U2 on a Mitsubishi Electric heat pump: Overheat discharge temperature: discharge thermistor (THERMO_ASSY DIS, TH1) detects 130C or higher
Short answer
On a Mitsubishi Electric heat pump, U2 means: Overheat discharge temperature: discharge thermistor (THERMO_ASSY DIS, TH1) detects 130C or higher. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.
Reviewed 23 September 2026 · 10 sources
What it means
On the Ecodan Co2 Quhz
The manuals for this range word it in different ways:
- Overheat discharge temperature: discharge thermistor (THERMO_ASSY DIS, TH1) detects 130C or higher.
- Refrigerant zero abnormality: refrigerant loss detected by secondary current value at startup.
Part involved: Discharge thermistor TH1 / water circulation / LEV; R744 refrigerant circuit / compressor.
When it shows: TH1 >= 130C Detected by secondary current value at startup operation.
Likely causes:
- 1 Water not circulating in outdoor unit water circuit (cylinder unit not filled, air trapped, leak/crushed/blocked pipe, isolating valve closed, cylinder pump valve closed, water pipe frozen, gas cooler blockage); 2 Pump1 in cylinder unit not operating (defective pump1 or cylinder unit board); 3 Erroneous detection by defective TH1; 4 Defective LEV coil; 5 Defective refrigerant circuit part (LEV, insufficient refrigerant from leakage).
- 1 Refrigerant leakage (evaporator breakage/corrosion, refrigerant piping damage/corrosion, gas cooler damage/corrosion); 2 Defective compressor compression.
On the Ecodan Hydrodan
The manual says: High discharge temperature (TH4) / high compressor surface temperature (TH33).
Part involved: Compressor discharge thermistor TH4 / comp. surface thermistor TH33.
When it shows: TH4 > 125C, or 110C for 5 min; discharge superheat (TH4-T63HS) > 70C for 10 min; TH33 > 125C (no restart until < 95C).
Likely causes:
- 1 Overheated compressor operation caused by shortage of refrigerant; 2 Stop valve not fully open; 3 Defective thermistor; 4 Defective outdoor controller board; 5 Defective action of linear expansion valve; 6 Clogging with foreign objects in refrigerant circuit (water ingress freezing); 7 Unit will not restart while TH33 >= 95C.
On the Ecodan Puhz Sw Split
The manual says: High discharge temperature (TH4) / high compressor surface temperature (TH33).
Part involved: Compressor discharge thermistor TH4 / comp. surface thermistor TH33.
When it shows: TH4 exceeds 125C, or 110C for 5 min; TH4 >= 110C for 30 s after 90 s of defrost; discharge superheat abnormal; compressor surface TH34 > 125C (no restart until < 95C).
Likely causes:
- 1 Overheated compressor operation caused by shortage of refrigerant; 2 Stop valve not fully open; 3 Defective thermistor; 4 Defective outdoor controller board; 5 Defective action of linear expansion valve; 6 Clogging with foreign objects in refrigerant circuit (water ingress freezing); 7 Unit will not restart while TH33 >= 95C.
On the Ecodan Puhz W Monobloc
The manual says: High discharge temperature (TH4) / high compressor surface temperature (TH33).
Part involved: Compressor discharge thermistor TH4 / comp. surface thermistor TH33.
When it shows: TH4 exceeds 125C, or 110C for 5 min; during defrost TH4 > 110C for 30 min; compressor surface thermistor (TH33/TH34 depending on model) exceeds 125C (W112VHA: 170C) - no restart until it falls below 95C.
Likely causes:
- 1 Overheated compressor operation caused by insufficient refrigerant; 2 Defective thermistor; 3 Defective outdoor controller board; 4 Defective operation of LEV; 5 Unit does not restart while compressor surface thermistor >= 95C.
On the Ecodan R290 Puz Wz
The manual says: High discharge temperature (TH4) / high compressor surface temperature (TH33).
Part involved: Compressor discharge thermistor TH4 / comp. surface thermistor TH33.
When it shows: TH4 > 125C or 110C for 5 min; TH4 >= 110C for 30 s after 90 s of defrost; discharge superheat > 70C for 10 min; TH33 > 120C (no restart until TH33 < 95C).
Likely causes:
- 1 Overheated compressor operation caused by shortage of refrigerant; 2 Stop valve not fully open; 3 Defective thermistor; 4 Defective outdoor controller board; 5 Defective action of linear expansion valve; 6 Clogging with foreign objects in refrigerant circuit (water ingress freezing); 7 Unit will not restart while TH33 >= 95C.
On the Ecodan R32 Puz Wm
The manual says: High discharge temperature (TH4) / high compressor surface temperature (TH33).
Part involved: Compressor discharge thermistor TH4 / comp. surface thermistor TH33.
When it shows: TH4 exceeds 125C, or 110C continuously for 5 minutes; TH4 >= 110C for 30 s after 90 s of defrost; discharge superheat > 70C for 10 minutes; TH33 exceeds 125C (compressor does not restart until TH33 < 95C).
Likely causes:
- 1 Overheated compressor operation caused by shortage of refrigerant; 2 Stop valve not fully open; 3 Defective thermistor; 4 Defective outdoor controller board; 5 Defective action of linear expansion valve; 6 Clogging with foreign objects in refrigerant circuit (water ingress freezing); 7 Unit will not restart while TH33 >= 95C.
On the Ecodan R32 Zubadan Puz Hwm
The manual says: High discharge temperature (TH4) / high compressor surface temperature (TH33).
Part involved: Compressor discharge thermistor TH4 / comp. surface thermistor TH33.
When it shows: TH4 exceeds 125C or 110C for 5 min; during defrost TH4 > 110C for 30 min; TH33 exceeds 125C or 110C for 5 min (no restart until TH33 < 95C).
Likely causes:
- 1 Overheated compressor operation caused by shortage of refrigerant; 2 Stop valve not fully open; 3 Defective thermistor; 4 Defective outdoor controller board; 5 Defective action of linear expansion valve; 6 Clogging with foreign objects in refrigerant circuit (water ingress freezing); 7 Unit will not restart while TH33 >= 95C.
On the Ecodan Ultra Quiet Puhz W Vaa
The manual says: High discharge temperature (TH4) / high compressor surface temperature (TH33).
Part involved: Compressor discharge thermistor TH4 / comp. surface thermistor TH33.
When it shows: TH4 exceeds 125C, or 110C for 5 min; TH4 >= 110C for 30 s after 90 s of defrost; discharge superheat (TH4-T63HS) > 70C for 10 min; TH33 > 125C (no restart until TH33 < 95C).
Likely causes:
- 1 Overheated compressor operation caused by shortage of refrigerant; 2 Stop valve not fully open; 3 Defective thermistor; 4 Defective outdoor controller board; 5 Defective action of linear expansion valve; 6 Clogging with foreign objects in refrigerant circuit (water ingress freezing); 7 Unit will not restart while TH33 >= 95C.
On the Ecodan Zubadan Puhz Hw Monobloc
The manual says: High discharge temperature (TH4) / high compressor surface temperature (TH33).
Part involved: Compressor discharge thermistor TH4 / comp. surface thermistor TH33.
When it shows: TH4 exceeds 125C, or 110C for 5 min; during defrost TH4 > 110C for 30 min; compressor surface thermistor (TH33/TH34 depending on model) exceeds 125C (W112VHA: 170C) - no restart until it falls below 95C.
Likely causes:
- 1 Overheated compressor operation caused by insufficient refrigerant; 2 Defective thermistor; 3 Defective outdoor controller board; 4 Defective operation of LEV; 5 Unit does not restart while compressor surface thermistor >= 95C.
On the Ecodan Zubadan Puhz Shw Split
The manual says: High discharge temperature (TH4) / high compressor surface temperature (TH33).
Part involved: Compressor discharge thermistor TH4 / comp. surface thermistor TH33.
When it shows: TH4 exceeds 125C, or 110C for 5 min; TH4 >= 110C for 30 s after 90 s of defrost; discharge superheat abnormal; compressor surface TH34 > 125C (no restart until < 95C).
Likely causes:
- 1 Overheated compressor operation caused by shortage of refrigerant; 2 Stop valve not fully open; 3 Defective thermistor; 4 Defective outdoor controller board; 5 Defective action of linear expansion valve; 6 Clogging with foreign objects in refrigerant circuit (water ingress freezing); 7 Unit will not restart while TH33 >= 95C.
Is it safe?
On the Ecodan Co2 Quhz
| 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.
Manual reset: Outdoor error cancelled by switching the cylinder unit earth leakage circuit breaker OFF, waiting until the outdoor board LEDs go out (about 1 minute), then ON again (service manual GHH15010).
On the Ecodan Hydrodan
| 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.
On the Ecodan Puhz Sw Split
| 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.
On the Ecodan Puhz W Monobloc
| 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.
On the Ecodan R290 Puz Wz
| 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.
On the Ecodan R32 Puz Wm
| 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.
On the Ecodan R32 Zubadan Puz Hwm
| 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.
On the Ecodan Ultra Quiet Puhz W Vaa
| 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.
On the Ecodan Zubadan Puhz Hw Monobloc
| 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.
On the Ecodan Zubadan Puhz Shw Split
| 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
On the Ecodan Co2 Quhz
- 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. Check the primary circuit pressure gauge (typically about 1-2 bar when cold on sealed systems) and look for visible leaks; do not top up or bleed unless your installer has shown you how and the filling loop is then closed.
- 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.
On the Ecodan Hydrodan
- 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.
On the Ecodan Puhz Sw Split
- 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.
On the Ecodan Puhz W Monobloc
- 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.
On the Ecodan R290 Puz Wz
- 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.
On the Ecodan R32 Puz Wm
- 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.
On the Ecodan R32 Zubadan Puz Hwm
- 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.
On the Ecodan Ultra Quiet Puhz W Vaa
- 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.
On the Ecodan Zubadan Puhz Hw Monobloc
- 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.
On the Ecodan Zubadan Puhz Shw Split
- 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 Co2 Quhz
- 1 Check water circuit (fill, bleed, repair, melt frozen sections); 2 Check/replace pump1 or cylinder board; 3 Measure TH1 resistance, replace; 4 Check LEV coil/CN724; 5 Replace outdoor unit.
- 1-2 Replace outdoor unit.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (refrigeration / R744 CO2).
Certification: High-pressure CO2 (R744) refrigerant competence (Mitsubishi-trained); F-gas regulation not strictly applicable to R744.
On the Ecodan Hydrodan
- 1 Check intake superheat, check for refrigerant leakage, charge additional refrigerant; 2 Check stop valve fully open; 3-4 Power off/on and check whether U3 is displayed; 5 Check linear expansion valve; 6 After recovering refrigerant, remove water from entire circuit under vacuum for more than 1 hour.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (refrigeration / F-gas).
Certification: UK F-gas Category I certification (R32, A2L mildly flammable).
On the Ecodan Puhz Sw Split
- 1 Check intake superheat, check for refrigerant leakage, charge additional refrigerant; 2 Check stop valve fully open; 3-4 Power off/on and check whether U3 is displayed; 5 Check linear expansion valve; 6 After recovering refrigerant, remove water from entire circuit under vacuum for more than 1 hour.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (refrigeration / F-gas).
Certification: UK F-gas Category I certification (R410A).
On the Ecodan Puhz W Monobloc
- 1 Check intake superheat, refrigerant leakage, charge additional refrigerant; 2-3 Power off/on and check if U3 is displayed; 4 Check LEV.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (refrigeration / F-gas).
Certification: UK F-gas Category I certification (R410A).
On the Ecodan R290 Puz Wz
- 1 Check intake superheat, check for refrigerant leakage, charge additional refrigerant; 2 Check stop valve fully open; 3-4 Power off/on and check whether U3 is displayed; 5 Check linear expansion valve; 6 After recovering refrigerant, remove water from entire circuit under vacuum for more than 1 hour.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (refrigeration / F-gas).
Certification: UK F-gas Category I certification plus competence for flammable A3 refrigerant (R290).
On the Ecodan R32 Puz Wm
- 1 Check intake superheat, check for refrigerant leakage, charge additional refrigerant; 2 Check stop valve fully open; 3-4 Power off/on and check whether U3 is displayed; 5 Check linear expansion valve; 6 After recovering refrigerant, remove water from entire circuit under vacuum for more than 1 hour.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (refrigeration / F-gas).
Certification: UK F-gas Category I certification (R32, A2L mildly flammable).
On the Ecodan R32 Zubadan Puz Hwm
- 1 Check intake superheat, check for refrigerant leakage, charge additional refrigerant; 2 Check stop valve fully open; 3-4 Power off/on and check whether U3 is displayed; 5 Check linear expansion valve; 6 After recovering refrigerant, remove water from entire circuit under vacuum for more than 1 hour.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (refrigeration / F-gas).
Certification: UK F-gas Category I certification (R32, A2L mildly flammable).
On the Ecodan Ultra Quiet Puhz W Vaa
- 1 Check intake superheat, check for refrigerant leakage, charge additional refrigerant; 2 Check stop valve fully open; 3-4 Power off/on and check whether U3 is displayed; 5 Check linear expansion valve; 6 After recovering refrigerant, remove water from entire circuit under vacuum for more than 1 hour.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (refrigeration / F-gas).
Certification: UK F-gas Category I certification (R410A).
On the Ecodan Zubadan Puhz Hw Monobloc
- 1 Check intake superheat, refrigerant leakage, charge additional refrigerant; 2-3 Power off/on and check if U3 is displayed; 4 Check LEV.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (refrigeration / F-gas).
Certification: UK F-gas Category I certification (R410A).
On the Ecodan Zubadan Puhz Shw Split
- 1 Check intake superheat, check for refrigerant leakage, charge additional refrigerant; 2 Check stop valve fully open; 3-4 Power off/on and check whether U3 is displayed; 5 Check linear expansion valve; 6 After recovering refrigerant, remove water from entire circuit under vacuum for more than 1 hour.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (refrigeration / F-gas).
Certification: UK F-gas Category I certification (R410A).
What you might notice
What owners and engineers report
3 owner and engineer reports mention this.
- Heat pump will not start on the Ecodan Puhz W Monobloc: 1 report
- Keeps stopping / cutting out on the Ecodan R32 Puz Wm: 1 report
- Insufficient heating (house not warm enough) on the Ecodan Zubadan Puhz Hw Monobloc: 1 report
Sources
- Ecodan QUHZ-W40VA Service Manual (GHH15010) ↗ · GHH15010 · page 13 · Reviewed 23 September 2026
- Ecodan Hydrodan EHWT17D-MHEDW Installation Manual RK79D203K04 ↗ · RK79D203K04 · page 50 (PDF p.51) · Reviewed 23 September 2026
- Ecodan PUHZ-SW(75-100-120)(V-Y)HA-BS Service Manual (OCH755) ↗ · OCH755 · page OCH755 p.24; OCH525C p.22 · Reviewed 23 September 2026
- Ecodan PUHZ-W112VHA-BS Service Manual (OCH562D) ↗ · OCH562D · page OCH562D p.19; OCH605A p.16; OCH465D p.21; OCH439N p.55 · Reviewed 23 September 2026
- PUZ-WZ(85-100-120)(V-Y)AA(-BS) Service_Manual (OCH880) ↗ · OCH880 · page OCH880 p.38; OCH816 p.34 · Reviewed 23 September 2026
- Ecodan PUZ-WM(50-60-85-112)V(H-A)A Service Manual (OCH727A) ↗ · OCH727A · page 25 · Reviewed 23 September 2026
- Ecodan PUZ-HWM140(V-Y)HA Service Manual (OCH748A) ↗ · OCH748A · page 22 · Reviewed 23 September 2026
- PUHZ-W85-112VAA(-BS) Service Manual (OCH681) ↗ · OCH681 · page 16 · Reviewed 23 September 2026
- Ecodan PUHZ-HW140VHA2-BS / PUHZ-HW140YHA2-BS Service Manual (OCH439N) ↗ · OCH439N · page 55 · Reviewed 23 September 2026
- PUHZ-SHW112-140V/YHA Service Manual (OCH526) ↗ · OCH526 · page 26 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026