Well, I thought turning the bulb over fixed it. Now it's 7 days later and the customer called back saying the coil iced up again. This is the first time in 7 days. He said the outdoor temp was 71 and they were trying to pull the house temp down to 69. The coil iced up and condenser unit tripped out. Probably low pressure switch. If it's the txv valve why is it doing this sporadically? If it's the air flow across the coil- why is it doing this sporadically? It is a new r-410a straight cooling system with a mortex evap coil and rheem classic condenser. Could the blower motor be failing? The supply ducting in the crawlspace also has air leaks all over but the old system operated under these same conditions and didn't ice up. New unit is same size as old unit. Any ideas?
We still don't know what the pressure readings were at any point. Everything points to low airflow so that's why pressure & temp readings would help. A faulty TXV is always suspect nowadays since they're so common too. If the airflow is O.K. & pressures & temps are O.K. then two other possible things could be the blower motor cutting out(circuit board , relay, motor, even loose wire) or the outside contactor is sticking intermittently.
An engineer designs what he would never work on.
A technician works on what he would never design.
Need to check furnace to see if blower is rated for a/c tonage? Sometimes the furnace blower has to be changed out to a larger assembly for proper air flow. Jumper duct under coach needs to be installed and connected. Check air flow from all s/a registers.
Post size of system, model numbers of equipment both indoor and out. Model number of indoor coil. And as asked is this a downflow system or upflow?
I agree i would check your airflow, also inspect the blower wheel, ive seen it where the blower wheel is caked up with junk that it doesn't move enough air across the coil. Inspect the coil too there is a chance its covered in junk too. Are we overlooking the possibility of low airflow and low charge possible? What are the pressures when the system is "working fine"?