@derek-m thanks for the update, I've had it switched off for a few weeks for the purpose of my testing. There is actually no control on this install yet other than LWT. I've lowered the temp to 40C as I am also challenging the installers lack of radiator upgrades (for another thread!)  I have has to run the DHW manually by opening up that 2-port and raising the temperature, but sometimes i forget or cant get back to manually close that valve and lower the temp so my bills have been high.
Radiators all are sized for peak load AND a rapid heat up time. If the rapid heat up time is designed out with weather compensation there is no need to replace radiators..
So the original quote (pre-design survey) included new upgraded Rads throughout. Once Covid restrictions lifted a surveyor came around and measured all the rooms and windows and noted the external wall composition, he seemed thorough and said it would be put into the design calculator. I have never seen a design.....
When the plumbers came around to do their site survey they looked at the rads and said they were fairly new and didn't need upgrading. My thoughts on this upon completion (when I thought it would be completed) is that I would get a discounted price as they haven't installed the rads and associated valves, so I left it at that.
However, as the months passed and we entered winter it gave me an opportunity to test the rads out in real world against LWT flow temps.  My recent discovery is that it is losing 5C before it even hits the distribution (see part 1 thread) so the room temperatures to flow temps are actually better than in this spreadsheet (as we are 5C less than the LWT setpoint).
I wanted to see how balancing the rads and flow temperature impacted room temperatures. My exterior house composition is a mixture of 50% solid brick (soft brick and lime mortar), 25% cavity wall and 25% solid brick enclosed by a conservatory (which i am regarding as insulation for that part of the house).
As i had a house full of kids and my elderly mum I didnt want to plunge the temperatures and freeze everyone, so I started at a high flow temperature 50C as left by the installers and checked the room temps and TRV4 balancing settings.
note:Â When the now removed boiler was running I had balanced all rads to be 12C Delta using the TRV4 balancing method as opposed to the return lockshield method as this gives a more accurate method of recording.
I also played with the Grundfoss Circ pump, it was left on constant speed 2 (fastest) by the installer but I have read that Constant Pressure maybe be beneficial where buffer tanks are installed. It probably wont make any difference to most installs but I was just inquisitive.
At around the same time each day i would record room temperatures and outside temperature as well as KW used.  At the hotter flow temperature some rooms were going over 21C whereas others would not reach, so i would adjust the lockshield (open) on those underperforming rooms or close the overperforming rooms.
Eventually, to where we are now I have most of the TRV4 lockshields fully open and i am hoping for a couple of warmer days to see how that impacts room temperatures, noting that the Daikin has a COP of >4 at 35C LWT and 7C outside. So i'm looking for those 7C days as the benchmark.
Summary:
You can see that Bedroom 3 and the Play Room never reach temperature even at high LWT, one of these rads is a single panel and the other is half size so in essence another single panel. The other rooms are not too bad but not great either.
When the ASHP is plumbed properly (thread 1) this will impact the performance positively but those two rooms at a minimum will not perform based on these stats.
The KW used is interesting, the difference in the 50C LWT compared to the 40C LWT is around 50% more at the higher temperature, so that proves a point that some of our experts on this forum keep mentioning and well worth listening to.
I have basically been a human compensator in this trial, my aim is to find the lowest LWT to heat the rooms to the warmest desired level and only use TRVs or a lockshield to limit those rooms which I don't want at that level.
The rads are basically no longer balanced as I had to open all the TRV4 lockshield to maximum flow to keep temperatures up as the LWT was lowered.
Of course I shouldn't have had to do any of this as my installer should have designed it properly and the plumbers should have stuck to the design (if it existed).Â
I have passed this information on to the installer and wait to hear the reply.
So the original quote (pre-design survey) included new upgraded Rads throughout. Once Covid restrictions lifted a surveyor came around and measured all the rooms and windows and noted the external wall composition, he seemed thorough and said it would be put into the design calculator. I have never seen a design.....
When the plumbers came around to do their site survey they looked at the rads and said they were fairly new and didn't need upgrading. My thoughts on this upon completion (when I thought it would be completed) is that I would get a discounted price as they haven't installed the rads and associated valves, so I left it at that.
However, as the months passed and we entered winter it gave me an opportunity to test the rads out in real world against LWT flow temps.  My recent discovery is that it is losing 5C before it even hits the distribution (see part 1 thread) so the room temperatures to flow temps are actually better than in this spreadsheet (as we are 5C less than the LWT setpoint).
I wanted to see how balancing the rads and flow temperature impacted room temperatures. My exterior house composition is a mixture of 50% solid brick (soft brick and lime mortar), 25% cavity wall and 25% solid brick enclosed by a conservatory (which i am regarding as insulation for that part of the house).
As i had a house full of kids and my elderly mum I didnt want to plunge the temperatures and freeze everyone, so I started at a high flow temperature 50C as left by the installers and checked the room temps and TRV4 balancing settings.
note:Â When the now removed boiler was running I had balanced all rads to be 12C Delta using the TRV4 balancing method as opposed to the return lockshield method as this gives a more accurate method of recording.
I also played with the Grundfoss Circ pump, it was left on constant speed 2 (fastest) by the installer but I have read that Constant Pressure maybe be beneficial where buffer tanks are installed. It probably wont make any difference to most installs but I was just inquisitive.
At around the same time each day i would record room temperatures and outside temperature as well as KW used.  At the hotter flow temperature some rooms were going over 21C whereas others would not reach, so i would adjust the lockshield (open) on those underperforming rooms or close the overperforming rooms.
Eventually, to where we are now I have most of the TRV4 lockshields fully open and i am hoping for a couple of warmer days to see how that impacts room temperatures, noting that the Daikin has a COP of >4 at 35C LWT and 7C outside. So i'm looking for those 7C days as the benchmark.
Summary:
You can see that Bedroom 3 and the Play Room never reach temperature even at high LWT, one of these rads is a single panel and the other is half size so in essence another single panel. The other rooms are not too bad but not great either.
When the ASHP is plumbed properly (thread 1) this will impact the performance positively but those two rooms at a minimum will not perform based on these stats.
The KW used is interesting, the difference in the 50C LWT compared to the 40C LWT is around 50% more at the higher temperature, so that proves a point that some of our experts on this forum keep mentioning and well worth listening to.
I have basically been a human compensator in this trial, my aim is to find the lowest LWT to heat the rooms to the warmest desired level and only use TRVs or a lockshield to limit those rooms which I don't want at that level.
The rads are basically no longer balanced as I had to open all the TRV4 lockshield to maximum flow to keep temperatures up as the LWT was lowered.
Of course I shouldn't have had to do any of this as my installer should have designed it properly and the plumbers should have stuck to the design (if it existed).Â
I have passed this information on to the installer and wait to hear the reply.
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Hi Saf,
Sorry to hear about your further problems.
I would suggest that you ask your installer for a copy of the heat loss calculations for each room, along with the radiator sizing criteria that they employed in the design. If they are not forthcoming MCS may be interested, though on second thoughts maybe not. 🙄Â
If you measure all your radiators and go to the Screwfix site you will be able to obtain details of their nominal output rating. Once you have that I can provide you with a formula to calculate the heat energy output at different LWT values.
The installer had Daikin at my property for almost a full day and both left without finishing the job (see threads 1 & 2) and the Daikin Controller is completely unconfigured apart from the LWT. The controller doesn't even have any menu items to scroll through at the moment so maybe it needs a reset., but regardless, that controller isn't set up to do anything apart from LWT.
The heating system with the boiler used Honeywell evohome and it was great, saved a heap of cash on my very old inefficient boiler. I don't know what the ASHP control design was ever meant to be but the plumbers turned up and had to figure out how to use the Evohome with the Daikin Mono and indeed the Daikin engineer was also scratching his head. None of them have hands on with the evo and i had to change the settings to support HP operation in terms of cycling and run time - however, it is just the cycling and run time of the Grundfos circulation pump that it is controlling rather than the HP itself.
So this is how its operating currently:
1) HR92 Smart TRVs communicate wirelessly to the Evohome controller and call for heating or turn off the demand , I currently have several of this set very high so in effect fully open all the time.
2) Evohome controller wirelessly switched the CH relay, which in turn powers on the Grundfos pump and opens the 2-port valve (I am assuming its opening the valve, i have never witnessed it so it could be permanently open).
3) As the Daikin HP is permanently on a set LWT, the flow switch and temperatures fire up the HP as required. I currently have it on 24/7 anyway in this cold weather (see thread 2)
4) The DHW is not configured, the 2-port valve is not connected electrically so I am manually opening up that port to heat the water and close it when i remember!
5) The mechanical DHW Cylinder stat is not mounted or connected electrically.
6) The evohome cylinder stat is in the cylinder socket so I can at least see the HW temperature for my manual operations.
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my thoughts (assuming the installer and Daikin cannot figure it out)
1) The Daikin controller should be able to replace the evohome, albeit I would lose the HR92 TRVs - but I could sell the whole pack for a decent sum.
2) The Daikin controller should be able to operate the DHW zone valve and pump when the DHW schedule/reheat is required.
3) The evohome DHW relay could be connected to the zone valve and pump to at least get flow to the cylinder using the evohome cylinder stat to close and stop those when temperature is reached. The problem is telling the Daikin to increase temperature to heat the hot water.
4) If the evohome stat was used there is no need for the mechanical stat as the ASHP would never reach dangerous temperatures (and pressure).
5) this should have been all designed and worked out before they ever came to site, but hey ho, this is where we are at...
@derek-m thanks for your offer of assistance, I am hoping it wont come to that as after a rocket from me today they are sending a plumber around tomorrow to go through my list of defects. Although when they say plumber rather than engineer I do worry. Once the F&Rs are reversed (corrected) I will be able to get some better figures based on the real flow temperature. It was quite impressive running it at 40C setting, losing 5C before the first Radiator yet still getting up to temperature in the biggest rooms with T2s installed. I am thinking the Playroom will need a T2 and the Bed3 will need a T3 or a wider T2.  But lets wait and see what tomorrow brings, I don't want us to be doing anything unnecessary when its their job to do it.  I can't imagine how less technically orientated people get on with all this stuff.
@derek-m I'm trying to get some knowledge so I can converse and challenge the installer rather than them try and fob me off.  If the installer hasn't completed the job by 21st Feb (deadline I've set) I will need to seek another MCS engineer to get it through the RHI application, so I need to be fully armed with all aspects of the system.  Once upon a time I was a Building Services engineer so I can do the majority of the work myself but at the moment I am hands off as I don't want to touch anything until the installer has thrown in the towel.  It has been 25 years since I was in the trade so these domestic ASHP are new to me but I am learning how they work pretty quickly (with yours, google and this forums help).
Background: The original survey had the Daikin Mono 16KW ASHP located on a West Facing back garden "Sun Trap" wall, located on the external wall of where the boiler used to be. After several more surveys the Installation Company Director came round and determined it should be on the North Wall (side of house).
I challenged the Installer on the following grounds:
1) The width of the North passage is very narrow so there is not much space for the exhaust
2) The Northern passage is cold, receiving no Sun.
3) Planning permission concerns/noise to neighbour concerns.
The installer said they had installed hundred of ASHP in those positions and never had a problem with any of the issues raised and would indemnify me against any planning permission come-backs.  He said there was no other alternative location suitable.  As these guys are MCS certified and a large company I could only accept what he was saying as an honest and accurate account.  My remaining concern was the noise to the neighbour, however their closest window is >7 metres away and in winter they wouldn't have the windows open.  If noise became an issue I could maybe erect a noise reducing fence and channel the air flow somehow.
The Pros to having it on the North Wall:
1) Out of sight on the side of the house which is not used for any access.
2) Shortish pipe run to the DHW Cylinder, approximately 4 metres of pipework (outside).
3) The passage is a wind tunnel which keeps an airflow across the ASHP, only on very still days is their not a breeze going through there.
4) The passage is sheltered from most of the wet weather.
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The alternative was the West wall by the conservatory/Kitchen.  My thoughts were that all the associated ASHP plumbing and controls would be installed where the Boiler used to be and the existing F&R 22mm could be used from that cupboard to the Rads and Cylinder.  However the installer was looking at putting the cylinder in that cupboard as well so that would never fit.
Pros:
1) The ASHP would be in a sun trap location, being on the warmest spot in the garden.
2) The exterior pipework would be minimal with just the gap between HP & Wall being exposed.
3) The cupboard would fit the buffer, Backup heater pressure vessel and controls. The Controller would be located in a used room (the kitchen) rather than in an airing cupboard as is the case for the current setup on the North wall. I'm wondering whether a buffer and backup heater are even required!
4) existing F&R distribution pipework can be used.
5) it would give us back our space in the airing cupboard for sheets etc which we have lost in the current setup.
Cons:
1) Its visible and would be blowing on us at our outside table (in summer) - I'm not bothered about what it looks like and maybe it wont be on so much in the summer anyway? Outside air con?!
2) It's exposed.  The fan would be full-on exposed to the westerly gales, if these are up at 50/60/70mph in the winter storms could this damage the unit? This is my biggest concern for this position.
3) The pipe run to the DHW Cylinder would be over the specified 10m in the Daikin manual. Not by much, its difficult to say how long the pipe run is as its all hidden, i would say 10-15 metres, but the run is all internal so there shouldn't be much heat loss along the way, the same heat loss existed when the boiler was there.
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photos to follow, this website is having trouble uploading today.
Silly question perhaps, but did the installer give any reasons as to why they felt it's the only position available? Any expert worth the name should be able to back up their assertions with reasoning.
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and SPH5000 inverter
1 x Myenergi Zappi
1 x VW ID3
Raised beds for home-grown veg and chickens for eggs
"Semper in excretia; sumus solum profundum variat"
@majordennisbloodnok only that they couldn't fit everything in to the area on the West Side of the building where the boiler used to be.  Another option briefly aired was to use the Garage for all the associated plumbing and cylinders, but i already have a full garage anyway so didnt want to lose more space and it is a detached garage away from the property so in my view the heat loss would be far greater.  The decision to put it on the North side came very late, maybe 6-7 months are i engaged them! At that point i just wanted it over with as the Green Homes Grant voucher was expiring.
