@gordonengland We have an ASHP installed under BUS with MCS approval; we have a Sunamp Thermino ePV210 unit - both installed as part of the replacement of the gas boiler and 99 litre DHW. As we do not have a space for an MCS approved capacity tank, the Sunamp was a small solution to a big problem. So in short, yes you can have a Sunamp instead of a conventional DHW tank. (Keep an eye out for my review of the Sunamp in the next day or so in this august organ!) Regards, Toodles.

Posted by: @gordonengland

↑

is it mandatory to have cylinder? Or is it straight forward to run an ASHP system purely for heating?

To get the grant you are supposed by the rules to heat your home and DHW via the heat pump. MCS then states the minimum sized based on number of bedrooms or likely inhabitants which ever the greater 

Posted by: @toodles

↑

@gordonengland We have an ASHP installed under BUS with MCS approval; we have a Sunamp Thermino ePV210 unit - both installed as part of the replacement of the gas boiler and 99 litre DHW. As we do not have a space for an MCS approved capacity tank, the Sunamp was a small solution to a big problem. So in short, yes you can have a Sunamp instead of a conventional DHW tank. (Keep an eye out for my review of the Sunamp in the next day or so in this august organ!) Regards, Toodles.

Think you found a sympathetic installer. As the grant rules state

(2) A heat pump meets the suitability criteria in relation to the eligible property, or a property to which regulation 14(1)(b) applies, for which it is installed where—

(a)it provides heating—

(i)solely to that property, or to both that property and any related property, and

(ii)for the purpose of both space heating and hot water heating, using liquid as a medium for delivering that heat,

(b)it is capable of meeting the full space heating and hot water heating demands of that property.

@johnmo I took this matter up with my installer; it looked to me as though the DHW provision had to be supplied by the heat pump according to MCS ‘guidelines’. I said to my installer that I was a little concerned about my system not appearing to be compliant with this guideline. My installer said that having the Sunamp to provide the hot water demand would not pose a problem for the BUS grant. I have no idea how honest / keen the installers are to comply with MCS forms but mine was filled in and they paid up. In mitigation, the Sunamp can (and is sometimes) charged from my Solar PV kit; the MCS bod who contacted me by phone after the install was carried out enquired as to whether I had heating and hot water supplied with the new installation to which I honestly replied ‘Yes’ as both units formed part of the one contract. Regards, Toodles.

@toodles Hi there thanks for your helpful info. I asked Sunamp the same question as they sell packaged systems with a few ASHP manufacturers( comes on the same pallet) They too mentioned the BUS scheme was OK ( not sure if this is England only though , I’m in Scotland)But these are”OK MCS”Sunamps have both Electric inputs and ASHP inputs, but a bit dear than a DHW cyl set up ? My Sunamp was 2nd hand ( cost just £560 so it don’t owe me much as I’ve saved that amount in heating oil costs over the last 2 years. So I could get a new Sunamp that does both… we can get £9k in rural grant from HED/EST for an ASHP not sure what the BUS rules are. Plus I’ve already had a grant towards insulation and an interest free loan for the solar set up so not sure if BUS would cough up 😊 anymore.

lastly when I do the numbers for this older 147 sq m stone cottage( EPC “B” though ) Space heating Running costs come out much the same as what I’m paying for oil ( approx 750litres at 75p)

Please with the Solar PV and both batteries though and still to go through a Winter with the new £10k ( 75% grant aided)  worth of insulation, which was a big project needing lots of new joinery, plastering and painting.

Perhaps the ASHP is a bridge too far and I should quit when I’m ahead😊

@gordonengland Poisonally, I would say it is always worth giving the option of an ASHP consideration. Having lived with our ASHP system since February 2023, I would not wish to go back to a gas boiler system now. There are to me, so many advantages with even constant temperatures with no hot or cold spots, a virtually silent system where (in our own case at least), we can’t even hear a pump running or water passing through the system. There is one minus point I feel - during the winter, when we go out to catch a bus, we suddenly meet the cold air which comes as a bit of a shock to the system! We are so well insulated and buffered from what the weather can throw at us with the heating running so effortlessly, the outside world really is ‘something else’. Would I go back? Not Ever, Not No How! Regards, Toodles.

Posted by: @gordonengland

↑

Sunamps have both Electric inputs and ASHP inputs, but

Do your maths with Sunamp and ASHP. They used to do a low temperature one for heat pumps, but now they do not. So your heat pump has to be able to run at 60 or above for the full recharge period, so CoP will be rubbish. A cylinder on the other hand is slowly heated over an hour and ramps up temperature slowly to give a way better CoP.

Posted by: @toodles

↑

Would I go back? Not Ever, Not No

We ran out gas boiler at low flow temperature WC and kept house just the same as we do with the heat pump. So can't tell the difference really.

Think you don't miss, stupid high temperature heating systems, the UK insists on with lots of on an cycles etc. Sooner they ban S and Y plan the better. Make it mandatory for all heating systems to be low temp PHWD system or combi boiler hooked up a low temperature heating system.

@johnmo I was unable to set the gas boiler at a more moderate temperature due to there only being one control to set the system for DHW and heating with - and as I only found out at the time we had decided to replace the system due to partial failure, BG had set the rating as a 16 or 18 kW boiler as the engineers tend to leave the boiler on the factory preset position. Had they done their job properly, the preset would have been moved down to 6-8 kW’s but of course, they weren’t paying the bills! Regards, Toodles.

@njt Keep us posted - I hope it all goes well for you. Mine's in 3 weeks.

@lucia 

Going well up to now, we should have hot water later tomorrow and heating Thursday.

Heat pump all fixed and wired in. 

Cylinder, volumiser, pressure vessel fitted and started to be piped up

3 further rads to fit. Hot and cold feeds need running and connecting along with rads feed and return. Bits of wiring here and there to finish off.

Gas meter removed today also.

Bonus the weather has been perfect so far, warm and sunny, doing this through winter would be awful without heating/hot water.

Nice pleasant chaps.

At least it gives me a chance to try to get my head around the settings before it gets too cold.

@njt Great, that seems very on the ball - quite fast.  It's a 6Kw isn't it? The same as mine? Or not?

@lucia 

It's a Daikin 8kw with 210L Stelflow slimline cylinder. 

I did ask will there be glycol or anti freeze valves used, he said at octopus they install both, and test for correct glycol dosage on annual service. 

I'm new to all this, but only ever read it was either one or the other, not both?