markocosic

We had some rough ground; made it rougher with a 20 ton excavator moving some of it around / installing a heat pump ground loop etc; and needed to tidy it up. 1) Cultivate / till it (nearest tractor will do) 2) Now what...raking this area by hand requires Olympian endurance... You will need: 4x 3 metre / 10 foot long 2x4s 3x 1 metre-ish / 3 foot-ish long 2x4s 2x logs as extra weight 2x pipes (for corner marking) 2x ratchet straps (spares useful...) 1x small car And it works bloody amazing for levelling and compacting *just right* for putting grass back. The mk1 attempt (6 metre wide rake on a Ford Focus) was a little ambitious. The mk2 attempt (without logs) did fudge all. The mk3 (four logs) was too much of a handbrake. The mk4. you see...just right. I would guess 100-150 kg. Smooths it AND is flat/heavy enough to kick all the field stones and tree roots etc up and out onto the surface. Ready to absolutely not throw in the back of your wife's car like it's a glorified wheelbarrow and spend the journey home wondering how long it'll take to remove all the insects. 😇 Ratchet straps (free end wrapped around the frame once and clamped with a piece of wood; hook end on the car to avoid flying metal bits if it breaks) are the perfect strength for being able to pull this along without being too deadly to car or tree when you get ambitious and chop down to 2 metre width do this bits between the trees... Next month expect a post about moles. 😂

I've had a chance to play with a few sorts as a DIY office jockey type. Copper is ace in tight spaces with lots of complex gubbins to connect up. Very compact. Very well behaved in terms of support; pressure drop; etc. Do yourself a favour and use press fit to allow 100% dry fit before assembly rather than end feeding as you go..unless you're really ace at measuring as you go. Undoing/redoing 28 mm tees or 35 mm tees in end feed is not fun. MLCP is perfect for lairy first fix labourers. It seals internally and the diffusion barrier is buried deep in the pipe. Feel free to drag it across concrete, around the corners of rough cut metal studs, step on it repeatedly, use it as a towrope etc. It'll seal perfectly every time. Compression nut or press fit. Not widely available in smaller diameters though and the fittings are restrictive. Hep2o is delicate as heck; what with sealing on that outside and being made of scratch prone chewing gum; but it's very much easier to pull through like a wire/available in smaller sizes and does better on pressure drop for a given draw off volume. If mistrusting somebody lairy to first fix - mlcp. If trusting people to first fix and caring for draw off volumes more - hep2o. And transitioning to copper/screwed brass for the fiddly bits in a plant room when required.

And an ultrasonic meter not a clockwork meter; for performance at low starting flow rates.

Just sack the instruction manual (manufacturer's opinion; not law) into the bin where it belongs. They are covering continental scenarios where houses have basements (not a good place for propane) and you're not allowed to pipe in unlimited amounts of methane or store 30 kg of propane within the home.

Flushing pipe is easy. You'll f**k the heat exchanger in the heat pump long before you have to worry about muck settling in the pipe.

Metering is my day job. Clamp on meters are naff and fairly spendy. Micronics U1000 is the benchmark. Retail £1000 apiece. Inline meters in small sizes are cheap as chips and easy enough to cut into an existing system if you're serious. Consider it part of the survey. Replace with a spool piece (spacer) if you decide not to go ahead with a heat pump install. A DN20 meter (130 mm x G1" body) is £130. A DN25 meter (260 mm x G 1 1/4" body is £175. Meter unions go from 1" flat face couplings to a 3/4" male thread. (pair with 3/4" female to 22 mm compressions) Or from 1 1/4" to 1" male thread. (pair with 1" female to 22 mm or 28 mm compressions) Use selective isolation to work out what the flowrates in branches are. Start with everything on. (so that pipes are showing full pressure drop) Then isolate one radiator. The difference in flow is what that radiator was flowing. Then turn it on again and isolate something else etc. I wouldn't bother personally. Guestimate based on what you know about what you have. If the primaries are short you'll be ok. Piping a 6 kW (old school fixed speed ground source) heat pump into 22 mm copper then a 200 litre volumiser (tank in series) then 1" manifolds to 16 mm MLCP to some rads is a job for me for the next couple of weeks. 🙂

I'll let you know this winter @de devil tail It isn't rated for high temperatures and pressures in the district heated blocks. It isn't flexible enough that you would want to use it for underfloor heating. But for cold/hot drinking water and low temperature heating I think it will be just fine. 🙂

IME pretty uncomfortable to have 3 kW zero kW 3 kW Xero kW blowing at you.

Not so. If the heating goes off at 15C (because solar gain and internal gains equal the losses) then your number is 0 at 15C and 8kW at design condition (excluding internal gains) This extends the modulation range required and means it's more likely that you spend longer operating at/near the minimum outputs.

I don't think so. The time spent at full load is very small. (plot the temperature difference each hour of the year as a load duration curve) Lots will be spent in the happy 25-75% range if your unit is sized at 100% of design load. E.g. From: https://www.researchgate.net/publication/291352700_Stochastic_Modelling_and_Simulation_of_Energy_Flows_for_Residential_Areas With VDI reference method from: VDI, “4655 Referenzlastprofile von Ein-und Mehr- familienhäusern für den Einsatz von KWK-Anlagen,” Verein Deutscher Ingenieure (VDI), pp. 3–18, 2008. You can use hourly temperature data and a "balance point" to get similar curves for your choice of climate and building fabric standard.

Go for two far smaller ones. Oversizing not a good idea for cycling, life expectancy, comfort etc. COP often drops at minimum output too. One thing to note is distribution of work. Upstairs unit will do almost nothing in heating season. Downstairs unit will no almost nothing in cooling session. Because cold air falls. On this basis a multi split is perhaps not quite so silly in efficiency terms Consider a single 10kW unit with a 7kW head downstairs and a 5 kW head upstairs perhaps? Or a pair on single splits at say 5 kW and 3.5 kW (cooling rating; just outputs will be higher). Might even get away with 3..5 kW and 2.5 kW on the cooling rating. They will then modulate down beautifully in all conditions and operate near to their efficient mid load operating point most of the time.

Thermal stores with coils in have lousy available capacity per unit of stored water. I think their main advantages are the lack of discharge; and being able to use the bottom of them as a buffer for the space heating / heat pump defrosting.

I'm resurrecting this @Dan F based on the "could you rock a small heat pump with a small cylinder" discussion here; and in particular the comments form @HughF on "but Glyn's 5 kW Samsung setup into a 1m2 coil works ok" etc prompted by @JamesPa and @sharpener comments too. That is a 150 litre Vaillant / OSO slimline cylinder with a 1m2 coil. He "holds off" the reheat of the hot water to two time periods each day; in order to only "reheat from cold" rather than "topping off" the tank. The nominal setpoint is 43C. It gets to about 45C at the top of the cylinder with stratification. That is giving a COp of >4 when outside temperature is >7C outdoors. Which us most of the year: https://youtu.be/kkNx2oSO-S4?t=808 Why is @Dan F's Mixergy setup so pants in DHW preparation then? Light bulb. Coil location. Mixergy are forced to put the coil in the stupidest possible place so that they can do the "only partly fill the cylinder" party trick. Like; right at the bloody top: Whereas a regular cylinder will have it at the bottom. This means that the heat pump into a Mixergy primary coil is going whammo; straight into the hottest part of the cylinder; hence being unable to dump the heat from the compressor into the cylinder at anything other than some deltaT above the hotter part of the cylinder. You could manually run the Mixergy charging / destratification pump; to stir up the cylinder and make it all the same temperature. That would mitigate the effect; at the expense of the water at the top of the cylinder being unusable until such a time as the whole lot is heated. But what you want is a coil either at the bottom or rising through the entire cylinder. Even a modest area then gives you an ok COP if the heat pump that's charging it has a modest output. I had in my head that "a small coil like a Mixergy would be no good even on a 7 kW class heat pump" without having clocked where that coil was and the effect that this would have. I'm now wondering out loud about these: Was previously toying with plate-loading a direct cylinder that would fit under an oven: https://osohotwater.co.uk/product/super-xpress-hot-water-cylinder/ Now toying with an absolutely boggo coil cylinder (0.8 m2) under an oven. (1160 high even with all the expansion and inlet group etc in "180L = 163 litre actual capacity) https://osohotwater.co.uk/product/super-coil-hot-water-cylinder/ Not ideal by any means (why don't they make one of these with a say a 2m2 coil in this form factor...) but perhaps not horiffic. The large coil variants all have a ruddy great T&P relief stuck out the side; in addition to being 595 mm not 580 mm width. (too tight even for the bravest of squeezing it in place of a kitchen unit jobs) https://osohotwater.co.uk/product/delta-geocoil/ And the Vaillants have the T&P relief and an immersion heater cover in addition to everything being side exit/needing external expansions etc 😕 https://www.vaillant.co.uk/downloads/product-manuals/unistor-1/unistor-pre-plumbed-heat-pump-cylinder-domestic-installation-and-maintenance-instructions-1956775.pdf

I said "let's stop here" to avoid taking the piss / wasting any more of their time if they wouldn't install an unvented to my main. Broadly though they have a recipe to work to. Everything must meet the specs in a backside covering way; for both the equipment AND the piping/emitters. He warned that they'd NEVER accept microbore and would want to repipe the lot even if the 10 mm was only the drops behind the plasterboard etc. I wouldn't expect anything remotely complex from them.

Unfortunately the "no plans" you've received @Dillsue isn't lying to you; as it was in the days where they were claiming that regs prevented them offering an export tariff without MCS. I don't think you have any leverage there; other that to ask them to confirm which of their T&C's they're citing in that response. Which should force a response given their obligation to be honest with customers.

Could you provide a copy of the emails please @Dillsue? I'll raise this very bluntly with them if the dates on your emails are after the date they changed their terms and conditions. Dishonesty is not permitted under the terms of their supply license; and to say one thing yet do another with the evidence in writing would be naughty / a fair reason to request the termination of the supply license; which is rejected if they agree not to do it again etc.

Don't think I'm stopping with the PV... 😉

You're welcome folks. 😉 https://gtec.co.uk/clause-5-8-octopus-opens-up-the-solar-pv-market-with-a-paragraph/ (Octopus caved / reviewed their policy and has decided to heck with this MCS nonsense)

They don't seem to do hot water cylinder cupboards on the continent. It's either a wall hung tank in the bathroom, wall hung tank on the balcony, or standalone tank in basement. So this thing just sits against a wall in a room. Demolish the cylinder cupboard and sit it against a wall type thing. It would be ideal if it were 56*56*1800 say, so it could be a kitchen unit easily. That wouldn't work with their fat blown foam/plastic body tank though. For houses you could, if so inclined, build a plastic tank with everything up top, ready to shove the space heat and hot water pipes through the old boiler flue hole... Doesn't get *that* cold here and if space isn't quite such the constraint.one can afford insulation.

This is a major issue in the UK at the minute. Not just the ticket (£1000 and a Mickey Mouse course) but the experience generally (flaring pipes / brazing pipes). I think it'll disappear as more folks ask for domestic AC though. And it'll be plumbers who upskill to fit these rather than air conditioning folks who do domestic plumbing. Europe is more relaxed about this stuff. In the DIY sheds €600 minisplits; €150 vac pump/flare tool/gauge set kits; off you go. When it's limited charge R290 the FGas requirement disappears and it's just the plumbers being scaredycats as the barrier.

You're describing a Rotex HPSU. Matey in Lithuanian countryside has an old one. Outdoor unit is tiny because it's a split rather than a monobloc. (done to avoid freezing and to make routing there primarily pipework a piece of push) Indoor unit is a thermal store with ALL the valves and gubbins on top. Daikin bought them out. They appear to have done nothing with that business/product line. Low volume to them. Too much mucking about with plumbers for the to respect it. https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.daikin.ch/content/dam/document-library/installation-manuals/heat/air-to-water-heat-pump-low-temperature/hpsu-3xx-h/FA_HPSU_compact_4_0081414544_12_0615_web_GB_Installation%20Manuals_English.pdf&ved=2ahUKEwif0Mf64b6AAxUyS0EAHatMDm4QFnoECA4QAQ&usg=AOvVaw3onoP7Ujj8OQACfr5HaoZs Bit crappy because coil type heat exchanger for DHW. Simple but poor performance. Also the outdoor unit is a long in the tooth R410a product with meh performance. As a concept though, a split system with thermal storage rather than hot water storage has many plus points. Samsung TDM style systems that add in a fan coil to deliver heating/cooling would be even nicer perhaps. https://www.samsung.com/uk/business/climate/tdm-plus-specifications/

It also used to give the government the heebie jeebies until recent living memory. (dad was very happy to have one in the 80s once it became legal) My understanding is that insurers don't like tanks in attics. Water damage is spendy and the claims histories for the types of "in need of some love, on average" property that still have vented cylinders are nasty. Probably pales into insignificance vs the rental premium mind you! Air to air for space heat in the flats, plus a towel rail. Electric shower and a vented cylinder? How about a modulating tankless heater for the whole flat? (effectively an electric combi) No Gas ticket. No G3. No stored water. No overflows/discharges. If Sunamps weren't such a joke one can see why the landlord market might like those. I'll link again to Qvantum. https://www.qvantum.com/ISH23/GSHPM It's a thermal store (bucket of hot water that you don't drink) with a plate heat exchanger for producing hot water on demand. No Gas ticket. No G3. No stored water. No overflows/discharges. You bring ambient temperature water (effectively a ground array; which could also be topped up using heat from outside air) to each apartment from a communal setup. They have a heat pump for DHW, space heat, and space cool tucked in a kitchen cupboard etc. Plus a magic tank that does what Sunamp ought to do in terms of producing hot water on demand... I think they're onto something.

Hmmm! Thoughts out loud: This is: - A 6 kW could input from a standard "low temp" F-Gas heat pump - A cylinder setpoint of 42 degC, which best case gives 150 litres of shower water (allowing for some destratification), and then reheats at 6 kW - And a NEW cylinder with decent insulation but perhaps more importantly a completely clean 1m2 coil that runs halfway up the cylinder. Looks like it works nicely; heat pump wise; and it'll also have low standing heat losses etc. I'm sold on this being a functional option The capacity is miniscule though due to the temperature it is being operated at. Works for a self confessed hair shirt. I perhaps wouldn't want to be the father selling this to a wife and 2.4 long haired daughters though. I would roll my eyes at it if buying the place. If it were a more modern heat pump you could perhaps have 50C for the same COP; if reheated at the same rate. Still a relatively low capacity cylinder. Now to the "miscellaneous old cylinder" option for a "typical retrofit" (rather than a brand new cylinder, purchased independently of the heat pump, either for reasons of necessity or due to poor planning) It's for sure gonna have higher heat losses. What is the coil? 0.6 m2 is quite different to 1.0 m2. Is it in the bottom of the cylinder only (trying to stir the thing up using convection currents) or does it extend through more of the cylinder? Is it clean, or has it been heated to 80C in the southeast of England and is there the usual 20 of scale on the coil / in the bottom of the cylinder? Was it ever big enough at 60C? Is it gonna be big enough at 42C or 50C? Did you want an invented to sack off all the roof tanks and pumps etc? Given the small material cost of a cylinder vs a paid heat pump install, and the opportunity to get it all without VAT, would you be daft not to swap it? Probably. Retail (what the fitter would charge) on those slimlines is 1165+VAT https://midsummerwholesale.co.uk/buy/vaillant-heat-pumps/vaillant-cylinder-150l Retail on the biggest baddest cylinder in that range is 1605+VAT https://midsummerwholesale.co.uk/buy/vaillant-heat-pumps/vaillant-cylinder-300l Some will say fuggit; do it. I think this is the reality of anybody serious about an upgrade. Some will ask to reuse an old piece of shite with the potential to be a scale filled liability that was last touched by the fitter etc. Or cause complaints due to low stored volume. The fitter will say naah, not worth the risk. Now say the cylinder is relatively new. Say it might / will probably actually work. If fitters are looking for work, and price is a consideration, they might entertain taking the time to check if they can use that and the risk of touching it last. Reality: they're not looking for work. Demand exceeds supply. They're going to choose the jobs which pay the most. If you're interested in a new cylinder you'll get a fair price for a new cylinder. If you're not interested in a new cylinder you're going to get much the same price. This only changes once supply exceeds demand. The big boys and girls have additional constraints. BG evidently won't install ANYTHING other than in accordance with the manufacturer's backside covering instructions. Fitters won't get the leeway. You can't DIY this because of the f**king MCS cartel. Not just the grant. It's not even legal. (planning) Nor can you MCS space heating only. Not grant eligible. And that's perhaps the kicker. Don't blame the installer for wanting to include hot water. They're obligated to otherwise the job costs £5k more. And if they're gonna do hot water to get the grant - you automatically increase costs by £5k by not doing hot water - to then they think you're daft for not going all out on maximum performance and pleasure and resale value, but perhaps can't articulate this in the best way? I think MCS are f**ks and HMG are fools for promoting them. Just in case that wasn't clear before! Octopus are known to be targeting 90s Barratt estates. Where there are 30 year old vented cylinders in houses due for their first bathroom swaps/cylinder swaps etc. And much of the heating was still large bore copper. Probably not accidental?

Agree with MCS and PD I don't think this should be zero rated. That, like grants, is liable to end up in the installer pockets. Yes to grant removal BUT it should be along with carbon (i.e. gas) being taxed to create the no brainer commercial model. If you need another incentive, perhaps to sweeten the deal for the homeowner who initially does the work, rather than subsidising the long term operation too highly, I'd perhaps make it a stamp duty rebate of £5k.

I'm happy to say it looks like it'll function (fudged up working left for all and sundry to see!) but I think you'd be daft to spend say £5k to do a half job rather than £6.5k to do the whole job; especially given the lifecycle cost benefits and probably also the property value uplift from having decent hot water (vs a tiny old gravity tank) I don't sell heat pumps btw. Or install them. I actually work in the district heating/cooling sector...