Posted: Wed Jan 13, 2021 10:22am
That should be fine then, just don't tell them that you think there might be a problem - just let them service the unit(s) and then ask them to demonstrate to you how it performs under heating and cooling requests. Any decent engineer will take temperature readings in your presence, and show these to you as evidence of the unit's performance.
If desirable temperatures can't be achieved, then they will probably cite low gas in ht eunit and top it up as a quick fix - this is not the way to do it tbh and goes against all protocol as low gas generally indicates a leak somewhere in the system which should be fixed first - otherwise the same problem will recur again, and again.... However, most customers happily accept a top-up, as this will geerally resolve the issue (for a short time anyway) and will be cheaper than the engineer going through the whole process of finding and repairing a leak...