@parmstar sorry to hear about your problems. What is your heat pump model number, the calculated heat loss of your home and the design flow temp?
I just want to get an idea if this is something we can solve on the forum or if you need to pursue a fight with your installer which as you've noted might be difficult.
@parmstar so on the temperature front it's clear they just didn't design as you asked. Your actual heat losses could be over 10% higher than that with the temps you want, so that might explain the problems getting to the right temperature recently.
There's definitely more to look into though. The £750 of electricity you used, is that all from the heat pump or overall? If that's just the heat pump then that is shockingly poor efficiency, so bad that I almost can't believe it's that.
Do you have data for how the heat pump itself is doing? There's a service called Melcloud that you might have been given access to that should give you some charts and figures, or if not your controller might give you info about energy usage, heat energy delivered, on time etc.
Any idea what design temperature they went for? That’ll help us determine if the rads are the correct size for the rooms and will help us choose what size heat pump should have been installed.
Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.
My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.
@oswiu thanks for getting back to me. There is no way of monitoring energy usage for just the heat pump as they installed the wrong model of control unit - this is a separate issue that I have raised with them. The figure quoted is for total electric which is stoll
way way more than my standard bill
@hugh the first column of the table is the design temp
@parmstar that’s the room temperature. I need to know what flow temperature they designed for. This is the temperature of the water that flows round the radiators and makes a massive difference to the cost and performance.
For example, an 11kW ecodan will deliver 11kW at -3, but only when heating water to 35 degrees. That’s fine for running UFH at a proper pipe spacing, but no good for retrofit onto existing radiators.
Ask it to deliver 55 degree water and it will struggle to deliver 7kW (probably)…
Tl;dr - your heat emitters are too small
Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.
My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.
@oswiu 6.56kW continuous house usage for 14 days straight, at the backstop rate…
3kW into the heat pump and a 3kW backup immersion running too?
Or the ecodan running at a cop of under 2 because it’s uplifting to 50 degrees when it’s -5 outside?
Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.
My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.
@hughf the immersion heater is connected to an iboost so isn’t linked with the melcloud
also forgot to mention the ASHP is facing a fence and is probably recirculating cold air which isn’t helping
Posted by: @parmstar@hughf the immersion heater is connected to an iboost so isn’t linked with the melcloud
also forgot to mention the ASHP is facing a fence and is probably recirculating cold air which isn’t helping
-- Attachment is not available --
Therein is the likely issue with the majority of your performance issues. The siting is not ideal as the cold expelled air has insufficient space to escape. The ASHP is therefore having to draw in it's own expelled cold air and working it's nuts off to reheat that air. Not at all well situated and unlikely to work efficiently.
Retrofitted 11.2kw Mitsubishi Ecodan to new radiators commissioned November 2021.
14 x 500w Monocrystalline solar panels.
2 ESS Smile G3 10.1 batteries.
ESS Smile G3 5kw inverter.
@morgan no other place to site it unfortunately - the installer never made me aware of any of this and claimed it would be fine as it’s within clearances. It’s also within 1m of the property boundary which is a no no!
Wow the positioning of that heat pump is shocking. It's barely got any room behind it, it has almost no room around it, it's well closer than 1m to the property boundary and it's made an ice rink!
OP you might have luck getting the installer to move it by proving they've installed it contrary to the instructions in the manual. If they're registered with Mitsubishi, then I imagine Mitsubishi won't be happy with them... You're better off with a very well lagged longer pipe run in my opinion.
On the flow temp, 50C is quite high and so not the most efficient, but it's not the worst. Make sure you have weather compensation set up for when it gets a bit warmer.
- 26 Forums
- 2,197 Topics
- 48.4 K Posts
- 62 Online
- 5,854 Members
Join Us!
Podcast Picks
Latest Posts
-
RE: Who's your electricity provider and what's your tariff?
@agentgeorge It is so marginal for us that (and I hope!...
By Toodles , 15 minutes ago
-
RE: Seal the Deal: Don't Let Your Heat Pump Leak Energy
@transparent I think the committee might get into some ...
By Toodles , 21 minutes ago
-
Samsung ASHP Support in Midlands area?
Hi all, Per title.... can anyone recommend a ASHP ser...
By Andehh , 42 minutes ago
-
How to Understand Wiring Up a Heat Pump
Hi everyone, I’m looking to get a better understandin...
By Renewables345 , 47 minutes ago
-
-
RE: Help me keep the faith with my air source heat pump installation
I reckon the curved pipes may be the flexis, good idea ...
By JamesPa , 3 hours ago
-
That's why you can just add one full year, and...
By DREI , 3 hours ago
-
RE: Why Air Release Valves and Deaerators are Non-Negotiable
When I had my system serviced recently, I asked the guy...
By Old_Scientist , 3 hours ago
-
May I present the maths I referred to earlier when disc...
By Transparent , 3 hours ago
-
RE: RDSAP10 effect on existing heat pump EPC rating?
How many times and dates have epc sap rules been change...
By Tim441 , 4 hours ago
-
RE: Heat Pump + Tado Setup: Smarter Control for Secondary Pumps?
There is no straightforward way to maintain excellent c...
By Pirate Rich , 4 hours ago
-
RE: Rodents! A word of warning for heat pump owners
I think similar care should be taken against vermin ing...
By Transparent , 4 hours ago
-
RE: Large heat pump options for church building
Hi Mars thanks for the mention. Church projects are n...
By Aventus Eco , 7 hours ago
-
RE: Heat Pump Installers: Competence, Illusion and the Hard Truth Homeowners Must Face
Agreed. There’s tricky, and then there’s diving into a ...
By Mars , 7 hours ago
-
-
RE: Moving FIT array onto a Tesla Powerwall 3 possible?
@judith The PW3 can accept AC or DC inputs. Regards, To...
By Toodles , 1 day ago
-
RE: DESNZ doing a survey which asks the right questions!
Its great to hear of your approach and success with the...
By JamesPa , 1 day ago