@derek-m Ah yes - that's this one (photo attached)

I've had a look at a video online of one attached to a regular gas boiler.  Presume the same principal

- turn off the system

- close both red valves

- follow his instructions

Should this be done on a regular basis?  I didn't even know I'd got one!!!

@sarah

I suppose the answer is 'how long is a piece of string'. The frequency of how often to clean your filter will depend upon how much debris accumulates within the system. If you find that after cleaning the filter, the flow rate increases, then periodically check the flow rate and clean the filter when it starts to fall. Otherwise maybe every 6 months initially, reverting to once per year as the system gets cleaner.

Is it the service manual you have for reference? At the bottom of page 6 it states the water flow rate range is 10.0 to 24.8 l/m. Similar to mine, though I have also seen the tank installation manual be a bit more specific that the flow rate should be 24l/m. Not sure what to make of that difference. There is discussion in other threads about altering the flow rate to manage the difference between flow and return temperatures to 5°C, but if the manifold temps of 28 and 21 are typical then you have a slightly too large difference, which is to be expected if the flow rate is lower than it is meant to be.

The main potential problem with the lack of insulation on the pipework around the tank is that that is where the flow and return thermistors are clipped to the pipes. They are just below the main FTC box, one to the right and the other is behind the plastic box to the left of it. Without insulation covering them they are likely to be below the temperatures of the water in the pipes themselves and may be resulting in the pump raising the actual circulation temperatures more than it needs to.

I had one thought about checking to eliminate one possible issue – when the bathroom and bedroom are up to temperature but the living area is not, is the heat pump still running and the heating circuit still flowing? Just in case for some reason the living room is not able to keep a call for heat 'live'.

Related to your general high costs, when looking at the summary of settings pics you posted you have the tank heated to a high temperature, and a very small drop in temp to trigger a reheat. And a high Legionella temp kept for 3 hours every two weeks. The high target temp will demand more energy to get to reach, and heat loss from the tank and pipework will drop 5° in about ten hours even if you don't draw a cup of water off thus triggering a small amount of HW work from the pump but at the least efficient end of its range. I would recommend setting the schedule so it has a break thus triggering a new HW cycle at some point in the day when you have solar production, dropping the target temperature to 50 or less ( some people go for 45-48), and increasing the drop to 10 or more.

As a comparison I heat the tank once a day (in the afternoon to get the most of any solar power) to 50°, and have the schedule restricted to three hours so it won't heat again until the next day (for various reasons I won't go into). By the following morning the measured temperature of the tank has dropped by about 10° yet the water is still hot enough for two showers.

Legionella protection is required of the installers at setup, but is widely considered to be unnecessary and turned off by many users. If you want to keep it I would at least recommend changing it to 60° for an hour perhaps, rather than 3 hours – as it is done by means of the immersion element.

I don't understand the second page of the settings though. HHC? And what flow is at 15°C?

I'll stop there – I've added quite enough for one post I think!

@derek-m I've cleaned out the filter - not dirty at all - I guess this is because it's underfloor heating ?  Good to know how to do it and I didn't even realise I had the release tool - I did wonder what that was for !!

Posted by: @sarah

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@derek-m I've cleaned out the filter - not dirty at all - I guess this is because it's underfloor heating ?  Good to know how to do it and I didn't even realise I had the release tool - I did wonder what that was for !!

At least you know that the filter is clean. I don't suppose that it has made any difference to the flow rate.

The next task will be to confirm that all the manual valves in the pipework are fully open. Then make a note of the setting of all the flow regulation valves at the UFH manifolds.

What are the manifold temperature gauges reading?

@harriup OK - changed legionella settings to:

Temp - 60 (it was 65)

Frequency 15

Start 10:00 (was 03:00)

Max Op time 1 hour (was 3 hours)

Duration of max temp 1 minute (was 30 mins)

OK - it's Friday night and I'm still looking at my ASHP settings - but this is it for the night now!  In addition to the legionella changes - I've also changed the hot water temp to 50 degrees - (was 55) and the drop to 10 degrees (was 5) - I've attached picture of the changes.  I've also lagged most of the hot water pipes 🙂  Once again...thanks so much for all your help and advice.

Posted by: @sarah

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hot water temp to 50 degrees - (was 55) and the drop to 10 degrees (was 5)

interesting as doesn't seem to make any difference to speed of pump - for the last couple of days I've had it at 3 and running info shows 13 - I change the pump speed to 5 and running information still 13 - maybe this is the highest mine will go? 

Posted by: @sarah

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interesting as doesn't seem to make any difference to speed of pump - for the last couple of days I've had it at 3 and running info shows 13 - I change the pump speed to 5 and running information still 13 - maybe this is the highest mine will go? 

If you are changing the pump speed on the FTC controller, it will only vary the flow rate if it is wired to the main water pump and is actually varying the pump speed. Do any of the pumps have two cable connected?

If, as I suspect, the main water pump is not being controlled by the FTC controller, the only way to vary the flow rate would be by using the button on the actual pump. I suggest that you download the manual for the pump.

@derek-m yes I think you're right - I can only see one wire and they are on number 3 the highest setting.  Had a QUICK look at a manual on-line - but that's a little beyond me.  I guess this was how it was designed.

Posted by: @sarah

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@derek-m yes I think you're right - I can only see one wire and they are on number 3 the highest setting.  Had a QUICK look at a manual on-line - but that's a little beyond me.  I guess this was how it was designed.

What are the readings on the temperature gauges at the UFH manifolds?