Hvac

[snake]

Hi need some help,I just tried to fire up the A/C unit.will not start up nothing not even a Humm.so I started poking around and found in the picture there is a switch once I push it down it all works great, but once I let release it nothing.no reset button either. Any thoughts before I call a Tech thanks.

 

[hunt2elk]

That is your contactor. Check to see if you have 24 volts across the coil. If not the problem is upstream. Either the control wire is bad, thermostat not calling for cool or the furnace mother board is not passing 24 volts outside.

 

[snake]

That is your contactor. Check to see if you have 24 volts across the coil. If not the problem is upstream. Either the control wire is bad, thermostat not calling for cool or the furnace mother board is not passing 24 volts outside.

Thermostat is calling for cool that much I know.

 

[cr8crshr]

Thermostat is calling for cool that much I know.

Have you measured the capacitor to see if your voltage is going to and out of it? Most likely that is where the problem lies...They have a tendance to leak also so look closely to see if there is oozing out of it either at the top or sides...cr8crshr/Bill

 

[hunt2elk]

Have you measured the capacitor to see if your voltage is going to and out of it? Most likely that is where the problem lies...They have a tendance to leak also so look closely to see if there is oozing out of it either at the top or sides...cr8crshr/Bill

The capacitor has absolutely nothing to do with why the contactor isn't being energized. Not only that, but the op stated that by manually pulling in the contactor, the fan and compressor started, which proves the capacitor is good.....

 

[snake]

The capacitor has absolutely nothing to do with why the contactor isn't being energized. Not only that, but the op stated that by manually pulling in the contactor, the fan and compressor started, which proves the capacitor is good.....

I am thinking it's that switch not good at electronics

 

[BB BELLA]

calling the contactor a switch tells me this job is above your pay scale!

 

[snake]

calling the contactor a switch tells me this job is above your pay scale!

Yup I am not worthy lol.

 

[BB BELLA]

you can quickly cause yourself a much higher bill for repair doing something wrong than hiring an ac pro to just fix a simple transformer replacement! AC has a lot of detail to make it work right and continue to work right! without putting gauges on a system even a pro wouldn't know if it's working properly!

 

[Scott Engelhardt]

Always start with the simple and work from there. Most of the air/heat issues I have ever had were thermostat related

 

[bm02tj]

When you turn on AC does the furnace fan start
If it does check for 24v ac volts at small yellow wires on side if no power follow wires may have a manual reset high pressure switch if so press little button in center
Also could have low pressure switch open as you had a leak check for 24 across switch

 

[snake]

Thanks all, i have a tech coming this week.

 

[snake]

When you turn on AC does the furnace fan start
If it does check for 24v ac volts at small yellow wires on side if no power follow wires may have a manual reset high pressure switch if so press little button in center
Also could have low pressure switch open as you had a leak check for 24 across switch

yes the fan comes on as it should.

 

[ESOXER]

Side note, if you need a new AC unit get one now.
2025 there's a new refrigerant that will be standard. From what our contactor at work told me it's slightly flammable and there will be a control sensor attached. If it detects anything abnormal it will lockout and require a service call.

 

[cr8crshr]

The capacitor has absolutely nothing to do with why the contactor isn't being energized. Not only that, but the op stated that by manually pulling in the contactor, the fan and compressor started, which proves the capacitor is good.....

I missed that one so sorry for the reply...cr8crshr/Bill

 

[hunt2elk]

Side note, if you need a new AC unit get one now.
2025 there's a new refrigerant that will be standard. From what our contactor at work told me it's slightly flammable and there will be a control sensor attached. If it detects anything abnormal it will lockout and require a service call.

Agree, I predict a big run on 410A units this summer. I sell Trane, and they are talking about having their plants switched over around July to make the Jan. 1 deadline. This whole refrigerant changeover is a bunch of crap imo. We were told at the first seminar for the new refrigerant that this whole thing was a bill attached to one of the Covid relief packages by some politician.

 

[snake]

Up date it was a low pressure switch. thanks for all the great advice.

 

[Moms68]

R410A will be phased just out as R-22 was a few years ago. Both will still be available for some time to come, but will increase in cost of course. I wouldn't jump on the band wagon to ditch older systems that are still serviceable. Many of the older systems are built to last many moons.

CE