Heat Pump Not Heating in Martinez

Heat Pump Not Heating in Martinez

A heat pump that quits heating rarely means the whole unit is gone. It is a refrigeration loop run in reverse, and the common failures are single components. A reversing valve stuck in cooling. A defrost control letting the coil ice up. A refrigerant charge that has bled low. A contactor that won't close. The compressor and coils, the costly parts, usually survive.

Martinez sits on the Carquinez Strait and catches bay influence, so winters are cool but mild, nothing close to the cold-climate threshold where a heat pump genuinely runs out of capacity. That matters for diagnosis: a Martinez heat pump that can't keep up in winter is reporting a fault, not losing a fair fight with the weather.

Two housing patterns show up around town, and they fail differently. Older homes near the downtown core were often retrofitted with ductless mini-splits, which throw error codes when something goes wrong. The post-war neighborhoods run conventional ducted heat pumps with the usual mechanical and electrical failure points. We figure out which you have, trace the fault to the part, and write the repair and the cost on an estimate before any work starts.

Common causes

Reversing valve stuck in cooling. When the reversing valve hangs or its solenoid coil dies, the heat pump keeps running in cooling and pushes cold air all winter. We read temperatures across the valve and test the coil voltage. A bad coil is a cheap part; a stuck valve body is a brazed repair, and we tell you which it is before quoting.

Low refrigerant charge. A slow leak drops heating capacity until the unit runs constantly and still feels weak, sometimes with ice on the outdoor coil. We gauge the system, compare to spec, find the leak with electronic detection or dye, repair it, and recharge. Recharging without sealing the leak just resets the clock on the same problem.

Defrost control fault. On cool, damp Carquinez mornings the outdoor coil frosts, and a working heat pump runs a defrost cycle to clear it. A failed defrost sensor or board leaves the coil iced, and an iced coil cannot absorb heat from outside air. We watch a defrost cycle and verify the sensor and board are timing correctly.

Failed contactor or capacitor. The contactor energizes the outdoor unit and the run capacitor starts the compressor and fan. A pitted contactor or a weak capacitor leaves the condenser silent or humming without starting. Both are fast meter checks and both are on the truck, so these are typically fixed the same visit.

Mini-split fault on a downtown retrofit. A number of older Martinez homes near downtown run ductless mini-splits added during a retrofit. When one stops heating it is often a sensor, an outdoor board, or a head-to-condenser communication fault. These report error codes; we pull the code, interpret it against the manufacturer's chart, and confirm with measurements.

Aux heat strips not engaging. Ducted heat pumps usually carry electric backup heat for cold starts and defrost intervals. A failed strip or sequencer leaves the home cold on the worst mornings even when the heat pump itself runs. We check strip continuity, the sequencer, and the control wiring.

How we diagnose it

• Determine whether the home runs a ducted heat pump or a ductless mini-split, since each has a different failure profile.
• Confirm the thermostat is calling for heat and that the outdoor unit responds to the call.
• Read line temperatures across the reversing valve to verify the system is truly in heating mode.
• Gauge the refrigerant charge against spec and leak-check if it reads low.
• Inspect the outdoor coil for ice, watch a defrost cycle, and meter the contactor, capacitor, and aux heat.

$75 diagnostic, credited toward any repair over $200. You get a written quote before any work begins.

Heat Pump Not Heating in Martinez: common questions

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This is usually a heat pump installation & service in Martinez job. See our heat pump installation & service overview or the Martinez service area.