Outside fan not turning on, not getting signal to contactor
#1
08-07-15, 02:07 PM
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Outside fan not turning on, not getting signal to contactor
Hey all,
I noticed my house wasn't cooling and it appears if I depress the contactor it'll start cooling. I used my multimeter to chase the 24v from the house, thermostat is good to the air handler, signal is good going outside. I trace the wire that it is connected to from the service panel until it disappears in to a hole going in to the outside unit. So I have power from the house, but losing a connection somewhere between that connection and when it comes back out to the contactor.
I'm competent at tinkering with things. But definitely hesitant to start pulling the condenser apart chasing that wire.
Anyone understand where I'm at in this process and can offer suggestions?
Thanks
I noticed my house wasn't cooling and it appears if I depress the contactor it'll start cooling. I used my multimeter to chase the 24v from the house, thermostat is good to the air handler, signal is good going outside. I trace the wire that it is connected to from the service panel until it disappears in to a hole going in to the outside unit. So I have power from the house, but losing a connection somewhere between that connection and when it comes back out to the contactor.
I'm competent at tinkering with things. But definitely hesitant to start pulling the condenser apart chasing that wire.
Anyone understand where I'm at in this process and can offer suggestions?
Thanks
#2
08-07-15, 02:46 PM
Forum Topic Moderator
If you have 24 volts to the condenser but do not have it to the contactor it is probably a pressure switch lockout.
What is the make and model number of the condenser?
What is the make and model number of the condenser?
#3
08-07-15, 02:56 PM
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#4
08-07-15, 03:25 PM
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That unit has a high pressure cutout and low pressure cutout. The high pressure cutout should have a red reset button on it.
The problem is more likely the low pressure cutout signifying low refrigerant charge.
You could disconnect power and look inside the unit. You'll see two sensors each with two wires soldered into the refrigerant lines. One will have a little button at the wire end.
The problem is more likely the low pressure cutout signifying low refrigerant charge.
You could disconnect power and look inside the unit. You'll see two sensors each with two wires soldered into the refrigerant lines. One will have a little button at the wire end.
#5
08-08-15, 10:10 AM
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#6
08-08-15, 11:35 AM
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You may have to remove the side panel to get access to the pressure switches. As Houston mentioned, the high pressure switch usually has a reset button (often red in color) on the end of the switch. Since you have a multimeter, you can check the pressure switches with your meter. Normally, the switches are closed (continuity through switch). I would suggest that you turn off power to both the outside and inside (air handler) unit. Set your meter on the lowest ohms scale and read across the terminals on each of the switches. If you find that one is an open circuit, you'll have found the problem. Now you need to determine whether the switch is bad (unlikely), or if there is a condition (pressure is too high or too low) that caused the switch to open. You can temporarily jumper across the switch that's open and see if you get cooling. However, until you determine why the switch is open, I wouldn't run the A/C with the switch jumpered for any length of time (<10 min).
#7
08-12-15, 08:24 AM
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Chased the entire length of the switches wiring, definitely no reset switches. Knowing that they were unlikely to fail, I called a tech because it was probably pressure related. The last guy who worked on my system overpressurized it.
