Ämne: Compressor heating

[hudson0804]

Hi All,

Sorry for the English I will try and keep it exact.

I have a nibe f730 it has been in for approximately one year I have followed the guidance here (https://www.varmepumpsforum.com/vpforum/index.php?topic=71174.0) not word for word and I will confirm the settings when i have chance to connect to nibe link.

Here is the thing, my heat pump is blocked as it is still too warm for my heating to begin heating the house, HOWEVER, the compressor status daily switches to heating (not hot water) but heating and the upstairs radiators get warm, not hot but warm.

I dont understand what is causing the heating to call for heat.

Am i missing something obvious?

[Josth]

Hi! If the outdoor temperature falls below e.g. 16°C in average during the last e.g. 8 hours in the night it starts heating the house. Depends om the settings i menu 4.9.2.

[hudson0804]

Thanks for the response. 4.9.2

Stop heating 16 degrees
Stop additional heat 4 degrees
Filtering time 7 hours.

So is this behaviour regardless of indoor temperature? 

[Josth]

Well, yes if there's no indoor room temperature sensor installed it acts according to the heat curve settings. At this time of the year the top of the radiators should have a temperature like e.g. 28°C when heating the house. Difficult to feel at all with just the hand. During the coldest days of the year the heating temperature can normally be up to 55°C with heat-pumps. Very different from a house designed with a high temperature gasboiler.

[hudson0804]

I've not fully wrapped my head around the heating curve I followed the guidance posted here

Should i enable my room thermostats as they're turned off in the system at the moment

[Josth]

With heat-pumps the best is to have fully opened radiator thermostats and control the temperature with the heat curve settings. This maximizes the efficiency. Maybe in the bedrooms the thermostats can be used to keep a slightly lower temperature if needed.   

[hudson0804]

Ok this is what I had originally configured as recommended here.

I think I need to better understand the heating curve

Is there any kind of rules I should follow for the curve or is the setup guide from this forum sufficient?

[Josth]

The manual is easy to follow i think: https://www.nibe.eu/assets/documents/25073/431832-1.pdf  page 31-42. The goal is to find the curve settings thats gives the preferred indoor temperature regardless of outdoor temperature from the autumn until the spring. Days with e.g. strong sunshine will of course give a little bit higher temperature anyway at least if there is no indoor room sensor.

[hudson0804]

Perfect I will give that a try.

[hudson0804]

Should I just follow the "tips" given in the manual. As tight now it's warm.in the house. Maybe too warm.23.5 degrees but the coldest outside was earlier over night at 4 degrees. It's now not that cold.out and warmer than I'd like inside.

Should I wait for colder weather perhaps.

Also. What's the deal with window ventilation. I have window vents in every room apart from wet rooms where there is extraction vents for the heating i assume and the kitchen.

I've been told these vents must stay open for the performance of the heating system. But I do t understand why letting  in cold air helps the system.

[Josth]

If it's too varm inside the house the curve offset in menu 1.1 should be reduced 1 to 2 steps. Wait min. 24 hours and check indoor temperature again.

Modern house regulations requires that all the indoor air shall be replaced within 2 hours. Houses must be built with a ventilation system that fulfills that. Window vents have to be open to let fresh air in to living room and bedrooms. There are other kinds of ventilation systems that pre-heats the fresh air before it is distributed to the rooms in rather big ventilation pipes (like the extract air  pipes).

[hudson0804]

Thank you for the explanation. I have moved the curve mentioned from 5 to 4

Will monitor the situation

Thank you again.

[hudson0804]

Actually wanted to correct myself.

I change the heating curve in 1.9.1.1 the side reading said 5 I changed it to 4.

Is this not the correct?

[Josth]

The standard curve is 5 with underfloor heating in concrete slab. But for each specific house you might have to step up och step down the curve slope according to the tip on page 33.