marshian

I’m fairly happy with it now - there are no low flow alarms - circuit is running constantly at 0.5 m3 per hour Boiler on restart peaks at 50% modulation but rapidly drops to 10.6 % modulation and happily sits there for 30 mins before flow and return temp rise to the point the boiler turns off and waits for it’s restart point Mean Rad temps are around 27 deg C and if flow temp is 30 deg return to the boiler is 24 deg C Roughly 4.0 to 4.9 kWh per HDD so I am using a smidge more gas than scheduled heating (3.5 to 3.9 kWh per HDD) but the room comfort makes up for that - it wasn’t about saving energy it was about making a stable house temp

I'm pretty sure that when I was in the middle stage I was getting a lot of cycling Right now the number of cycles per day is between 14 and 21 (So less than 1 cycle per hour) Watching the boiler yesterday it would burn for ~30 mins and be off for 45 mins - this was consistently the pattern throughout the day. (Fired 5 times overnight according to the ViCare app)

Warning long post - Bit of a catch up going on Still working with the boiler to get the house heating where I want it In November I was still heating to a schedule Got the weather comp pretty much dialed in for that type of heating method now. I've tempered the HW demand boxes appetite for throwing everything the boiler has to give at the HW tank (I've opened the the gate valve on the HW Tank return to 33% - lower than this and the boiler occasionally hunts a little as well as opening the bypass a little which you don't want on HW heating) On weather comp a 1,4 Slope is a good compromise for scheduled heating - lower than that and the house takes a little too long to get to temp. (especially the living room which as I've said a few times is slightly compromised - a 600 x 1400 T22 rad at one end of a 6.2m x 3.6m room was on the borderline when I did the heat loss calcs last year but I thought with less cycling and a more constant flow temp from the new boiler planned it would be OK) Higher slope than that and it gets the house up to temp a little quicker but too many rads shut down and then the circulation flow is too low for the boiler to be happy. Flow temps at the boiler around 8 deg C outside temp is 40 deg and return at the boiler is around 30 deg C All the rads are running at around 6 to 7 deg drop between flow and return I'm pretty near my target 4,00 kWh/HDD (slightly over some days when temps are a little warmer - slightly under when cooler) On one day the boiler did one burn from 3 pm to 7.30 pm which I am really happy about but more importantly all the rooms warmed up equally - even the living room but that's nothing to do with getting the weather comp dialed it...... What the difference?? I dipped my hand in my pocket weekend before last and purchased a new rad and I fitted it back end of last week. 700 x 1400 K33 (triple panel, triple convector) Yes I know it's a smidge below the min recommended height above the floor - I'll fix that next summer (consequence of raising the floor level by 20mm when I fitted oak flooring) but it's solved the rooms issue of always being the last to get to target temp. At the weekend Mrs BC (not known for her tolerance of cool temps) actually said can we have the heating off.............. In December I moved to 24/7 heating with set backs (as opposed to off with scheduled heating) As a result I moved to a WC curve of 1.0 with 2 deg setbacks however Initial results were good from a Mrs BC perspective but sheesh it really didn't work well on warmer days - the house overshot temps and my kW/HDD was way over target. WC is supposed to be better than that so I was a little disappointed. The other main issue was the boiler wasn't modulating down to min before shutting down (I think reduced circuit size was having an influence due to some rooms being up to temp and others still needing heat) I have controls on my phone for Boiler and room temps I decided to push it a little and try 24/7 with no set backs and over the course of 5 days I reduced the curve from 1.0 to 0.6 and the slope from 4 to 0 However I know the rooms in my house that lose temp fastest and they are areas not used all the time (Study, Front hall, kitchen - all north facing) so a few areas as still on schedule the rooms used most are now pinned 24/7 on anywhere from 18 to 21 depending on room function Anyway Flow temps at Outside Temps for the three WC curves are below Outside Temp WC 1.4 WC 1.0 WC 0.6 20 20 20 20 10 36 32 27 0 49 42 33 -10 60 51 39 So in a nutshell at 0 deg outside where I was running 49 deg C on scheduled heating slots - I moved to 24/7 with setbacks running 42 Deg C and I'm now running 33 Deg C 24/7 effectively with no set backs The boiler runs for nice long periods at min modulation - initially I was a bit concerned that it was going to be an expensive experiment but kW/HDD is slowly shifting back towards my design target of around 4.0 Last week as we were home for Xmas I had time to experiment and set the majority of the TRV's as high limiter (ie 2 deg above the room target temp) and watched to see if rooms exceeded the target temp - a couple did so I knocked back the flow to those rooms using the EB4 TRV bodies restrictors. This was clearly a little too coarse an adjustment so had to revert back and so instead dropped the WC curve down to 0.5 and now most of the TRV's don't intervene at all - the heating is on 24/7 with no setbacks in the main living areas and bedrooms - I still have a couple of areas where I am using scheduled heating (Front Hall, Study, Utility and Downstairs Loo) because these rooms either lose far more heat being on the north side of the house or have slightly oversize rads which makes them respond quickly to heat input. Now all I need is a cold spell so I can see how the curve works with a much colder outside temp Hope you all had a good Xmas and wishing you all a Happy New Year

"Pump over" into the header tank is normally down to the pump having too much pressure for the circuit demand/size Those Grundfos Alpha pumps have a lot of different pumping modes and they don't have a great reputation compared to the old three speed basic pumps but I can see from the first picture the old pump was running on max speed. The fact that they are both fitted upside down makes my teeth itch a bit (but they are in the correct flow direction according to the arrows on the casing) I tried to work out what I was looking at circuit wise and labelled up this picture Your plumber might be right and there is a blockage somewhere but that's pretty tricky to find Does the boiler behave on HW cycle ie doesn't cut out

And that is why even though I could balance my system pretty well on cheap DIY lockshields I made the choice to invest in flow control TRV bodies or high quality lockshield valves with very linear performance characteristics because every time a TRV intervened it upset the system balance so found myself constantly tweaking and never happy The high quality lockshields were more money than the flow control TRV bodies

Less temp swings - fabric of the building and furniture/furnishings all get to the same temp - don't need as high a target temp to feel comfortable because there aren't any cooler periods

I meant to say as far as shrinkage is concerned - gluing the lengths makes a huge difference The 250ml size comes with it's own in built brush applicator (Bigger sizes don't) - it's a contact adhesive which goes off fast but has a great bond https://insulation4less.co.uk/products/high-temperature-pipe-insulation-adhesive-all-sizes Also get a insawlator and a "pipe lager pro" mitre box and with off-cuts make up glued 90 deg bends in advance https://www.amniosense.co.uk/sale-product/pipe+lagger+pro I used off cuts to make up glued 60 or 90 deg soldered joints bends and "pulled pipe bends" in advance Bear in mind I was working in a 2 to 3 ft crawl space under my ground floor so anything I could do to prepare for what I was doing in advance was a huge reduction in working time in a cramped enviroment. Because I was doing both 15mm and 22mm diameter copper - I chose my insulation size so both sizes had very close outside diameters meaning that once the mitre box was set up it worked for both (so I hit the adjuster bolts with some thread lock after it came lose a few times and required resetting - been fine since)

I should have added that too (Although I'm in the bit of Norfolk that Suffolk didn't want as opposed to being 8 miles up the road in the bit of Suffolk that Norfolk didn't want - got to love boundaries that are weird

I used Tubolit by Armacell Insulations4less had it in box qty so when I did all the pipework in the loft and under the void floor downstairs I managed to use a whole box of 22mm and 15mm https://insulation4less.co.uk/products/tubolit-polyethylene-pipe-insulation-all-sizes?variant=39554327085109 I would however try to find a local supplier because insulation4less isn't great when it comes to cost of shipping for orders under £500

When I did local pub quizzes we commonly used "Nofolk n Good"

Lovely job - if you can clearly feel the difference in room temps then you will almost certainly notice the reduction in energy usage very disruptive work but hugely worthwhile

Were they trained - really trained? The move to condensing boilers really was just swapping one box on the wall without a condensate pipe for another box on the wall with one - I don’t remember my gas engineer doing heat loss calcs or saying that I need to upgrade my rads to get the best efficiency out of my new “Goverment mandated boiler” It was 2006 and the only question I remember is did I want a combi so I could lose the HW tank (which I didn’t) My journey to lower flow temps only started when I started educating myself and the latest boiler replacement was mainly driven by the fact that previous boiler couldn’t run a flow temp below 50 without cycling 8-10 times in an hour

Maybe a similar journey here except I wasn't confident going to ASHP from where I was with a condensing boiler I'm not sure we were stupid - More uninformed or un-educated

Made me chuckle reading that - I'm still getting closer to the advice given by yourself now 5 out of 13 rads/rooms are now running pure weather compensated flow temps with no TRV influence OP - Bearing in mind the Viessmann boiler on PDHW will throw everything it can at the HW cyl (so 80 deg HW) I think I'd be running copper to and from the cyl - Low temp CH circuits plastic would be fine but I'd do copper for the Hot loop

Agreeing with you ST Typical boiler efficiency improvements going from non condensing operation ie 70 deg flow and a 55 deg return to a lower 55 deg flow and 40 deg return is around 6 % Going to the next stage that is from above to a 35 deg flow and 27 deg return is another 5 % improvement Flip those figures round and compare SCOP’s or COP’s when increasing flow temps and I bet it’s a lot more significant

It only takes a few rads stealing a little too much flow to starve the furthest rads - benefits of those flow setting valves is that the flow is fixed at exactly what the rooms/rads need and no more. how much do you value your time? how much grief do you get for the rooms that aren’t getting warm Fully open circuit in my house and the pump is moving 0.5 m3/hr and that’s being shared out across 13 rads in a system with a total volume of 150 Litres (excluding HW)

Less effort than setting up a radiator circuit from scratch - Main difference is that each one can be set up with the correct flow rate before fitting Setting up with a lock shield depends on how good (or how much valve authority) your lock shields are (or have) Precis - Some lock shields are utter garbage very few are excellent - I looked at buying the IMI ones but the EB4 bodies with 6 settings was cheaper

No I don't

@Dee Use the @ before a users name to tag someone (they get a notification they’ve been mentioned) and you should get a drop down to pick from If I was doing it again I would use the flow setting (auto balancing type) by either Drayton (I use Wiser TRV’s but they work also with conventional Drayton TRV’s) good explanation here or the Danfoss equivalent Either may accept your existing TRV Heads with adaptors (not sure if they are compatible or not) good explanation of the Danfoss valves here Fundamentally they both do the same thing - allow you to set up specific flow rates to individual rads that are not affected by system pressure changes (like when TRV heads start intervening in the circuit) Both types work with the lockshield valve wide open

Not a problem - you shouldn’t need diverters for those rads (OK they are column rads by name but not in the modern sense) Just for giggles this was the view into the bottom tube of the column rad in my bathroom (first picture) So poor manufacturing tolerances meant opportunity for water to go straight thro from flow in to return out rather than be forced up the columns

Just for clarification when I hear the term column rads I think of this But I have this suspicion based on a google that you mean

When I did the job I drained the system down in the summer (I had some other things I needed to do pipework wise) and I did all the EB4 Bodies at the same time (I had purchased them over the previous few months as and when I had a little spare in the household maintenance and repairs budget) If I had my time again I would go for the Flow setting version as the 6 position ones on a few rads are either on a setting to low (but the next setting is far too much) or on a setting too high (but the setting below is far too low) In fact I may well replace all my EB4's with the flow setting ones next year just to "fix the few" All my lock shields are wide open - The ability to control the flow thro a rad via the TRV body for me is so much better than trying to tweak lockshield valves that as soon as any TRV's in the system start to try to control room temps the circuit pressure changes and the lockshield valves are no longer set correctly

Several manufacturers do 130mm copies of the old style grundfos pumps Willo, Trident, Onyx - you can even get a BNIB Grundfos one it you search hard enough. I went for a DAB which has a little more functionality - recommended by my gas engineer because he won't fit the Alphas any more

When you live in an area impacted by Huricanes and Tornados in the USA - you build cheap as it's cheaper to rebuild - Bricks and mortar don't fare any better when faced with a powerful force of nature

Replacing them with what - same again?? Consider replacing them with a TRV body that either offers 6 adjustable flow settings (Drayton EB4 Bodies) https://www.toolstation.com/drayton-wiser-smart-radiator-thermostat/p50334?store=null&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&gad_source=1&gclid=CjwKCAiAjp-7BhBZEiwAmh9rBcR1wEcxM8xrixvxTn8Bc1p-xOOXyXr6japIK4NNc0FIGr8jR9ikXhoCQlEQAvD_BwE Or the newer Flow control bodies https://www.toolstation.com/drayton-auto-balancing-valve/p19480?store=null&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&gad_source=1&gclid=CjwKCAiAjp-7BhBZEiwAmh9rBTeH1kZaQ_VTDZBUakAjHVXcBD_mDBrVqQzDCF5dQqvOZAbLI3VfHhoCTp8QAvD_BwE Either of the above will enable you to run all the flow control at the TRV end and have the lockshield valve wide open OK so cycling isn't an issue Ref Diverters - A lot of cheaper column rads don't have diverters or if they do the quality control isn't great - I had three column rads that all had different return temps despite very similar flow temps - One of them I was lucky to get any drop at all. They basically work fine at higher flow temps when the heat rises up the columns faster than the flow thro the rad - but when flow temps are lower without effective diverters they don't work so well https://www.bestheating.com/milano-flow-diverter-15mm-inlet-chrome-63476?gad_source=1&gclid=CjwKCAiAjp-7BhBZEiwAmh9rBQMqlsl_fWADI-zBoT93tixIGwN2tEfg3xTNkQsP8lPsOfTaOWPSDxoCAOIQAvD_BwE&gclsrc=aw.ds These diverters fixed all of them to give a decent drop between flow and return and the rads get warm all over If you've purchased good quality column rads with clearly marked flow and return ends and the location of the diverter and they are piped up with the flow and return correctly you should be fine