ᐅ Underfloor heating with an air-to-water heat pump. House gets too warm when the sun is shining.

Created on: 4 Dec 2019 14:18
C
chewbacca123
Hello everyone,

I have a general question.

We moved into our new build four months ago. The living area on the ground floor has three large floor-to-ceiling windows facing south. We have underfloor heating and an air-to-water heat pump.
It provides a really comfortable temperature inside the house, but we have a problem – whenever the sun is shining in winter, even if it’s -2°C (28°F) outside, the temperature suddenly rises to 24°C (75°F) in the living room. It gets uncomfortably warm in here, and the underfloor heating can’t be turned down quickly.
Should we assume that the large floor-to-ceiling windows are responsible for the heat gain? A photo of the south-facing side of the house is attached.
What would you do – always lower all the blinds as soon as sunlight is forecast? That seems quite annoying...
We have motorized blinds controlled by Somfy. Would you consider buying a sensor that automatically lowers the blinds at a certain temperature?

Thanks in advance for your replies.

Neues zweistöckiges Haus auf Baustelle mit weißer Blockfassade, pinker Dämmung und großen Fenstern
B
Bookstar
12 Jan 2021 09:41
So, last night there was another disruption with defrost cycle 760. The whole house is getting cooler, losing about 1 degree.

Today, I switched the variable speed pump from automatic to manual. Now it runs at 1500 liters per hour instead of 800 liters per hour. This also doubles the flow rate in the bathroom.

I’m curious to see what will happen. Maybe the whole system will break down now.

I’ve read in another forum about pump voltage values—10 volts nominal and 3 volts effective. I don’t see anything like that on my system, and there is no option to adjust it.

It would be great if someone could check the menu to see what options they have under variable speed pump settings, or if you can find this voltage setting anywhere?
A
Alessandro
12 Jan 2021 09:46
Which settings can you select on the pump?
Shouldn't it modulate directly along with the heat pump?
B
Bookstar
12 Jan 2021 09:51
Alessandro schrieb:

What settings can you choose on the pump?
Shouldn't it modulate automatically together with the heat pump?

I can set it to automatic, so it modulates accordingly. But in my opinion, that doesn't work for me because the flow rates are too low.

That's why I have now set it to manual, with 100% max and 40% min.
H
halmi
12 Jan 2021 09:55
@Bookstar have you reduced many circles? What software version does your machine have?
B
Bookstar
12 Jan 2021 10:06
halmi schrieb:

@Bookstar did you reduce many loops? What software version is your machine running?
All loops are open. The software version is the latest, installed two weeks ago. I will upload a csv here.













































































































































































































































































































































































































































































12.01.2021 10:12
System status:
Heat pump type LWA 12
Heat pump type HDT_9
Software version V3.85.6 (r6445)
Bivalence stage 1
Operating mode Heating
Actual power 6.69 kW
Defrost requirement 6.9%
Last defrost
##########
System settings:
Utility lockout without external heat source
Room sensor No
Integration Return line
Mixing circuit 1 No
Fault without external heat source
Domestic hot water 1 Sensor
Domestic hot water 3 without external control input
Domestic hot water 4 Setpoint
Domestic hot water 5 with external heating element
DHW + heat pump max 0.0 h
Pump optimization Yes
Access Customer
Pressure monitoring On
Heating circuit control Outdoor reset
Mixing circuit 1 control Outdoor reset
Boost heating with mixing
Electric anode No
Heating limit Yes
Remote maintenance Yes
Pump optimization time 10 min
TDI message Yes
Release external heat source 60 min
DHW reheating No
Max reheating DHW 5.0 h
Smart Grid No
Mixing circuit 1 control fast
Compressor heating Yes
Temperatures:
Return limit 45.0°C (113°F)
Hysteresis heating circuit 1.5 K (2.7°F)
Hysteresis DHW 5.0 K (9.0°F)
Max temperature difference TR 7.0 K (12.6°F)
Release external heat source -2.0°C (28°F)
TDI target temperature 60.0°C (140°F)
Max outdoor temperature 40.0°C (104°F)
Min outdoor temperature -20.0°C (-4°F)
Setback up to -20.0°C (-4°F)
Hysteresis mixing circuit 2.0 K (3.6°F)
Max domestic hot water temperature 60.0°C (140°F)
Min return setpoint temperature 15.0°C (59°F)
Pump efficiency:
Heat distribution system Underfloor heating / radiant heating
Heating control Manual
Nominal heating output 100%
Minimum heating output 60%
DHW control Automatic
Cooling temperature difference 5.0 K (9.0°F)
Additional heat source 1
Type Heating element
Function Heating and DHW
Position Integrated
Output Out 1
Pump pre-run:
Pump pre-run external control input 60 s
Priorities:
Domestic hot water 1
Heating 2
Swimming pool 3
System configuration:
Heating Yes
Domestic hot water Yes
FlexConfig:
OUT 2 ZIP
OUT 3 FP1
Heating curves for heating 27.5°C (81.5°F)
Operating hours information:
Operating hours compressor 1 5689 h
Compressor 1 impulses 6327
Average runtime compressor 1 00:53
Operating hours external heat source 1 100 h
Operating hours heat pump 5689 h
Operating hours heating 4867 h
Operating hours domestic hot water 816 h
Temperature information:
Flow temperature 28.1°C (82.6°F)
Return temperature 25.3°C (77.5°F)
Return temperature setpoint 26.6°C (79.9°F)
Hot gas temperature 62.3°C (144.1°F)
Outdoor temperature -3.1°C (26.4°F)
Average temperature -4.7°C (23.5°F)
Actual domestic hot water 48.0°C (118.4°F)
Target domestic hot water 48.0°C (118.4°F)
Heat source inlet -2.6°C (27.3°F)
Max flow temperature 60.0°C (140°F)
Compressor intake -3.1°C (26.4°F)
Compressor heating 51.3°C (124.3°F)
Superheat 7.5 K (13.5°F)
Target superheat 7.1 K (12.8°F)
Flow sensor 1 19.0°C (66.2°F)
Flow sensor 2 24.5°C (76.1°F)
T
T_im_Norden
12 Jan 2021 10:17
Do I understand this correctly:
Heating system minimum output 60%?
Does that mean the minimum heating capacity is 60%?
If so, reduce it to 20% or something like that.