Installation and Commissioning · 4 lessons
Commissioning a heat pump system
Commissioning proves the system works as designed and leaves a record of how it was set up. The water side comes first: clean water carries heat.
Have a go
0Does normal static pressure establish adequate circulation?
Tap an answer
Clean water
Dirt and corrosion block small passages and slow the flow. Systems are cleaned before commissioning; BS 7593 is the code of practice for treating heating water. A magnetic filter catches magnetic sludge, and inhibitor slows corrosion, but neither replaces proper cleaning.
Fluid and pressure
The commissioning record notes the fluid, any glycol and its concentration, the air removed and the fill pressure, saying whether a reading was cold or hot. Topping up plain water dilutes glycol's frost protection, and a pressure that keeps falling needs investigating.
The paperwork
The handover pack lists the equipment, design, commissioning results, control settings and maintenance needs, as finally installed. For an MCS certified installation, the MCS contractor registers it and issues the MCS certificate, which is separate from electrical and building control paperwork.
Explaining it
A heat pump runs for longer than a boiler, with cooler radiators, and an air source unit drips and steams a little when it defrosts. Showing the customer their everyday controls, and who to call about an error code, heads off a lot of worried phone calls.
Common mistakes
- Judging glycol or inhibitor strength by the colour of the water.
- Topping up a system that keeps losing pressure without finding out why.
- Handing over records that describe the original design, not what was installed.
The lessons this guide comes from
- Flushing and cleaning
- Filling, venting and pressure
- Records and MCS paperwork
- Explaining the system
Keep learning
Sources
Sources checked 31 October 2026. Guidance, grants and official pages can change.
- MCS: Our roleMCS as a quality mark for small-scale renewable systems, with product and installation standards for certified installers.