SS MAYFLOAT
Admiral
- Joined
- May 17, 2001
- Messages
- 6,372
Please note that not all contactors even though may have the same specs, are different.
A couple of years ago, I changed all the contactors on 5 HVAC John Zink units that are electric heat. I replaced them with 3 pole - 40amp - 24volt Copeland brand contactors. I went by recommendations from other service techs about their dependability. Shortly afterwards, I had problems with the low voltage transformers tripping their breaker. I would check each contactor to see which ones were shorted. Would never find any shorts. I'd reset the unit and it would be fine for a couple of days and then trip out again.
Last friday, I got called as the front of the store was at 50*F. All 3 dining room units were tripped out. Outside was 15*F with 30mph winds with blowing snow. Wind chill was -5*F. After 3 hours of trying to find all the problems, I got all 3 going on only one stage of heat only by unhooking the second stage heat.
I go back to my supplier and ask what is up with these contactors. All I was told was "They should work, that is what those units call for. So, I pick up 5 Honeywell contactors and install them. I hook up all the stages. First stage kicked in without any problem. However when the second stage went to kick in, the contactors tried to pull in, but wasn't able to.
I then decided to check the resistance on the coils. The Copelands coil read 4.2 ohms and the Honeywells read 5.0. I leave the store and go to another distributor (RSC) with my meter in hand. Their brand is Totaline which is a Carrier company. I opened up their contactors and measured the coils that read 7.2 ohms. Oh yes, these are the ones I need. I replaced all of the contactors with this brand and now the HVAC units are working excellent. The amp draw on the low voltage transformer is about 35% less than what I had put in several years ago.
My school boy assitant argued with me that it had to be something else causing the excessive load. I let him spend 8 hours yesterday figuring it out with no luck.
BTW, I had an old Honeywell contactor on my truck that said "Made in the USA". The coil on that one read 7.4 ohms. The Copelands, Honeywells, and Totalines are made in China. Go Figure:facepalm:
A couple of years ago, I changed all the contactors on 5 HVAC John Zink units that are electric heat. I replaced them with 3 pole - 40amp - 24volt Copeland brand contactors. I went by recommendations from other service techs about their dependability. Shortly afterwards, I had problems with the low voltage transformers tripping their breaker. I would check each contactor to see which ones were shorted. Would never find any shorts. I'd reset the unit and it would be fine for a couple of days and then trip out again.
Last friday, I got called as the front of the store was at 50*F. All 3 dining room units were tripped out. Outside was 15*F with 30mph winds with blowing snow. Wind chill was -5*F. After 3 hours of trying to find all the problems, I got all 3 going on only one stage of heat only by unhooking the second stage heat.
I go back to my supplier and ask what is up with these contactors. All I was told was "They should work, that is what those units call for. So, I pick up 5 Honeywell contactors and install them. I hook up all the stages. First stage kicked in without any problem. However when the second stage went to kick in, the contactors tried to pull in, but wasn't able to.
I then decided to check the resistance on the coils. The Copelands coil read 4.2 ohms and the Honeywells read 5.0. I leave the store and go to another distributor (RSC) with my meter in hand. Their brand is Totaline which is a Carrier company. I opened up their contactors and measured the coils that read 7.2 ohms. Oh yes, these are the ones I need. I replaced all of the contactors with this brand and now the HVAC units are working excellent. The amp draw on the low voltage transformer is about 35% less than what I had put in several years ago.
My school boy assitant argued with me that it had to be something else causing the excessive load. I let him spend 8 hours yesterday figuring it out with no luck.
BTW, I had an old Honeywell contactor on my truck that said "Made in the USA". The coil on that one read 7.4 ohms. The Copelands, Honeywells, and Totalines are made in China. Go Figure:facepalm:
