HVAC Site - Professional HVAC Contractors Forum banner
1 - 8 of 8 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
Working on an improperly draining A coil in an American Standard downflow fan coil unit.

Maintenance guy allowed to filter to clog a month ago and some initial dust still could be slightly clogging the coil.

R-22 pressures have been checked. The pvc condensate drain is clear.

This coil has been cleaned twice with green Diversitech light foaming concentrate cleaner from Michel.

Condensate leak stopped and then started leaking again after a month.

Though we've used it for years, have others found a better or more effective coil cleaner than the green Diversitech?

Fan is variable speed (non adjustable) and air flow does not seem to be an issue.

Anything else besides a partly clogged coil that could suddenly cause this 8 yr old system to develop a condensate leak - other that what we've mentioned above?

Suggestions welcome.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #2 ·
I appreciate the previous helpful suggestions!

This was with the 8 year old 2 ton A/S counter flow fcu in cooling mode

The plot thickens....

The coil has been cleaned again and the underside has been blow out carefully with compressed air. Without effect.

Techs have worked on this unit three times and have no clue.

Installing plexiglass instead of the lower door cover, we see the leaks! It's not the drain pans. The condensate drips are coming from the underside of the coil (it's downflow with the coil on top) The drips are coming from one or two single rows representing the copper tubing running horizontally in the coil about 1/4 of the way from the top of the A. (Maybe 4" down from the top)

There is some condensation drips from the opposite side of the coil at about the same height....but much more on one side than the opposing side.

As mentioned earlier the R-22 pressures were checked recently and may need to be checked again. Does this sound like a refrigerant issue?

We've yet to experiment with the variable speed motor speeds. Not sure if more or less fan speed might be helpful.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #7 ·
Initial HVAC tech apparently checked the freon charge on the wrong unit outside - of the 3 at this location.

The improper draining of the coil was the result of slightly low freon, though there was still enough to cool the home, so the typical clue was not there.

We got there by applying a piece of plexiglass on the front of the FCU in place of the usual door, so we could observe the condensate dripping from the coil. Those drips emanated from this A-coil about 1/3 of the distance from the top.

Problem solved.
 
1 - 8 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top