Residential 2-Stage Options?

Harry_6

I'm looking to spec a boiler of about 750 Sq. Ft. radiation for a home, but it's a Mouat system, so I absolutely want a 2-stage setup. The last time I did one of these it was for a large home and I was able to get a commercial-size Burnham (5009B) with a 2-stage gas train, which is an option for that boiler. Because we live in a backward society, they don't offer 2-stage for a smaller boilers. Anyone have knowledge of someone who does, or a way to do this without voiding a warranty?

Jamie Hall

EDR of 759 square feet? If you match the boiler to that size pretty closely, I'm not sure why you need a two stage burner? Although you surely need a vapourstat to control whatever you put in.

Harry_6

Strictly speaking, I may not. But I was pretty happy with the fast startup and the ability to, at low fire, just produce steam exactly as fast as it was consumed, and hover indefinitely at 2 Oz's. with very little cycling.

Jamie Hall

Harry_6 said:

Strictly speaking, I may not. But I was pretty happy with the fast startup and the ability to, at low fire, just produce steam exactly as fast as it was consumed, and hover indefinitely at 2 Oz's. with very little cycling.

Don't get me wrong -- I'd be happy with that, too. But... at somewhere around 182K net BTU, or 235K net BTU with the pickup factor, I'm not sure what you're going to find that is both simple and reasonably priced. Cedric, the biggest of the boilers I maintain, is half again as big (and so is the system) and cycles off on pressure (set at 7 ounces) only on very long recovery runs. Is the complexity worth it?

gerry gill

We use Maxitrol SR500 regulators for that.

Harry_6

Which brings me back to the original question: Does the use of a dual pressure regulator on a boiler not specifically stated as being suitable for one void the warranty? I'd be happy to use dual-pressure (especially on an ultra-low pressure system, like a Mouat or Broomell) except for that. Yes, it is more complicated, especially for a small system, but it better approximates a simmering coal fire.

Oh, for a modulating atmospheric burner! Except what with the electronics that would no doubt be used, it would be even more complicated. I'd still rather see a round Honeywell 'stat than a "Nest" any day.