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Hot water rads off steam boiler

68GMC Member Posts: 36
Hello all,

I'm trying to do the engineering of a hot water rad zone (no indirect hot water heater), off my steam boiler.

I've looked around this site and others, but am still confused on a couple points. Dans article on hot water zones dealing with just rads shows just a thermometer to control the water temperature in the water zone, the bypass valves and bypass loop determine how much water gets recycled into the boiler to be reheated (in a nutshell). The way he descibes it, the thermostat for the hot water zone goes into a relay, to the transformer, to the ciculator. The circulator only runs when the hot water thermostat calls for "heat. In theory, you could run the circulator all day long with this system, because the water will never get over, in his example, 180 degrees. And his way the steam zone can run whenever it wants, the boiler can be making steam and the circulator can still be running, because the bypass loop allows enough cooling of the water, and there is a 30 degree error range if the boiler pressure changes or water temps drastically spike. He does get into an aquastat further down when discussing other piping arrangements.

Other articles suggest an aquastat in the system, my owners manual suggests an aquastat right in the boiler if you were to run an indirect hot water tank. That way the aquastat controls the ciculator, but now you have to wire the aquastat to shut off at 180, to allow the boiler ot make steam, but if the hot water zone wants heat the aquastat has to be wired to run the boiler to heat the water, etc. etc.

<a href="http://www.comfort-calc.net/Electrical/Wiring_Steam_Boiler_w-Indirect.jpg">[url=http://www.comfort-calc.net/Electrical/Wiring_Steam_Boiler_w-Indirect.jpg]http://www.comfort-calc.net/Electrical/Wiring_Steam_Boiler_w-Indirect.jpg</a>

<a href="http://www.heatinghelp.com/article/17/Hot-Water/76/Condensate-Hot-Water-Heating">[url=http://www.heatinghelp.com/article/17/Hot-Water/76/Condensate-Hot-Water-Heating]http://www.heatinghelp.com/article/17/Hot-Water/76/Condensate-Hot-Water-Heating</a>

<a href="http://www.heatinghelp.com/files/articles/1360/346.pdf">[url=http://www.heatinghelp.com/files/articles/1360/346.pdf]http://www.heatinghelp.com/files/articles/1360/346.pdf</a>

<a href="http://www.comfort-calc.net/steam_indirect_piping.html">[url=http://www.comfort-calc.net/steam_indirect_piping.html]http://www.comfort-calc.net/steam_indirect_piping.html</a>

Do you run an aquastat in the boiler ONLY for an indirect hot water heater?

Should I run an aquastat in the hot water feed, after the boiler, before the circulator, as a safety measure, or just good plumbing?

Since an aqustat will have a "well", how would I pipe that into the feed pipe?

If I never want to fire the boiler to heat the hot water zone, can I forget the aqustat, just to keep things KISS?

The first link shows a fairly clear wiring diagram, the Taco SR501 is the relay, power in, power out to circulator, I believe the top would be the hot water zone thermostat, to thr right is the aquastat either in the boiler or in the feed line, and then the thermostat connections for the steam zone. Right.....?
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