Central a/c has no pwr.?
Question:have replaced fuses, start &run caps. unit still won't come on,only the house fan,not the fan&compressor in the unit.
Answers:
webster maybe the contactor coil is fried or the contacts themselves are fried sometime a critter will crawl up in there and OUCH! can you hear it humming? see pic below
maybe fan and compressor need replacing you don't mention how old the unit is sounds like something went belly up in the unit
Well you know what to do. Call the man. Admit defeat and cll the man.
Unless you have recently changed the thermostat and it could be a simple mis wiring there, your going to need a pro.
check inside the unit for a simple relay thats pulled in by the thermostat and brings on the condenser and before you work on this unit turn the power off usually the voltage is 220v
or if its a regular wall unit or window unit check the capacitor that stores power to bring on the condenser.. its a big round black cannister... again becareful this stuff is carries voltage
If your unit has power you need an amp probe to check how much power is traveling through the wires.
There are ratings on the outdoor unit for SLA, RLA and LRA.
These mean Start Load Amps, Run Load Amps and Locked Rotor Amps. If you know this (by reading the equipment tag) and us a probe to check how many amps you are using then you will know what the problem is.
I don't know your abilities but as a serviceman I would manually push in the contact's on the outdoor unit and see if it comes on.
If it does then you have a controls problem. If it doesn't then you have a contacts, power, compressor or wiring problem within the unit.
I hope this helps. I do except email if you choose.
It is highly unlikely that your fan and compressor went bad at the same time. It sounds like you have a problem with the contactor for the outside unit. The contactor has 2 main parts to it. The coil - which usees the voltage (24 VAC) from the thermostat to pull in, and the contacts which use the line voltage (240 VAC) to start the compressor and the fan. If your coil or contacts are bad these 2 items won't work . The easy way to check the coils is to push the contactor in with a screwdriver or other similar object. If the fan/compressor comes on, you have a problem from the thermomstat to the coil(whether it be the thermostat, connections, wiring, or the contactor coil) If it does not come on, you need to have a way to check the voltage on the contactor. A small multimeter or voltage tester will do. If you check each lead, you should have 120 Volts AC to ground(touch one meter lead to the wire coming in and the other meter lead to a part of the metal frame of the unit) and if you check both incoming wires, you should have 240 VAC or something close to this. If you do then you either have bad contacts, capacitor problems, or the fan and compressor both went bad at the same time. not very likely. If you do not have the right voltage, check from the wires on the top of the contactor back to the small disconnect by the unit and see if there is voltage there. If not, go back to the main breaker panel and do the same check there. If you do have voltage, are the wire connections good, is the disconnect on, or if it is one of the type where you pull out the busbar or fuses with a plastic holder.. make sure it is in right and seated in the disconnect properly. If you feel uncomfortable getting this involved call a service tech. Good Luck!
More Related Questions & Answers...