Roby Posted January 12, 2021 Share Posted January 12, 2021 New to ashp world.Is it normal for the recirc. pump to run constantly even when the heating and hot water are off.The noise is driving me mad not to mention having a pump eating my leccy. Link to comment Share on other sites More sharing options...
SteamyTea Posted January 12, 2021 Share Posted January 12, 2021 (edited) Sounds to me like you have bigger problems. In a well designed and fitted CH system, the recirculation pumps should be virtually silent in operation, and they only use a few watts of power. Start by describing the system. Is it UFH, radiators Type of ASHP Controller Temperatures you are running it at Edited January 12, 2021 by SteamyTea Link to comment Share on other sites More sharing options...
ProDave Posted January 12, 2021 Share Posted January 12, 2021 No the circulating pump should only run when the HP is running. The noise might just be that a lot of heat pumps demand a high water flow so need the pumps running on a faster setting than might otherwise be required Link to comment Share on other sites More sharing options...
Roby Posted January 17, 2021 Author Share Posted January 17, 2021 Hi guys . Thanks for the reply.it's an ecodan 8.5kw.Covering 78m2.All radiators,no ufh.Ftc 4 or 5(pretty sure).Hot water set at 45 and heating at 21.Still experimenting at the moment and the only setting I've changed since the install is to bring the water temp down from 50 to 45.Have an electric shower at the moment so one tank of hot water a day is more than enough.Heating is a must as I have a wife who has disabilities,so any advice on set up and running would be very much appreciated also. Link to comment Share on other sites More sharing options...
SteamyTea Posted January 17, 2021 Share Posted January 17, 2021 There are usually 2 flow temperature settings. One for the DHW (is that the one you set to 45⁰C) and the one for the space heating. The space heating is usually set lower for underfloor heating systems, but as you are all radiators, 45⁰C seems a reasonable temperature. 8.5 kW seems large for your size place, but that should work to your advantage to keep the CoP higher, which is what you want. Link to comment Share on other sites More sharing options...
Roby Posted January 17, 2021 Author Share Posted January 17, 2021 Hi ,the setting I changed is only the max he temp.To be honest I wouldn't know where to find the flow rate settings.According to the readings on the controller (I know they're not accurate) but Im getting a cop of less than 2.Any suggestions?? Something definitely not right.Are there settings I should be looking at.?Can't get the installer back at the moment due to Corona restrictions so going to be stuck for a while Link to comment Share on other sites More sharing options...
Nickers Posted January 27, 2021 Share Posted January 27, 2021 Hi, This sounds very much like my experience with our 8.5 kw Ecodan PUHZ-8.5VAA ASHP & HWC system installed about a year ago. 3 pumps were running continuously. I contacted the Installer. The cause was FREEZE STAT MODE. When outside temp drops below a certain level, (I think 5 deg. C , but not sure) the pumps run to prevent the Heat Pump freezing when inactive. This is the default installation setting unless Anti-freeze is added to the water in the heating circuits. My Installer came back and added Glycol to the system. It had to be pumped in as the system is under pressure of 1 to 1.5 bar. Once this has been done, FREEZE STAT MODE can be disabled. Obviously, this mode should not be disabled unless Anti-Freeze has been added to the system to the correct concentration. Check with a qualified Installer. Link to comment Share on other sites More sharing options...
Stones Posted January 27, 2021 Share Posted January 27, 2021 As above, anti frost settings probably main culprit for pumps being on, although the default temp at which this activates can be changed in advanced settings. Circulation pumps can also be set to overun/circulate behind actual operation of the heat pump itself, again can be changed in advanced settings. Link to comment Share on other sites More sharing options...
gavztheouch Posted January 29, 2021 Share Posted January 29, 2021 On 17/01/2021 at 11:38, SteamyTea said: There are usually 2 flow temperature settings. One for the DHW (is that the one you set to 45⁰C) and the one for the space heating. The space heating is usually set lower for underfloor heating systems, but as you are all radiators, 45⁰C seems a reasonable temperature. 8.5 kW seems large for your size place, but that should work to your advantage to keep the CoP higher, which is what you want. Is it not the opposite, ie you can get a better cop with a slightly undersized heat pump not oversized? Link to comment Share on other sites More sharing options...
SteamyTea Posted January 29, 2021 Share Posted January 29, 2021 4 minutes ago, gavztheouch said: Is it not the opposite, ie you can get a better cop with a slightly undersized heat pump not oversized? No. It is to do with the mass of air that flows though the heat exhanger. A larger ASHP has a larger area heat exhanger. This allows a greater mass of air to pass though. As the energy is extracted by dropping the air temperature, less of a temperature drop is needed to extract the same amount of energy. This has the added bonus of less chance of freezing up, and less noise because of slower flows. I dislike using the fridge analogy, but if you leave your fridge door open a little bit, you may still have a lower temperature inside, but you will notice that the compressor is constantly running and there may be a lot of frosting up. Link to comment Share on other sites More sharing options...
gavztheouch Posted January 29, 2021 Share Posted January 29, 2021 11 hours ago, SteamyTea said: No. It is to do with the mass of air that flows though the heat exhanger. A larger ASHP has a larger area heat exhanger. This allows a greater mass of air to pass though. As the energy is extracted by dropping the air temperature, less of a temperature drop is needed to extract the same amount of energy. This has the added bonus of less chance of freezing up, and less noise because of slower flows. I dislike using the fridge analogy, but if you leave your fridge door open a little bit, you may still have a lower temperature inside, but you will notice that the compressor is constantly running and there may be a lot of frosting up. Makes sense. So has the thinking changed as everything I read of merit when it comes to heat pumps say you need to size as close as possible to your load to prevent short cycling. They say it’s this cycling that really hits performance? Link to comment Share on other sites More sharing options...
PeterW Posted January 29, 2021 Share Posted January 29, 2021 5 minutes ago, gavztheouch said: Makes sense. So has the thinking changed as everything I read of merit when it comes to heat pumps say you need to size as close as possible to your load to prevent short cycling. They say it’s this cycling that really hits performance? short cycling happens when load drops below minimum power and most will modulate down to a fairly low load however if you have underfloor heating a single zone calling for heat then it won’t be able to cope and will short cycle. This is why you must install a buffer and blender with UFH despite what some of the manufacturers will tell you as this allows the ASHP to heat the buffer and that allows a longer heat cycle. Link to comment Share on other sites More sharing options...
SteamyTea Posted January 29, 2021 Share Posted January 29, 2021 1 hour ago, PeterW said: This is why you must install a buffer and blender I think that 'must' needs to be in bold, as in always install one the correct size. 2 hours ago, gavztheouch said: So has the thinking changed as everything I read of merit when it comes to heat pumps say you need to size as close as possible to your load to prevent short cycling. I think it is a problem that came about with traditional 'plumbers'. They just do not understand how a HP works. I would think that a buffer is useful in most heating systems to help efficiency. Link to comment Share on other sites More sharing options...
joth Posted April 8, 2021 Share Posted April 8, 2021 On 27/01/2021 at 17:53, Nickers said: Hi, This sounds very much like my experience with our 8.5 kw Ecodan PUHZ-8.5VAA ASHP & HWC system installed about a year ago. 3 pumps were running continuously. I contacted the Installer. The cause was FREEZE STAT MODE. When outside temp drops below a certain level, (I think 5 deg. C , but not sure) the pumps run to prevent the Heat Pump freezing when inactive. This is the default installation setting unless Anti-freeze is added to the water in the heating circuits. My Installer came back and added Glycol to the system. It had to be pumped in as the system is under pressure of 1 to 1.5 bar. Once this has been done, FREEZE STAT MODE can be disabled. Obviously, this mode should not be disabled unless Anti-Freeze has been added to the system to the correct concentration. Check with a qualified Installer. thanks for this - finally got our system commissioned last week. I have exactly this issue, with an extra wrinkle that the zone 1 pump also triggers the fan on our fan coil unit, so in the current cold snap I have 4 motors running 24/7. I wouldn't mind terribly if the primary pump were firing for a few minutes every 10 or something, but this is a bit much. It's already taken 25 visits from the MCS installer to get to this stage so I'd rather just resolve this myself if I can. As the system has had Glycol added and was MCS signed off, am I supposed to be assured (by MCS standard) that no freeze stat is needed? Link to comment Share on other sites More sharing options...
joth Posted April 9, 2021 Share Posted April 9, 2021 20 hours ago, joth said: As the system has had Glycol added and was MCS signed off, am I supposed to be assured (by MCS standard) that no freeze stat is needed? Answering myself - the installer says now it has glycol it is indeed fine to just turn off Freeze Stat completely. Which of course opens the question why hadn't he already done that, and I wonder how many other installs are out there with it needlessly enabled, along with numerous non-optimal settings, but whatevers. Link to comment Share on other sites More sharing options...
jfb Posted April 9, 2021 Share Posted April 9, 2021 On 29/01/2021 at 19:36, PeterW said: This is why you must install a buffer and blender with UFH despite what some of the manufacturers will tell you as this allows the ASHP to heat the buffer and that allows a longer heat cycle. I thought I heard that if you are running UFH that the UFH pipework can effectively be the buffer tank but you are saying that is wrong. My situation is: small conversion (70m2) , just UFH downstairs running 4 loops of pipe but as one zone (no upstairs rads), heat pump (5KW region) for DHW and UFH, UVC upstairs by bathroom. I hadn't accounted for a buffer tank so might need to think where it could fit as space is tight. Can you advise: 1. What size of buffer tank would be suitable? 2. Is it best/easiest to put the buffer tank upstairs with the UVC or can it be put downstairs by the UFH manifold? thanks Link to comment Share on other sites More sharing options...
joth Posted April 9, 2021 Share Posted April 9, 2021 (edited) 5 hours ago, jfb said: I thought I heard that if you are running UFH that the UFH pipework can effectively be the buffer tank but you are saying that is wrong. My situation is: small conversion (70m2) , just UFH downstairs running 4 loops of pipe but as one zone (no upstairs rads), heat pump (5KW region) for DHW and UFH, UVC upstairs by bathroom. I hadn't accounted for a buffer tank so might need to think where it could fit as space is tight. Can you advise: 1. What size of buffer tank would be suitable? 2. Is it best/easiest to put the buffer tank upstairs with the UVC or can it be put downstairs by the UFH manifold? thanks 1/ Will depend on the exact size of ASHP and volume of UFH loops. The larger the ASHP the higher the total circulation volume (pipes + buffer) will need to be, Our install just used a tiny 5L low loss header, to allow hydraulic decoupling but not really proving much buffer, as we have relative long runs in the circuit anyway. (And, not a lot of room) 2/ It's only needed for the heating circuit so it's bound to be workable OK if you put it there by the UFH manifold. If you have the primary pipe from the ASHP external unit coming into the upstairs UVC room AND the controller is there with it then that could work too. Where is the expansion vessel, filter, primary pump a 2-pos valve going? Edited April 9, 2021 by joth Link to comment Share on other sites More sharing options...
LA3222 Posted December 2, 2021 Share Posted December 2, 2021 @joth just looking at this, is there a dip Switch for freeze stat? Trying to turn this rubbish off - can see it in the aux options, not sure what to do with this? Link to comment Share on other sites More sharing options...
LA3222 Posted December 2, 2021 Share Posted December 2, 2021 Solved - set the temp to ** to turn off! Link to comment Share on other sites More sharing options...
joth Posted December 2, 2021 Share Posted December 2, 2021 6 hours ago, LA3222 said: Solved - set the temp to ** to turn off! Well sleuthed! I totally forgot about that. Yes, not obvious at all was it. Link to comment Share on other sites More sharing options...
Adam E Posted March 6, 2022 Share Posted March 6, 2022 Hi I realise this is an old post but covers my problems I am trying to turn on the Freeze stat mode on my ecodan 8.5kw asht latest version when I go into auxiliary settings I can find no mention of freeze stat the system has glycol antifreeze but when I seen this pie chart I was concerned as how much it was running any ideas how I can turn this off. Adam Link to comment Share on other sites More sharing options...
LA3222 Posted March 6, 2022 Share Posted March 6, 2022 2 hours ago, Adam E said: Hi I realise this is an old post but covers my problems I am trying to turn on the Freeze stat mode on my ecodan 8.5kw asht latest version when I go into auxiliary settings I can find no mention of freeze stat the system has glycol antifreeze but when I seen this pie chart I was concerned as how much it was running any ideas how I can turn this off. Adam See my post above...its in the author settings within the control menu Link to comment Share on other sites More sharing options...
Adam E Posted March 6, 2022 Share Posted March 6, 2022 Hi what are the author settings Link to comment Share on other sites More sharing options...
joth Posted March 6, 2022 Share Posted March 6, 2022 On mine it's in Operation Settings Link to comment Share on other sites More sharing options...
Adam E Posted March 6, 2022 Share Posted March 6, 2022 Brilliant thanks so Much I have just turned it off, really easy when you know how thanks again. Adam Link to comment Share on other sites More sharing options...
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