AirSourceHeatPump or GasBoiler Advise much appreciated

[lavadiy]

I'll try not to make this a lengthy initial post but have lots of information i can feed into it. (Please bear with the read...there may be some work for someone here)

So...
Bought a house as a bit of a do-up project after it had a flood.
House came with V old Gas boiler + open vented Rad system. BUT had an AirSourceHeatPump (ASHP) fitted + New mains pressure DHWT with 2 internal coils. 1 fed from ASHP + GAS boiler, other fed from new Thermal Solar panels.

All good?

WRONG.

I don't want to bad mouth the company (I do, but wont) but it was installed COMPLETELY incorrectly. I can expand on this greatly if needs be to justify the next stage. But with near £1000 electricity bill for a quarter when not living there was the first alarm bell.

I ripped every pipe and RAD out of the house, and have moved the water tank (Viessmann Vitocell 300B) down to the garage to be near the ASHP (Viessmann Vitocal 300A). There is also a buffer tank connected to the ASHP (Vitocell 100 or 200 or something).

Now i want to get it all connected up again.

I've been over various options back and forth and it all basically comes down to cost.

To get my heatpump back and running, assuming the heat destination of rads or UFH is already there, i've been quoted around 10k. This is just to plump everything in the garage, connect the solar etc (they used 15mm pipe before for the Solar connection to tank. Just wrong).
Coupled with around 10k for UFH upstairs and downstairs, to be ideal for the ASHP temps, is 20k to get a system up that i've not had to fork out for the dear bits (ASHP, Tanks, etc).

I just can't do it.

I can't go to standard rads to reduce cost due to low temps needed.
low temp rads for whole house come in around 8k (only looked at jega so far mind).

I've decided on UFH downstairs at around 5k regardless and i can fit that myself up until manifold and get plumber to do that.

So i've now started to look at maybe a decent Gas boiler so can use UFH downstairs and standard rads up stairs to save cost. I know you can reduce temp to UFH with mixing and then run the rads upstairs at 65/54 whatever the norm is.

This would be fine and i could plumb the internal rads myself and get plumber to connect all up which should'nt be near 10k! (IMNSHO)

UFH would be zoned with actuators etc and upstairs on TRV's.

That's all cool....BUT i really want to go down the Weather comp route that the ASHP deploys. From what i've read its the best savings.

We will be in this house for a LONG time so i want to get it right given the budget.

So question is is there a way to run mixed temp (i.e UFH downstairs + standard rads upstairs) AND still deploy weather comp?

Anyone got any recommendations on that route or am i going down the wrong path completely?

For anyone still at the end of this post. Thank you for your patience. I'm at a complete loss in what to do and have been bitten a) with the crap install in the first place and b) previously with tradesmen promising the earth but not knowing how to do it. (Not a reflection on all tradesmen whatsoever just personal experience).

I can't do the whole thing myself as i'm not a professional plumber by any shouts and dont know all the ins and outs and gizmo connectors or valve things required.

Any pointers?

 

[Homesafe]

You need Alec!!

 

[dcawkwell]

You don't say the air source heat pump you have.
But if it has an immersion heater element built in as a booster and this was coming on then there would be a big electric bill.

Where in the UK are you?

 

[snb]

probably nothing wrong with the install.

most likely the set up.

Biggest reason for high electric bills are because you set it to come on and off. Leave it turned on all the time then it will operate using the compressor rather than using the back up (immersion often 6kw) everytime it is asked to operate

Often causes the electric bill to be nearly 3 times as much.

 

[Agile]

OP, how many solar panels and why is 15 mm tube from them wrong?

Tony

 

[DeltaT2]

The COP on most ASHPs drop greatly at <8 ° C. So who in their right mind would fit them & as for heating domestic hot water, far.ing at thunder springs to mind!!!

Also, most ASHPs I've removed have been on a standard tariff leccy??!!
Though last winter was milder, the two prior were not. -16 ° C in some parts of Scotland.

The ex-used car salesmen that were/are selling this 'Greenwash' technology are clueless!!

To make the most of a bad lot, have your UFH running 24/7 & ensure you have night set-back controls. Also, double check your leccy tariff??!!

 

[lavadiy]

Thanks for the replies.

most likely the set up.

Biggest reason for high electric bills are because you set it to come on and off. Leave it turned on all the time then it will operate using the compressor rather than using the back up (immersion often 6kw) everytime it is asked to operate

Indeed the ASHP should be set to run constantly. However it was being triggered to run from an old rotary timer with a,b,c,d. This IMO is wrong straight away. The pumps were also driving from this old timer to circulate the heating circuit so without pumps on the HW wasnt getting around the rads.

The settings on the AHSP (vitocal 300a) on the big red control panel (dont know the model) were set as default to be on constantly but due to its integration with the old system was not working as it should. A viessmann commissioner confirmed this.

There is tons i can go into in why the old system is set up wrong, and didnt want to flood the post as a moan. I've also had it confirmed by a few ppl in the trade locally that the firm that put it in are quite as you say "grab the money and run". I tried for months to get them back to look at it when i first got the place but it was like trying to get blood out of a stone.

It was also trying to heat the massive hot water tank of water, which then when the system was off would obviously cool down. There is no plate exchanger installed so the HP couldn't reach the temps easily of the DHW which had a therm sensor set at 60o.

Also the temp sensors for the heat pump on flow and return were taped on to flow and return rad pipes! With electrical tape. Not installed into correct sensor valve thingies. The outside sensor was right by a window around 1m off the ground which is also wrong according to the instructions.

There is a ton more things to go into.

But if it has an immersion heater element built in as a booster and this was coming on then there would be a big electric bill.

Where in the UK are you?

Nope. no immersion heater element in the system. Which is probably something we do want to boost the DHW occasionally.
I'm located between staffordshire and shropshire. PM if you're need more specifics

OP, how many solar panels and why is 15 mm tube from them wrong?

only 1 solar panel when ideally for the larger coil in the vitocell tank its been recommended to have 2. 15mm pipe feed was all black and charred as though the temperature was too high. I've been advised you normally want Flexi Pipe DN25 or at least a lot thicker pipe to carry the volume at high temps.

 

[mysteryman]

This all points to poor installation and commissioning.

 

[lavadiy]

Absolutely. Hence me ripping it all out and starting again.
I've had a guy who knows the stuff and how it should be done really well, however the costs just dont work out.
He does'nt have a plumber see so has had to get another to quote for the pipe work and he knows about the setup etc and can commission it.

2 lots of profit i guess so i'd really like a plumber who knows about all the renewable stuff well.

That aside, as i have gas to the property i wondered if it will be cheaper to just go decent Gas boiler. Something like Viessmann 200. I know that can do weather comp but wondered is it the right approach with UFH at low temp and Rads upstairs at normal temp combined with WC.