Heat pumps · Error codes · Ideal Heating
P0Ideal Heating · HP290
P0 on an Ideal Heating HP290: Low Pressure Error
Short answer
On an Ideal Heating heat pump, P0 means: Low Pressure Error. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Low Pressure Error.
Part involved: suction pressure.
Likely causes:
- Low pressure sensor reading faulty (P1 = P2); outdoor unit covered with snow/ice; air-to-refrigerant HX blocked/dirty; insufficient clearance/ventilation; fan fault; EEV not operating or EEV wiring (CN33/EEV1) wrong; low refrigerant charge.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
What you can check
- Note the code or fault message shown on the controller/Halo and when it appeared; check the heat pump's isolator and consumer-unit breaker are on. Check the outdoor unit is not blocked by snow, ice, leaves or stored items and that air can flow freely around it.
What the engineer will check
- Compare P1/P2 comp pressures (unit status 5.8.6.1); check coil and airflow; check fan; check EEV operation/click and wiring; leak test and recharge; replace outdoor PCB/low pressure sensor.
Who to ask for: Heat pump engineer competent with R290 (A3, highly flammable); refrigerant-circuit work requires Cat I/II F-gas plus City & Guilds 6187-21 or equivalent (I&M p.93 warning).
Certification: F-gas Cat I/II + C&G 6187-21 (R290) for refrigerant work; electrical work by competent person.
Sources
- HP290 Monobloc Heat Pump System - Installation & Maintenance (UIN 240080 A09) ↗ · UIN 240080 A09 · page 106 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026