F5 on a Mitsubishi Electric heat pump: 63H connector open (high pressure switch connector circuit open)
Short answer
On a Mitsubishi Electric heat pump, F5 means: 63H connector open (high pressure switch connector circuit open). The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 9 sources
What it means
On the Ecodan Hydrodan
The manual says: 63H connector open (high pressure switch connector circuit open).
Part involved: High pressure switch 63H / connector 63H.
When it shows: 63H connector circuit open for 3 minutes continuously after power supply.
Likely causes:
- 1 Disconnection or contact failure of 63H connector on C.B.; 2 Disconnection or contact failure of 63H; 3 63H working due to defective parts; 4 Defective C.B.
On the Ecodan Puhz Sw Split
The manual says: 63H connector open (high pressure switch connector circuit open).
Part involved: High pressure switch 63H / connector 63H.
When it shows: 63H connector circuit open for 3 minutes continuously after power supply.
Likely causes:
- 1 Disconnection or contact failure of 63H connector on outdoor controller circuit board; 2 Disconnection or contact failure of 63H; 3 63H is working due to defective parts; 4 Defective outdoor controller circuit board.
On the Ecodan Puhz W Monobloc
The manual says: 63H connector open (high pressure switch connector circuit open).
Part involved: High pressure switch 63H / connector 63H.
When it shows: 63H connector circuit open for 3 minutes continuously after power supply.
Likely causes:
- 1 Disconnection or contact failure of 63H connector on outdoor controller circuit board; 2 Disconnection or contact failure of 63H; 3 63H is working due to defective parts; 4 Defective outdoor controller circuit board.
On the Ecodan R290 Puz Wz
The manual says: 63H connector open (high pressure switch connector circuit open).
Part involved: High pressure switch 63H / connector 63H.
When it shows: 63H connector circuit open for 3 minutes continuously after power supply.
Likely causes:
- 1 Disconnection or contact failure of 63H connector on outdoor controller circuit board; 2 Disconnection or contact failure of 63H; 3 63H is working due to defective parts; 4 Defective outdoor controller circuit board.
On the Ecodan R32 Puz Wm
The manual says: 63H connector open (high pressure switch connector circuit open).
Part involved: High pressure switch 63H / connector 63H.
When it shows: 63H connector circuit open for 3 minutes continuously after power supply.
Likely causes:
- 1 Disconnection or contact failure of 63H connector on outdoor controller circuit board; 2 Disconnection or contact failure of 63H; 3 63H is working due to defective parts; 4 Defective outdoor controller circuit board.
On the Ecodan R32 Zubadan Puz Hwm
The manual says: 63H connector open (high pressure switch connector circuit open).
Part involved: High pressure switch 63H / connector 63H.
When it shows: 63H connector circuit open for 3 minutes continuously after power supply.
Likely causes:
- 1 Disconnection or contact failure of 63H connector on outdoor controller circuit board; 2 Disconnection or contact failure of 63H; 3 63H is working due to defective parts; 4 Defective outdoor controller circuit board.
On the Ecodan Ultra Quiet Puhz W Vaa
The manual says: 63H connector open (high pressure switch connector circuit open).
Part involved: High pressure switch 63H / connector 63H.
When it shows: 63H connector circuit open for 3 minutes continuously after power supply.
Likely causes:
- 1 Disconnection or contact failure of 63H connector on outdoor controller circuit board; 2 Disconnection or contact failure of 63H; 3 63H is working due to defective parts; 4 Defective outdoor controller circuit board.
On the Ecodan Zubadan Puhz Hw Monobloc
The manual says: 63H connector open (high pressure switch connector circuit open).
Part involved: High pressure switch 63H / connector 63H.
When it shows: 63H connector circuit open for 3 minutes continuously after power supply.
Likely causes:
- 1 Disconnection or contact failure of 63H connector on outdoor controller circuit board; 2 Disconnection or contact failure of 63H; 3 63H is working due to defective parts; 4 Defective outdoor controller circuit board.
On the Ecodan Zubadan Puhz Shw Split
The manual says: 63H connector open (high pressure switch connector circuit open).
Part involved: High pressure switch 63H / connector 63H.
When it shows: 63H connector circuit open for 3 minutes continuously after power supply.
Likely causes:
- 1 Disconnection or contact failure of 63H connector on outdoor controller circuit board; 2 Disconnection or contact failure of 63H; 3 63H is working due to defective parts; 4 Defective outdoor controller circuit board.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: Not stated as auto-recovering in the service manual; code is logged in the outdoor unit error history.
Manual reset: Clear via RESET on the main remote controller after the cause is fixed; service manual actions include switching power off and on to recheck.
What you can check
- Note the code, unit and ref. address shown on the main remote controller and contact your installer (Mitsubishi user manuals: 'Make a note of the error code number and contact installer'). Check the heat pump breaker/isolator at the consumer unit is on and read the primary system pressure gauge (if fitted) so you can report it. A single reset from the main remote controller (RESET, then Yes) may be tried; if the code returns, do not keep resetting. Do not open the outdoor unit, cylinder/hydrobox or any casing.
What the engineer will check
On the Ecodan Hydrodan
- 1 Check 63H connector on C.B.; 2 Check 63H side of wire; 3 Check continuity, replace defective parts; 4 Replace C.B.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (controls / wiring).
On the Ecodan Puhz Sw Split
- 1 Check connection of 63H connector on outdoor controller circuit board (test point diagram); 2 Check the 63H side of connecting wire; 3 Check continuity by tester and replace defective parts; 4 Replace outdoor controller circuit board.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (controls / wiring).
On the Ecodan Puhz W Monobloc
- 1 Check connection of 63H connector on outdoor controller circuit board (test point diagram); 2 Check the 63H side of connecting wire; 3 Check continuity by tester and replace defective parts; 4 Replace outdoor controller circuit board.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (controls / wiring).
On the Ecodan R290 Puz Wz
- 1 Check connection of 63H connector on outdoor controller circuit board (test point diagram); 2 Check the 63H side of connecting wire; 3 Check continuity by tester and replace defective parts; 4 Replace outdoor controller circuit board.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (controls / wiring).
On the Ecodan R32 Puz Wm
- 1 Check connection of 63H connector on outdoor controller circuit board (test point diagram); 2 Check the 63H side of connecting wire; 3 Check continuity by tester and replace defective parts; 4 Replace outdoor controller circuit board.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (controls / wiring).
On the Ecodan R32 Zubadan Puz Hwm
- 1 Check connection of 63H connector on outdoor controller circuit board (test point diagram); 2 Check the 63H side of connecting wire; 3 Check continuity by tester and replace defective parts; 4 Replace outdoor controller circuit board.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (controls / wiring).
On the Ecodan Ultra Quiet Puhz W Vaa
- 1 Check connection of 63H connector on outdoor controller circuit board (test point diagram); 2 Check the 63H side of connecting wire; 3 Check continuity by tester and replace defective parts; 4 Replace outdoor controller circuit board.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (controls / wiring).
On the Ecodan Zubadan Puhz Hw Monobloc
- 1 Check connection of 63H connector on outdoor controller circuit board (test point diagram); 2 Check the 63H side of connecting wire; 3 Check continuity by tester and replace defective parts; 4 Replace outdoor controller circuit board.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (controls / wiring).
On the Ecodan Zubadan Puhz Shw Split
- 1 Check connection of 63H connector on outdoor controller circuit board (test point diagram); 2 Check the 63H side of connecting wire; 3 Check continuity by tester and replace defective parts; 4 Replace outdoor controller circuit board.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (controls / wiring).
What you might notice
What owners and engineers report
1 owner and engineer report mentions this.
- Heat pump will not start on the Ecodan Puhz W Monobloc: 1 report
Sources
- Ecodan Hydrodan EHWT17D-MHEDW Installation Manual RK79D203K04 ↗ · RK79D203K04 · page 49 (PDF p.50, Error Codes (C.B.)) · Reviewed 23 September 2026
- Ecodan PUHZ-SW(75-100-120)(V-Y)HA-BS Service Manual (OCH755) ↗ · OCH755 · page OCH755 p.22; OCH525C p.20 · Reviewed 23 September 2026
- Ecodan PUHZ-W112VHA-BS Service Manual (OCH562D) ↗ · OCH562D · page OCH562D p.17; OCH605A p.14; OCH465D p.19; OCH439N p.54 · Reviewed 23 September 2026
- PUZ-WZ(85-100-120)(V-Y)AA(-BS) Service_Manual (OCH880) ↗ · OCH880 · page OCH880 p.36; OCH816 p.32 · Reviewed 23 September 2026
- Ecodan PUZ-WM(50-60-85-112)V(H-A)A Service Manual (OCH727A) ↗ · OCH727A · page 23 · Reviewed 23 September 2026
- Ecodan PUZ-HWM140(V-Y)HA Service Manual (OCH748A) ↗ · OCH748A · page 20 · Reviewed 23 September 2026
- PUHZ-W85-112VAA(-BS) Service Manual (OCH681) ↗ · OCH681 · page 14 · Reviewed 23 September 2026
- Ecodan PUHZ-HW140VHA2-BS / PUHZ-HW140YHA2-BS Service Manual (OCH439N) ↗ · OCH439N · page 54 · Reviewed 23 September 2026
- PUHZ-SHW112-140V/YHA Service Manual (OCH526) ↗ · OCH526 · page 24 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026