Air conditioner rattles upon startup

[Mike Lewis]

My trailer's A/C makes a knocking sound when I start it up. It still runs and it still cools. What is going on? Thanks.

[Oldtimer]

One might pull the outside cover off n make sure nothing has come loose. It’s happened before.

David

[cpaharley2008]

Check the mounting bolts, mine were loose on one of my Escapes..........

[MVA]

Originally Posted by cpaharley2008

Check the mounting bolts, mine were loose on one of my Escapes..........

Depends on the "knocking noise". I had some unwelcome wasps make a nest in the outside squirrel cage fan. The nest made the fan unbalanced when the AC was started. Beyond checking the hold-down bolts as others commented, I would remove the cover (4 screws) and see if something is in the fan. BTW - I was told by ETI that an owner had a dead mouse in the fan once that unbalanced the fan.

2 cents

[Mike Lewis]

Wasp nest sounds very likely, as they are everywhere here, and I saw some swarming around the trailer roof a few days ago. I've been a wasp mass murderer today.

[Vermilye]

@ithout hearing the noise, it is difficult to know whether it is the normal compressor start up "thump" or something else. If it is the start up thump, adding a Micro-Air Easy Start is an expensive, but effective cure. It will also let you use a smaller generator to power the AC.