I have a roof mounted carrier unit that cools only intermittently. When it isn't blowing cool air, the fan still works. The little research I have done suggests it might be a mere matter of cleaning the coils. If this is the case, what would be the best way to do this? Otherwise, what might be causing the problem?

Thank you.

If your comfy, I'd at least take the panels off and look at the coils. The coils would have to be pretty crummy to affect cooling, but anything is possible.

While the unit could be going off on high pressure or low pressure, it's hard to tell. The fan could be stopping or even blowing in the wrong direction.

Special solvents are available for about $12 a spray can. It can be a very messy job.

Thanks. Still haven't had a chance to get up on the roof; will report back when I do.