marshian

I was a bit surprised at what I saw - quality control clearly not the best Sounds like they are functioning relatively well - verticals really do seem to need a bit more flow and a slightly higher flow temp than an equivalent T11 or T22 to get the same heat output Worth a look - I have a very large vertical (Millano) with a built in diverter and after my experiences above I had a good look in that one and it's 100% diverted

So first section completed Yes I know the edge closest to the roof tiles and felt isn't supported - it's just acting as a dust/condensation cover for the insulation

Up to about 2 years ago that's all I used.................... Mainly because I had a dos based programme for calculating rad sizing for rooms and that's the only unit of measure it used

Verticals are a pain - you have to sacrifice some delta T at the rad - they aren't as good as heat emitters and need a good bit of flow - restricting them doesn't work very well Ladder type towel rails are the work of the devil - they don't balance very well - they are rubbish as heat emitters and generally they live to short circuit!!! My bypass rad is a 1400 x 500 T22 in the hallway - it has a flow rate of 7% of the total - keeps the hall at 18 deg and allows the boiler to fire if the circuit shrinks to just a few rads

Depends on the rads - running 60 deg flow on my old glow worm I was struggling to better 8 deg on a T11 and 14 on a T22 rad I gave up worrying about getting rads to the highest possible delta T and just concentrated on getting the right mean water temps to heat the rooms So in responding to your last question a higher than 10 deg delta is going to make life worse for your boiler so no don't aim for more aim for less The rads get noisy because you are restricting the flow so generating system noise Open the lockshields a little and lower the pump speed and keep it on a fixed speed - proportional will do the opposite of what you want Just for an example I'm running a ~30 deg flow temp at around zero deg outside air temp - I get a delta at the boiler of 7 deg Pump speed is 2 (fixed) and is around 0.5 m3/hr - there are 13 rads in the circuit My biggest rad 700 x 1400 K33 has a flow in of 30 deg and a return of 24 deg and it's getting nearly 20% of the total circuit flow but it's a big room and one rad has to heat that room

the passing of @joe90 reminded me I hadn't come back to this topic So taking on board the sensible part of @Gus Potter's post and finding no local SE remotely interested in doing any calcs - the majority didn't even respond to an email and those that did said it wasn't worth their while or advised me it would be prohibitively expensive - I guess expensive is a relative thing the few that did respond wouldn't even give me a ball park so I'll take that as a brush off. So in the interests of getting my head round it I did some myself - unfortunately I do them the practical way A section of the loft I stripped of the existing boarding that has been down for 30 years I was surprised at the weight of the boards removed - it was all double boarded with 10mm OSB and 12mm chipboard (pretty sure I laid the OSB and then found it a bit flexible underfoot so double boarded it with 12mm Chipboard to stiffen it up So area covered was 13.8 m2 Weight of the boarding removed 197 kgs So loading was 14.2 kgs per m2 for the old boarding So new boards 18mm OSB work out at 10.3 kg / m2 so 142 kgs To raise the floor area in this section I need to use 7 I-Beams and at 3 kg per m length that's 50kgs Total weight 192kgs for new raised loft flooring (or 13.91 kg/m2) Oh but I hear you say what about the insulation - so lets cover that 150mm superglass loft insulation is 10.76 kgs per pack - each pack covers an area of 7.71 m2 That's 1.38 kg /m2 100mm superglass loft insulation is 11.28 kgs per pack - each pack covers an area of 12.12 m2 That's 0.9 kg /m2 So based on doubling up 150 with 100 a 13.8 m2 area will need 32 kgs of loft insulation or 2.28 kg/m2 So the total load, I-joists, boarding and loft insulation is 16.2 kg/m2 I'm quite comfortable with that.........

As a Vauxhall/Opel Fruit I demand pics OK please share some pics - quite partial to a well sorted shovit

Well I defer to your "Boiler Knowledge" cos I only have good knowledge about Glow Worm boilers (although that crosses over to Valliants) but if a 38CDi Classic can run 40/30 then I'd say the system is too restrictive right now to allow it to do that with a 10kW min

Made me chuckle because I'd just written a post about just that situation - rads with inbuilt diverters which don't

I'm not sure if it helps but I put vertical rads in two bath rooms (the towel rail ladder type rads just weren't cutting it) They were heating the rooms fine at higher flow temps (~55 plus) but one was bloody awful at lower flow temps {~40 deg C) They were both had equally poor delta T between the flow and return at either higher flow temps or lower flow temps but one definately wasn't much of an improvement on the old ladder type towel rail. I took the worst one off the wall removed the lockshield and trv and shone a torch down it whilst taking a picture from the other end That light you can see is the clearance around the inbuilt diverter I knocked it out and fitted one of these (trimmed it to size) Difference was like night and day you could feel the first 3 columns getting warm the flow rising to the top and the the cooler water leaving the rad down the columns on the other side. It was so effective I did the same to the other identical rad - and that one was better too and now they heat the bathrooms to 22 deg C fine even at ~30 deg flow temp

Sounds to me like the boiler isn't seeing enough flow to keep it happy in the initial purge and high output phase unless the flow temp is set high enough that it doesn't overshoot (most boilers initial fire/purge is at 75% of max before they start modulating down) I had similar issues with a Glow Worm 24kW boiler which had a similar 10kW min - my resolution to run lower flow temps was to sacrifice the delta T at the rads - ie increase the pump speed and or and free off the rads will still maintaining the balance in the system. If you have an ABV in the circuit you could try increasing the flow thro it a little but ultimately returning flow back to the boiler via an ABV isn't great for efficiency Microbore to the rads isn't necessarily a problem (if it's just a short section from main flow and return that are 22mm) If your heat loss at around -2 is 6kW and the min modulation is 10kW it should be able to cope with that 10kWh with 6kWh requirement is going to run for ~30 mins in the hour with all rads in circuit provided you have the flow thro the boiler above the min which will be 10 lpm However once TRV's start to close the circuit size is going to shrink quite quickly Increasing rad sizes might make things worse - will result in rooms getting to temp faster if you can't get the flow temps down to work with the larger rads. A volumiser might help - it was in my plan to deal with the glow worm I had but as it was 14 years old I chose to replace it instead. I can understand you not wanting to replace a boiler that is only 6 years old I'd try increasing the flow rate thro the circuit first and see if you can get the boiler to cope with a lower flow temp and not overshoot on the initial fire/purge

Unfortunately many of them don't - they are "conditioned" to throw an oversize white box on the wall and set it up with S Plan No heat loss calcs to determine the optimum boiler size No weather compensation and HWP resulting in an elevated flow temp to cope with both HW and CH No optimisation of boiler settings to ensure the HW and CH requirements are matched to the boiler settings UK is miles behind Europe where this is concerned in so many aspects - even down to constant BBOE set up of Rads which loses 5% heat output. If you choose a Viessmann 100-W "Heat Only" my only recommendation would be not to spec/purchase a 11kW version (they can't be range rated like the 16kW or larger ones)

Sounds like the last AA meeting I went too

I'll be there around 7pm (depending on the work situation) If I leave work late I may chose the eat option - chicken curry looks like a good move (not a fan of Pizza)

Now that makes more sense turning them off and on again won’t be great for efficiency optimisation

When I worked for British Sugar we had boilers producing superheated steam to run a steam turbine to generate electricity - the “waste” steam was used to boil the sugar solution under vacuum until it crystalised and was spun off from the molasses It’s been a while since I was in that game but I guess the advantage was both the electric generated and the steam post turbine were fully used - even the condensate was recovered and put to use. Current work I was pretty sure our CHP unit (Combined Heat & Power) does better than that too (gas powered monster of an engine that runs a generator to produce electricity but again we use the engine exhaust heat to support our steam generators that also run on gas but have massive heat recovery systems on the flue gases. Still with a monthly gas bill the wrong side of £250,000 we need to minimise any waste in the system. When gas prices spiked as a result of the Ukraine situation our gas bill hit over half a million per month - that really screwed with our costs to manufacture products!!!!! I’m honestly surprised that a gas powered electricity generator that supplies the grid is as poor as 400g of CO2 per kWh generated - normally generation at scale is a lot more efficient

Either you have a unit of measure error or the gas power plant is bloody rubbish

last 3 years I’ve driven my gas usage down from 16,500 kWh a year mainly with insulation improvements and a bit of tech East Anglia is also quite mild compared to up north but not as mild as the pigs front legs so you definately have an advantage there. Increasing Loft insulation is my current project - can only do it in the winter as even in the shoulder months the loft temp with a large area of south facing roof space gets unbearable - going from a varable insulation level (patchy 70mm in 60% of the loft area and 200mm in the other 40%) to 320 mm everywhere but it’s slow going as I’m having to remove all the loft boarding Living alone is a huge advantage if your temp tolerance is quite high - mine is and I comfortable at 18 deg C unfortunately SWMBO isn’t and that means a compromise - I prefer a compromise that results in less noise 🙂

Good analysis - I’ve been doing the same….. last year (Act Nov 2023 to Nov 2024) I used a total of 8,250 kWh of gas for CH, HW and cooking heating to a tight schedule and putting up with a wide range of temps in different rooms - SWMBO did not like this heating regime at all and was rather vocal about it - she especially didn’t like going into rooms heated to a lower setback temp because used infrequently and as far as she was concerned the house was never warm enough - esp the living areas despite them being 21 to 22 deg C In Dec 2024 I went 24/7 heating with a much narrower difference between rooms (whole house roughly same temps - little lower in bedrooms and higher in bathrooms and living areas but interestingly at a lower set point 20.0 for living areas) Majority of Rads have TRV’s set to an elevated target (limiters) Boiler is running WC and room temps are managed by a constant flow rate thro the rads at a low flow temp rather than TRV influence at higher flow temps I’ve worked out based on 2 mths data that this change is going to cost me an additional £65 a year…… That I am very happy to pay it’s a cheap price to pay for improved comfort levels and a very very quiet wife 😉

Re-band would only be at the point you sell it normally?? Our house scraped into Band D - I did go thro the appeals process because it really should have been just inside C based on value at the time of banding however I lost the appeal (I didn’t do enough research and unfortunately during the review and appeal I’d already done some improvements which were included in error at review) It’s been extended now so sits firmly in band D so I’ve no worries about moving up a band if we ever sell it (been here 34 years now and no plans to move yet)

Excellent Thank you very much - I’ll send you a PM

Not watched it yet but heat geek talk about sunamps

on that basis I think I’ll treat your future blogg posts as thread resurrections in future

And once they do fail, as a customer of the failed company you get migrated to whatever company that is prepared to pick you up (or get told to accept you) and potentially that could be Scottish Power and I have no bloody wish to be back with them again so I'll stick with Octopuss

I know 3/10 poor rant - needed more variety in the expletives Sorry I'll try to do better next time!!