Who has a Supco Hard Start on their A/C unit?
I recently purchased the Supco SPP6 hard start capacitor and I have a couple questions for those who have this unit and have also installed it themselves. First off, even though I've read on this f...
Forum Discussion
Confusing, Huh?
SPP6 is the right size and SUPCO will agree with that. There's debate whether it should be SPP6 or SPP6e. One of our resident RV tech gurus, Chris Bryant, prefers the "e" version but allows that SPPCO will recommend the SPP6.
Do you know that your Dometic A/C does NOT already have a Start Assist? I'm not an engineer either but here's what I know:
- your A/C needs two "run" capacitors - one for the FAN motor and one for the Compressor
- the two run caps may be individual - two connecting points on each
- if there are two individual caps there will probably be a jumper connecting one side of each of them
- or could be a dual capacitor - both in one - terminals would be marked something like COM for a Common Wire, FAN for Fan, HERM for Compressor (the hermetically sealed refrigeration portion of the A/C)
All this means you need to know that there is presently only a Run cap wired to the compressor. Those capacitors are usually silvery metal. If there are other components, then it already has some form of start assist. There can be only one start assist. The wiring diagram may show that there was one as an option that wasn't actually installed. That's why you must look and figure out if one's already there. If there's a third cap, probably hard plastic with a metal retaining ring holding it together at the top, it's part of a start assist device.
If you can see the sides of the caps, you can see the capacitance rating numbers. They're in MicroFarads, probably shortened to "MFD."
FAN will be less than 10MFD, HERM around 45MFD and Start (if present) around 100MFD.
See how this compares with what you see up there. Be sure the power is OFF at the source. Don't touch the cap terminals till you have shorted across them with an insulated metal tool. They're meant to store a charge so you want to be sure it's bled off.
Take pictures of the capacitor area and wiring diagram if you can and post them.
And be encouraged - IF you find NO start assist already in place, the two wires on the SPP6 go to HERM and COM, and it doesn't matter which is which.
SPP6 is the right size and SUPCO will agree with that. There's debate whether it should be SPP6 or SPP6e. One of our resident RV tech gurus, Chris Bryant, prefers the "e" version but allows that SPPCO will recommend the SPP6.
Do you know that your Dometic A/C does NOT already have a Start Assist? I'm not an engineer either but here's what I know:
- your A/C needs two "run" capacitors - one for the FAN motor and one for the Compressor
- the two run caps may be individual - two connecting points on each
- if there are two individual caps there will probably be a jumper connecting one side of each of them
- or could be a dual capacitor - both in one - terminals would be marked something like COM for a Common Wire, FAN for Fan, HERM for Compressor (the hermetically sealed refrigeration portion of the A/C)
All this means you need to know that there is presently only a Run cap wired to the compressor. Those capacitors are usually silvery metal. If there are other components, then it already has some form of start assist. There can be only one start assist. The wiring diagram may show that there was one as an option that wasn't actually installed. That's why you must look and figure out if one's already there. If there's a third cap, probably hard plastic with a metal retaining ring holding it together at the top, it's part of a start assist device.
If you can see the sides of the caps, you can see the capacitance rating numbers. They're in MicroFarads, probably shortened to "MFD."
FAN will be less than 10MFD, HERM around 45MFD and Start (if present) around 100MFD.
See how this compares with what you see up there. Be sure the power is OFF at the source. Don't touch the cap terminals till you have shorted across them with an insulated metal tool. They're meant to store a charge so you want to be sure it's bled off.
Take pictures of the capacitor area and wiring diagram if you can and post them.
And be encouraged - IF you find NO start assist already in place, the two wires on the SPP6 go to HERM and COM, and it doesn't matter which is which.
