Lone Star Cooling and Heating
Get help with Heat Pump Repair
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Call (325) 219-0005A heat pump that is stuck in heating or cooling, iced over, leaning on its backup heat or not running at all, traced to the defrost controls, the reversing valve, the outdoor unit or the thermostat and put right.
01Heat pump repair
Heat pump faults tend to show up in winter, and each of these points at a different part.
Cold air when the thermostat calls for heat, or warm air when it calls for cooling, usually traces to the reversing valve, the electrical coil that shifts it, or the thermostat wiring and settings that tell it which way to run. The signal is checked before the valve is blamed.
Frost that keeps building until the outdoor coil is buried in ice means defrost is not doing its job. A failed defrost board or sensor, an outdoor fan fault, a low charge or water dripping onto the unit from a gutter are the usual causes.
When aux heat shows nearly all day, the heat pump itself is not carrying its share. The outdoor unit may have stopped, the charge may be low, or the thermostat may be calling for backup it does not need. Heating bills climb until the cause is found.
If the indoor fan runs but the outdoor unit never starts, the building is being heated by backup alone, or not at all. A capacitor, contactor, breaker or control fault is the usual reason, and most of them are electrical repairs.
02Normal or a fault
A heat pump does several things in cold weather that can look alarming. Telling them apart saves a needless worry, or catches a real failure.
A light, even frost on the outdoor coil that disappears after a defrost cycle. Steam and a brief whoosh as the unit changes over. Long running times on cold days while the rooms hold the setting. Aux heat showing for a short while after a defrost or on the coldest mornings.
A coil that stays white or builds into solid ice. Cold air from the vents while the thermostat calls for heat. Aux heat showing most of the day in weather the heat pump normally handles. An outdoor unit that hums, grinds or will not start. These point at a failed part rather than the weather.
Heat Pump Repair
Serving Abilene, TX.
03What fails
Three parts set a heat pump apart from an air conditioner, and they account for faults an air conditioner never has.
The defrost control watches the outdoor coil and, when frost builds, shifts the system briefly into cooling to warm it. If the sensor fails, the board misreads it, or the outdoor fan keeps turning when it should stop, the frost wins. Ice then blocks the coil, the system moves less and less heat, and the backup heat quietly takes over the load.
The reversing valve is what lets one refrigerant circuit both heat and cool. An electrical coil moves it on a signal from the thermostat, so a heat pump stuck in one mode is checked in that order: the thermostat setting and wiring, the coil, then the valve itself. Backup heat is staged by the thermostat too, and one that is set up wrongly can call for it far more than the building needs.
04In the meantime
None of this fixes the fault. It keeps the building warm and the outdoor unit from further damage.
Leave the ice where it is. Chipping or scraping at it can bend the fins or puncture the tubing of the outdoor coil and cause a refrigerant leak.
Where the thermostat has an emergency heat setting, selecting it runs the backup heat alone and rests an iced or failed outdoor unit. It costs more to run, so it is for the wait, not the long term.
A breaker that trips again after one reset is reacting to a fault. Leave it off and mention it when calling.
05Questions
It runs the backup heat alone and keeps the outdoor unit off. It is meant for times when the heat pump has failed or iced over and needs to stay off until it is repaired. Because backup heat costs more to run, it is a stopgap rather than a setting to leave on.
That is almost always the defrost cycle. The unit briefly switches into cooling to warm its outdoor coil, the outdoor fan stops, and the melting frost gives off vapor. It ends on its own and heating resumes. Smoke with a burning smell is different, and means switching the system off.
Often the fault is the electrical coil that shifts the valve, or the signal from the thermostat, and both are routine to fix. Replacing the valve itself means recovering the refrigerant and brazing in a new one, which is major work, so on an older system it can tip the decision toward replacement.
If it smells of burning, is leaking water, or the outdoor unit is humming without its fan turning, yes: switch it off at the thermostat. A system that runs but does not keep up can usually stay on until it is looked at.
What the system is doing, when it started, what the thermostat is set to and what it reads, and whether the outdoor unit is running. The age of the equipment and a photo of its label help a technician arrive prepared.
Lone Star Cooling and Heating
Call Lone Star Cooling and Heating, have us call you, or describe the issue.
Prefer to talk?
Call (325) 219-0005