@saz And in my experience the installers completely ignored it and let it just drip onto the patio on which the ASHP stands

@witchcraft mine sits on my drive - the installer lifted some of the block pave and popped some gravel in there to act as a soak away. 

@witchcraft This can be dangerous if the condensate freezes to ice in very cold weather. Can lead to falls etc.

@suzyq for insulation I would really consider insulated plasterboard if I was you. You can just retro fit and it'll go miles to helping you within rooms. Yes it's more than plain plasterboard, but you can basically use it everywhere for walls and ceilings.

Posted by: @batalto

@suzyq for insulation I would really consider insulated plasterboard if I was you. You can just retro fit and it'll go miles to helping you within rooms. Yes it's more than plain plasterboard, but you can basically use it everywhere for walls and ceilings.

Using modern materials in an old building is a recipe for disaster. You risk trapping moisture in the walls and creating a cold, damp environment. There are natural wall insulation products available (cork, sheepswool) but far and away the best thing you can do first is just stop the draughts...leave the walls alone for now.

Posted by: @suzyq

Thank you @Saz i downloaded the installation guide yesterday but could not see the dimensions, so appreciate you posting this, with the guide. 

 

They are going to do a soakaway with gravel now, which is better. 

At first they were going to put the pipe into the soil to drain thst way, and put decorative gravel on top.

 

All the products have been delivered today, apart from the 45l buffer tank, which they have said Vaillant is out of stock so the heat pump company have sent a Low loss header and said this does the same job?. Does it?

 

I know a buffer tank is a reserve of water and more expensive than a low loss header. Will it be alright or shall I try hold out for a buffer tank, if time.

Hi Suzy,

Sorry for the delay in replying.

With regard to a buffer tank, I have done quite a bit of research, reading manuals and write ups and watching youtube videos, and it would appear that they can perform a number of duties. Some useful, and some not so useful when incorporated in an ASHP system.

It would appear that a buffer tank would be required in large heating systems, where the water pump within the heat generator, be it an oil or gas boiler or a heat pump, would not be able to provide an adequate water flow around the whole system, so would require one or more secondary water pumps to be installed. This arrangement would probably lead to some degree of mixing of the warmer water and cooler water within the buffer tank, which not really a problem with the oil or gas boiler, can have a detrimental effect when used with a heat pump, and can reduce the overall efficiency.

Heat pump manufacturers often provide details of the minimum water system volume that is required with each size of heat pump. Various people suggest that this is a requirement to help reduce short cycling of the heat pump, which may partially be the reason. But if a system does not have zoning valves and too many TRV's, then the heat emitters that do not have complete flow restriction may provide adequate system volume.

Reading through a Vaillant manual that I discovered just prior to answering your query, I find a more plausible reason is as a heat store to assist with the defrosting cycle on an ASHP. During the defrost cycle, the refrigerant gas flows in reverse around the heat pump, so instead of heat energy being absorbed from the outside air by the evaporator, and transferred to the water via the condenser, the heat pump is now extracting heat energy from the water and transferring the heat energy to the evaporator to melt the ice build up. This action will cool the water flowing through the condenser and would in turn have a cooling effect at the heat emitters. By installing a heat store in the form of an adequately sized  buffer tank, the cooling effect at the heat emitters is removed or at least reduced.

My personal assessment is that rather than install a buffer tank in the normal manner, as would be the case with an oil or gas boiler, to instead install it as a heat store. I am not certain, without carrying out testing, whether it would be better located in the water flow from the heat pump, as shown in diagram D on page 29 of the attached document, or in the return pipework as shown in diagram C.

The manual states that a 7kW Vaillant requires a minimum water volume of 20 Litres, so a Low Loss Header may be adequate, dependent upon its size.

Hi everyone.  Really sorry this has taken such a long time to get back and post.  I came on the forum just before I decided to go for ashp install under the RHI process.  Not sure where the time has gone. At the time I had read quite a few nightmare install story's and was hoping mine wouldn't be one of them..

The good news first.  I managed to get the installation done and RHI approved within a date of the deadline. However,  what I did not know at the time, how many things would be wrong with the install. Poor work, non compliant electrics, insulation, so many things that hadn't been done right.  It has been a lengthy ongoing process and I have tried to keep perspective on the problems but I am now worn down with it all. 

I am at the compla8nt stage. Although a lot the work has been redone. I wanted to see if you can please help guide me on, have I got the most energy efficient install I should have ended up with? A lot of corners seem to have been cut, different workmen picking things up and I'm struggling to put it all down to the M cs. Not sure if it will do any good from what I have read but think it is the only way to get some stndard work and get the company to come back.

The first thing I would like to know if someone could advise is, would you expect the heating engineers, to have done a plan drawing , before starting,  setting out where all the equipment would fit in the space

cynical answer no I wouldn't expect a "typical" ASHP installer to have done a system drawing, and certainly not one that you've said has been "poor". only the "good" ones do. 

That said, professionally they SHOULD have done one and the "MCS handover criteria" says so as well, but the experience of most people on here who've had systems installed for them is that you don't get one (and those criteria aren't really worth 2p).

most people on here who want to understand their system and improve it end up drawing their own system diagram. It has happened several times that a user drawing that diagram and working through it on here with help from forum members, leads to someone spotting a really blindingly obvious / stupid installation mistake. 

@suzyq, welcome back, and so sorry to hear about your horrible install. @iancalderbank is right in what he’s said. I’ll reply in more detail tomorrow on the back of a small announcement highlighting the bodged state of heat pump installations.

@suzyq, also, which heat pump did you opt for, and can you please provide more details on the complaint - who has it been lodged with, and I’m interested to hear what the response has been.

Thanks @iancalderbank I think you are right, professionally they should have done one The second lot who came said they would have done one! I spokevwith another guy and they said they do them. Unfortunately, I have to rely on the experts 🙄 to do it the best way.. The trouble is, everyone workss differently, so other people coming in taking over, then working around what has already been done, trying to put things right 🙃, intricate pipework, doesn't mean it is now the most efficient.for my house, only muddle along. I am hoping the mc swill see this as an initial negative. 

Thanks @mars, I did try and post to start with again update in intro section but struggled to do this as already member, plus tro7ble logging in. The system I went for was a vaillan t 7kw, with buffer tank,  hydraulic unit. I had to have a l8w loss header to start with, then changed to buffer when back in stock.,this is one of my concerns. 

I have yet to start with the mcs, the difficulty putting it all down, so it is taken seriously and to check what I am saying is what you would expect from their standards. It is a shame that the recce part is a separate entity. It would be better if it was dealt with a whole. I am worn down with it all, had to give myself time off from it,  but really need to start to address it all and get finished once and for all. 

Dealing with different work trade people has not been as enjoyable as I thought it would be,  more so when the work is terrible, perhaps too soft, however I want the work to be done right!