Coleman 3500A816 Furnace with AC

[tlmarshall]

I've got a problem. The symptoms are that the AC did not always come on when it should have and I would have to fiddle with the thermostat to get it to come on. It would shut down like it should. I tried replacing the thermostat but that didn't help.

Then one day I got it to come on and then it would not shut down it got very cool in the trailer and I finally had to flip the switch to the standby position to shut it down. It has been that way every since (about a month and a half). In that time I have tried replacing the blower relay switch (#3110-3301) and the T-stat Reversing Relay for 2 wire A/C (# 3110-3311A).

The other night it got chilly enough I decided to run the furnace for a short time and that is when I discovered that the furnace won't come on. It usually has a delay but after about 20 minutes the fan had not come on. I don't know if the element heated as I didn't have time to pull it apart and check it.

Does anyone have any suggestions? Please help I really can't afford to replace this thing now.

[Robert]

Hi,

When it doesn't come on, is the inside and outside units BOTH not coming on ?


When it would not shut off, was it BOTH units inside and outside not shutting off ?


Aside from parts already replaced, the only ones left in the circuits are:


System Switch # 3110-3321 @ $9.68

Fan Switch # 3110-3331 @ $9.67

Sequencer # 3115-3571 @ $39.99


Shipping = $6.75 to $12.00 depending on order.


The system and fan switch can play into the a/c problems.

The sequencer alone controls heating elements and blower motor for heat mode.



Did you replace t-stat with same type ?



If interested in the above, please add to cart and order through PayPal or call toll free to 1-877-263-7860 and charge to Visa or Mastercard.



Thanks.


Take care and best wishes,
Robert

[tlmarshall]

I have since found the problem with the heater. In trying to figure out what was wrong with the AC a switch that shouldn't have been moved got moved.

Not coming on yes both both units don't come on.
Not shutting of. My son the electrician says that although neither fan (inside blower fan & outside the fan on top of the unit) shuts off the compressor does cycle on & off. He can tell this by the vibration in the tubing coming to the inside coil and the fact that the coil doesn't ice up.

The thermostat was not for the 2 wire but wiring was modified to work. Although the AC was still not kicking on when it called for it.
This was before I had not found a vendor for Coleman parts, just a couple local electricians who happened to have gotten a Coleman brand thermostat in stock at the time.

[Robert]

Hi,

Do you have the t-stat set to HEAT and AUTO for a/c mode ?


The furnace switches would be set for COOL and AUTO.


For cooling, the indoor blower is controlled by the blower relay in a/c control box.


The outdoor condenser fan is controlled by t-stat and contactor in the condenser unit.



Would need to test the entire low voltage circuit to find fault(s).


Thanks,
Robert