LGA120SH1Y

[hvac wiz 79]

i am very familiar with these units but seen something today that sort of has me frazzled ... y1 & y2 inputs energized, no errrors & even checked safeties which are all closed & no voltage drops (27.25 i think) no voltage to comp. cont. 1 or 2 .. totally ASSuming internal communication ... i moved over dip switches shift & test to simulate same inputs ... at first nothing .. even more odd the LED display acted funky .. both decimal points illuminated as opposed to the one i am accustomed to seeing .. moved switchs away then back .. scrolled through 2 ttimes no go .. 3rd time .. poof .. comp one energized then next stage initiated & it came on .. lol .. moved back switches into normal demand & presto it works .. lol ..any idears ?

[techrider]

Any chance this unit has the novar/lennox integrated control.

[hvac wiz 79]

M1-3 if im not mistaken

[techrider]

ran into some issues with interface boards that as of yet no one has been able to explain. I swear there are ghosts or gremlins in some of them. I've questioned some control guru's and and they just shrug and scatch. Good Luck.

[master mechanic]

Was the blower LED and OCC LED input lights illuminated on A-55 circuit board when the problem occured. Do you have economizer on this unit? Did you turn off disconnect before entering test mode?

[hvac wiz 79]

yea G & occ were lit, along with y1 & y2 .yes there is an economizer. but oas light was not lit obviously as it was 100* & such .. no i did not turn unit off b4 testing it because i was hoping to find exact issue b4 reseting it.