SBMS Posted June 12, 2023 Share Posted June 12, 2023 Has anyone had any success with scheduling when the hot water function on their heat pump is activated? We are on intelligent octopus so get electricity at 7.5p 11pm to 5am. Does it make sense to only schedule the heat pump to heat water during these hours? Are there any downsides to this? And as a bonus question, is it as simple as activating the scheduling function on the nibe f2040? thanks Link to comment Share on other sites More sharing options...
JohnMo Posted June 12, 2023 Share Posted June 12, 2023 If you have solar PV, schedule when that's active, heat the water for free. Link to comment Share on other sites More sharing options...
sharpener Posted June 12, 2023 Share Posted June 12, 2023 (edited) 56 minutes ago, SBMS said: Does it make sense to only schedule the heat pump to heat water during these hours? Are there any downsides to this? Yes. Not really if it will provide enough hot water for you. If not then an afternoon boost makes sense, if you have PV it will be free, if not at least the air temperature is likely to be higher so you will have a slightly better CoP. Don't know about the Nibe specifically but scheduling the HW is a pretty basic feature and as a high-end product I imagine Nibe will give you the option (perhaps more than one). Edited June 12, 2023 by sharpener Link to comment Share on other sites More sharing options...
SBMS Posted June 12, 2023 Author Share Posted June 12, 2023 We do have PV, not commissioned yet. How have others set up their system? Is it better for PV to use a clamp and use the immersion, or just use the PV to assist with running the heat pump? Link to comment Share on other sites More sharing options...
Conor Posted June 12, 2023 Share Posted June 12, 2023 We run ours exclusively on off-peak. Timer set 5-9am. At the weekends also have on middle of day as we tend to have visitors and higher hot water demand. Yet to ring out. Link to comment Share on other sites More sharing options...
sharpener Posted June 12, 2023 Share Posted June 12, 2023 Use the PV to run the heat pump, at least to do the heavy lifting, you will benefit by a factor equal to the CoP. Depending on the HP characteristics it may not heat to the temp you want, or start cycling on and off, or not do a legionella cycle unaided, those are situations where the immersion can usefully help out. Link to comment Share on other sites More sharing options...
SBMS Posted June 12, 2023 Author Share Posted June 12, 2023 Thanks all. Link to comment Share on other sites More sharing options...
IanR Posted June 12, 2023 Share Posted June 12, 2023 1 hour ago, SBMS said: And as a bonus question, is it as simple as activating the scheduling function on the nibe f2040? Assuming you have either the SMO 20 or 40 controller then there is a Scheduler for Hot Water (and a separate one for Climate (Space Heating/Cooling). In the Scheduler there's a Tab for up to 2 daily periods to schedule the the HW On. If neither are active then it will come on any time it needs to across the day. If you want to restrict the times it will heat water then activate one or two of the tabs and set a time on each day within the tab that you wish it to operate. Link to comment Share on other sites More sharing options...
SBMS Posted June 13, 2023 Author Share Posted June 13, 2023 23 hours ago, IanR said: Assuming you have either the SMO 20 or 40 controller then there is a Scheduler for Hot Water (and a separate one for Climate (Space Heating/Cooling). In the Scheduler there's a Tab for up to 2 daily periods to schedule the the HW On. If neither are active then it will come on any time it needs to across the day. If you want to restrict the times it will heat water then activate one or two of the tabs and set a time on each day within the tab that you wish it to operate. What’s your setup Ian? Have you got the timer active? Link to comment Share on other sites More sharing options...
IanR Posted June 14, 2023 Share Posted June 14, 2023 27 minutes ago, SBMS said: What’s your setup Ian? Have you got the timer active? The Schedule? No, not really. On the SMO40 I block the compressor over night (so that nothing runs) and then allow it to run during the day whenever there is a call for heat. I guess you could call it a timer, but Blocking is not specific to hot water or climate. 1 Link to comment Share on other sites More sharing options...
mary Posted November 4 Share Posted November 4 I know this is an old post but I have a related question. I have just moved to a house with a Nibe ASHP and it’s all very new. I am just concerned we are using it wrong as our leccy costs seems high. we have not used the heating part as yet. The hot water is scheduled on 4.30-5am on the lower tariff. We have never run out of hot water or had a lukewarm shower (usually shower at 5pm ish) Does this mean we are somehow re heating the water as I’ve read other post ls where people have to heat during the day to keep the temp? sorry for the basic questions but it’s all new! We are 2 people in a 3 bed house and use washer 3x a week and have 2 very quick showers a day! Link to comment Share on other sites More sharing options...
JohnMo Posted November 4 Share Posted November 4 4.30am to 5.00am isn't long enough to enable a heat pump to heat a cylinder, unless it's very big heat pump. So I would suspect the immersion is kicking in if you are seeing high electricity usage and have plenty of hot water. I would get the instructions book out, or download if you don't have a copy. Heating once is ok, but I would give it 1 to 1.5 hours to heat - depending on water usage. Make sure the set temperature is 50 or below, to get a decent running cost. Make sure the immersion settings are off - this will depend on you risk (or perceived risk) to legionella, plenty of info on here, do a Google search. But key is you don't want it coming on during normal heating of cylinder. I heat once, and it's just enough for the day, I have heated twice and had lots of hot water, but cost more, did leave on all the time, that used loads of electricity. Link to comment Share on other sites More sharing options...
FarmerN Posted November 4 Share Posted November 4 Mines a NIBE GSHP . Have water heating on all day set at 48 degrees C . If I get up early, I boost water heating to 53 C while we are on cheap rate. Theres a 2 hr “ more hot water” button. Not looked at Scheduling yet. What I would like to do is Schedule night water heating at a higher temperature that day temp. Currently running at COP of 6+ while ground is still warm so heat on Economy 7 is costing very little. Link to comment Share on other sites More sharing options...
PhilT Posted November 4 Share Posted November 4 2 hours ago, mary said: The hot water is scheduled on 4.30-5am on the lower tariff. We have never run out of hot water or had a lukewarm shower (usually shower at 5pm ish) Does this mean we are somehow re heating the water There are also 2 of us and the domestic hot water takes 30 minutes each day to heat up for everything we need, that's it. I don't think you have a problem. Link to comment Share on other sites More sharing options...
mary Posted November 4 Share Posted November 4 Thanks all bit confused as PhilT seems to be think it’s OK but JohnMo seems to think 30mins won’t be enough to get it heated i have the instructions so I’ll try to work it out - I think there are 2 switches saying cylinder immersion and booster immersion / both are on The system was put in 8 yrs ago and previous owners didn’t really give us much information but they had a teenager so their usage would have differed I guess we have it set to 45 degrees and the Legionnaire thing is currently off which was done by last owner I guess Link to comment Share on other sites More sharing options...
Gone West Posted November 4 Share Posted November 4 38 minutes ago, mary said: I think there are 2 switches saying cylinder immersion and booster immersion / both are on Just thinking about it logically, I would turn both off and see what the effect is. 1 Link to comment Share on other sites More sharing options...
mary Posted November 4 Share Posted November 4 Yes I thought about it but I’m a bit scared 😂🥴 Link to comment Share on other sites More sharing options...
JohnMo Posted November 4 Share Posted November 4 (edited) 49 minutes ago, mary said: it confused as PhilT seems to be think it’s OK but JohnMo seems to think 30mins won’t be enough to get it heated Really depends on heat pump size. A normal heating cycle for me with a 6kW heat pump is anywhere from 50 min to 1.5 hrs. Or @PhilT has a big heat pump and small cylinder? Edited November 4 by JohnMo Link to comment Share on other sites More sharing options...
JohnMo Posted November 4 Share Posted November 4 5 hours ago, mary said: concerned we are using it wrong as our leccy costs seems high. From heat pump alone you should be getting a CoP of 3 or so for DHW. So if only heating for 30 mins a 6kW would be using 1.0kWh. if you are actually heating continuously by immersion your usage will be way higher. And lead to high energy usage and high running costs. Link to comment Share on other sites More sharing options...
mary Posted November 4 Share Posted November 4 This is where I have no clue about things likeCOP! I’ll check the manual and try to work it out Would it be safe to turn off both immersions to check? Link to comment Share on other sites More sharing options...
Gone West Posted November 4 Share Posted November 4 1 hour ago, mary said: Would it be safe to turn off both immersions to check? Safe, but you might run out of hot water. Link to comment Share on other sites More sharing options...
sharpener Posted November 4 Share Posted November 4 5 minutes ago, Gone West said: Safe, but you might run out of hot water. That would be diagnostic for what was really providing the HW all along. If it makes no difference then the HP is capable of doing it and you should see a reduction in the bill. If you start to run out then you need to heat with the HP more often or for longer. Link to comment Share on other sites More sharing options...
mary Posted November 4 Share Posted November 4 Thanks everyone / I’m used to a combi boiler so this is a whole new world (of pain 😅) Link to comment Share on other sites More sharing options...
mary Posted November 4 Share Posted November 4 I’ve checked and it’s a NIBE 8kw F2040 so maybe 30mins a day isn’t enough to warm water to 45 each day and it’s using an immersion to keep warm as the shower is still hot now at 5pm and the water goes on at 4am? Link to comment Share on other sites More sharing options...
JohnMo Posted November 4 Share Posted November 4 20 minutes ago, mary said: using an immersion to keep warm Hence the cost. Maybe if immersion is keeping warm, then heat pump doesn't actually do anything. Link to comment Share on other sites More sharing options...
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