HELLO HOPE EVERYONE IS KEEPING BUSY WITH THE HOT WEATHER.
2 days ago i changed a 3-ton r-22 condenser for a 2 family home the unit is for the 2nd floor apartment. The original condenser was dirty and the head pressure was too high, 300-315 psi tripping on high head. So i sold a new condenser. I installed a luxaire (guardian) 3-ton r-22 condensing unit. Vacuumed, test with nitrogen braze etc... Charged it by ambient 80+30 =110 f. Instead of weight because the manual and side of condenser did not list any amount. I charged the unit to 75 psi (45 f) suction low side 225 liquid high side. Super heat of 10-15 f .. I received a call the next day the conditioned space was not being cooled. The apartment was ranging from temps from 82-75 f with thermostat set at 69 f. I diagnosed the system, went into the attic seen that the evaporator is getting cold. The unit is draining condensate. The blower motor is working (squirrel cage). The indoor unit is a magic aire hydro air , air handler. The return only 1 central return is sucking up hot air of a temperature of 90 f. However the supply air coming out of the registers is a lazy 70 f. I know delta t is important and i also know that you need to be under 60 f to successfully cool. The air handler is a fixed orfice. However this machine has a hydro air hot water evaporator coil right before this machine provides air flow to the supply plenum. I noticed on top of the machine a can of nu brite that a lazy tech must have never thrown out. I tried to clean the coil to increase air flow with my own coil cleaner however the unit is still not cooling. The return filter was clean and i currently have the return filter out to try to increase air flow across my evap coil. I am not sure if the duct is insulated internally because i seen no insulation on the outside of the duct. There is no attic fan and very little insulation. I am really stuck on what to do. Any help would be appreciated. Should i remove the hydro air coil i believe it is causing a restriction but i am not positive. I even tried removing some refrigerant to make the coil colder but it did not help. Thank you