marshian

OK - so almost certainly an ABV Well we need to establish if the return via the ABV is warm first 🙂 Have you done that yet??? If there are numbers on it it will probably either relate to operating pressure in which case the higher the number the better in terms of shutting down flow or just be a number scale in which case I don't know - you'll just have to experiment Here is what I'd do if I don't understand the impact of something like this Firstly boiler needs to be firing - your flow temp is 60 deg - that's enough to burn so be careful with hands on pipe tests First with hands on pipe above and below (or a temp clamp) wind the dial round to the max number Does the pipe below feel warmer or cooler If it feels warmer then the number shown equals more return If it feels cooler then the number shown equals less return Then repeat the other way wind the dial to the min value That should tell you what number to set it too (The number that makes the pipework below it cooler) PS It's lefty loosey 😉 sorry Please don't do that (in bold) - the hot end is the flow the cool end is the return it does not matter which end the TRV is the flow and return and it's path thro the rad doesn't change Nearly all TRV's have a double arrow on them - they work in either flow direction. All lockshields don't care either - they can be on flow end or return - if fact remember before we had TRV's we had a valve with a knob on one end of the rad so we could turn it on and off or slow the flow (the other end would have the same valve but with no knob on it acting as a flow restrictor when balanced) I'm none of those things BTW - I just have an interest in getting my heating to perform at it's best and made quite a few errors on the way. "Experience is what you get when you don't want it" I don't think they've given up on you but it's clear to me you take a little while to grasp / understand stuff so you need a little more explanation than just "do this"

@SteamyTea mate never stop what you do - it's brilliant and 100% appreciated - from a maths perspective it's art

Did anyone invite @Dee?

I've entered it on the house calendar - there was nothing on that day so house rules are whatever is on the calendar first is the priority I'll wear a name badge but it won't be my user name on here - I wasn't allowed my normal handle because (expletive deleted) But to help you all out I'll add a picture to my name badge This is me Honest when I look in a mirror that's what I see

If the ABV is letting flow past........... Remember - I keep saying water is lazy - it takes the shortest path if it can Shortest path is via the ABV straight back to the boiler - this will be robbing flow and reducing pressure that could reach the furthest rads You are on pump speed 3 so max'd out Your flow temp is 60 but your return is 50 much higher than the expected 42 You've got rads that don't heat up despite spending hours trying to balance I reckon you'll find that the temp above the ABV when the boiler is firing will be 60 - the temp below it will be above 50 maybe as high as 55 That's my punt - I might be wrong but lets see

If a supplier (expletive deleted)s up for me I send them a bill - after passing it around depts they normally end up paying it.

@Dee PS next time take all the mops out of the way - it's quite hard to follow pipes in a photo with stuff in front of them Looks like a bit of a heath robinson pipe layout and there is probably some more lagging that could help a little to keep the heat inside the pipes. If it's inside the house not so much of an issue but if it's outside the heated area then I'd be lagging the heck out of it

Blue one is an ABV valve then - I think if you can get a close up picture of it maybe we can get a make off it and do a bit of googling and see if there are destructions out there What you can do in the meantime is put your multimeter and clamp on the pipe below it that returns to the boiler and also above it and see if when the boiler is running on a burn there is a temp difference Alternatively go old school and pull off a bit of lagging above and below it and use your hand to see if there is much of a temp difference. The bigger the temp difference the lower the flow thro it Is that do-able?

Thanks for this - I went down the replacement boiler route despite being pretty confident my house was ASHP ready simply because I didn't want to end up with a miss-matched set up under MCS and resulting higher bills. What I am considering is a small ASHP in combination with my gas boiler (create a "Hybrid" system) to do the shoulder season heating and possibly HW - there will be no MCS grant application required (it's pretty clear to that the BUS grant is inflating costs for full installs) and I can do the majority of the install myself - just needing an electrician for the electrickery bits

Is that picture saying room temp target is 13 deg C?

Thank you for clarifying that - was not aware that 9kW ASHP had potential to modulate down to 3 KW - thought it was 50% at best

@JohnMo Of course I'm plucking numbers out of the air - my intro even said so "What would an MCS calculation come up with" So a 9kW ASHP can get down to 6kW - so a 6kW min input with a 3.5 kW heat loss at -2 That is designing a system to bloody cycle - No? How bad is it going to be at 10 deg C OAT?

100% this esp in bold I'm running a gas boiler at a WC flow temp of 34 deg C at -2 Return temp at 34 flow is 27 Deg C Boiler after a restart is modulating down to 3.2 kWh and running between 60 and 80 % of the time What would an MCS calculation come up with - a design flow temp of 45 deg and mandate a 9kW heat pump - the room temps would be bouncing of the TRV's acting as overheat limiters. I'd turn the flow temp down to 32 and the ASHP would cycle like a twat and give a COP of 2.5 or less That's just stupid or mad!!! (I've not decided which yet)

Agreed it's a great idea - however I'm sorry to say that my view is it would be as effective as below

Might be worth a separate thread on the two items pictured - perhaps someone more knowledgeable will be able to identify what they are??

In other news When on scheduled heating last year with higher slope 1.4 and higher level 4.0 I was bouncing the room temps off the target and using TRV's to control so needed a level of bypass to allow the circuit to still have flow when a significant number of the rads were closed by TRV's. Note - I always had one rad with elevated target (above what was achievable) and that was the Hallway rad Reasons - biggest heat loss (quite a large area across two floors 31.7 m3 or ~12% of total house volume - it's not a box shaped house) - ceilings are also landings above so effectively low heat transfer - Stairwell is double height "room" - only served by one radiator (it's big but I deliberately didn't over size it because of both space and I didn't want it over heated as the roomstat which turns off the CH is also in the hallway) Anyway that one hallway rad was not enough to supply the flow required to keep the boiler happy so by pass cut in when circuit got down to 2 or 3 rads in play. Tuesday evening I shut the bypass fully (well set it so that pressure required to open would be only achieved if all rads were closed) not sure why I had left it at the previous setting but I guess it was just something I didn't think about I am suspecting now that there has been some flow thro the bypass even with all rads in circuit because the number of cycles per day has dropped significantly - OK it's been colder but previous days have been just as cold and number of cycles is definitely reduced in a 24 hr period - will be interesting to see if that improvement continues as outside temps rise!!!!

Be interested on how much the boilers cycled - my bet would be not much more than they would with a flow temp of 50 and a room temp target of 20. It must be a fairly decent boiler to get down to 40 flow temp setting - My old Glow worm gas boiler had a minimum of 39 - that was the lowest temp it could be set too but damn thing wouldn't stop cycling constantly unless you put the flow temp up to 45 then it could just about cope with restarts.

I think it's a brilliant idea - accountability for the taxpayers coinage being rinsed thro the MCS scheme Trouble is EPC isn't much better for giving stupid results - now I haven't had an EPC survey done on my house because we have lived here 34 years - they didn't exist when we bought it and I don't need to do one unless we sell it - However it is needed for the BUS grant so I looked into it when I was making the decision to either go for replacement gas boiler or ASHP. Had a bat and ball email chain with a local EPC "inspector" in detail about the process and to be honest I was totally unimpressed with the responses to questions I asked - got the feeling it was a box ticking exercise and at £70 was an expensive box ticking exercise with very little value Examples of why I think this I have 75 mm of PIR under my suspended wooden ground floor it made a massive difference to heat loss in the property but it's not easily accessible to inspect - I said would photo's taken from when I was doing it help to prove that it was insulated This was the response The survey itself is a 'non-intrusive', it is purely a visual survey, meaning an Assessor can only enter information into the software that creates the EPC if they can see and photograph it, for instance if a loft cannot be accessed for any reason (may be the hatch is sealed because it has been painted over) an Assessor would record the loft insulation as unknown, the software would then assume the insulation levels to be 'as built' dependant on the age of the property, where as in reality there may well be 300mm in place. So in summary my suspended floor would be assumed to be un-insulated because Building regs at the time did not require it and because the openings have been covered by a solid oak floor it's not viewable All my rads are sized for flow temps in mid 30's to maximise condensing efficiency and the work I've done to improve the house has driven gas usage for CH and HW down from 25,000 kWh per year to under 9,000 I asked if this had a bearing on EPC results This was the response To answer the question about Kwh usage stated on the EPCs of the properties around you, these figures are all estimated from assumptions of occupancy based on the things such as the size of property, for instance for a four bed house it would be assumed that there will be five occupants and with a two bed house three occupants and therefore more usage in the four bed property. Now this of course is not always the case and the occupancy levels could be very different in reality! Now I can get that HW demand changes with occupancy and 20% of my gas usage is HW generation that's fair enough but CH usage reduces with insulation and to my mind doesn't change with occupancy!!!! Same size house as mine that does have EPC similar double glazed windows and doors is 18,000 kWh for Ch and 3,000 for HW EPC is 49 - E So that and a provisional guide from Octopus of £13,500 for ASHP install (less the 7500 BUS grant) I didn't bother and bought a new gas boiler I'm convinced the whole world is quite mad!!!!

So one might be a pressure relief valve (the black one) but the other looks like a std ABV valve just one I haven't found on google images

I have two sonof temp and humidity meters and following some helpful advice from @Sparrowhawk on how to calibrate the sensors I trust them much more than I did All you need is a bit of salt

Between 55 and 60 in all areas except the loft - thats crazy high

Just to explain what an ABV does - it’s a circuit pressure activated bypass It should be set to open only when the circuit is too small for the boiler to be happy with flow thro it. my old glow worm boiler needed 10 litres per min (absolute min it would run with) when the CH circuit got down to less than 3 rads the flow was below 10 lpm so it would fault out - introducing an ABV into the circuit allowed a small amount of recirculation back to the boiler maintaining a min flow of 10 lpm - it did however mean the boiler cycled a lot but a cycling boiler was preferable to a fault code that stopped the boiler and required resetting manually

Having two ABV’s would be a bit odd - unless you have two heating zones?? If that was the case then you’d be balancing rads in each zone not trying to balance the whole circuit as one……. any chance of some context - ie what pipes are they on and what pipes do they link too?? oh and a really simple check if they are ABV valves and they are allowing flow is when the boiler is on a burn see what the temperature of the pipes above and below those two pictured is. If temps are same or similar it would indicate that they are allowing flow back to the boiler This would reduce the pressure in the CH circuit leading to rads not getting warm (or hot) and raise the return temp to the boiler and lead to increased cycling when the circuit gets smaller as TRV’s start to close or close completely

They both look like ABV’s to me - yikes

Love that second one - brilliant!!!