Latest Discussions : HVAC

MarkV

10:33AM | 09/26/01
Member Since: 04/05/01
32 lifetime posts
I received a Honeywell programmable thermostat as a gift, but I'm having problems with it. It is a CT3300, 24VAC unit, which is suitable for use with my oil furnace. I'm an engineer, currently working on electric motor design, and I was previously the service manager for a motor controller company, so I've got a good grasp of electronics and wiring.

When I wire it up, the heat will not come on. The fan works, as does the A/C, but the heat will not come on. If I hit the reset button on the White Rogers control section of my furnace, the furnace will come on for 1 heat cycle. After it shuts off it won't come on again unless I hit the reset button again. The furnace is a Brock, is about 4 years old, and worked fine with the old murcury Sears thermostat and my voltages all seem to be fine. To make things more interesting, I had the furnace serviced 2 days ago, and the service manager came by to see what he could do. He couldn't figure out why it didn't work, so he hooked up the Honeywell T8132 programmable thermostat that he sells, and it worked fine.

I've called Honeywell and they tell me that there must be something wrong with my system, and that I should have it checked out by a qualified technician. I told them that I had done that, and that the system worked with the other thermostats (the T8132 apparently has the exact same control board as the CT3300), but I was told that it must just be a coincidence. I've seen enough flakey boards to doubt this.

Does anyone have any suggestions?

p.s. I can't get a hold of the sales receipt, so I don't think I can return it. I may be able to exchange it, though.

Jay J

12:26PM | 09/26/01
Member Since: 10/26/00
782 lifetime posts
Hi MarkV,

Hopefully Harold will come along and actually have an answer.

But, in the meantime, have you retried the original thermostat? That may give you a clue. If the old unit 'operates' the same as the new one, I think you'll be in a better position to determine where the problem lies.

My best to ya and hope this helps.

Jay J -Moderator

PS: God Bless America!

TIM THE BOILER MAN

04:53PM | 09/27/01
Member Since: 09/17/01
8 lifetime posts
Have you looked at the wiring of the new thermostat since the service manager was there. He may have changed the wiring from the way you did it.
Tim

MarkV

10:13AM | 09/28/01
Member Since: 04/05/01
32 lifetime posts
Thanks for the prompt responses.

To clarify a few things, I have tried the new thermostat 3 times and have had the same problems. After each attempt, I have gone back to the old one, which has been working just fine. I actually did the wiring for the unit I got from the furnace service manager. I've labelled the wires and wired it up the same.

I think I'll try to exchange it this weekend and give it another try.

Any other thoughts would be appreciated, as always.

Thanks.




Post a reply as Anonymous

Photo must be in JPG, GIF or PNG format and less than 5MB.

Reply choose button

Anonymous

Post new button or Login button
Register