MilliVolts, not 5v, 12, 24v for gas valves?

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ColeR

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Ok, there is a fireplace insert store I have been talking to about getting the old gas valves that they throw away when they replace a old fireplace units. I said I would give them a 6pack of home brew for pulling these valves that are headed to the scrap yard, one man garbage is another gold… I’m not buying them, as they said I could go though the garbage and pull them myself, but I just don’t have the time. Kind of a thank you for giving my their garbage, that sounds weird.

But now I have the problem of he said they open and close on MilliVolts not 5v, 12, 24v voltage that I am use to.

I plan on using the BCS-460, and I think the output is 5v, so now I need a relay and transformer to get down in to the Millivolt range? Is this possible?

If so any good links? To the products I will need…

CR-
 
Those valves are activated by the millivolt output from a thermocouple in the pilot flame of a gas operated appliance. This is DC so you would need a rectifier but no transformer would be required. It is conceivably doable but I do not give advice on how to modify gas equipment for fear of incurring liability. In fact I advise against such modification and would not do it myself. The nature of your question suggests that you should not do it either. If you are bent on this course get someone with experience in these things to help you.
 
I have some experience with millivolt gas systems. A lot like using a 5v signal to trip a relay that controls a 220v heating element, you can use a relay to control a millivolt system. Your board will output a 5v signal when it wants to call for heat, which will trip a relay that would allow the millivolt thermopile signal to turn on the gas valve. The thermal pile generates a few hundred millivolts when it is heated by the pilot light, one of the two wires goes directly back to the gas valve and the other typically goes through a series of switches before it returns to the valve and trips the gas solenoid. For instance in a pool heater, it goes to on/ off switch, thermostat, water pressure switch, overheat switch. So the signal from the thermopile only makes it back to the gas valve to turn on the gas if... switch is on, thermostat calls for heat, the pressure switch sees the filter is running and no overheat is detected. You would have one lead going back to the gas valve and the other going through a relay that would only allow voltage when the brewtroller sent 5v to the relay and "called" for heat.
 
Fireplace gas valves usually have a low BTU output capacity. Before you bolt one on a burner make sure the valve capacity is close to the burner output. The valves are adjustable for 10 to 15" wc, LP, about a pound of pressure. Your burner may need to operate at a higher pressure than a pound. To Rube Goldberg a gas product designed for a certain application probably isn't the best thing to do......The caveats: To each his own, till death do you part, self annihilation not covered under this policy, speed kills.
 
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