2 diesel heater exhausts into one skin fitting

[mrangry]

I bought an eberspacher hydronic diesel heater and two plinth heaters and planing to fit these on the boat next week. Prior to purchasing this I had bought one of the Chinese diesel air heaters. Whilst I like the idea of the wet system, I am thinking of fitting the air heater as well as I think it would be more of an instant type of heat compared to the wet so thinking of fitting both.

My question is, if I fabricate a "y" piece of tubular stainless steel is there any reason why I couldn't fit both exhaust tube out through a single skin fitting. I have no plans to run both heaters at the same time.

 

[Sticky Fingers]

Sounds like a recipe for CO poisoning.

 

[sailorman]

wet heating is not very efficient o/b

 

[mrangry]

Sounds like a recipe for CO poisoning.

Why?

 

[mrangry]

wet heating is not very efficient o/b

I am looking for hot water and the wet system is simple to install with inobtrusive pipes compared to the air

 

[sailorman]

I am looking for hot water and the wet system is simple to install with inobtrusive pipes compared to the air

BUT is it efficient as a space heater ???

 

[mrangry]

BUT is it efficient as a space heater ???

For heating water??

 

[Sticky Fingers]

Sounds like a recipe for CO poisoning.

Why?

Because you're connecting the exhaust of one system into the pipework of another. It might be fine, exhaust to exhaust. But it might not - what safeguards stop backwards flow of exhaust gases from the running unit backwards out of the the intake pipework of the idle system? That intake takes air inside the boat (probably). Would you automatically think that is safe?

 

[mrangry]

Because you're connecting the exhaust of one system into the pipework of another. It might be fine, exhaust to exhaust. But it might not - what safeguards stop backwards flow of exhaust gases from the running unit backwards out of the the intake pipework of the idle system? That intake takes air inside the boat (probably). Would you automatically think that is safe?

View attachment 102035

Good point, another skin fitting it is then

 

[Sticky Fingers]

Right decision I think.

 

[Steve_N]

I had 2x exhaust skin fittings side by side on my old boat, one for the Hydronic and the other for the Airtronic, It always piqued peoples' interest but was definitely the only correct way to do it. You may well find too that there are in fact occasions when you want both running at the same time.

 

[Boater Sam]

Good point, another skin fitting it is then

Thankfully you have seen the light before you were consigned to perpetual darkness.
Making adaptations to any fuel burner exhaust is verboten in all regulations, land, sea, and air.

 

[Boathook]

Because you're connecting the exhaust of one system into the pipework of another. It might be fine, exhaust to exhaust. But it might not - what safeguards stop backwards flow of exhaust gases from the running unit backwards out of the the intake pipework of the idle system? That intake takes air inside the boat (probably). Would you automatically think that is safe?

View attachment 102035

The combustion air inlet on my propex is via a skin fitting by the exhaust. I thought that the diesel were the same. If so there is no real problem unless you try to run both at the same time when back pressures will possibly cause a malfunction.

 

[Sticky Fingers]

Maybe ok. I’d still not risk it.

 

[pcatterall]

If You are confident about your welding then why not?
However fitting an extra through hull next to the first should not be a problem/ safer, simpler and the kudos of twin exhaust ports ! Also as stated you could use both together. That would be my solution but, then, my welding is C..p!

 

[mrangry]

Th

If You are confident about your welding then why not?
However fitting an extra through hull next to the first should not be a problem/ safer, simpler and the kudos of twin exhaust ports ! Also as stated you could use both together. That would be my solution but, then, my welding is C..p!

I have no issues with fabricating a stainless fitting, the concern seems to be backfeeding exhaust gases through the other inlet. This could be overcome by taking the combustion inlets from fresh air I suppose.

 

[cherod]

Non return valves ?

 

[Boathook]

Th

I have no issues with fabricating a stainless fitting, the concern seems to be backfeeding exhaust gases through the other inlet. This could be overcome by taking the combustion inlets from fresh air I suppose.

I thought that the heaters were sealed units so the combustion air inlet should always be outside. This is the same as what used to be called balanced flue units and any modern 'heater' at home normally takes combustion air from outside to improve safety.

 

[mrangry]

Non return valves ?

Yes, bit tricky with an exhaust, I suppose I could bastardise a wastegate but it could end up being more effort than fitting two exhaust skin fittings.

 

[scottie]

Non return valves ?

Not a good idea on exhaust pipes in my experience they can stick