold without any more tank penetrations. I have 2 manifolds on my boat. All of the feeds have ball shut off valves so no starvation can take place. If you winterize your main engine, close the fuel valve.

@TJM Could you snap photos to show how the manifolds work to supply fuel?

[TJM]

Yes, I can take some pictures and text them to you.
One manifold is connected to a Reverso OP-7 diesel fuel pump which primes the fuel lines / filters upon a filter change. The best improvement I made so far. I can change out a fuel starved line and filter within minutes. I can also transfer fuel from port to starboard tanks and visa versa if needed.
The second manifold if connected to my oil changing system. Both engines and genny are connected to this. Makes oil changes quick and clean.

[paulga]

Thanks Tom. I received it. I will have more questions when I get time to work on this.

Originally Posted by TJM

Yes, I can take some pictures and text them to you.
One manifold is connected to a Reverso OP-7 diesel fuel pump which primes the fuel lines / filters upon a filter change. The best improvement I made so far. I can change out a fuel starved line and filter within minutes. I can also transfer fuel from port to starboard tanks and visa versa if needed.
The second manifold if connected to my oil changing system. Both engines and genny are connected to this. Makes oil changes quick and clean.

[paulga]

@marco flamingo , when you run the 8 ft duct through the bilge, how did you seal the bilge odor inside?

Originally Posted by Marco Flamingo

My boat had a Wallas diesel heater. When that needed parts that were no longer available, I went with a $150 Chinese diesel heater (3 years ago). Some of the old ducting I used, some I improved. The Wallas had a fresh air intake to the outside. I eliminated that and now simply take air from my well ventilated engine room.

I added both a muffler and an intake silencer. The original install made for a whining noise outside the hull. More irritating to a neighbor than to me, less irritating than a generator, but still something easy to eliminate. I fabricated a muffler (as the common diesel heater mufflers are not suitable for interior spaces) similar to a "glass pack" muffler out of common copper pipe (shown in this thread at post 37). Wallas makes an exhaust muffler out of $tainless $teel for about $300. My silencer on the air intake is one from Ebay. Recommended as the intake whines almost as much as the exhaust. Both are now silent.

The little heater fuel pump is a tick type and could be heard when at anchor. I suspended the pump from the rubber fuel lines and wrapped the pump in pipe insulation (the brown "smurf tube" commonly sold at hardware stores). It now can't be heard in the cabin.

The air duct is not a common size and one is generally forced to buy small lengths. The air is quite hot (it melted one of my crocs on the cabin floor, also shown in the above thread at post 53). I would use the special heat-tolerant aluminized duct when near the heater. However, that duct is usually kind of an accordion pleat and therefore not that efficient for longer runs. Turns out that long runs and lots of elbows are what kills these little heaters as they can't "breathe" and coke up. That said, I needed to run one "Y" over 8 feet through the cold bilge to get to the V berth. I used 3" pipe insulation as the duct (the brown stuff, again) to keep the air warm. Worked fine and can apparently take more heat than a pair of crocs.

[Marco Flamingo]

I've only read about "bilge odor" here on TF. If I ever had that, I'd first fix the black water tank or whatever was causing the odor. Maybe a "dry bilge" is so dry that it doesn't get the exchange of water that keeps the odor away? Maybe some boat in stinky water?

I sealed my ductwork where it passed through bulkheads or in/out of conditioned space in a couple of ways. The ductwork for the original Wallas heater was apparently installed by a blind one-armed man with a Sawzall. Oversized randomly shaped holes that showed several attempts had been made. Since the primary holes were a couple ducts coming out of the engine room, they also allowed engine noise in to the cabin and the head.

When re-doing, I cut a large patch of mass loaded vinyl with a hole just the size of the duct. That allowed me to thread the duct through the patch and then attach the patch to the bulkhead. Cut down on sound and air infiltration at the same time. I then used canned foam glue to really seal things in place. I think this might also mask a stinking bilge.

For the semi-split foam pipe insulation that I used for ducting, I used a hole saw sized 1/8" less than the foam insulation O.D. That allowed me to jam the duct through the hole and it self sealed.

[paulga]

Thanks, one dumb question

How do you attach the vinyl patch to the bulkhead?

Btw, the bilge does not stink, but does not smell the same as the cabin. When underway, there is diesel smell.

Originally Posted by Marco Flamingo

I've only read about "bilge odor" here on TF. If I ever had that, I'd first fix the black water tank or whatever was causing the odor. Maybe a "dry bilge" is so dry that it doesn't get the exchange of water that keeps the odor away? Maybe some boat in stinky water?

I sealed my ductwork where it passed through bulkheads or in/out of conditioned space in a couple of ways. The ductwork for the original Wallas heater was apparently installed by a blind one-armed man with a Sawzall. Oversized randomly shaped holes that showed several attempts had been made. Since the primary holes were a couple ducts coming out of the engine room, they also allowed engine noise in to the cabin and the head.

When re-doing, I cut a large patch of mass loaded vinyl with a hole just the size of the duct. That allowed me to thread the duct through the patch and then attach the patch to the bulkhead. Cut down on sound and air infiltration at the same time. I then used canned foam glue to really seal things in place. I think this might also mask a stinking bilge.

For the semi-split foam pipe insulation that I used for ducting, I used a hole saw sized 1/8" less than the foam insulation O.D. That allowed me to jam the duct through the hole and it self sealed.