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Fine tuning my Steibel Eltron wpl17 ASHP

Air Source Heat Pumps (ASHPs)

Last Post by Kev M 4 years ago

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Hr_3

(@hr_3)

Eminent Member Member

Joined: 4 years ago

Posts: 16

Topic starter 25/12/2021 9:31 pm

Hi All

I've had my ASHP installed now since October and am beginning to understand how it works etc

We are generally happy with the system, we're not cold nor have issues with water

So I am turning my attention to trying to get the system running as efficiently as possible,

The scop so far is 3.64 and seems to now be rising, (the other day it was 3.72 when it was - 1 and a milder day 4.0) I am working this out by dividing heat generated kW with power usage kW (which is what the installer and manufacturer suggests)

Usage so far is approx 14kw per day since being fitted on heating, water is fairly negligible overall.

The unit is a steibel eltron wpl17 and does have a weather compensation mode, its curve is set as 1.0 and the system seems to overshoot the temperature, our daytime temp is 19 and it does always go to 20. I was considering dropping the curve to 0.8.

The rads were all new with all new pipework (mainly 22mm with 15mm off shoots) and rads are all stelrad k2.

Heat loss on property is 6112kw.

I can also manually adjust flow rate and kelvin if that helps but I think the complexity of all the settings is where I'm somewhat stumped.

Any ideas? Happy to provide any details needed, manuals etc

👍

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Kev M

(@kev-m)

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Joined: 5 years ago

Posts: 1276

26/12/2021 8:37 am

@Hr_3,

Your numbers sound quite good. Is that heat loss at design settings? Where do you live; that makes a difference too? Similar numbers for me are: about 20kWh/day from October for a 160m2 house with a heat loss at -3C of c.8000kW, heated to about 21C. Do you have averages for a shorter time, say December to date?

I don't know anything about your ASHP but are you controlling it through room thermostats? If you can reduce the flow temperature by adjusting the compensation curve and it still heats your house that's going to be worth a try. I can heat my house with my K2 radiators at 35-40C in all the weather we've had this year so far.

I think @Derek-M is looking for you too.

This post was modified 4 years ago by Kev M

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Hr_3

(@hr_3)

Eminent Member Member

Joined: 4 years ago

Posts: 16

Topic starter 26/12/2021 9:29 am

Hi Kev

A few questions to your qs

Heat loss at design? What does that mean? Heat loss was based on u values and done using the mcs calculator by the installer

Live in Suffolk, I think it was done as heating home to 20/21c when it is - 2 outside

I'll check re averages for a shorter period

Controlled by a thermostat in upstairs hallway and a timer for when it calls for heat at 19c and an eco mode for overnight at 15.5c (never really comes on, think twice?)

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Derek M

(@derek-m)

Illustrious Member Member

Joined: 5 years ago

Posts: 4425

26/12/2021 11:43 am

Posted by: @hr_3

Hi All

I've had my ASHP installed now since October and am beginning to understand how it works etc

We are generally happy with the system, we're not cold nor have issues with water

So I am turning my attention to trying to get the system running as efficiently as possible,

The scop so far is 3.64 and seems to now be rising, (the other day it was 3.72 when it was - 1 and a milder day 4.0) I am working this out by dividing heat generated kW with power usage kW (which is what the installer and manufacturer suggests)

Usage so far is approx 14kw per day since being fitted on heating, water is fairly negligible overall.

The unit is a steibel eltron wpl17 and does have a weather compensation mode, its curve is set as 1.0 and the system seems to overshoot the temperature, our daytime temp is 19 and it does always go to 20. I was considering dropping the curve to 0.8.

The rads were all new with all new pipework (mainly 22mm with 15mm off shoots) and rads are all stelrad k2.

Heat loss on property is 6112kw.

I can also manually adjust flow rate and kelvin if that helps but I think the complexity of all the settings is where I'm somewhat stumped.

Any ideas? Happy to provide any details needed, manuals etc

Hi Hr_3,

As you have suggested, I would recommend changing the weather compensation curve from 1.0 to 0.8. Then use the Comfort Level setting to achieve the desired temperature.

Looking at your operating data I would say that your heat pump appears to be working quite efficiently, and other than the above change I don't think that there is much more that can be improved.

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Kev M

(@kev-m)

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Joined: 5 years ago

Posts: 1276