I know there are a few A/C wizards here on the forum. My AC air handler has a fan relay that has had a connection fry twice now. I replaced the relay about 3 months ago, putting a new terminal female spade connector on the affected lead/wire. The photo is of the old relay and the connection that burned off the relay was #5. Night before last we came home to a hot house and I found the wire to the number 6 connection had burned off the spade connector on the relay - the relay terminal was OK though, unlike the first time when the #5 spade was burned off and the housing was melted.
This time I was able to replace the lead/wire and the spade connector and we were back in business. The air handler/heater is a Heil circa 1984. The condensing unit and evaporator coil are less than a year old. The heater, fan and heat exchanger were all in very good condition and the AC guy said it didn't need to be replaced. The fan motor and squirrel cage are new. Can the relay be faulty to cause this and if it's not that any idea why the terminals are frying and what I can do to prevent it? Would loose connections cause it? I found the overflow drain pan level shut down wires loose when the AC quit about 6 mos ago. I checked all the wires and wire nuts that were accessible. Do I need to replace the heater - air handler? I appreciate any help.
Thanks
KAHR PM40/Hoffner IWB and S&W Mod 60/ Galco IWB
NRA Endowment Member, TSRA Life Member,100 Club Life Member,TFC Member
My Faith, My Gun and My Constitution: I cling to all three!
The loose wires on the overflow safety would not cause 5 & 6 to burn because they are low (control) voltage. 2, 4, & 5 are high voltage. I would look for a loose wired at both the relay as well as where they terminate from each of those. Short of a loose wire, most likely the relay. Don't worry about 1 & 3 as they are low voltage
RPBrown wrote: Thu May 31, 2018 1:11 pm
The loose wires on the overflow safety would not cause 5 & 6 to burn because they are low (control) voltage. 2, 4, & 5 are high voltage. I would look for a loose wired at both the relay as well as where they terminate from each of those. Short of a loose wire, most likely the relay. Don't worry about 1 & 3 as they are low voltage
Thank you, RPBrown. The photo is of the first one that failed and was original to the unit c.1984, so I figured it just failed. The current relay has no visible damage, rather the wire burned at the crimp on the female spade connection to terminal 4. I ordered a back-up relay as a precaution. I checked all the spade connections and wire nuts, but will recheck. Looks like I may have to follow the high voltage wiring out completely to make sure everything is tight.
KAHR PM40/Hoffner IWB and S&W Mod 60/ Galco IWB
NRA Endowment Member, TSRA Life Member,100 Club Life Member,TFC Member
My Faith, My Gun and My Constitution: I cling to all three!
RPBrown wrote: Thu May 31, 2018 1:11 pm
The loose wires on the overflow safety would not cause 5 & 6 to burn because they are low (control) voltage. 2, 4, & 5 are high voltage. I would look for a loose wired at both the relay as well as where they terminate from each of those. Short of a loose wire, most likely the relay. Don't worry about 1 & 3 as they are low voltage
Thank you, RPBrown. The photo is of the first one that failed and was original to the unit c.1984, so I figured it just failed. The current relay has no visible damage, rather the wire burned at the crimp on the female spade connection to terminal 4. I ordered a back-up relay as a precaution. I checked all the spade connections and wire nuts, but will recheck. Looks like I may have to follow the high voltage wiring out completely to make sure everything is tight.
Another possibility is either a power surge (not likely though) or a motor that is over amping but that would probably kill the relay before the wiring. Then if its 1984, could just be old brittle wiring. Hard to diagnose by a picture but those are the possibilities.
