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Thread: lennox wiring
06-22-2005, 07:06 PM #1
On a Lennox HP29 condenser being used with a CBH17 blower coil with electric heat what is the purpose of the G1 terminal on the condensing unit. I know it has something to do with the heat but what exactly does it do and can you get away without using it....
06-22-2005, 08:40 PM #2
Where is this terminal? On the LV terminal strip? I've installed many HP29's and don't recall seeing it.There is nothing more frightful than ignorance in action....Mark Twain
06-22-2005, 08:57 PM #3
Its on the low voltage terminal strip.......its an HP-29-090 condenser.......
06-22-2005, 10:11 PM #4
Ahhhh 7-1/2 ton. I do only resi., but, I did go to Davenet and looked at the wiring diagram. It shows 'G' from the thermostat being wired directly to 'G' on the HP29 and 'G1' from the HP29 being wired to 'G' on the blower coil.There is nothing more frightful than ignorance in action....Mark Twain
06-23-2005, 12:20 AM #5
Yeap, G1 goes to G at the indoor unit.
Lennox HS/HP29, and L-Series units over 5 tons usually have a minimum on time timer in the outdoor unit.
I forgot the exact length of the time, but if the thermostat calls for cooling, and the call ends before the timer is up, the outdoor unit will continue running until the minimum on timer is satisfied. The outdoor unit will sends 24v back to G to keep the fan running during that time.
It comes in real handy when you are working on one up on a roof. Don't have to go looking for thermostats to turn the system on.If more government is the answer, then it's a really stupid question.