Model 765-5856 pilot lit no main burner lighting

[tech528]

120vc present at transformer,24 vac coming out of transformer.120 vac present at bottom of thermostat transformer,no 24 vav coming out ,blower motor runs when switched to on,and when switched to a/c.main burner assembly wont.ignite

[Robert]

Not sure what you're calling a thermostat transformer.

Clarify your statements and better clarify what is wrong.



Thanks,
Robert

[tech528]

standing pilot burning,turn up thermostat to call for heat,nothing happens. transformer is sending 24 vac to terminal board,no 24 vac after that.There is a relay that takes 120 vac to the bottom to power blower motor. Then it 's suppose to apply 24 vac to the rest of the 24 vac system,the gas valve and the limit switch

[Robert]

The 24vac should go from terminal board to t-stat, then on call for heat go to the limits and on to gas valve.


Once chamber heats up, fan/limit switch closes to turn on the blower motor.


IF you get 24vac at terminal board, but not at t-stat, check wiring in between.




Thanks,
Robert