Seeing occasional bubble in A/C sight glass

[Mikepier]

One day I was cleaning my yard and I noticed when I went to check on my outdoor A/C unit, I saw an occasional bubble float by in the A/C sight glass, like once every 3 seconds. After checking every couple of days, I did not notice it anymore. Does this mean I have a leak, or is the freon just expanding and contracting with the weather? The day I saw the bubble it was warmer ( about 50 degrees) than it had been. The unit has been off since the end of summer.

[Steve Kraus]

Non expert opinion:

Might be low. The only way to know would be to have someone hook on gauges and read the high and low side pressures. Since that will cost money you could also take temperature readings of the air both immediately before and immediately after the evaporator coil (the cooling coil in the house) without contacting anything to get just the air temps and report back here. Someone who will not be me might then give you a better opinion based on the temperature drop across the coil on whether a service call is required.

If it's low and presuming it was once correct there has to be a leak but it could be very tiny and you could go on for years. However, efficiency will drop all the while.

[S. Barker]

sight glasses are only accurate above 70 degrees. under that, you'll see vapor.

s

[Duff]

Sounds like the correct charge to me. Don't worry about it.

[Mikepier]

I guess I'll have to wait another couple of months before I fire it up and see. I know last summer I did not see bubbles when the unit was running and the house was ice cold. So hopefully those bubbles I saw don't mean anything.

[Zyp]

An expert's opinion;

It may be normal for the conditions at the time. The only correct method to check the refrigerant charge [providing the DX is a TXV] is for a refrigeration service technician to check the sub-cooling on the condenser.

It's likely ok.

[Bubba]

Who on earth gave you that line of bullshit? Show it to me in writing by someone of "weight" Bubba

[HVACTECH2]

There is no way I can give an answer to this question. There is a lot more involved than you would think. what type of metering device do you have on your system? just seeing a bubble doesn't really mean anything. it could be normal depending on temperature, metering device, etc... any system should have regular yearly maintenence. this would detect any problems.

[Stormin Mormon]

Huh? Refrigerants liquify when they are cool.

What's the source of your (??) information (??)

I've not heard that.

[Stormin Mormon]

Was the system running? Were you air conditioning the house at the time you looked into the sight glass?

[Mikepier]

No the system has been off since late Sept. I just happened to be cleaning my yard recently and I looked at the sight glass when I saw the occasional bubble.

[Stormin Mormon]

On a non-running system, the sight glass is not at all useful to tell you much of anything. I'd just disregard, and see what happens when you call your AC guy for the spring time clean and check.