I have a bit of concern regarding a contract for Solar thermal and PV panels we have signed up for with a Scottish provider (I won't mention their name for the moment, but they seem to be reputable). Very much against my usual habit (doh!) I signed up without having a full spec given me about which I'm very embarrassed.

Today I received the full spec sheet (dated December 2nd which was when we signed) along with a letter (dated December 16th) telling us about the full pre-fix survey soon to be carried out. However, the first thing that struck me was the mention of a 150 litre cylinder (Gledhill single Coil, unvented). This was to be solar heated by "1xKloben 12 Tube CPC collector". Looking on the Kloben site this is 2.16 square metre of panelling.

We are getting a solar cylinder rather than a thermal store, and in our discussion with the salesman we had talked about them providing a 250 litre size cylinder which he thought would be adequate for the DHW needs as family of 2 adults and up to 7 children (we are foster carers). We discussed a future use of 1 bathroom and 3 shower rooms. However, we seem to have been downsized.

Firstly, any comments on the sizing appreciated, and how to deal with a company that might be trying to fob us off with something smaller than my needs. I realise this is a wee bit after the horse has bolted scenario, but thank for any input.

I think I might put up the full spec in a while, just for comment, but that is my main concern.

A with-holding of "what a plonker" comments would be much appreciated.

Also - Single coil - how does that work? Thermal needs 2 coils - 1 for the solar, 1 for the boiler

Hmm. Thanks. Probably best, as suggested, if I provide the complete spec sheet for thermal and pv as it reads. I should add that the firm concerned are registered with an organisation called REAL (Renewable Energy Assurance LTD). Does that mean anything good?

Thermal System Components:

1xKloben Sky 12 CPC Collector
1x150 single Coil Gledhill Solar Unvented Cylinder
1xHeat Transfer Fluid
1xSolar Control Pump Station
!x18 ltr Solar Expansion Vessel
1x Solar Controller Display Unit with 3 Probes/Sensors
1x Comi-Sol Valve
1x Mixer valve
1x Stainless Steel Solar flex pipe
1x copper pipe
1x insulation and fittings
1x Roof Mounting Kit, Sealant and Foam
1x Copper Pipe, Fittings and insulation required
1x Electrical fittings required
1x Installation of 3amp Spur

PV System Components:

16 x 240 Scheuten Multisol Gold PV Panel
1x Power One 3.6 DC to AC Inverter
!x Solar Generation Meter
1x Bespoke Roof Mounting Kit
1x Cabling Requirements

Something very odd going on. Do you have an existing boiler? Or are you an all electric house. Even if the system was designed as a solar + electric I would have expected to see an immersion heter on there.
Another question - whats a Comi-Sol valve? and why the mixer valve? What is that doing?

All in all I think you've been sold a pup..... On a fundamental basis your tank is not big enough for solar application, for house like wht you've. (Curiously enough, I have 1 bath & 3 x showers, so feel tht I can comment well on your requirements).
Something worth remembering is that Solar is a "One hit" system - you collect the energy you collect in the day, and use it. The tank needs to be big enough to hold enough water to cope with your 24 hour use, and the panels need to be big enough to reheat it the next day.

Hi,

Yes well spotted a pre heat system

If you haven't got a combi boiler, and didn't tell them you intended to fit one before the SWH was fitted, they have the wrong spec. You can't conect anything but the SWH to the cyl they'll supply, as it's a single coil.

"I'm going to contact the supplier with my concerns now and see what they have to say."

The 14 day cooling-off period, if it applied anyway (and I am aware Scottish law is different in many cases) will have gone, but if offered, the chance to step back and decide whether to go ahead with revised, correct, spec or get your money back would be good.

How does the price compare with others of which you are aware? (That's for your own comparison - I'm not asking you to share that here).

Good luck.

Nick

Good Luck

Forgetting the existing gas boiler for the moment - The single coil cylinder should be a twin coil cylinder if you were thinking of adding a wood burning boiler, one coil for solar, one for wood. That would be OK but would require to be separate from the existing DHW system that you've already got.

If your existing gas boiler (not a combi) heats water via a hot water cylinder then you really need a 3 coil cylinder - we were going to do this (already got oil boiler + wood Rayburn) and was going to add solar thermal but, honestly, a 3 coil tank is getting a bit expensive and complicated (probably why this company is ignoring it).

If you're not happy that this system is adequate and you want your deposit back then take a trip to your local trading standards officer who will give you advice and some letter pro-formas etc. Don't worry it's early days and it wouldn't be too difficult to show that the salesman clearly had no technical knowledge of your requirements.

The cost as far as we were originally concerned was for a solar cylinder of 250 litre (as you suggest would be suitable for us Wookey) and the fixing, pipework and solar panelling to adequately supply that. We contracted to pay a set price for that, and I think that will suit us fine everything else being equal. It included a PV system of 3.87 kw.

Clearly, also, we need a tank with more coils than the first spec suggests. It was certainly made clear at the initial talk that we wanted the gas boiler and a future woodburning stove connected. So the price included those provisos as far as we were concerned. And clearly we need more solar panels.

So hopefully the new spec will look a lot more realistic. And of course if it didn't we would make a noise.