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: 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).
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: 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).
I have passed this information on to the installer and wait to hear the reply.
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. 🙄
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.
@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.
