Just started working with this commercial maintenance company (mostly banks and strip malls).
Me and another tech go to service call at this bank the unit is a Lennox rtu heatpump mod:CHP16-653-9Y. He takes the cover off and looks and finds unit frozen. He says he dont know why its doing it (he is not really a HVAC tech, he is a maintenance tech).
I ask him the history of the unit. he says last time he was here it was off on high pressure switch. I told him it might be a restriction or txv, he says he doesnt think so he thinks its low charge and tells me to come by tommorrow and add some 22 and see what it does.
I return the next morning and start unit up pressures are a little low (didnt let unit run long) added about a lb of r22 68F outside, 72F inside pressures at 50 and 250,subcooling high, cannt remember what i had for superheat. Called tech up and told him i think there is a restriction or txv failure.
Next day,,,Service call to same bank, go by today and find unit frozen up. Thaw out and check pressures 50 / 55 and about 275 with 72 outside temp (didnt get return). I called bad txv.... What do you guys think.