No A/C - http://www.hvacmechanic.com/ Forums

Original message

drewmo

68.76.100.75

"No A/C" , posted Fri 6 Jun 21:47

I have an old Armstrong furnace AG61-120D. Went to turn on the AC (its 90deg) and nothing happened. Tried the furnace and everything is fine. I called a tech and he told me the unit is to old and he doesnt know how to troubleshoot the problem.
I know there is 240V going to the unit, I dont know what to do from here. It seems like the part that the switch wires are going through (should be 24v i believe) is only showing 4v? but isnt that the same thing that makes the furnace run?

Replies:

Houston204

98.196.66.53

"Re(1):No A/C" , posted Fri 6 Jun 22:14:

Is your contactor pulled in? Do you have 240 volts at L1 to L2 and T1 to T2?

Does the capacitor appear swollen on top?

Capacitors will hold a charge for @ 90 seconds after removing power. Short across the terminals after waiting 90 seconds (or pushing in the contactor) to verify that it is safe to handle. (Use a screwdriver)

"Tip of the Day" Remember to remove power first.

[this message was edited by Houston204 on Fri 6 Jun 22:16]

dennisshort

71.31.246.105

"Re(2):No A/C" , posted Sat 7 Jun 10:58

if my capacitor is swollen do i need to replace it??

Houston204

98.196.66.53

"Re(3):No A/C" , posted Sat 7 Jun 13:55

Yes, you must replace a swollen capacitor. Match microfarad and voltage. My example is a 40MFD + 5MFD 370 volt dual capacitor. Some models have a 440 volt cap.

Write down your terminal = wire combination before replacing it.
Herm = ?
C = ? ?
Fan = brown

"Tip of the Day" Remember to remove power first.