HEAT AND AIR WON'T WORK

[DISPATCHER42]

LAST THURSDAY MY AIR COND QUIT WORKING.THIS IS AN OUTSIDE UNIT. NO HUMING OR ICING.FURNACE MODEL COLEMAN 3500A816. CHECKED BREAKERS NOT TRIPPED, CHECKED FOR VOLTAGE ALL SEEMS OKAY EVERYWHERE. TRIED TO TURN FURNACE ON NOTHING PUT FAN ON NOTHING CHANGED OUT THERMOSTAT 2 WIRE IT WORKS NOTHING ELSE DOES.HEATER WENT OUT FEW MONTHS BACK SERVICE TECH CHANGED A FAN RELAY HEAT SENSOR IT THEN WORKED FINE. I DO NOT HAVE AN OWNERS MANUEL AND YOUR PARTS SITE DOES NOT LIST THIS PART COULD BE CALLED BY ANOTHER NAME. COULD YOU HELP

[Robert]

Hi,

Where you said you changed out t-stat 2 wire and it works, what are you saying works ?

Little confused there with your other statements.


Does the inside blower work with fan switch in the Fan ON/Continois mode ?



Thanks,
Robert

[DISPATCHER42]

THE T STAT CLICKS BUT NOTHING TURNS ON. NO THE BLOWER DOSEN'T COME ON WHEN THE FAN SWITCH IS ON CONTINUIOUS. NOTHING COMESW ON. THERE IS NO HUM INSIDE FURNACE OR OUTSIDE AIR UNIT

[Robert]

You need to first check the breakers in home panel and inside furnace to ensure none are tripped.


Then test transformer in the a/c control box inside furnace.


Test PRIMARY-LINE side for 240 VAC and then if you have 240 VAC, test SECONDARY-LOAD side for 24 VAC .


IF you have that also, trace red wire from transformer all the way to t-stat for any damage, loose connection, etc.. .


Sounds like you lost the 24 volt low voltage circiut.


Thanks,
Robert