My Fan Delay relay started shutting my blower fan on and off very erratically, so I ordered a new one and went down to the local motormart and picked myself up a relay so I could bypass the original circuit board with the imtegrated time delay for the time being. Anyways The fan works as it should now and the heat pump comes on but the auxiliary heat coils wont come on now. I used the ground and green (t)on the coil of the relay and the reds (1 and 3) on the switched part of the relay. I taped up red (a) white (6) and blue (ground 4). Now Im no wiring expert by any means, but If I look at the diagram it shows me 6 and 4 get connected via a relay, but if i check the white wire (6) it has 24 volts to it. so is this right? can you connect a hot wire and ground together? (i tried and the aux heat comes on) so Im just wondering what they are doing in this diagram and if i shouldnt go get me a dpdt relay instead of the spdt relay so i can make that connection via a relay if it is right. My heat pump will more than likely get us thru till new board gets here but Im just curious now. Sorry if this is confusing and thanks for the help.
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Help me with this wiring diagram (air handler Time Delay)
- Thread starter ls1jay
- Start date
nehog
Well-known member
You need either two relays or one relay with dpst contacts. The existing controller has two sets of contacts, so you must emulate that configuration.
nehog
Well-known member
As I see it that second set of contacts energizes a remote relay (probably a thermal type) to turn on the elements.
Thank you! Do you know the reason they are connecting a hot (25v white wire) Directly to ground with that set of contacts. My knowledge in ac wiring is very limited and that just seems odd to me so im curious.
It is a common practice to ground one side of control transformer secondary. They are grounding the BL wire to keep onside of the transformer secondary at zero reference to ground.
The Red wire is ungrounded and will be 24 volts in reference to ground.
Note three points to a fuse in the red wire, this protects the transformer from overload or short circuit.