Heat pumps · Error codes · Trianco
Er45Trianco · Activair R32 (S700 / S1200 - FG 9007 / FG 9012)
Er45 on a Trianco Activair R32: High outlet water temp protection under heat mode
Short answer
On a Trianco heat pump, Er45 means: High outlet water temp protection under heat mode. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: High outlet water temp protection under heat mode.
Part involved: water flow / water temperature.
Likely causes:
- Inadequate water flow rate.
- Set outlet water temperature is too high.
- Outlet water temperature sensor or main PCB damaged.
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
What you can check
- Note the exact code shown on the controller (a photo helps) and report it to your installer or the manufacturer's service line.
- Check the heat pump's supply breaker/isolator at the consumer unit is on (do not open any casing).
- Check the heating system pressure gauge reading (if one is fitted) and tell your engineer if it is below the level set at commissioning; do not attempt to refill unless you have been shown how.
What the engineer will check
- Check pump, filter and water circuit (no block).
- Adjust set outlet water temp to normal working range.
- Replace outlet water temp sensor or main PCB.
Who to ask for: heating / hydraulics.
Certification: Competent heating engineer (manufacturer training recommended).
What you might notice
Sources
- Trianco Activair Air Source Heat Pump S700, S1200 - Installation and Service Manual (R32, FG 9007 / FG 9012) ↗ · 2022-04 issue · page 11, 21 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026