Rinnai Gas water heater - Fitting a 1.1m flue pipe?

[Richard10002]

My narrowboat has a Rinnai 58e gas water heater fitted in an open space, but under a worktop in the galley. In reality, it is the only place it could be fitted, without the danger of us banging our heads on it, or having an excessively long additional gas pipe.

It only feeds the shower. The Hot water to the galley and bathroom sink are fed from a Truma combination heater and water heater, which only holds 12l, so not enough for a shower.

The interior of the space, above, to the sides, and to the rear of the heater, is coveted in an aluminium heat reflective sheet.... Like those designed to go under motorbike seats to protect your bum from the exhaust heat - they can cope with around 1200C as far as I can tell.

The thing works fine, the aluminium gets hot, but nothing has caught fire yet. I've got two CO monitors, and neither has gone off to date.


However, I think it should have a flue, and need a bit of help in going about it:

I've bought a draught diverter, which will leave about 1.1m from the top of the diverter to the steel roof.

The various flue kits seem to be interchangeable between the Rinnai 58e, the Morco 61B/E, and various other heaters, so here's the Morco selection of stuff:

http://www.morcoproducts.co.uk/stock-5-19/Water_Heaters/D61B.html

It looks like I could buy a complete flue conversion kit, plus an additional flue terminal pipe, and I would have enough to make it work:

http://www.morcoproducts.co.uk/component-576/Complete_Flue_Conversion_Kit_D61BE.html

http://www.morcoproducts.co.uk/component-573/Flue_Terminal_Pipe_600mm_x_90mm.html

However - this leaves me with 2 concerns:

1) can you join the flue pipes internal to the boat, and how do you do this? A chap at Midland Chandlers suggested that you couldn't join them, but I'm not convinced he was particularly interested in helping me to find a solution. If you can't join them, can I buy a 1.1m length of 90mm flue, and what should it be to carry away the gas combustion gasses?

2) if the flue pipe is internal, and it would be rising next to the gas cooker, would it need to be twin skinned, e,g.

http://www.woodburningstovesandflues.co.uk/twin-wall-flue-pipe-dinak-dw-4inch

(although the example above doesn't accommodate a 90mm pipe which is the diameter of the above flues).

Or could I wrap it in the sort of stuff that is around the exhaust.

I hope this makes sense, and that someone can help.

Many Thanks,

Richard

 

[pete]

Not boating but I used to do a lot of work on natural gas flues in domestic premises we used Selkirk's flue. it is twinwall and can be easily joined using the twist and lock system built into the pipe and fittings. Its probably cheaper than marine flue systems and comes in 3" 4" 5" and 6" and 1.5 metre lengths or shorter, this was not stainless but was suitable for external use, I think they do stainless steel flues but they are 5" and greater.
http://www.selkirkchimney.co.uk/products/insta-lock-gas-vent.html
pete

 

[William_H]

I would imagine that the flue pipe will go up thropugh the bench top then up to the roof. So yes you woulod need insulation around the flue pipe in ant area it is likely to be touched and through any heaedlining. I would imagine the flue pipe is joinable usually by having a section expanded in diameter for the next pipe to fit into. I su8ppose something simialr for the double flue type which is what I would go for. good luck olewill

 

[Richard10002]

I would imagine that the flue pipe will go up thropugh the bench top then up to the roof. So yes you woulod need insulation around the flue pipe in ant area it is likely to be touched and through any heaedlining. I would imagine the flue pipe is joinable usually by having a section expanded in diameter for the next pipe to fit into. I su8ppose something simialr for the double flue type which is what I would go for. good luck olewill

But where to find 90mm internal diameter twin walled flue. Like the Selkirk, they all seem to be made in multiples of inches - 75mm, 100mm, 125mm etc., or is there an adapter to take the 90mm at the top of the heater up to 4" or down to 3", and vice versa at the top where it would join the chimney?

What kind of sealant to use at the joints if I can find them?

Very difficult, even with the power of the internet

 

[Richard10002]

I think I'll be moving this to a bit of an unsightly location in the saloon, but where it will fit near the roof, so I can fit the bespoke double skinned flue which is only about 17" long/tall.

Thanks to all for trying, but I don't think there is an off the shelf solution