Class II Foot Mount 120V Input and 24V Output, 40VA Transformer (Packard PF12440)
40 VA120V24V
$31.49
Control transformers
The transformer makes the 24 V that runs your thermostat and controls. Match the input volts, the 24 V output and the VA rating.
- 1Input volts: must match your supply, like 120 or 208/240
- 2Output: 24 V for most home systems
- 3VA: same or higher than your old one
Class II Foot Mount 208/240V Input and 24V Output, 40VA Transformer (Packard PF22440)
40 VA208/240v24V
$30.99
Foot Mounted 120/208-240V (Primary) 24V (Secondary) 40VA Transformer (Packard PF42440)
40 VA24vFoot
$36.99
Foot Mounted 120/208/240 Vac Transformer with 9 in. Lead Wires and Plastic End Caps (Resideo AT140B1214)
40 VA240V27 V.O.C.
$44.49
Multi Mount 120V (Primary) 24V (Secondary) 40VA Transformer (Packard PM12440)
40 VA120V24v
$50.99
Multi Mount 208-240V (Primary) 24V (Secondary) 40VA Transformer (Packard PM32440)
40 VA24vMulti
$48.99
Transformer, 40VA, 60 Hz, 120/208/240V Primary, 24V Secondary, Foot Mount (White Rodgers 90-T40F3)
40 VA208V24v
$28.99
Transformer, 40VA, 60 Hz, 120/208/240V Primary, 24V Secondary, Multi-Mount (White Rodgers 90-T40M3)
40 VA240V24v
$55.49
Transformer, 40VA, 60 Hz, 120V Primary, 24V Secondary, Foot Mount (White Rodgers 90-T40F1)
40 VA120V24v
$36.49
Transformer, 50VA, 60 Hz, 120/208/240V Primary, 24V Secondary, Foot Mount (White Rodgers 90-T50F3)
50 VA208V24v
$61.99
Foot Mount 120/208/240/480V (Primary) 24V (Secondary) 75 VA Transformer (Supco SXT79R)
75 VA208V24v
$100.49
Foot Mount 120/208/240/480V (Primary) 24V (Secondary) 75VA Transformer (Packard PF52475)
75 VA24vFoot
$96.49
Multi Mount 120/208/240/480V (Primary) 24V (Secondary) 75VA Transformer (Packard PM7541MCB)
75 VA120/208/240/480V24v
$102.49
Transformer, 75VA, 50/60 Hz 120/208/240V Primary, 24V Secondary, Foot Mount (White Rodgers 90-T75C3)
75 VA120V24v
$131.99
Numbers rubbed off your old part?
Ask us to find it
Send us your unit's model number and a photo of the plate. A real person will find the part for you.
What it does
It steps line voltage down to 24 V for the thermostat, contactor coil and control board.
Why they fail
A shorted thermostat wire or a bad part on the 24 V side can burn it out. Find the cause before you swap it.
When to call a pro
The input side carries line voltage. If you are not sure, a licensed tech can find the short and replace it. Read the guide.