Trane HV unit GRAA60PDJBON......staging ?

[maxster]

DATED A98 on the s/n 100% outside air 2 speed SF ..HI contactor..LO contactor.2 exact burner sections one in front of the other then the air goes into the ducted garage space..like this OA>dampers>fan>burner>burner >>>>into the space all on the horizontal curbing of the roof.with LO fan i can get the W1 but the mystery here is with HI fan W1 runs,but to get W2 i have to jump W2 then the TR trips 24V on its CB...after 30 seconds.does HI fan get 2 burners or just 1 thinking the CB trips. might it be just the furthest burner away in HI speed? the call for W1 or W2 were jumps right at the rooftop panel but had to use 2 jumps to get W2 and the HI fan...thanks. i have Trane here hunting down a relay board with K4/K8 glass relays missing on it and everything on the terminals and a sequence of ops ...its 40F here now no swet but looking for sequence NOTE on that CB trip,if i disconnect 24V at one Honeywell ignition mod its ok(and read the wire 24v to ground to verify a call is there) reconnect it and the CB trips after 30 sec stamped on this K4/K8 relay board is Dual Tri Connection Board terminals on it R2,2W1,2W2,3W1,3w2 back to the question if i lost you are there 2 burners in HI fan...............:couch:

[jayguy]

Relay K12 switches the low speed to high speed when energized. Depending on how it is wired (some of the other model numbers would help indicate this), K12 is either energized on a call for cooling (by a separate cooling stat) or it is energized by a manual high/low switch (also installed separately). The heating stages are not wired to switch the fan.

The second stage of heat is usually not from a thermostat but they are usually run at the same time especially since they are modulating gas valves. I have seen many that had the 2nd stage turned on based on a time delay or outdoor air temperature but those are units that were field modified.