Heat pump contactors
Contactors switch power to compressors, fans and heaters when the control system calls for heating or cooling. When one fails, the symptom often looks like a dead system — which is why coil and contact checks come before ordering. In winter heating work, check the fan and compressor starting load the contactor switches, and confirm coil voltage, poles and current from the old part.
Request a Quote — contactors Compatibility Guide
Typical use
Contactors switch power to compressors, fans and heaters when the control system calls for heating or cooling.
Common symptoms and failure signs
- A unit that will not start, or stays on when it should stop
- A contactor that chatters
- Pitted, burned or stuck contacts
- Repeated contactor failure — check coil voltage, load and control signal before reordering
A symptom alone does not prove this category is at fault. Check wiring, connectors, power and the system documentation first, and do not order by symptom alone.
Specification checklist — what to confirm before ordering
On a small screen, swipe sideways to see the full table.
| Field | Why it matters | Where to find it |
|---|---|---|
| Coil voltage | Wrong coil voltage means the contactor will not pull in, or will burn out | Existing contactor, control circuit |
| Poles and current rating | Must suit the load it switches | Existing part, system documentation |
| Terminal layout and mounting | Wiring and fit must transfer | Existing part measurements |
| Auxiliary contacts, if fitted | Some circuits need them; some do not | Existing part, wiring diagram |
Common mistakes
- Ordering by pole count alone, without current rating.
- Ignoring a control-signal fault and blaming the contactor.
- Working on a live high-voltage circuit without qualification.
Must bring with your inquiry — contactors
- Coil voltage and number of poles
- Current rating and the load it switches (compressor, fan, heater)
- Terminals, mounting and any auxiliary contacts
- Symptoms: chatter, stuck contacts, clicking with no run, or intermittent operation
- Quantity range and delivery region
Common mismatch cases (generic, not a diagnosis for your system)
- Same poles, different coil voltage: the contactor will not pull in reliably, or will not hold.
- Same coil, lower current rating: the part can overheat or fail early under the real load.
- Contactor replaced, control signal not checked: clicking with no run can also come from the control circuit, not the contactor alone.
Also in Resources: a printable contactor checklist with coil, poles and current fields.
Request a Quote — Heat pump contactors Compatibility Guide
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