Thanks for your responses. I'll try my best to answer as many questions as I can. Some of this goes a bit over my head!
1. The house isn't large and has cavity wall insulation and double glazing. I think I remember the installer saying that the requirement was just too much for the next lower kw model, so it is oversized.
2. The installers brought a buffer tank and then realized they couldn't fit it in the space and decided it wasn't needed. So it wasn't planned that way. If I understand it correctly then I believe it is a single loop system.
3. There are two Grundfos pumps as far as I can see. (see pics). I cannot get a good pic of their locations without dismantling the cupboard. As far as I can see the silver one pumps water through the heat meter, flow meter and the TF1 and out to the heat pump. The red one is connected to the incoming pipe from heat pump and leads towards the two zone valves.
4. See pic of zone valves (I believe the white one is for hot water).
5. I have TRVs, a couple weren't fully open so I opened them, no notable change in the flow.
6. I will check the hot water flow rate the next time it goes on. The 'forced' mode doesn't switch it on automatically for some reason, even though the temp is 3 degrees below the target temp.
7. I found the flow meter, it is on the vertical pipe (downward flow) between the heat meter and the Fernox TF1 filter.
8. The MMSP unit is a Eastron SDM630-Modbus V2.
9. I have checked the flow rate on the Sontex. I can only see one flow rate and its 1.455 m3h which by your calculation would be 24 lpm!! Could this be it then? Was the Samsung controller screen just giving me a dodgy reading?
7. I found the flow meter, it is on the vertical pipe (downward flow) between the heat meter and the Fernox TF1 filter.
Suggest you check orientation limits of your flow sensor. Some makes and models shouldn’t be orientated with downward flow direction due to risk of air trapped in measuring tube. Does your HP rely on flow reading to operate properly?
Also you only mentioned 15mm pipes… presumably there are transition pipes somewhere between 35mm primary and the start of the heating loop?
Do you have the radiators split over 2 22mm branches or are they all on one linear distribution. I ask this because a single 15mm pipe can only carry 2.75 KWh of heat at DT 5. And a single 22mm pipe can only carry 6kw at DT5.
Also in the depths of winter 13 LPM Flow may struggle to deliver the potential output of your HP. EG
Output at DT5 13LPM /60=0.22LPS
0.22 X 4.2 shc X 5 = 4.62KWh heat carrying capacity
at a delta T of 7 this would rise to 8.4KWh
but your HP is rated 12KWh.
having said that, as you said, your heat pump may be larger than your heating needs.
@riponowl to have the flow meter on adownward pipe is just plain wrong. Its more than "not recommended" as the others have suggested. Its specifically forbidden in the manufacturers (samsung) installation instructions.
you will be getting dodgy readings if its installed wrong. Double check the direction.
If it really is downwards, that could mean that your actual flow rate is the number from the heat meter's flow meter - so its possible you don't have a flow rate problem per se. BUT you could still get flow rate errors on the samsung controller, if the samsung thinks the flow rate (as reported by its flow meter) is too low, even though it isn't. Its only just over the point at which you would get errors (12lpm). You are within your rights to ask your installers to remediate this by moving the flow meter to somewhere that complies with the MI's . obviously thats a disruptive piece of work.
I am curious though that you still have two pumps. So you might actually have two loops , potentially with close coupled T's rather than a buffer, which could have different flow rates, or you might have 1 loop with 2 pumps in series, which is unusual and much harder to get good flow control on. its impossible to tell what the logical layout is purely from the pictures. Can you please draw a diagram - its doesn't have to be a work of art - blocks and lines, showing the pipe topology: where they join / tee, and where each of the major components (pump, valve etc) is.
to have the flow meter on adownward pipe is just plain wrong. Its more than "not recommended" as the others have suggested. Its specifically forbidden in the manufacturers (samsung) installation instructions.
@iancalderbank Youve made a slight misquote: I never said “not recommended” however I did say I thought the flow sensor information was possibly needed to be accurate as the information is used by the heat pump within it’s controls. Can you elaborate if this is true? I attach page 28 and highlight the section.
7. I found the flow meter, it is on the vertical pipe (downward flow) between the heat meter and the Fernox TF1 filter.
Suggest you check orientation limits of your flow sensor. Some makes and models shouldn’t be orientated with downward flow direction due to risk of air trapped in measuring tube. Does your HP rely on flow reading to operate properly?
Also you only mentioned 15mm pipes… presumably there are transition pipes somewhere between 35mm primary and the start of the heating loop?
Do you have the radiators split over 2 22mm branches or are they all on one linear distribution. I ask this because a single 15mm pipe can only carry 2.75 KWh of heat at DT 5. And a single 22mm pipe can only carry 6kw at DT5.
Also in the depths of winter 13 LPM Flow may struggle to deliver the potential output of your HP. EG
Output at DT5 13LPM /60=0.22LPS
0.22 X 4.2 shc X 5 = 4.62KWh heat carrying capacity
at a delta T of 7 this would rise to 8.4KWh
but your HP is rated 12KWh.
having said that, as you said, your heat pump may be larger than your heating needs.
@sunandair apologies no offence intended.. I just thought the comment needed to be firmer! AFAIUI the samsung heat pump will use the flow rate value to A) decide whether to complain loudly with an error if its too low B) as an input to the maths for heat output value displayed on the controller (which is just a statistic, so not end of the world if wrong) C) as an input to the control algorithm that tunes the pump flow speed with PWM vs the target DT. But it seems like the OP doesn't have PWM pumps. A) is my concern in their system. from what I understood from watching graham hendra's "how to install a samsung" youtubes a while back, if the system has the error message as per A) for long enough, it will shut down to protect itself.
to have the flow meter on adownward pipe is just plain wrong. Its more than "not recommended" as the others have suggested. Its specifically forbidden in the manufacturers (samsung) installation instructions.
@iancalderbank Youve made a slight misquote: I never said “not recommended” however I did say I thought the flow sensor information was possibly needed to be accurate as the information is used by the heat pump within it’s controls. Can you elaborate if this is true? I attach page 28 and highlight the section.
My earlier comments are also above...
I was the one who said 'not recommended', which may have been a bad choice of words. I was trying to use words that would not cause utter panic, before the full details had been ascertained. Without a full system schematic we don't know if the flow is actually downwards or otherwise.
Looking at the manual I don't see the word 'forbidden', only the 'possibility' of 'drain down' or 'bubble formation'. Since the system is supposedly sealed, with any air having been removed, the likelihood of either should be minimal whatever the direction of the flow.
What I do find of concern is the large discrepancy in readings between the Samsung flowmeter and the one included with the MMSP system. I don't have details of the actual flowmeter installed, and have not read through the Samsung manual to see if there are any controller settings that require adjustment for different size or type of flowmeter. Can any Samsung owners suggest any settings that may need to be adjusted?
What I do find of concern is the large discrepancy in readings between the Samsung flowmeter and the one included with the MMSP system. I don't have details of the actual flowmeter installed, and have not read through the Samsung manual to see if there are any controller settings that require adjustment for different size or type of flowmeter. Can any Samsung owners suggest any settings that may need to be adjusted?
having Read The FM umpteen times whilst installing my own. there is only one flow meter type, the one that comes with it, and nothing to adjust or configure.
So has the system not been piped up as we would assume, and the information from the Samsung flowmeter is correct for the pipe in which it is installed?
Has the MMSP flowmeter been correctly installed and configured, and providing reasonably accurate readings?
Where are the two water pumps installed and what effect are they having on the flow of water around the system?
My crystal ball is away for repair, does anyone having a working one they could use to find the correct answers? 😋
Thanks again for all your responses. I am away from the heat pump for a few days so I can't do any further investigation right now. I did start on a diagram before I left so I will get that finished and posted next week.
Looking back at some of the photos I already have I think the flow meter is visible, I've highlighted with red box.
I also have close up ones which are taken 'blind' as I can't see the screen so apologies for the bad quality. Also not sure of the orientation. I can check that when I get back. Hopefully I've got the right component.
