TPL on a Kensa heat pump: Load (heating distribution) side water pressure P1 below the low-pressure limit
Short answer
On a Kensa heat pump, TPL means: Load (heating distribution) side water pressure P1 below the low-pressure limit. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 4 sources
What it means
The manual says: Load (heating distribution) side water pressure P1 below the low-pressure limit.
Part involved: P1 load pressure sensor / heating system pressure.
When it shows: Error level per manual: Fault or Warning.
Likely causes:
- Distribution-side water pressure has fallen below the set low limit; top up and check load-side water pressure setup (clears above 1.5 bar by default).
- General heating practice (not in Kensa table): system leaks, pressure loss after bleeding radiators, expansion vessel faults.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: yes - clears when condition clears (per manual action text).
Manual reset: unknown.
What you can check
- Note the code shown on the controller/LED; check the heat pump isolator and consumer-unit breaker are on; check thermostat/timer settings. Read the heating-system pressure gauge (or controller pressure screen) and note the value.
What the engineer will check
- Follow Kensa fault table actions: Distribution-side water pressure has fallen below the set low limit; top up and check load-side water pressure setup (clears above 1.5 bar by default). Top up load side to >1.5 bar via filling loop (Kensa user manual suggests owners may do this; treated here as engineer/competent-person task), find cause of pressure loss, check expansion vessel.
Who to ask for: Heating engineer / GSHP installer.
Certification: MCS-certified GSHP installer recommended; Kensa-trained.
What you might notice
Sources
- Kensa Evo Heat Pump Installation manual ↗ · V32 · page 50 · Reviewed 23 September 2026
- Q80 Series Heat Pump Operational Manual ↗ · Version 2 · page 23 · Reviewed 23 September 2026
- Shoebox Heat Pump Operational Manual (User Manual) ↗ · Version 8 · page 26 · Reviewed 23 September 2026
- Kensa Shoebox NX heat pump Installation manual ↗ · V12 · page 40 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026