JohnnyB

I don't think I need a volumiser either, there is more than 30 ltrs of water in my UFH pipes and another 10 ltrs in my F&R pipes, plus everything else. Would changing it for a volumiser make much difference to the efficiency? I'm starting to understand there's probably a lot of things in my system that's not needed and it could have been a lot simpler

Thanks for all the input. I'm going to have to make time to see is the HP is cycling, watching it for 10-15 minutes it seems to be fine, I assume the fan would stop if it is shutting down. I'm also trying to read up on heat pumps and heating, exactly what I didn't want to do and why I used plumbers who are supposed to know what they are doing but there are so many things you are saying that I don't really understand. I'm trying to build 2 houses and thought this was one thing I could leave to others to sort easily, didn't realise HPs need to know so much just to run them efficiently! I had a message yesterday from the plumber and they have another unit like mine that is getting a similar COP which the client has full monitoring on. They have emailed Samsung for advice and he is going to try to get out to me before Christmas to take a look and see if he can see anything obvious. I have been looking for more info and it seems that the video linked to above, and ringi, aren't the only people saying really low flow temperatures don't equal a good cop. If I set the flow temperature so it's leaving the HP at 30-35deg I would probably have the heating on 2 or 3 times per day to warm the floor up, but that isn't as comfortable as having the flow temperature at 23-25 deg and the floor at 20-22, which kept downstairs at a fairly constant 20deg. The higher temp has helped the COP, it was 2.8 yesterday, but it was off all night and has taken a long time to get the floor back up to temperature this morning. The problem of a well insulated house and floor, it doesn't need much heat. Maybe I can set the system so it uses the floor temperature as the set point instead of the room temperature, put water in at 35deg but switch off when the floor gets to 25deg and come back on when it cools down to 22 or something like that. Should be slow heat and cool down times for the floor. I have 60mm screed with 2 layers of 100mm PIR insulation beneath and it seems to hold it's heat for several hours. By LLH are you referring to my buffer tank and pump? What you are saying is the opposite of what I thought I was understanding when reading on the renewable heating hub forum, that the main pump should be running faster than the secondary pump. I have noticed this valve is set to a low pressure and the water seems to be passing along the shortest distance. I was told this is to allow water through if the valve doesn't open and the pump starts, but I can't see why I even need the valve there as the pump only starts if it is open and it doesn't divert the water, just stops it flowing. I do have a diverter valve on the main F&R the switches the flow between DHW and heating. As mentioned before I didn't want the buffer in there but was told I had to have it. If they can't sort this sufficiently I will insist it is removed. I really can't see the need for it when I can't close the loops, there is no zoning and I have a lot more than 50 ltrs in my pipework without the buffer, they have fitted 32mm flow and return to the HP and the buffer, my DHW cylinder and buffer are 3-4 mtrs apart because of space issue with 32mm pipe between them, must be about 15mtrs of 32mm pipe

@JohnMo If only I had time to sit for an hour and see what the pump is doing, I'm trying to finish off the house! I don't have a smart meter indoor display, but the Samsung controller will show the power being it used by the HP. I'll have to watch that and see if it shows anything interesting. It's a real shame they don't give access to proper data. My pumps are identical and both set on the same setting, plumbers said that was necessary. They are mostly both on at the same time, apart from when the DHW cycle is on or occasionally one to the HP will be on without the other for a few minutes, the HP pump will occasionally start up without the thermostat calling for heat. I've turned the flow temperature up and will turn it off when it gets to 4pm and see what happens to the indoor temperature. (I'm on Octopus Agile which isn't a great tariff for a cop of 2 at the moment!) The plumbers told me the internal thermostat isn't great and that I needed an external one, but in the video @IGP linked to Glyn is using the internal thermostat and it sounds like it is working well for him so that could be an option. Glyn had the flow temperatures basically the same in the WC settings as the COP dropped if the flow temperature dropped below 33 deg.

@IGP Thanks for the link, I watched the video then read he has updated to firmware so it works with a PWM pump and he can drop the flow temperature lower without effecting the efficiency. I don't have a PWM pump but maybe my pump would be better on a lower speed? Something to discuss with the plumber. @JohnMo I only have the Samsung controIs and can't see details of what is running when and how long it is running for etc., is there an easy way to find out cycle times without an energy monitor like you have on your system? We don't have zoning, there are no actuators on the UFH manifold. I've read lots of your comments on here so have been trying to keep it simple, although the plumbers have insisted we have to have a buffer for the warranty and one pump for the HP and another for the UFH pipework so it isn't as simple as you would recommend. I think if I set mine to 35 deg we will be rather warm and our feet will cook, I haven't been above 30 at the water outlet yet and that was already quite warm, although if it only heated the slab to a lower temperature and then switched off we could probably control it that way.

I have recently had a 5kW Samsung gen 6 heat pump fitted, been running about 10 days, and I had a look at the energy used and the energy generated on Friday and I'm getting a COP of about 2 so something isn't right. I've contacted the plumbers who are going to take a look but I wanted to get a few thoughts from here on how I am running it. The plumbers are known locally as being good and only fit heat pumps so they should be able to sort it but always good to have some knowledge before they try to explain things away. It's a new self build with UFH and I have been running it 24/7 with the water outlet at the pump between 23 and 30 deg, regulated by the WC. The temperature on the floor is about 20-22 deg which keeps the house around 20 deg. Is there a point where the flow temperature can be too low so the heat pump is cycling and not running efficiently? Should I be using the thermostat in the house to switch the heating on and off with a higher flow temperature instead of running it low and constant? Anything else I should be asking about?

Sorry for the slow reply, I've been rather busy trying to get enough finished in the house to be able to move in and haven't been on here for a while. I didn't use the compriband in the end as it needs a reasonably smooth/flat surface to work, and hempcrete isn't smooth. I ended up using the Illbruck FM330 expanding foam and that has worked well for my situation. I used it under the windows as well. I have done it but still have the main house to do next year so I will look at that for next time. As mentioned above I used airtight foam which has worked well but doesn't feel quite the right thing to be using with hempcrete but at this stage there have been a lot of compromises that's very few things I regret yet. It varies depending on the exterior finish and the wall build up needed to make the cladding longer up with the brickwork as we want it, but the thinnest sections are 380mm of hempcrete and 440 at the thickest.

Thanks, I hadn't seen that, although I do remember reading the thread you linked to a while back but I couldn't find it again this morning - I quess because I wasn't looking in the ASHP section. My quote isn't as high as that one, although I do have quite a bit less going into mine. My space limit is in diameter but have standard height ceilings. I can get a 600mm diameter tank in there but there's not much room for lots of pipework around it. I know they have said a pre plumbed tank wouldn't fit. @Dave Jones I do wonder if i am paying over the odds, hence the post. This isn't being done with the grant so I don't have to go MCS registered. The problem I have is I don't have the knowledge to sort it myself and don't have a local plumber I know and trust to do it well. I've done most small jobs myself and haven't needed a plumber for years. This company have a good reputation and have installed a lot of ASHP locally and seem to know what they are doing. It depends on how much over the odds I'm paying and if there are cheaper ways of doing it. I have read a few of your posts this evening and it seems your advice is to keep it very simple. Speaking to Nick earlier today I'm going to look into a Sunamp, or even a standard hot water tank heated with an immersion heater, with the ASHP just connected to the UFH. That may help.

How much are people being quoted to get a 5kW ASHP installed in a new build? I have just been quoted £8k as below. It seems rather expensive to me but after reading a few other threads on here it may not be too bad? This is for the 'annexe' and the grant will be used againest the main house. I was given an estimate of £13k after the grant for the heating and second fix plumbing in the house, which was the cheapest quote I received. It was hard to even get quotes on that about a year ago. Any suggestions for sensible quotes in Suffolk if this isn't sensible? Thanks.

Yes, that would work but I'm not sure I have the time. I would need to wait for the plasterer to come and put a thin coat on and then let it dry before I could fit the windows. The windows are arrive about the same time the plasterer is coming to start on the internal walls. My previous attempts at plastering have been terrible so I'm not going to try doing it myself.

Thank you Nick, that is very kind. cuold you send me your address please and I'll head round at some point very soon

I'm looking for advice on sealing around the windows and doors in our hempcrete house. I was thinking I would use compriband tape and then airtight tape on the inside between window frame and studwork but the hempcrete doesn't have a smooth even finish and there are gaps under the timber spacers fixed to the timber frame. Does compriband expand into small gaps and holes to seal tight againest the weather or would I be better to use FM330 foam and then us something else in the gap between the frame and wall to insulate the gap? If I used the foam any ideas on options to insulate the gap if it doesn't have compriband tape in there? Compriband would seem a little expensive/overkill if I use FM330 to seal the outside. The outside is timber clad so I will have timber around the outside reveal and the inside will have woodwool board and then plastered. Also any thoughts on fixing plates? I was thinking of simple metal strips but are there other options? Thanks, Johnny

My new connections was in January this year and I had to have at least a the standpipe as Nod's picture with pipe going to the edge of the road for them to fit a meter to before they would fit the meter. They sent someone out to check it was all to their spec a few days/weeks before they came to make the connection. If you contact whichever compnay supplies your water they will give you a quote and a list of their requirements, what you have to pay them for and what you can get other contractors to do. I dug the trench, fitted the stand pipe with a pipe going to a point they specified My cost was about £3k with about half of that being the cost to close the road.

@ReedRichards You are right that a heating system is more comfortable to live with and discussing it over the weekend we are coming to the conclusion that we should be fitting a heat pump, but when we were planning the build the intention was to put this building up cheaply and fit it out to a basic level to start with. We planned to use this as extra space for a games room/yoga studio/additional space when family and friends come to stay. We were then planning to fit it out as a full house as we had time and funds to do so. I have several years worth of free logs stored already and more drying so it is free heat. Most of the year it won't need any heat so lightling a fire when we want to use it seemed fairly simple. As it happens timings haven't worked out as planned, we started building a lot later than expected and ended up building this buildng first. It's turned out to be a slightly quirky building and a space I really love that I can imagine living in once we want a smaller house, although my wife isn't so sure she wants to do that. We will probably spend a year living in it while we build the main house that we are now planning to start next year. We have been discussing fitting an air source heat pump over the last few days and the plumbers are going to give us a price for that. We've already had UFH pipes fitted in the screed ready for future use so it would make sense to use those. From their initial estimates it will probably be about the same cost as fitting a woodburner as a reasonable stove and flue isn't a cheap option, especially as it needs to go through the airtight membrane. The main issue is that several things have been designed around the woodburner being where it is including the staircase going round it and the walls of the 'chimney' surround supporting the 1st floor landing so the space for it can't be removed at this stage.

We did discuss electric heating but he said that would be hard to make work as direct electric heating needs offsetting with solar, which we're not putting on the annexe only on the main house. If I combine @Dave Jones and @ReedRichards suggestions, specifiy a hear pump but never get round to fitting it, maybe we can get around it.

We didn't have SAP calculations done at planning stage, or before we started to build. so wasn't aware of the need for heating controls until now.