Heat Pump Repair & Service in Greater Houston

Our technician arrives and checks: Is the outdoor unit running (compressor humming, fan spinning)? Are there any visible ice formations on coils or lines? Is the indoor unit delivering conditioned air? Do vents feel warm (heating mode) or cold (cooling mode)? This visual check quickly reveals whether we’re dealing with a no-operation problem or degraded performance.

We check the thermostat display to see what mode it’s calling for (heat vs. cool) and what the system is doing (matching or mismatched). A thermostat calling for heat while the system delivers cool immediately points to reversing valve trouble.

We connect manifold gauges to measure low-side and high-side refrigerant pressures. Heat pump pressure readings differ from air conditioner readings because the system operates in two opposite modes, but the fundamentals are the same: proper charge shows normal pressures; low charge shows low low-side pressure; overcharge shows high pressures.

We measure pressures in both heating and cooling modes if possible, comparing them to the system’s design specifications. A low-side pressure that’s abnormally low in heating mode points to refrigerant leak or a stuck metering device. A pressure that’s high in cooling but low in heating might indicate reversing valve malfunction.

We calculate superheat on the low-side line and subcooling on the high-side line in both heating and cooling modes. This data tells us whether refrigerant charge is correct, too high, or too low.

• In cooling mode: High superheat points to low charge or restriction; low superheat points to overcharge.
• In heating mode: Abnormal superheat suggests low charge or compressor issues; abnormal subcooling suggests charge or high-side restriction.

Heat pump superheat and subcooling are different than for a simple AC system because refrigerant direction reverses. We account for this difference during calculation.

We verify that the reversing valve switches correctly when you change the thermostat from heating to cooling mode. We listen for the valve solenoid to energize (audible click or buzz), then verify that the system responds—thermometer at indoor vents should change from hot to cold (or vice versa) within a minute or so.

We also test the defrost cycle in heating mode: the heat pump should periodically pause heating (you’ll notice a brief warm air stop), energize a solenoid valve, and run the compressor in reverse to defrost the outdoor coil. If defrost isn’t working, ice can build up and prevent heating.

We test capacitors (common failure points), compressor continuity, contactor operation, and fan motors using multimeters and specialized testers. A failed capacitor might prevent the compressor from starting in heating mode but not cooling. We isolate which component isn’t working.

We also test the thermostat’s reversing valve signal. A thermostat that isn’t sending the correct signal to the reversing valve solenoid explains why the system won’t switch modes.

We inspect the indoor evaporator coil for ice formation, frost, dirt, or visible damage. We check the outdoor condenser coil for debris, leaves, or ice accumulation. Poor outdoor coil function (from blockage or ice) is a common cause of weak heating in winter.

We verify that return air is flowing freely—no blocked filter, no closed vents. Blocked returns can starve the system of air to condition, causing weak heating and cooling and potential coil freezing.

If pressure readings suggest refrigerant loss, we use electronic leak detectors to scan all refrigerant connections, both coils, and line joints. Heat pump systems have more connections than simple AC (reversing valve solenoid, liquid check valves, defrost valve) so more places for leaks.

Once we locate a leak, we identify its severity and location—surface leak on a line connection (simple solder fix), or internal coil leak (more involved repair).

We explain findings clearly: “Your low-side pressure is reading 40 PSI in heating mode when it should be 55 PSI. We found a slow leak in the heating line connection. Your reversing valve is responding correctly, compressor is running, and defrost cycle is functioning. The repair is a solder fix plus a refrigerant recharge—about [cost]. With proper charge, you’ll get full heating output again.”

We present options for major failures: compressor replacement vs. system replacement, with honest economics.

Once approved, we proceed:

• Leak repair and recharge: Purge, solder, pressure-test, evacuate, and recharge with manufacturer-specified refrigerant.
• Reversing valve replacement: Requires partial refrigerant evacuation and careful component swap to avoid air entry.
• Defrost valve repair: Replace solenoid or valve body if stuck; test defrost cycle after replacement.
• Capacitor or contactor replacement: Quick swap with immediate testing.
• Compressor replacement: Full refrigerant evacuation, compressor swap, and precise charge.

All work follows EPA regulations.

After repair, we test the system in both modes: call for heat, verify that warm air flows from indoor vents, check that reversing valve clicks, measure pressures and superheat in heating mode. Then call for cooling, verify cold air output, check pressures in cooling mode. We run the system through a complete heating-cooling cycle to confirm balanced operation.

We test defrost cycle in heating mode by letting the outdoor coil ice up slightly, then verifying that defrost energizes and defrosts the coil without stopping heating to the home.

We document all pressure readings, component test results, and repairs for your record. We explain what we found and what habits prevent future failures.