Reversed Thermostat operation. Never have seen this.

[rockdad]

Coleman 7975A56 sn# 029065527. The blower housing mounted control box has been added to operate AC at some point.
OH.....Nice site by the way!

Dirty power to the trailer plus following up on who ever was in this unit before me. Sequencer & switching relay were smoked. Bad T-stat, Bad 18-2 stat wire and broken high limit switch.

Relay was an RBM 6313-228 replaced with Steveco 290-293Q.
Sequencer was a Thermodisc 7670-307 replaced with WR 24A34 series. Replaced limit, t-stat & wire.

When all said and done to get AC you turn stat UP and then DOWN for heat. I have checked control box wiring, wire for wire against the schematic....numerous times.

Works perfect only backwords. What did I miss?? Thanks for your help.

[Robert]

Hi,


Set two switches on front of control box to COOL and AUTO .

At t-stat, IF it has switches, set to HEAT and AUTO .


Then set for temp desired.


In winter, change switch on box to HEAT.



If wired correct, should work fine. The a/c is controlled by reversing relay inside box.


That is how a 2 wire system operates.


Thanks,
Robert

[rockdad]

Robert,
No switches on stat. Have previously done what you posted. As it is now, Box set to cool and auto. Will not bring AC on unless you turn stat UP. Turns off when turned backed down.
Likewise in Heat setting. Turn stat DOWN and it will fire. Turn stat back up and gas valve will drop out.

I brought in one of my Techs to recheck my work. He's not seeing it either but where else can the fault be?

[Robert]

Is the t-stat an actual 2 wire t-stat ?

If so, my thoughts are either the replacement sequencer and /or relay are not correct or they are wired wrong.


When you set the switches at box to COOL and AUTO, a/c should immediately come on.


As you raise the temp lever at t-stat higher, the a/c should go off.


Whenever the home temp goes above t-stat setting or gets even with it, the a/c comes back on.



Wherever t-stat is set, temp in home above that will energize a/c, temp below that will turn a/c off.


Thanks,
Robert

[Robert]

Go here to see correct sequencer and blower relay:

http://www.mobilehomerepair.com/ColemanAC.html



Blower Relay # 6313-2281


Sequencer (Reversing Relay) # 7670-3071




Thanks,
Robert