Smith 19A-gas (& in general) versus G8

Steamhead (in transit)

twinning two G8 boilers- say a 3-section and a 4-section? You could use a Vaporstat to drop the smaller one out once the pickup factor is satisfied, and save much fuel.

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steve_173

I need more sq ft steam than the G8 allows for in gas. There is a jump up to the 19A. The 3 section 19A is rated at 929 sq ft (versus my net of 735, but I may need more than a 33% pickup). Smith couldn't tell me exactly how the lo-hi-lo firing reduces the sq ft of steam (burner is a Powerflame JR15A).

How is the series 19A in general? As good as the series 8? The combustion efficiency of 81.6% on the 3 section 19A seems a bit low and is even lower than say the atmospheric Burnham Independence. Does this mean I won't gain any efficiency from the wet boiler design or just that the actual flame is less efficient?

steve_173

missed the fact that I could edit my post for a typo

EBEBRATT-Ed

Steamhead has this one right. You will be oversized with the 19. It's a good boiler but probably more than you need.

A 19 running at low load (we don't hit design conditions that often) will not be as efficient as two smaller boilers. Also finding someone to service the Powerflame (properly) could be a problem depending on your location.

Don't get me wrong Powerflame is a good burner (I was a rep for 10 years) but your kind of "in between" residential and comercial equipment. You may need a few extra controls to maintain the water line and to keep the idle boiler from flooding if you go with two boilers.




ED

steve_173

How does the sq ft of steam add? Just regular addition? On the G8, a 3+4 is 283+413=696 and a 3+5 is 283+525=808. In my case, I think I would have to do a 3 section and 5 section.

Will just any plumber know how to do this? I would guess that it needs a larger footprint than just a single boiler. What about the chimney being too large when just the smaller boiler is firing? Which would fire first? larger or smaller boiler?

Once the pickup is satisfied won't both boilers just shut off?

How common is it for the 1.33 factor to be inadequate in an older home? Should I try to measure all the piping runs and get the EDR of the piping?

Are insulated valves on the radiators worth the cost?

Thanks.

steve_173

What sort of extra controls would I need? The water capacity of two smaller boilers is greater than that of a larger boiler which I think is good for the system.

scrook_2

steam...

As it's steam though, it'll always be at "design conditions" as that will be the sq footage of radiation, not heat loss to the outside.

In any case get a guy who *knows* steam to pipe it, not all plumbers know steam, it's a bit of a lost art.