Jumping out Lennox gcs11 953 250

[iceage]

Doing pm on rtu's. I came across 4 older Lennox rtu's gcs11. Not sure how to jump these out. From the looks of it dc voltage is run into a control panel and then over to another panel in comp section to what is labeled A1 logic panel. This controller has terminals labeled sen,stat,24vac,econo,and heat cool at top. Not sure where I would be able to jump this unit to test. Schematic not helping. I am use to seeing terminal strip with r y w g etc

[toocoolforschool]

It sould have a test pin or something of that nature to run through the cycles, don't quote me though.

[ascj]

If you pull the stat wires off the logic panel. Terminals 1-5. Then if you jump terminal 2 to 5, all heat stages will run. If you jump terminal 2 to 4, all cool stages will run.

Here's the pdf for you....

[DPinst]

THe simulator is the best option for servicing the w-973 panel.

[2sac]

How can you do a PM without cycling the unit from the t-stat? T-stat is part of the system.

[iceage]

If you pull the stat wires off the logic panel. Terminals 1-5. Then if you jump terminal 2 to 5, all heat stages will run. If you jump terminal 2 to 4, all cool stages will run.

Here's the pdf for you....

Thanks asjc, that information really helped.

2sac, the stats are checked on pm's, but initially when on rooftop, units are jumped out ot test operation. Thanks all for your help.