Wiring for ra117a stack relay

daveanna

I'm replacing my original stack relay with the updated replacement part ra117a.but I'm not exactly sure how to connect the wiring inside. I can't get 24 volts to the TT wires to the thermostat and it's not working at all. HELP!!! 

Jamie Hall

T-T is not looking for 24 volts. All it cares about is whether it is seeing an open circuit (burner off) or a closed circuit (burner on).

STEVEusaPA

That primary control is outdated 1940's technology (and expensive). It should be replaced with something modern.

HVACNUT

It's 2023. Why on earth are you STILL using a stack primary? Is it because the burner is just as old? 
Do the thermostat wires go the stack relay or to a different relay? TT is usually jumped in the primary but don't do that if you're not sure.
Is the helix in step? (I can't believe I remembered that. But don't ask me what I had for breakfast.)

Steamhead

STEVEusaPA said:

That primary control is outdated 1940's technology (and expensive). It should be replaced with something modern.

This. @daveanna , can you post some pics of the unit this is mounted on? Also, where are you located?

EBEBRATT-Ed

I like old stuff but it's long past the time to get rid of any stack switch

120 volt power (after you go through all limit controls goes to terminal 1 (hot) and terminal 2 (neutral). Terminal 3 goes to burner motor. Terminal 4 goes to ignition transformer.

Sometimes you will find the burner motor and ignition transformer both on terminal 3.

Thermostat terminals are r-Red, w-white and B blue for a three wire thermostat.

For a two wire stat use r & w

BUT YOU NEED TO GET RID OF THAT CONTROL WITH IT'S 90 SECOND SAFETY TIMING IT IS FAR OUTDATED.

If your unsure what to do get some professional help.

And oil or gas burner can cause serious problems if not properly installed and serviced