Hi Bridget. It looks like your immersion (ie Booster Heater) has been used much more than it should have.

The accepted procedure it to run a disinfection cycle once a week to raise the hot water in the cylinder to 60 degrees. It uses the heat pump to raises the hot water to about 52 degrees, then the immersion to heat to 60, so the immersion runs for less than an hour each week.

Normally my hot water is much lower than this: 49 as 'Comfort' and 44 as 'Eco' in Daikin-speak. It heat to Comfort at 3pm when the outside air is warmest, and Eco at 3am so we have enough for showers in the morning. All that is done using the pump.

This is my running hours screen:

 and this is the compressor sub-screen (if that's a word!):

In short I don't think that noise can be anything to do with the immersion !

However you could lower your tank temperatures - what are they set at at the moment ?

@heat-pump-newbie Thank you.

As ever, you are correct.  The booster value has not changed so its not that causing the flow to rise and fall.

Useful to have your stats though.  We've had a bit of a nightmare.  The PCB was faulty so initially we only had hot water from the immersion heater and then they rigged it to manually switch to heating (but it was relying on the booster).  That got partially fixed, as firstly one and then another PCB was replaced.  We ran for a while on leaving temp of water as that was all that was working.

Then the hysteresis value of the hot water was set too wide so it wasn't heating up until it got down to 20 degrees, but we didn't know that so I was having to switch to boost, switch it straight off again but that diverted the system from heating to hot water.  

And finally, the disinfection has been dodgy.  It failed a few times, at one point was set to get to 70 degrees in 10 mins and couldn't and then the switch was getting stuck.  So all that will have used the boost.

All that seems to be sorted now, but has probably used a lot of electricity.

I think you have your hot water set on scheduled.  Ours is on heat up only - so just switches on demand.  The tank is at 50, hysteresis now at 10 so once it drops to 40 it switches across.

So far, so good on the weather dependent curve.  The thermostat in the hall has maintained a consistent 19 degrees which is comfortable.  I'll report back after a few more days.

Noise still a problem though.  The flow seems to vary from a quiet 11.4 l/min to a noisy 30.6/min and other values in between.  The noise is definitely coming from the water roaring through the pipes in the airing cupboard and that holding tank and also round the towel rail in the bathroom adjacent which seems to be connected into the circuit.

Hi - our hot water is on Schedule + reheat. The reheat setpoint is 40 deg and hysteresis is 10, and it only reheats occasionally.

Still noisy... argh !!

@bridgetjohn 

Hi Bridget,

So that we can try to help you cure the noise problem, could you provide details of the conditions under which the noise occurs and when it is quiet. There may be changes that can be made to how the water pump operates that will keep the flow rate within acceptable limits.

@bridgetjohn 

Hi Bridget,

The following is an extract from the manual.

5.2.5 To insulate the water piping
The piping in the complete water circuit MUST be insulated to
prevent condensation during cooling operation and reduction of the
heating and cooling capacity.

It would appear that your installer failed to do so.

Hi Everyone,

The text below is an extract from a Daikin installer manual. I wonder how many customers actually received this level of service?

10 Hand-over to the user
Once the test run is finished and the unit operates properly, please
make sure the following is clear for the user:
▪ Fill in the installer setting table (in the operation manual) with the
actual settings.
▪ Make sure that the user has the printed documentation and ask
him/her to keep it for future reference. Inform the user that he can
find the complete documentation at the URL mentioned earlier in
this manual.
▪ Explain the user how to properly operate the system and what to
do in case of problems.
▪ Show the user what to do for the maintenance of the unit.
▪ Explain the user about energy saving tips as described in the
operation manual.

@derek-m

It's crazy that simple things like those on the list weren't done, not in my case certainly. Filling out that table would have been a start. Also a verbal explanation at 'hand-over' is useless, unless the customer already understands every aspect of the system already.

Having links to online documents is all very well but the Daikin documents also assume a knowledge of heat pumps that the average customer just doesn't have. 

@heat-pump-newbie A verbal handover would be nice, we didn't even get that, my wife was just told it was working

@witchcraft Unbelievable !! And was it ?

@heat-pump-newbie It was working with a flow temperature of 55 degrees and no weather compensation, thanks to this forum I now know far more than the clowns that installed my heat pump

Hi Bridget,

I have had a further thought. What is the diameter of the pipework on your system? If you have a change in pipe diameter, then the velocity of the flow through the pipework will also change.

Hi Mars,

You have had discussions with the staff at MCS. Whilst they set the standards installation, do they have any responsibility for enforcement or is that down to some other organisation? If so who?

How do they deal with complaints about poor installation and commissioning by accredited installers?

Maybe time for a further video.