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Here you’ll find some information on potential NIBE ground source heat pump problems, along with some tips on how to diagnose and repair them.

NIBE 1145-1245 alarm troubleshooting

Alarm 52 Temperature limiter

This alarm is due to the immersion heat limiter within the GSHP tripping out, this will need to be manually reset and involves the front cover being removed from the GSHP.

Firstly, turn off the power to the GSHP via the isolation switch, to remove the front cover locate the two screws found at the base of the front cover on the left and right corners once the panel is removed the temperature limiter reset button can be pressed back into place with a small screwdriver.

Nibe 1145-1245 - alarm 52 temperature limiter

 

Alarm 45 Phase fault

This alarm indicates the motor protection cut out switch has tripped to an off position and will require a manual reset.

Firstly turn off the power to the GSHP via the isolation switch, to remove the front cover locate the two screws found at the base of the front cover on the left and right corners once the panel is removed locate the motor protection cut out switch and turn it back to it default position see the attached example below.

Nibe 1145-1245 - Alarm 45 Phase fault

High Pressure alarm

A high-pressure alarm is caused by a poor flow rate on the waterside of the heat exchanger in the heat pump this then leads to the system over heating and shutting down.

The most likely causes for this alarm are:

  • A lack of system water – 1 bar of water pressure is required within the heating system.
  • A blocked strainer valve.
  • Isolation valves on the system have been closed.
  • An air lock within the pipework.
  • A closed cylinder zone valve.

Alarm 51 LP alarm

A low-pressure alarm can occur if the glycol fluid level has dropped too low in the ground loop pipework side of the system, or if the filter valve on the ground loop pipework has a blockage this will need to be inspected and cleaned if required. This should be checked annually as part of your yearly service.

The GSHP system will commonly be running around 1 bar of system pressure on the ground loops. This pressure can vary in times of cold weather, so always check the level vessel for signs of glycol.

If the glycol levels require constant topping up this could indicate a possible leak on the ground loop pipework and should be investigated.

 

Nibe 1145-1245 - Alarm 51 LP alarm

NIBE S1155-S1255 alarm troubleshooting

Alarm 167 Temperature limiter

This alarm is due to the immersion heat limiter within the GSHP tripping out. This will need to be manually reset and involves the front cover being removed from the GSHP.

Firstly, turn off the power to the GSHP via the isolation switch. To remove the front cover, locate the single screw located above the display screen – once the panel is removed, the temperature limiter reset button can be pressed back into place with a small screwdriver. It will require a reasonable amount of force to reset this.

Nibe 1155s -1255s - Alarm 167 Temperature limiter

Alarm 165/166 Low pressure

A low-pressure alarm can occur if the glycol fluid level has dropped too low in the ground loop pipework side of the system, or if the filter valve on the ground loop pipework has a blockage, this will need to be inspected and cleaned if required. This should be checked annually as part of your yearly service.

The GSHP system will commonly be running around 1 bar of system pressure on the ground loops; this pressure can vary in times of cold weather so always check the level vessel for signs of glycol.

If the glycol levels require constant topping up, this could indicate a possible leak on the ground loop pipework and should be investigated.

Nibe 1155s -1255s - Alarm 165-166 Low pressure

 

High Pressure alarm

A high-pressure alarm is caused by a poor flow rate on the waterside of the heat exchanger in the heat pump; this then leads to the system over heating and shutting down.

The most likely causes for this alarm are:

  • A lack of system water – 1 bar of water pressure is required within the heating system.
  • A blocked strainer valve.
  • Isolation valves on the system have been closed.
  • An air lock within the pipework.
  • A closed cylinder zone valve.

Heat pump user guide

Need more help to resolve a NIBE ground source heat pump problem? You can contact our Technical Support Team via tech.support@nu-heat.co.uk or give them a call on 01404 540745 between 8am and 5pm, Monday to Friday.

Can’t find what you’re looking for?

You can contact our Technical Support Team or give them a call between 8am and 5pm, Monday to Friday.