Radiant Heating

Dwayne1010December 15, 2011

I am replacing Direct Spark Controls on Radiant Heaters at the Shop. Some controls are 24V as the gas valve is 24V. Some of the older one's are 120V as the gas valve are 120V. The 120V units get 24V from Thermostat that runs through a step up transformer to 120V and then into the control. In an effort to make all of the controls the same. Could I wire it from the Thermostat 24V to a 24V control and take the gas valve leads from the control and run them through the transformer and then to the gas valve? (To test I wired the gas valve directly to the transformer and lite the unit manually and it seemed to be OK) The spark control is 15 seconds on 15 seconds off for three trials before cut-out so it seems like it would work fine. Does anyone see any issues with that method? Also I noticed that the electrode and sensor are so close to the flame that they glow red hot. Is that to close or are they designed to withstand that much heat?. I also have read that a ground should be run from the mounting screw of the electrode assembly back to the unit. I noticed that whoever converted them to direct spark did not do that. Would that lack of ground cause harm to the control?

I am thankful for any assistance that someone might give to one or all of my concerns. Thank You, Dwayne

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Step up transformer that sounds odd. have you worked on this stuff before? Why do you want to change the way they are set up now?

    Bookmark   December 16, 2011 at 1:29PM
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Yes I have. Not a Pro but the Pro's replaced Four Bad Units in another building (at 800 a Pop+ Installation) that I took the " Bad One's" and cleaned the pilot tube out with a Q-Tip and they work just fine now. I don't use terms like "You All" because there are many reputable guys out there.
Transformer looks like a 24VAC transformer reversed (where 24V is the primary) and is feeding the module 120 volts but not the true 120 volts that they were made for.
I would like to convert them to the same 24 V DSI's. If that means changing them to 24V valves then that is what I will have done. That's one less thing to go bad.
Six bad 120v modules tells me something is wrong with that set up.
I can't see any reason to spend $3000 + Installation when 6 modules will run around $800 + Installation. Can anyone?
I know on my furnace after the igniter lights the flame and the flame sensor shuts it off neither glow or continue to glow red hot. This leads me to believe that the spark and sensor assembly may be to close to the flame.
When servicing anything I believe in looking for the underlying reason of problem to begin with and not just getting it to work. Thanks for your concern for safety

    Bookmark   December 17, 2011 at 10:36AM
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