Heating, Air Conditioning, Fridge, HVAC/AC PROBLEM


I have a Trane XE1200 3.5 ton heat pump package unit. Just recently the unit stopped cooling but the compressor is still running with normal amperage considering the high head pressure. I checked for freon and saw that there is a suction pressure of 20 lbs and a discharge pressure off aprox 275 to 300 lbs. which is not normal. The evap coils start to frost up which usually denotes that there is not enough freon in the system, however the high discharge pressure shows that there is freon in the system. The evap fan is  working well and the evap is clean. If I shut the unit off the system will cool for about 3 minutes with warm air coming from the condenser fan but after that time the air reverts back to ambient temp and the system stops cooling. The unit is about 10 years old.The unit has not been charged with freon before and I can find no leaks, if I try to add freon the discharge pressure keeps rising rapidly while the txv header lines continue to frost up. Can you please help with some advice.


Doubt your low on refrigerant as your head pressure is high and suction low, more like a partial restriction, either on your filter drier, metering device . You may have non condensible ( air ) your suppose to purge air out of your gauges when you hook it up before adding refrigerant. The air may be freezing at the metering device causing a restriction. Make sure all your supply registers are open, to make sure your getting maximum air flow across the indoor coil. When an indoor coil freezes does not mean that your low on charge only, not enough air flow across the coil will freeze it. When talking Heat Pumps, to keep confusion to a minimum, the condensor is called the outdoor coil ,the condensor fan is called the outdoor fan, the evaporator is called the indoor coil, and indoor fan, as the outdoor coil is the evaporator in heat mode. Recommend ( if drier is not restricted ) ( to check drier the whole drier should be the same temperature, if one side is cooler than the other, chances you have a restriction at the drier. )  reclaiming refrigerant ,compare amount you reclaimed to,the electrical data plate refrigerant charge. If possible after pulling a good vacuum weight in correct charge . I would install a new drier  

Heating, Air Conditioning, Fridge, HVAC

All Answers

Answers by Expert:

Ask Experts




40+ years diversified experience.An HVAC/Refrigeration Self Employed Contractor since 1986. NATE Certifield. Answer questions pertaining to Residential and Commercial Air Conditioning , Warm Air Heating, Heat Pump systems.Mechanical and Electrical troubleshooting of these systems.Be as detailed as possible when describing problem.Packaged unit or split systems.No appliance questions.


Installation and Troubleshooting, Mechanical and Electrical, in following areas, Refrigeration ( Walk In and Reach In Coolers and Freezers ) Commercial Roof Top and Packaged Heating/Cooling ( Natural Gas,Propane, Electric, and Heat Pumps ) Computer Room Air Conditoning Systems,Commercial Residential Packaged and Split Systems Air Conditoning and Heat Pumps.Warm Air Oil , Natural and Propane Gas Heating systems.

Graduated from Private Technical School in 1975. An HVAC/Refrigeration Contractor . Have Unlimited Heating/Piping and Cooling Contractor License.Limited Sheetmetal Contractors License.NATE Certifield. York Certifield Master Heat Pump Technician 1986. Served 33 years combination Active Duty Air Force , Air Force Reserves and Air National Guard in the HVAC/Refrigeration Shop/Mechanical Shop. Troubleshooting/Installing HVAC/Refrigeration Equiptment Worldwide. Retiring in 2003 as a Senior NCO ,and a Mechanical Superintendent.

©2017 About.com. All rights reserved.