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PUMPS & MOTORISED VALVES

Heating Pump Not Working

A heating pump may stop because of lost power, a seized rotor, failed capacitor, worn motor, blocked system or missing control demand.

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Isolate electrical power before opening pumps, actuators or wiring centres

Heating pumps and motorised valves may contain mains voltage and hot water. Stop if a pump is seized, very hot, leaking or if a valve actuator is buzzing continuously.

MOST LIKELY CAUSES

Start with these

No electrical supply The pump may not be receiving power from the boiler or controls.
Seized rotor Long periods without use can cause the rotor to stick.
Failed capacitor or motor The pump may hum but not turn.
Control fault The pump may not receive a run signal.
◫ Symptom variations Match the exact circulation or zone pattern. ⌄
  • Pump silent
  • Pump hums but does not circulate
  • Boiler heats but radiators stay cold
  • Pump body very hot
  • Heating works intermittently
✓ Quick checks Simple checks before removing covers. ⌄
  1. Confirm a heating demand exists.
  2. Check whether one zone or the whole system is affected.
  3. Listen for pump or actuator operation.
  4. Check system pressure and trapped air.
  5. Do not force seized valves or hot pumps.
1 Step 1 — Check for heating demand Isolate power before removing covers or touching wiring. ⌄

Confirm the boiler and controls are asking for heat.

2 Step 2 — Listen and feel for operation Isolate power before removing covers or touching wiring. ⌄

Without removing covers, note whether the pump hums or vibrates.

3 Step 3 — Stop if the pump is very hot or seized Isolate power before removing covers or touching wiring. ⌄

Switch off and arrange repair rather than repeatedly restarting it.

⌁ Common causes explained Why pumps and zone valves fail. ⌄

A heating pump may stop because of lost power, a seized rotor, failed capacitor, worn motor, blocked system or missing control demand.

⌘ Advanced diagnostics Heating-engineer checks and repair work. ⌄
  • Verify supply voltage.
  • Check rotor movement.
  • Test capacitor and motor windings.
  • Inspect control signal.
  • Assess system blockage and pump head.
▣ Parts that may need replacing Common components linked to this fault. ⌄
  • Circulation pump
  • Pump capacitor
  • Pump head
  • Isolation valves
  • Wiring connector
! When to call a heating engineer Conditions that should end basic troubleshooting. ⌄
  • The pump or actuator contains mains wiring.
  • The pump is seized, leaking or overheating.
  • A valve body is stuck.
  • One or more zones remain uncontrollable.
  • Internal testing is required.
? Frequently asked questions Common pump and valve questions. ⌄

Can I force a motorised valve open?

Use only the normal manual lever as described by the manufacturer. Do not force a seized valve body.

Why is a heating pump hot?

Some warmth is normal, but excessive heat with no circulation may indicate a seized rotor or failed motor.