AC/Heater not working

[BadAC]

Good Morning, new to the forum...I have a problem with my AC/Heater

They are 2 different units.

Heater runs on propane, AC is electric (one in attic, other outside)

Okay so they were both working a few weeks ago, now non of them are working.

Checked the following:
Circuit breakers at panel box are good,
Changed the fuses on the AC unit
replaced battery on Digital Thermostat (hunter mod 44110)
Checked to see if there is voltage going to the units (voltage stick) there is voltage going in on both units.

Thermostat:
Lowered temp to min and max and nothing happens. The thermostat does go "click" like its going on, but nothing is happening. I also checked the wires going from the Thermostat to the Heater, I do not detect any voltage there, don't know if any needs to be present.

also none of the fans come on.

Does anybody have a clue

[HayZee518]

check the control circuit transformer - probably is 24 volt. 120 volts for the primary - 24 volts AC for the secondary. might be a fuse in the secondary. let us know what you find.

[BadAC]

Am I suppose to be getting any sort of voltage coming out of the Thermostat (the wires). I check and I am not getting anything. I hear the "click" (probably the relay in the thermostat) go on but I have no voltage going to the AC unit (this is from the Thermostat to the Heater). Also where would this "control circuit transformer" be located. Thanks for the help, going to Lowes to see what they have.

[HayZee518]

if the thermostat is of the bi-metallic variety when the contacts close you will hear a click. it could also be a magnetic reed switch that closes when the magnet moves near the glass tube. for the thermostat to work you must have a voltage going into it and a voltage going out! look for a control panel near the compressor unit. you mention there are two parts - one in the house, this would be your evaporator coil and another outside. This is the condensor and compressor section.

[BadAC]

Found the problem, blown 3A fuse in the System itself (in the attic) . Now here is what is happening.

System says max fuse rating 5A, It had a 3A and that is what I replaced it with. Now the fan runs but when I turn on the AC the fuse blows after about a minute. Now I'm probably gonna have to check the wire for mice damage.

Thanks for the help, will continue to troubleshoot

[HayZee518]

the 3 amp fuse is probably too small. the control circuit's relays draw a small amount of current but added together will approach 5 amps. if the 5 amp fuse still blows then go looking for dried or broken insulation in the thermostat's line. some fuses are made to be a slo-blo there's a spring inside that opens readily when a true overload occurs but then allows current to flow when approaching the fuse's rating.

[BadAC]

THis things got automotive fuses, Replaced fuse with 5A, still blows when the AC kicks in. However it does not blow when the Heater comes on. I'll check the wiring leading to thermostat for any signs of damage. Or it might be the wiring going to the AC that is the problem.

Thanks HayZee for the help

[HayZee518]

before you go checking the wiring - take a look in the condensor unit. look at the compressor contactor. there should be a disconnect at the unit. shut it off and open a cover. test for power at the line side of the contactor with a good meter - not a voltage sniffer. you don't want power here at this stage. if the contact's crossbar is accessible, push it up from the bottom to see if it's free to move. if it moves ok, then, restore power to the unit. CAREFULLY push up on the contactor's movable part again with an insulated thing like a dry stick of the compressor starts and/or the condenser blower motor then the problem could be the operating coil of either the blower motor -or- the contactor for the compressor. I kinda think it might be the coil of either contactor because even though the wires might be tempting to mice, the coil is the next thing in the weakest link.

[BadAC]

Thanks, it's dark outside so I will check this when i get home from work tomorrow. Thanks for all the help.

[HayZee518]

if you have yahoo im add me to your list - buffalo12980 - then when we go checking this unit it'll be easier to chat instead of instant messages through the forum.