Heat Pump Commissioning Checklist (Benchmark and MCS)
Commissioning is where a well-designed heat pump either delivers its promised efficiency or gets condemned to a life of high bills. Work through the checklist in order and record everything — the Benchmark and F26B depend on it.
A heat pump that was designed properly can still perform badly if it's commissioned in a hurry: flow temperature left at the factory default, weather compensation never set up, emitters unbalanced, customer never shown the controls. The commissioning visit is where the design assumptions are proven on the running system — and where the two documents that matter, the HHIC Benchmark checklist and the MCS F26B handover certificate, get their data.
This is a practical commissioning checklist for air source (and, with obvious adjustments, ground source) heat pumps, in the order you'd work through it on site, ending with the records to complete before handover.
Key takeaways
- Commission against the design: the target flow temperature and heat loss figures are the pass/fail criteria, not the factory defaults.
- Flush, fill, pressurise and treat the system before running the heat pump — water quality failures kill heat exchangers and warranties.
- Set the weather compensation curve to the design flow temperature and confirm the system holds it at a steady state.
- Balance the emitters so every room reaches its design temperature at the design flow — this is where most 'my heat pump doesn't work' calls are born.
- Complete the Benchmark checklist and the MCS F26B at handover — one validates the warranty, the other supports MCS certification and the grant.
Before you start: the system must be ready
Commissioning starts before the compressor does. Confirm the system has been flushed and filled to the manufacturer's water-quality requirements, the inhibitor (and antifreeze, where the design uses it) is dosed and recorded, the system is pressurised to the design cold-fill pressure, and air has been purged from the circuit — including the heat pump itself, per the manufacturer's procedure.
Check the electrical side is certified and ready: dedicated circuit, isolation local to the unit, and controls wiring complete. The condensate drain, outdoor unit clearances and anti-vibration mounts are worth a final look now, because after handover they become a callback.
The commissioning checklist
With the system running, work through the settings against the design: set the design flow temperature and confirm the unit achieves and holds it; configure the weather compensation curve so the flow temperature tracks outdoor temperature as the design intends; set the DHW target temperature and the legionella cycle per the cylinder design; and configure the backup or immersion heater so it supports rather than substitutes for the heat pump.
Then prove the system: run the heating at a steady state and check the delta-T across the heat pump matches the design, confirm each emitter circuit reaches temperature, and run a complete DHW cycle. Record the readings as you go — flow and return temperatures, pressures, and the settings you've committed.
The factory default is not a setting
A heat pump left on its out-of-the-box curve will heat the house — expensively. The single highest-value commissioning action is setting the weather compensation to the design flow temperature and proving the house heats at it.
Doing this on a job? Heat Pump Handover Certificate (MCS F26B) — part of TradePlanr. Free to start, no card needed.
Balancing: the step that gets skipped
Heat pumps run at low flow temperatures with small delta-Ts, which makes emitter balancing far more consequential than on a boiler system. Balance the radiators or UFH loops so each room achieves its design temperature at the design flow rate — unbalanced systems overheat the near rooms, starve the far ones, and push the customer to wind the flow temperature up, destroying the efficiency the design promised.
Record the final lockshield positions or flow-setter readings where the system has them. It turns the next visit's fault-finding from guesswork into comparison.
Benchmark and MCS F26B: the records
Two documents come out of the commissioning visit. The HHIC Benchmark commissioning checklist records the appliance setup — flow temperature, weather compensation, system fill and pressure, water treatment, balancing and the commissioning readings — and is what most manufacturers require to validate the warranty. The MCS F26B handover certificate confirms the installation meets MCS requirements, records the performance estimate and documents that the customer handover took place; it supports the MCS certification that unlocks the Boiler Upgrade Scheme.
They are not interchangeable and both are needed on an MCS job. Complete them at the appliance while the readings are in front of you, and add both to the customer's handover pack alongside the electrical certificate and warranty documents.
Handover: the customer is part of the system
Walk the customer through the controls: what the weather compensation is doing, why the radiators feel cooler than they expect, what they can adjust and what they shouldn't touch. A customer who cranks the flow temperature to 55°C in week one undoes the commissioning — the handover conversation is what prevents it.
Record that the demonstration happened (the F26B asks for it), leave the user instructions, and make sure they know the service schedule that keeps the warranty alive.
Complete both records on site
TradePlanr has the Benchmark commissioning checklist and the MCS F26B as forms you fill in at the appliance — signed on screen and sent as branded PDFs before you leave the job.
From guidance to action
Frequently asked questions
What should a heat pump commissioning checklist include?
System preparation (flush, fill, pressure, water treatment), the design flow temperature and weather compensation setup, DHW and backup heater configuration, emitter balancing, steady-state proving readings, and the customer handover — all recorded on the Benchmark checklist with the F26B completed alongside.
Is the Benchmark checklist the same as the MCS F26B?
No. Benchmark records commissioning against the manufacturer's instructions and validates the warranty; the F26B confirms the installation meets MCS requirements and documents the handover. An MCS job needs both.
What flow temperature should a heat pump be commissioned at?
The one the design specifies — commonly in the 35–50°C range depending on the emitters. Commissioning proves the house reaches design temperatures at that flow; it isn't a number to pick on the day.
Do ground source heat pumps use the same checklist?
The heating-side checklist is largely the same. Ground source adds the ground loop: confirm the brine concentration, loop pressure and flow rates against the design, and record them with the other commissioning data.
Related guides
Air Source Heat Pump Installation Guide
System design, siting, commissioning and the Benchmark and MCS paperwork for an ASHP install.
MCS Certification Explained
What MCS is, why it gates the grants, and how to become and stay an MCS-certified installer.
The MCS Handover Pack: Complete Document Checklist
What goes in the MCS handover pack for solar PV and heat pump installs, who sends what, and how to hand it over cleanly.
Renewables Commissioning Paperwork: What You Need
Every document a renewables install needs at commissioning — solar PV, battery, heat pump and EV charger — and who each record is for.
