What we do

Details about Checkmark’s connecting, testing, commissioning and certifying package for DIY installs.

About the £349 package

Checkmark offers a fixed price package to help you legally and responsibly complete your DIY mini-split air conditioner / heat pump install. The price is based on connecting, testing, commissioning and certifying a 5kW or less ‘mini-split’ air-source air conditioner / heat pump with one outdoor and one indoor unit. It is ideal for those looking to put a unit in a home or garden office, workshop or other space.

What is included

1. A Pre-visit video call

A Pre-visit video call

A pre-visit video call to review the install, confirm the install work done so far, answer any questions and arrange the visit.

This is useful to ensure everything is ready for commissioning.

2. Connecting the pipework

Connecting the pipework

Flaring of the copper pipe ends, and connections to the outdoor and indoor units.

The quality of the flare is crucial, especially for refrigerants like R32 that operate at a high pressure.

3. Pressure leak test

Pressure leak test

This involves pressurising the lines and indoor unit with Oxygen Free Nitrogen and conducting a leak test (both a timed and joint bubble test).

A pressure test is more effective than a vacuum leak test because it is testing for leaks at system pressure, rather than under a vacuum which tends to ‘pull’ small leaks closed.

4. Evacuating the system

Evacuating the system

This involves connecting a vacuum pump to the system and removing air/nitrogen down to at least the vacuum specified in the system manual. A vacuum hold test will be performed and any issues investigated.

5. Commissioning the system

Commissioning the system When all tests are good, the pre-charged refrigerant will be released from the outdoor unit into the vacuumed pipes and indoor unit.

The system will then be checked to ensure it is operating to specification.

6. Certification and documentation

Certification and documentation System temperatures and pressures are checked against manufacturer data and recorded in a commissioning log.

This forms the first part of the service record.

What is not included

The fixed price package is designed to cover most DIY requirements. There may be extra charges if:

  1. The install is outside the M25 or more than 20 miles from Bromley, Kent.
  2. The pipe lengths are longer or shorter than the ‘pre-charge’ lengths that the unit allows in its documentation (often minimum 3m or maximum 15m per line).
  3. If pipes need lengthening or brazing (pipe runs are typically available up to 30m so this would be unusual)
  4. If condensate pumps need to be installed.
  5. The install is at a commercial premise.

The initial and pre-visit calls are designed to identify all of the above, meaning unexpected additional costs are avoided. If you have any questions then please don’t hesitate to contact us.