Finally got it up and running

[mk1_man]

Chuffed to bits, finally finished my diy install of my nice shiny 7kW Arotherm.  Have only used for dhw but working a treat once I realised that my esbe diverter valve was wired back to front and I was heating the ufh !

 

Just need to finish off wiring the OEM stuff.

 

Old boiler out :

 

New unit :

 

 

Primary Pro and anti-freeze valves

[TommoUK]

Good effort.  

[JohnMo]

Well done, looks tidy. Now all you need is the cooling chip, read up on here, the one they uses in gas boiler for some other reason is the same and a 1/10 the price.

[mk1_man]

Thanks, took a bit longer to install than I had planned, probably due to soldering all of the joints as opposed to hiring a press fit tool.  I was doing in in fits and starts but all in probably 4 - 5 man days in total.  Hard to see how the companies I got quotes from could quote £12k plus ( excluding BUS grant )  the parts were approximately £6k and that is including vat and purchasing as an individual, surely the bigger companies command a much better discount.  In my eyes just proves that the current situation is ripping off consumers and not delivering biggest bang from government investment.  My view is that it should be opened up to a much bigger market and simply install to a best practice guide but essentially make something like Open Energy monitor compulsory if you want to access BUS grant with a requirement to score at least a cop of 3 or above to qualify.  This would put the onus on installers and manufacturers to deliver the goods and stop it being an MCS monopoly.

 

Thanks for advice on cooling, I was going to look into it and have ordered the following at £11 delivered 🙂  https://www.theheatxchange.co.uk/vaillant-plug-coding-vai0020266328

 

[JohnMo]

18 minutes ago, mk1_man said:

current situation is ripping off consumers and not delivering biggest bang from government investment. 

Fully agree, but the government investment, is really the tax payer investment.

 

Should just stop the install grants, spend the money on plumber compulsory, low temp heating system design and installation training - do as part of Gas Safe and or G3 training so little or no escape. Heat pump is just a heat source, it's system design that is important bit for ASHP, GSHP and condensing boilers. The system shouldn't look or act any different, irrespective of heat source.

[Beelbeebub]

Waves flag for government spending the money on a guarentee scheme so that HP will cost no more than gas for 5 years. 

 

If the assumption is a scop of 2.5 then anyone getting a better scop actually saves more over the period making the payback loads better and gives time to rectify any under performing systems. 

[JohnMo]

36 minutes ago, Beelbeebub said:

Waves flag for government spending the money on a guarentee scheme so that HP will cost no more than gas for 5 years. 

Why? That will just be abused by the unscrupulous. A heat meter records negative heat output when cooling, so anyone could make the system look like it's got a poor CoP, even if fantastic during winter.

 

Just make all plumber training mandatory on low temp systems - then what issue? A simple low temp system should be getting a SCoP 3.5 min in the frozen north and 4 and above especially in the moderate temperature zone called southern England.

 

Stop grants, they are just getting rich quick schemes, the general public carry the tax burden front end, and as a consumer with shoddy practices and poor workmanship at the end.

 

[Beelbeebub]

1 hour ago, JohnMo said:

Why? That will just be abused by the unscrupulous. A heat meter records negative heat output when cooling, so anyone could make the system look like it's got a poor CoP, even if fantastic during winter.

 

Just make all plumber training mandatory on low temp systems - then what issue? A simple low temp system should be getting a SCoP 3.5 min in the frozen north and 4 and above especially in the moderate temperature zone called southern England.

 

Stop grants, they are just getting rich quick schemes, the general public carry the tax burden front end, and as a consumer with shoddy practices and poor workmanship at the end.

 

In order to qualify you have to have the supplied heat and consumption meter fitted (tamper proof box). 

 

Say your system delivers 10,000 kwh heat over a given period. At (for easy calculation) 10p a kwh for gas that would cost £1,000.

 

The scheme assumes your HP is 2.5 scop so your elec consumption would be 4,000 kwh. And at (again for ease) 35p kwh of elec you would have paid £1,400 for elec.  So the scheme pays you back £400 and your heating has cost no more than gas. 

 

If your Scop was actually 3.0 you would only have paid £1,165 and you're actually "made" £235. 

 

So the way to scam the system (aside from tampering) is to make your system more than 2.5 efficient. Oh no! (clutches pearls). 

 

The 2.5 assumption increases each year until it hits cost parity with electricity (3.5 in my example).

 

There would be a cap on total oaynents/subsidy of £7.5k so it would never cost more than current system. 

 

Aside from people outright tampering with the meter box I can't see how you can defraud the system except by making a really efficient system. 

 

As the actual performance would be availble (via the box) it could be published on a big website along with the installer details. Installers could then go to customer and say "look I regularly get 4.0, with your type of house so use me!". Gokd installer would be able to charge a premium and also be incentivised to minimise install costs. 

[Beelbeebub]

If we assume good case of a 3.5 scop install delivering 10,000kwh a year with gas/elec being 10p/35p that works out at £400 a year paid back and a saving for the customer (vs gas) of £400 a year.

 

Over 10 years that would be 4k paid back and at the end the customer is still paying exactly what they were on gas

 

10 years of near guarentee you will pay the same as if you were on gas gives plenty of time to sort out any botched installs. 

 

 

[JohnMo]

8 minutes ago, Beelbeebub said:

In order to qualify you have to have the supplied heat and consumption meter fitted (tamper proof box). 

 

Say your system delivers 10,000 kwh heat over a given period. At (for easy calculation) 10p a kwh for gas that would cost £1,000.

 

The scheme assumes your HP is 2.5 scop so your elec consumption would be 4,000 kwh. And at (again for ease) 35p kwh of elec you would have paid £1,400 for elec.  So the scheme pays you back £400 and your heating has cost no more than gas. 

 

If your Scop was actually 3.0 you would only have paid £1,165 and you're actually "made" £235. 

 

So the way to scam the system (aside from tampering) is to make your system more than 2.5 efficient. Oh no! (clutches pearls). 

 

The 2.5 assumption increases each year until it hits cost parity with electricity (3.5 in my example).

 

There would be a cap on total oaynents/subsidy of £7.5k so it would never cost more than current system. 

 

Aside from people outright tampering with the meter box I can't see how you can defraud the system except by making a really efficient system. 

 

As the actual performance would be availble (via the box) it could be published on a big website along with the installer details. Installers could then go to customer and say "look I regularly get 4.0, with your type of house so use me!". Gokd installer would be able to charge a premium and also be incentivised to minimise install costs. 

More rubbish costs for the tax payer to cough up, and pay some company to manage. More upfront costs for a heat meter and dedicated heat pump electric meter that read and record in almost real time, so CoP and SCoP make sense - all of this kit has to be paid by someone - either the tax payer or the person having the kit installed. "If your Scop was actually 3.0 you would only have paid £1,165 and you're actually "made" £235" but the metering system just cost £600 installed.

 

The OP install and many others on here show the cost of install doesn't need to be high, or cost prohibitive. Fact is a new full price heat pump isn't much of a cost premium over a good quality system boiler. And because the installer system see a cost benefit for the consumer in the way of a subsidy for a piss poor install, the consumer will still be ripped off.

 

Sorry don't believe any government money spent on these schemes, is money well spent. A couple of years after the grants were abandoned on PV, costs have dropped like a stone.

 

 

[JoeBano]

Nice and tidy! Probably better most install I’ve seen working on jobs 😂 

[Beelbeebub]

31 minutes ago, JohnMo said:

More rubbish costs for the tax payer to cough up, and pay some company to manage. More upfront costs for a heat meter and dedicated heat pump electric meter that read and record in almost real time, so CoP and SCoP make sense - all of this kit has to be paid by someone - either the tax payer or the person having the kit installed. "If your Scop was actually 3.0 you would only have paid £1,165 and you're actually "made" £235" but the metering system just cost £600 installed.

 

The OP install and many others on here show the cost of install doesn't need to be high, or cost prohibitive. Fact is a new full price heat pump isn't much of a cost premium over a good quality system boiler. And because the installer system see a cost benefit for the consumer in the way of a subsidy for a piss poor install, the consumer will still be ripped off.

 

Sorry don't believe any government money spent on these schemes, is money well spent. A couple of years after the grants were abandoned on PV, costs have dropped like a stone.

 

 

I would argue the costs would be lower than the current 7.5k BUS grant which seems to be, for reasons discussed, just seen as a bonus for the closed shop installers.  This incentivises doing jobs at max cost with little thought of the best performance. (as an aside it would be interesting to see if the average before grant cost of installs has risen by 2.5k since the grant went from 5 to 7.5k)

 

Yes the heat meter would cost a bit (that would be provided free to consumer as part of the subsidy) but if they are standardised and knocked out they aren't that expensive. No special elec meter is needed, the monitoring of power in is purely for cop calculation which isn't needed for the subsidy only heat delivered. The whole thing would be administered by the energy providers. 

 

This would allow the installer base to be widened out to beyond just MCS peeps (reducing costs and increasing choice). As you say the cost of a HP unit isn't much more than a good boiler and it seems that much if the "upgrades" needed like buffers, second pumps, fancy controls, replumbing in 28mm throughout, completely new cylinders etc is actually suourflous at best and harmful at worse. The best results seem to come from single zone, open loop WC systems with a single diverter and a cylinder with a high recovery coil. 

 

Better yet would be to only upgrade bits (like the cylinder) if required. So install the HP, leaving everything as is (cheapest option). After year, if scop isn't to satisfaction the customer isn't out of pocket but can upgrade the necessary but (maybe a rad and small section of pipe or the cylinder) 

[Dave Jones]

On 01/09/2024 at 16:59, Beelbeebub said:

Waves flag for government spending the money on a guarentee scheme so that HP will cost no more than gas for 5 years. 

 

If the assumption is a scop of 2.5 then anyone getting a better scop actually saves more over the period making the payback loads better and gives time to rectify any under performing systems. 

 

there needs to be a goal for price parity between gas and electric. The market would then take care of it.

 

1 kwh gas = 6p

1 kwh elec = 23p

 

 

[ReedRichards]

I'm not sure that foam insulation is suitable for outdoor use.  It's certainly not the type that is usually used.

[joe90]

21 minutes ago, ReedRichards said:

I'm not sure that foam insulation is suitable for outdoor use.  It's certainly not the type that is usually used.

I wrapped mine in tape self amalgamating. BT use it for waterproofing cable joints.
https://www.toolstation.com/self-amalgamating-repair-tape/p55262

[crispy_wafer]

Looks like the primary pro stuff to me?  Primary Pro 28mm x 19mm Insulation - 1 metre length (midsummerwholesale.co.uk)

Edited September 26 by crispy_wafer

[Beelbeebub]

1 hour ago, Dave Jones said:

 

there needs to be a goal for price parity between gas and electric. The market would then take care of it.

 

1 kwh gas = 6p

1 kwh elec = 23p

 

 

At the moment the green taxes on electricity are much higher than gas. 

 

The current SCOP need for a HP to "break even" with a gas boiler is about 3.5

 

This is perfectly possible but requires quite a bit of installer knowhow to achive. There are many tales of people who installed HPs and ended up with higher bills. 

 

If the green taxes were moved from gas to electricity, that break even SCOP drops to around 2.5 which is very easily achievable in all but the most ham fisted installs. 

 

Secondly, the installation of HPs needs to be made vastly easier. 

 

The planning and noise requirements need to be drastically streamlined. Noise in particular. 

 

New HPs are getting below 40db. If we had a system where a HP could be given a "hush mark" or something which would allow it to be sited anywhere as long as it it 1m from a neighbour's window. It would make a diffence. 

 

If the HP required less than 13A draw, being able to have it wired in to a spur off a ring main or even just plugged into an outside socket would make life easier. 

 

Basically we need to remove as many barriers as possible. A HP is potentially easier to install than a gas boiler. Not (as some here have proved) beyond a competent DIYer and certainly not beyond a decent plumber. 

 

Make them cheaper to run than a gas boiler and easy to install with minimal paperwork and the country will switch pretty rapidly. 

Edited September 26 by Beelbeebub

[IGP]

16 minutes ago, Beelbeebub said:

The planning and noise requirements need to be drastically streamlined. Noise in particular.

 

New HPs are getting below 40db. If we had a system where a HP could be given a "hush mark" or something which would allow it to be sited anywhere as long as it it 1m from a neighbour's window. It would make a diffence.  

To be fair, a lot of the new HPs have the ‘Quiet Mark’ but that’s nothing official from a regulatory perspective. 

[Beelbeebub]

Just now, IGP said:

To be fair, a lot of the new HPs have the ‘Quiet Mark’ but that’s nothing official from a regulatory perspective. 

Yeah, the key would be if the mark was basically a sidestep around a bunch of paperwork. 

 

The idea is that a plumber should be able to go to a plumbers merchants, grab a certified quiet) HP off the shelf and stick it outside a house with zero paperwork. 

 

If the HPs came with clip on cosmetic panels in different colours/materials so the things didn't look you'd left a chest freezer outside your house it would help. 

 

Just making them black, green and brown would be a big improvement. 

 

Wheelie bins are black, green and brown and we have accepted those outside houses now. 

[JohnMo]

Trouble is the big players like octopus want you have a system with a design flow temp of 50 degs. This maximises their profits, makes an easier install. Justification is a good selection of tariffs which are available (but for how long) so cheaper to run than gas.

 

10 minutes ago, Beelbeebub said:

less than 13A draw

That starts to get difficult, even a 6kW ASHP will have a power required of 3kW at sub zero and high flow temp. Without accounting for in rush current on motor start and the various outlets for immersion heaters driven from the ASHP.

 

Hybrid incentives are the only real way to get mass roll out. No internal changes to heating system required (you could though, to drop design flow temp). System runs 90% of the time on heat pump, if house has a combi no cylinder required. Just make weather comp manditory, boiler manufacturer have to provide an interface to allow this if boiler needs it. In nearly all cases a 4kW ASHP would be ok. 

[IGP]

I'm coming to make peace with hybrids in theory, assuming they are more like the Intergas ones, where they are running for 100% of the heating time, just topped up with heat from the combi rather than stopped and purely running on the combi. 

 

Then it's such a marginal step (psychologically) to full ASHP the next time people upgrade their heating / hot water in say 2035 / 2040...  

 

I would tier the BUS payment to be say £4/5k rather than the £7.5k for full ASHP installs. 

[sharpener]

2 hours ago, JohnMo said:

That starts to get difficult, even a 6kW ASHP will have a power required of 3kW at sub zero and high flow temp. Without accounting for in rush current on motor start and the various outlets for immersion heaters driven from the ASHP.

 

Unfortunately that seems to be the case, even the 3.5kW Vaillant can draw up to 14.3 amps (it is the same unit as the 5kW but with the output capped).

 

 

However you would probably want a separate circuit, just as you should have for a boiler or an immersion heater. But an existing boiler radial circuit would do for an HP up to 7 kW. With inverter drives you do not need to allow anything more for inrush/motor start.

 

A bigger problem though is that with an inverter drive you need to fit a Type B RCD and this is not allowed to be behind a Type A in your existing consumer unit, as discussed in an earlier thread. They are expensive and not available for all types of CU (and that includes Crabtree and Wylex until 2025). So in practice you may end up needing a new garage unit installed with Henley blocks. As I discovered, it becomes even more complicated with a battery setup as well.

 

 

 

Edited September 26 by sharpener

[mk1_man]

4 hours ago, ReedRichards said:

I'm not sure that foam insulation is suitable for outdoor use.  It's certainly not the type that is usually used.

 

The insulation is Primary-Pro, brilliant stuff and possibly the best for external use.  I am however going to be putting a sort of lid over it made up of some 40mm xps foam board I have. Conscious of need to maintain air to the anti-freeze valves.

[crispy_wafer]

QQ, How did you deal with the insulation through the wall?  I see they have plastic interface thingies for tidying the hole up, in two minds as to whether they are worth it though.

[Beelbeebub]

3 hours ago, JohnMo said:

Trouble is the big players like octopus want you have a system with a design flow temp of 50 degs. This maximises their profits, makes an easier install. Justification is a good selection of tariffs which are available (but for how long) so cheaper to run than gas.

Yeah. The core bit is what Scop van be achived. If it is better than about 2.5 then you have emitted less carbon per Kwh delivered burning gas in a power plant, transmitting it to your house and using a heatpump than if you burnt the gas in your boiler. At that point it's a climate win.*

3 hours ago, JohnMo said:

That starts to get difficult, even a 6kW ASHP will have a power required of 3kW at sub zero and high flow temp. Without accounting for in rush current on motor start and the various outlets for immersion heaters driven from the ASHP

Very true, you'proably be restricted to a 4kw nominal unit - but that should be enough for flats, new builds and terraced houses with decent insulation. 

 

Crucially if you could just stick the HP on the side of a building with no restrictions there's nothing to stop you fitting 2 or even 3 to your house. A ring main can typically handle 32A (7kw), it's just the pin plug that limits to 13A.

 

2 units (one upstairs and one down) would give you fantastic modulation plus redundancy. 

 

The main thrust was to make installing a HP really easy. Minimum rewiring, paperwork etc. 

3 hours ago, JohnMo said:

Hybrid incentives are the only real way to get mass roll out. No internal changes to heating system required (you could though, to drop design flow temp). System runs 90% of the time on heat pump, if house has a combi no cylinder required. Just make weather comp manditory, boiler manufacturer have to provide an interface to allow this if boiler needs it. In nearly all cases a 4kW ASHP would be ok. 

Yeah, hydrids are a good sokution, sadly excluded by the subsidy regime. The one that is 4kw and just sits outside and taps into the return pipework is neat. 

 

The other option if, we want to go with hybrid is straight up installing air to air multi splits. Completely sepwrate from your wet heating system. 

 

The fear with air to air systems is they could be used as cooling in summer and actually drive up consumption. But if we had "approved" models that were firmware limited to a minimum setpoiy of (say) 30C, they would onky be useful coolers in the worst heatwaves, where it might actually be a useful thing to have cooling from a national perspective. 

 

But an A2A. system is easy to install and cheaper. It overlays your existing system so you don't need to worry "what if it costs too much to run" or "what if it can't keep me warm in a blizzard". Your old system will still be there. It's just you'll have another way of heating your place 99% of the time. 

 

And then one day the boiler will break and the home owner will think - why bother replacing it, I can't remember when we last used it. 

 

Yes, at that point you need to sort out DHW, but there is time to do that. Maybe the UVC with a refiderqnt coil yhatborenends to be a normal head unit. Or the stand alone HP cylinders. Or even just an immersion cylinder. Not as cheap to run but simple.

 

 

* in reality, the 2.5 figure is a worst case as our electricity isn't exclusively gas anyway.