Heating, Air Conditioning, Fridge, HVAC/A/C Replacement vs Repair Issues
I own a property in Ecuador and have been fighting to get the A/C working properly for months. When I was there last the 4 ton unit worked for about 45 minutes then the refrigeration line froze. After the technician added a charge it worked OK for about 3 days when they returned to complete the work Ė they wanted to install a new drier.
Ever since, the unit only cools for about 30 minutes and despite the fact it is still running, does not supply any further cool air. The compressor is on the rooftop (sorry I didnít get the brand when I was there last) and there is a Fan Coil Unit Model EHXX48 by Refrigicenter International in the ceiling of the condo.
The current technician is now speculating that the refrigeration lines running from the roof to the coil may be collapsed somewhere along the way which creates a much bigger problem to repair. Is there a good way to test the integrity of the lines?
Taking this is a older unit, A/C Replacement vs Repair Issues- ,Has it worked fine for several years until now? Frozen refrigeration lines are caused by many things, such as a dirty indoor coil, to many supply registers closed, return duct grille too restrictive, refrigerant restrictions,such as a plugged filter drier. If this truly is an older system why would you all of a sudden have a kinked line set ? New installs yes that is possible. Incorrect metering device settings.If this is a new unit you can check the larger of the two line set for kinks.Check anywhere where you make a 90 degree turns, that's where they usually kink.Again if this is a older unit and it worked fine for years ,doubt you picked up a kink somewhere now.
New unit- Check for kinks in larger of the two lines.Reclaim total charge, weight it and compare to manufacture spec.for that unit ( matching indoor coil to matching outdoor coil ) if you have a piston metering device check to make sure the orifice size is correct. If you have a TEV metering check your subcooling temp.also superheat to manufacture spec. Basically the refrigerant charge that is stamped on the outdoor unit electrical data plate will give you the total charge for a matching indoor unit and 15 ft. line set.So if your unit calls for 6 lb 8 oz. and you have 15 ft. of line set that should be pretty close to what you need. If you remove and weight your current charge and it's way off that figure then you can make adjustments.
In closing check anything that may restrict air going across the indoor coil first, dirty coil, dirty filter, too many supply registers closed, collaped duct ,return grille blocked or not large enough.correct size duct system.Then check for a kinked line.( new unit )then refrigerant restriction, reclaim charge check weight of current charge to manufacture spec. replace drier .With a 4 ton system you should have a 3/8" OD liquid line and either a 7/8" or 1" 1/8" suction line depending on length of line run.