So over that 10 to 15 years of operation, how much does the power capacity of the heat pump reduce as the components age, degrade and get fouled?

Most articles I've read emphasize the important of sizing the heat-pump as a close as possible to the design heat demand, but presumably that ASHP capacity is when it's brand new, when the fine finned heat exchanger is perfectly clean and the compressor is as tight and well sealed as it will ever be, that 8kW heat pump is 8kW brand new out of the box, but what's it actually capable at year 10 when the heat exchanger is somewhat fouled , fins are coated with a layer of dirt or some areas even somewhat clogged and when the compressor internals are loosening up. 

I'm wondering if there could be an argument that having a bit of a safety margin (how much?) between the design demand and the heat pump capacity, to ensure it's still capable of meeting demand in years 10 or 15 ?

We have just had a Grant Aerona R290 installed and it seems to be having a problem in getting to the target DHW temp of 47c. It has a hysteresis setting of 6c and I recently discovered that it has a DHW temp correction of 2c in the Installation Controller - Main heat source configuration. It also has a DHW Set Temp of 45c on the controller display (but 450c on Econet24!). I suspect the latter is a default value though.

I think that the real target would be 47c plus the temp correction of 2c giving 49c. However, would it be "satisfied" if it came up to the hysteresis value of 49-6? Aaarrgghh! (It was much simpler with our older GSHP.)

I reckon this results in the HP attempting to get the DHW up to temp and therefore cycling as shown on Home Assistant:

I do not understand why the heat pump would just stop attempting to get the temp up to target.

Makes me wonder about Econet24 too - it lost Circuit 2 last week and I thought the power cut this morning would reset the link from the Econet300 to the server. Still no circuit2!

When I reduce the target or use the schedule to remove the DHW priority, the CH system works well with an existing UFH utilising Uponor controllers.

It doesn't help that there are some discrepancies between the Smart Controller manual and what the Smart Controller is displaying. There again, this technology is advancing at a fair old pace!

Anyone had similar problems with these heat pumps or Smart Controllers?

Any advice/tips would be gratefully received as I have racked my poor befuddled brain with this!

Thank you,

Gerald.

At a more sane hour I investigated.  It was definitely the heating system and it wasn't getting any better.  Some of the pipes were vibrating.  The noise was much louder indoors than out and removing the sides from the heat pump confirmed that neither the compressor nor the water pump was making a loud noise.     At this point I started to fear the need to dismantle internal walls behind which primary pipework had been hidden in order to reveal some unknown point where pipes were touching something that they were not previously touching.  Not a pleasant prospect.

After some more head scratching and consternation I decided to 'shock' the system by turning off the isolation valve behind the heat pump rapidly but momentarily, and then turning it back on again, all while the heat pump was still running.  Problem immediately vanished and so far has not reappeared.

Im guessing that an air lock had developed somewhere in the (necessarily) fairly convoluted primaries and was causing them to vibrate.  'Shocking' the system dislodged the bubble which is hopefully now sitting somewhere innocuous, like at the top of a radiator.

One for the toolbox I think.

My anecdotal evidence on the labour side is plentiful. From enquiry and planning stage (that we are personally going through) to the cases that we keep seeing being reported in the forums. The effect of the skill and labour shortages is very obvious. 

On the regulatory side, we are personally benefitting from some good steps taken to reduce the uncertainty on permitted development and locating a heat pump. As new models are quieter and more pleasing to the eye, this can help stimulate demand as it would allow large parts of the housing stock to be retrofit more quickly. 

There still is a lot more than could be done to reduce the burden on installers to notify/apply to DNO, building control, etc. I am no expert, but could some of these things only be justifiable during the initial tentative deployment and a different approach possible when it is being deployed at larger scale?

Like how many risk management layers are required to check whether a heat pump, a device typically using 2kW can be safely fit in a home served by a 60A fuse (I am assuming this is the lowest in a typical house)? Electricians are in short supply to install EV chargers and all that. There must be a way to reduce the burden of all this HP related paperwork.. Some of it is not regulatory, like the concept that we need a qualified electrician to run some comms cables for pump controls may deserve scrutiny... 

Is capture a worthwhile addition rather than the ShinePhone one provided by Growatt.

Can I mess up my settings by using and playing around on it. It wants my API code to link and no idea if that’s a good idea, whatever that is.  

Is there a better app to manage my system or as mentioned just stick with ShinePhone 

I'm trying to understand around the buffer tank and the set point on the dixel controller. What should the set point be set to as I understand that it only triggers the circulation pump when it reaches that +2c but if the WD curve is currently 25C and the set point is 30c, it won't ever reach it I thought? Sorry if this is dumb question 

I have just had my HP commissioned and i have an issue with the auto control. Currently I run the HP on auto from 03:00 to 10:00 and then 16:30 to 23:00. The house remains warm during the day so no need for the heating. I'm running on waterlaw when in auto. The problem is every time the HP starts in auto at 03:00 and 16:30, the controller gives a +5C offset to the waterlaw. I remove the offset, either by using the smart things app or the controller screen. However next auto time starts the +5C is added back in. I've looked through FSV settings and can't see anything that jumps out that I need to change. Any help really appreciated.

The latest EPC was over 13 years ago and it came out as grade D. I suspect that this was done prior to some of these upgrades (by the previous owner).

We typically run our heating at 18 degrees throughout the house (with a 2 degree set back over-night) and leave it running constantly throughout the winter months between about October and May.  We also heat domestic hot water using oil most of the time, although I do use the immersion if there is a battery surplus from solar (Generation based FIT) or if the Agile rates are cheaper than the cost of oil.

It's not to say that we would jump at moving to a heat pump immediately but, with the current cost of oil and the increase in BUS grant, the argument to do so has become more compelling.

If I go to the heat geek site, the estimated heat loss is about 19KW and it's hard to get them excited about our house unless we pay for a bespoke black label service. 

With an 18KW heat loss calculation and concerns about installers and poor SCOP achieved, I wonder if riding out Trump's warmongering and hoping that the cost of oil will drop is a better proposition. That said, if I do the maths using a formula that I found on another thread on this site, with our oil usage over the past 12 months, being about 2010 litres, we would need a heat pump of around 8KW.  

I do appreciate that an accurate figure only comes from a proper heat loss survey and this, quite rightly, involves time, effort and the use of software which needs to be paid for. I wonder though, why the on-line estimate is twice as much as what appears to be real use data - are our delta T's different, are incorrect assumptions from an out of data EPC being used or is it something else?

Your thoughts are welcome.

thanks.