[ttx3]

My AC fan stopped working a few days ago. I have checked a number of things and replaced the capacitor and contactor. The fan still didn't run. I then replaced the fan motor and the fan now starts and runs but shuts off after a minute or so. The compressor is running and I have checked that the unit is getting 240v. What else could I check?

[bitters]

I suspect the capacitor might be wired wrong. Is the new motor a 3 wire or 4 wire? Fan model number would help.

[ttx3]

Thank you for responding.It is 4 wires. The old motor was 3. 2 are going to the 'fan' on the capacitor and the other 2 are going to the contactor. The fan starts and runs in high speed but turns back off after 1 minute or so. I let it cool down and tried it again with the same behavior.

[bitters]

Ok, when you go from a 3 wire to 4 wire motor, you need to use a separate single cap. It sounds like you using the duel cap. Look on the cap and find the mfd, it should look like 35/5. You will want to use the smaller number, to get a new cap.

[ttx3]

Is a new single cap the only option? I thought I could use the duel cap. Not a problem to pick up a single cap.

Model number of the fan is S1-FHM3729. Dual cap is 55uf/7.5uf

[bitters]

Yes that is your only option, with the duel cap the motor is tripping off on overload. The bottom diagram shows how you want to wire it. Let me know how it turns out. Ok, 7.5 is what you need.

[ttx3]

Thank you very much. I will get this done tonight and let you know. The diagram helps a ton. Another person told me I could connect one to the 'fan' portion on the dual cap, the other to 'c' on the dual cap, and only connect one wire to the contactor. The remaining wire could be capped and not used.

[ttx3]

Well, as luck would turn out, I didn't make it in time to pick up a new single run contactor. I did get the fan to work. Turns out, 2 of the four wires are actually the same. I connected only 1 to the dual run cap and the other 2 to the contactor. I 'capped' the remaining wire and everything the fan runs great. I think I could have also connected that remaining wire to the 'c' terminal on the dual run cap. Would have had the same effect I think.