Armstrong AC loud at start up.

[dkrukosky]

My Armstrong TR25-14 AC unite has started making a terrible racket when it first starts up and only lasts for about the first 15-20 seconds then quiets back down. I know its not the squirrel cage fan as it runs consistently. I am thinking the compressor is going? Any thoughts?

[68 TWind]

I have the original Armstrong AC on my 68. It is loud for 10-12 seconds as the compressor comes on then just hums. It also makes a clunk when it shuts off. Been making the same sounds since I've had it for 7 years and lots of hours run tme.
Check the voltage at campgrounds, low voltage can cause issues at startup. Don't run the AC with your trailer just plugged into an extension chord and 15 amp circuit. The starting capacitor could be weak but they tend to either work or not. You need a meter that has the capacitor funtion to get see if it is up to specs.

[drboyd]

I'd replace the start capacitor to see if that helps any. It probably won't, but they''re less that $30, so it's a good place to start.