Gas and Oil Home Heating Furnaces - Frozen A/C Unit

Okay....attic unit still not running when I turn on thermostat. I've reset breakers at panel - none were tripped. I've looked for a reset button at attic unit and see nothing. My outside unit runs when I turn on the thermostat but nothing inside. Coil unit looks clean and also blower unit. It seems something is tripped due to the power surges but can't figure out how to reset it. Postponed service call until I get more advise. Any suggestions? Thanks.

On some attic units there is a separate breaker mounted next to unit,have you checked for this? Is your t-stat a Programmable one? You can take the outer cover(s) off of t-stat and turn OFF power to your Furnace/Air Handler as this will turn off power to the t-stat also. Then disconnect the red,yellow and green wires and tie them together and wrap with electrical tape.Then turn the power back on,this will by-pass the t-stat and if everything works,replace the t-stat.If your t-stat has a Heat/Cool/Emergency/Off and Fan On/Auto, turn first switch to Off and Fan switch to On.Does your unit have a Secondary drain pan and if so, is there water in it? Write back when you've checked these and we'll go from there.You can also turn off power to Air Handler and remove panel where t-stat wires enter and look at ALL wires and electrical components for Burnt markings and/or broken or loose wires.Take Care.

CoolBreeze---P.S.-- If you will click on reply when writing back, it will continue this thread and keep all replies together,instead of starting a new thread.

Actually it sounds like he has power to the Air Handler, otherwise, no 24 volt to turn on the condensing unit, which he says runs when demanded. It sounds more like a fan relay or fan motor failure.

You can have 24 volt low voltage to the Condensing Unit and none to the Fan/Blower in the Air Handler. If the A/H side of t-stat (Red to Green) does not make, this would be the result. Since it's easier to check t-stat than A/H components in the attic and this being the last known place of low voltage,this would be best place to begin IMHO. Power surges also can wreak havoc on Programmable T-Stats. Take Care.

CoolBreeze

I by-passed the t-stat and still only outside unit came on. When I reconnected the red, green, yellow wires to t-stat the outside unit no longer comes on even after hitting the reset button on the outside unit. Checked the garage panel for tripped breaker but nothing tripped.

I see no separate breaker at all.

Secondary drain pan has no standing water. Only a small amount of standing water in primary drain pan.

Removed panel on Air Handler and can see no evidence of burnt markings on any electrical components. All look very new.

Someone suggested the 'starter capasitor' (not sure of the spelling) at blower unit could have burned up. If so, can this be purchased at some place like Lowes or Home Depot?

Let me know what's next. Thanks.

Hi Sandy,

Do you have a Multi-Meter to check for voltage and continuity on your units circuits? It looks as though you will need to do this in order to locate the breaks in your units circuits. With all those power surges, you could have multiple problems.If you do and feel confident in your abilities, we can guide you in where/how to check, if not, you'll need to call a Contractor.Take Care and Best Wishes.

CoolBreeze