regards

Kev

https://youtu.be/-RY_epb1epQ

I’m putting together an upcoming video and I’m keen to use real-world homeowner footage. If you’re happy to share, please send anything you’ve got via WeTransfer to editor@renewableheatinghub.co.uk or DM me.

Thanks in advance… it all helps show what’s actually going on out there.

The objective reality is that a heat pump based central heating system can offer superlative efficiency and performance. However that performance is constantly on a knife edge, to use six sigma speak to obtain a satisfactory process capability index it needs to be operating within tightly measured and controlled parameters.

The preventative maintenance schedules I’ve seen are designed to prevent breakdown as opposed to ensuring efficient performance. It would be most insightful to have an episode in which an actual process/design engineer from one of the heat pump manufacturers (or an independent consultant) came on and defined which measuring devices were critical in order to maintain maximal efficiency. My hypothesis being that if, for example, flow temp and flow rate are critical process parameters, then the service should include a check (and/or calibration/replacement) of these sensors, because if they aren’t generating accurate data it’s a physical impossibility that the overall process can be operating efficiently. It’s not that big of a deal, you can obtain simulators to check flow and temp without the need for fancy calibration/metrology. 

The output of the process should drive the maintenance schedule/checklist. Only then would true efficiency be achievable. 

The main thing with flow is that it must be sufficient, which is basically dependent on the original plumbing and the state of the filters.  Cleaning out the filters is definitely a regular maintenance item.

Im far from convinced that performance is 'on a knife edge' but, just like mpg in a car, there are several faults that can affect it.  In my old Mondeo, for example, I knew the exhaust was going when my fuel consumption went up, generally before I could hear it.  I think that owners of heat pumps would be well advised to monitor performance, just like owners of cars would be well advised to monitor mpg.  Either tells you a lot.

And yes I agree critical things should be checked at service time, if practical.  This is where a robust checklist comes in.

The objective reality is that a heat pump based central heating system can offer superlative efficiency and performance. However that performance is constantly on a knife edge, to use six sigma speak to obtain a satisfactory process capability index it needs to be operating within tightly measured and controlled parameters.

The preventative maintenance schedules I’ve seen are designed to prevent breakdown as opposed to ensuring efficient performance. It would be most insightful to have an episode in which an actual process/design engineer from one of the heat pump manufacturers (or an independent consultant) came on and defined which measuring devices were critical in order to maintain maximal efficiency. My hypothesis being that if, for example, flow temp and flow rate are critical process parameters, then the service should include a check (and/or calibration/replacement) of these sensors, because if they aren’t generating accurate data it’s a physical impossibility that the overall process can be operating efficiently. It’s not that big of a deal, you can obtain simulators to check flow and temp without the need for fancy calibration/metrology. 

The output of the process should drive the maintenance schedule/checklist. Only then would true efficiency be achievable. 

The thing I like about a checklist like that is that it immediately sets the tone of the work being carried out. If it's your first service, the engineer will probably spend a lot of time not having to do a thing, but him or her saying "this didn't need doing, and nor did that or that" now comes ready packaged with the modifier "...but I did take the trouble to verify it". Any company putting together a sensible list of things to check is already taking a considered and methodical approach as long, of course, as they then follow it. If you get what that document says you'll get then I, in your situation, would be happy to pay that price.