sharpener Posted January 10 Share Posted January 10 The prospective installers came for a further(!) site visit yesterday and remarked there was a possible increase to £10k w.e.f. ?new tax year? Has anyone heard anything to this effect? I thought I was keeping an eye out but have seen nothing myself. Link to comment Share on other sites More sharing options...
joth Posted January 10 Share Posted January 10 Not heard of this, but hey this is how rumours work. Only thing I see is MCS Foundation calling for more subsidy for GSHP https://mcsfoundation.org.uk/campaigns/extend-the-boiler-upgrade-scheme/ My more cynical view is an installer mentioning this (maybe even rumour mongering this) has a very full order book, but wants to put people off going with another installer now and instead come back to them in N months when they may have more space. Link to comment Share on other sites More sharing options...
JamesPa Posted January 10 Share Posted January 10 2 hours ago, joth said: Not heard of this, but hey this is how rumours work. Only thing I see is MCS Foundation calling for more subsidy for GSHP https://mcsfoundation.org.uk/campaigns/extend-the-boiler-upgrade-scheme/ My more cynical view is an installer mentioning this (maybe even rumour mongering this) has a very full order book, but wants to put people off going with another installer now and instead come back to them in N months when they may have more space. That was also my first thought. I'm clearly also a cynic. Link to comment Share on other sites More sharing options...
sharpener Posted January 10 Author Share Posted January 10 No. They actively suggested putting my installation date back until after Easter. Yet they say they do not have much HP installation work scheduled at present (they do solar PV and other things as well) so have the capacity to do it earlier if I wish. We discussed the perverse incentive effect on their project flow but they didn't seem concerned. MCS are asking for increases from 2025. Other thing from them is this but not very relevant. Link to comment Share on other sites More sharing options...
sharpener Posted January 16 Author Share Posted January 16 Just seen on FB about this promotion from Worcester Bosch. Sounds like they are truly desperate to avoid penalties under the Clean Heat Market Mechanism. It would perhaps account for an uprated total of £10k of CHMM + BUS. Maybe it's what the installer was referring to. Link to comment Share on other sites More sharing options...
sharpener Posted January 26 Author Share Posted January 26 (edited) Installer still going on about it with a reference to Martin Lewis/Money Expert, and he sent link to OFGEM enquiry line 0330 053 2006. So I rang this, rather to my surprise answered quickly and helpfully, apparently no truth in it. Installer has now applied for BUS voucher, I got automated response from OFGEM with link to consent forms, all completed and acknowledged by email same day, quite impressive. Their Tech Director now wants a further (?5th) site visit, by his electrician, to consider whether to fit an extra consumer unit with Henley blocks. Am less impressed by this, have already explained it has to be fed via my battery/inverter system and there are 3 spare ways in the existing CU to do this. Edited January 26 by sharpener Link to comment Share on other sites More sharing options...
JamesPa Posted January 26 Share Posted January 26 4 hours ago, sharpener said: Their Tech Director now wants a further (?5th) site visit, by his electrician, to consider whether to fit an extra consumer unit with Henley blocks. Am less impressed by this, have already explained it has to be fed via my battery/inverter system and there are 3 spare ways in the existing CU to do this. The problem is simple, you have the wrong house for their way of doing things. Solution - change the house. Ignoring this though it sounds like progress. 1 Link to comment Share on other sites More sharing options...
sharpener Posted January 27 Author Share Posted January 27 22 hours ago, JamesPa said: Ignoring this though it sounds like progress. Yes, if a bit glacial. They also want their plumber to visit to agree the pipework layout, that is more essential as we need to decide on the port arragement for the custom thermal store from Newark Cylinders, but it will have to be a different day. Link to comment Share on other sites More sharing options...
sharpener Posted February 18 Author Share Posted February 18 On 27/01/2024 at 12:41, sharpener said: They also want their plumber to visit to agree the pipework layout, that is more essential as we need to decide on the port arragement for the custom thermal store from Newark Cylinders, but it will have to be a different day. Bit of an update. Electrician now happy to connect to the spare ways in the CU. Plumber did come as well, wants to change pipework to cyl coil from 15mm to 22. I thought we had knocked that one on the head back in August using yr cyl heating simulation @JamesPa so it is a bit of a backward move to have to re-visit it. As you say, I have the "wrong kind of house". Have already explained that heating the TS at the same time as the cyl will share the HP's output between them, so neither will have to accept the full 12kW. Will propose to define this by using a flow setter to restrict the flow to the TS (otherwise having negligible resistance it will hog all the flow and starve the coil anyway). Will proportion the flow 40/60% to suit expected daily heat cycle - 9kWh to TS and 6 kWh to cylinder - then they will take the same time to heat up and so continue sharing the o/p right to the end of the run. Lower heat transfer rate to cyl will mean smaller delta T so lower HP flow temp and better CoP, win-win if I can get them to accept it. Link to comment Share on other sites More sharing options...
JamesPa Posted February 18 Share Posted February 18 3 minutes ago, sharpener said: Bit of an update. Electrician now happy to connect to the spare ways in the CU. Plumber did come as well, wants to change pipework to cyl coil from 15mm to 22. I thought we had knocked that one on the head back in August using yr cyl heating simulation @JamesPa so it is a bit of a backward move to have to re-visit it. Sorry to hear about your plumber! At DT5 and 1m/s 15mm is good for 3kW. At 1.5m/s (which may be a bit noisy but is in spec for the pipework itself) 4.5kW. https://www.heatgeek.com/does-my-pipework-need-upgrading-for-a-heat-pump-with-cheat-sheet/ That is, in fairness, a bit low by normal standards. However if your heat pump will modulate down to this value and you are happy with a slower re-heat (but still faster than an immersion), what's the logical objection (other than the cylinders instructions which probably say 22mm)? If I recall correctly you are having a Vaillant pump fitted which is capable of a flow temp of 70. Assuming you are heating to 48 that's potentially a DT of up to perhaps 15 (assuming say 5C between water and flow) 20 in which case 15mm is plenty. Then use the immersion for legionella (or don't bother which seems to an increasingly common approach) Unfortunately most plumbers seem not to do design, they just follow incoherent rules! Link to comment Share on other sites More sharing options...
JoeBano Posted February 18 Share Posted February 18 What size cylinder have you got? Link to comment Share on other sites More sharing options...
sharpener Posted February 18 Author Share Posted February 18 3 hours ago, JamesPa said: However if your heat pump will modulate down to this value Doesn't have to because it will be split 7.5 kW to the TS and only 4.5 kW to the coil, so in winter 1.5m/s won't be exceeded. The 12kW Aro + will modulate down to 6 kW so in summer when not using the heating it might get up to 2 m/s, even at this velocity I could run for 6 hrs/day before getting a problem with erosion, see this discussion. 49 minutes ago, JoeBano said: What size cylinder have you got? . 210 l, this will give me a heatup time from tepid of 75 - 80 mins which in the small hours on E7 will be fine. Even with visitors we do not need more HW than that. There is also the immersion on a solar diverter to get us out of trouble. Link to comment Share on other sites More sharing options...
Beelbeebub Posted February 18 Share Posted February 18 Why not swap out the 15mm pipes? As a thought, switching to 22mm speed fit would get you a boost in flow/reduction in velocity with) potentially) easier installation. Yes 22mm plastic isn't as big a bore as 22mm copper but it is still bigger than 15mm copper. Link to comment Share on other sites More sharing options...
sharpener Posted February 18 Author Share Posted February 18 Massive difficulty in the route (see other thread for the full horror of it). Link to comment Share on other sites More sharing options...
JoeBano Posted February 18 Share Posted February 18 With reduced flow rate isn’t your heat pump going to cycle a lot when just doing hot water? I’m no expect just learning as I’m going but I worked out you will need 44lps for that cylinder size? Noticed with my heat pump (grant aerona3) delta t is normally around 3c Link to comment Share on other sites More sharing options...
sharpener Posted February 18 Author Share Posted February 18 No, please see the explanation upthread, the HP will turn down to 6kW, this will result in a flow velocity of 2 m/s which is just OK. Link to comment Share on other sites More sharing options...
JamesPa Posted February 18 Share Posted February 18 3 hours ago, sharpener said: Doesn't have to because it will be split 7.5 kW to the TS and only 4.5 kW to the coil, so in winter 1.5m/s won't be exceeded. The 12kW Aro + will modulate down to 6 kW so in summer when not using the heating it might get up to 2 m/s, even at this velocity I could run for 6 hrs/day before getting a problem with erosion, see this discussion. . 210 l, this will give me a heatup time from tepid of 75 - 80 mins which in the small hours on E7 will be fine. Even with visitors we do not need more HW than that. There is also the immersion on a solar diverter to get us out of trouble. That all makes sense. Unfortunately probably too much for some plumbers used to installation by numbers (but not ones they calculate). I wonder what happens if you just insist and offer to sign a contract of indemnity? Link to comment Share on other sites More sharing options...
sharpener Posted February 19 Author Share Posted February 19 16 hours ago, JamesPa said: I wonder what happens if you just insist and offer to sign a contract of indemnity? Thanks for the reminder. In fact I offered them a blanket clause about all pre-existing equipment following the Tech Dir's visit 9 Jan, I had forgotten(!), will mention it when am next in touch (still awaiting 13 Feb visit report). Will also remind them that Vaillant visited back in October and confirmed they were happy with it as it is. Link to comment Share on other sites More sharing options...
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