Cleaning the heat exchanger
Dirt that accumulates on the coils comes from airborne particles, insects, leaves, etc. which in conjunction with the high temperature of the coil can become ‘baked’ on and prove very difficult to remove unless you’re using the right cleaner.
So called “mechanical cleaning” using a brush or other tool is a good first step, but to clean the coil thoroughly you should consider a chemical cleaner. They cost pennies and the difference compared to mechanical cleaning can be profound, especially when it comes to maximising the unit’s efficiency and extending the period between services.
While there are products available that are environmentally friendly, for stubborn deposits you may wish to use a heavier duty solution like SuperClean.
Apply a protective coating to ensure long term corrosion protection
This is particularly important if the unit is near the sea. Due to the high levels of salt in the air in these environments, the aluminium fins can become corroded very quickly which will affect the unit’s ability for effective heat transfer.
External leak checking
Replace face panels
When replacing the facia panels ensure the casing fits correctly and snugly. Turn the unit back on at the isolator to make sure it functions appropriately.
You then want to check for vibrations, so operate the unit and force it to come on cooling; ramp the heating up to check this.
Listen and look at the unit to check it sounds as it should, and ensure the compressor or fan is not vibrating on bouncing on its brackets.
Now it’s time to ensure all sealing caps on connections to the refrigeration system are replaced. There will be two connections, one on the high side and one on the low side (they have valves on them and plastic caps).
Engineers can use existing caps unless they’re worn or have deteriorated, but it is a good idea to invest in tamper-resistant security caps.
Spanner-operated security caps prevent a member of the public from opening and venting the unit maliciously (like a car or bike tyre), and they also act as an extra level of security if the valve fails.
Visual check and completion of the F Gas Label
Focus on flared joints, as these are mechanical connections, and braised joints (again, you may need to move insulation out of the way). Engineers should also detail the weight and gas in the system on the F Gas label.
Before you leave, simply clean the fascia and case, remove any grease, fingerprints or grime using with a finishing case cleaner like EasyFinish.