Heat pumps · Error codes · Intergas
n021Intergas · Xtend hybrid heat pump
n021 on an Intergas Xtend hybrid heat pump: No flow in the CH circuit for at least 30 seconds
Short answer
On an Intergas heat pump, n021 means: No flow in the CH circuit for at least 30 seconds. The heat pump keeps running. An engineer is needed to fix the cause.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: No flow in the CH circuit for at least 30 seconds.
Part involved: flow switch / circulation pump.
Likely causes:
- Venting program (max 15 min) starts automatically; clears if flow regained for 30 s.
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Warning |
| Engineer needed? | Yes |
The heat pump keeps running.
Resetting itself: unknown.
What you can check
- Note the code shown on the controller and the model number on the unit's rating label before contacting your installer.
- Check that the heat pump's isolator and consumer-unit breaker are on; do not open any casing.
- Check the heating system pressure gauge reads within the range your installer set (typically 1-2 bar) and that the filling loop is closed.
What the engineer will check
- Check the circulation pump runs and the strainer/filter is clean.
- Vent air from the system.
- Check the flow switch/flowmeter and its wiring.
- Check isolation valves are open and minimum flow/volume is met.
Who to ask for: Heat pump engineer.
Certification: Heat pump installer competence; F-gas and flammable-refrigerant (R32/R290) handling competence for any refrigerant-circuit work.
What you might notice
Sources
- Intergas Xtend Monoblock Heating Solutions Installation Instructions V1.2 (88302401w) ↗ · V1.2 · page p.73 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026