NIBE ground source heat pump correct settings

Iannyboy

Hello there to everyone.
We are at our wits end with the setting up of our NIBE F1145 heat pump and we are hoping that someone who has some tried and tested settings can shed some light on the topic.
We have only recently moved in to our new home which we have been building for a couple of years now. We decided to install the ground source heat pump to help us with heating costs in the future and also to use a renewable source.
The pump seems to work fine but we recently got a huge shock when we submitted a meter reading and the bill was sky high. On further investigation we attached a monitor to the heat pump system to see what it is using and with our tariff it's working out around 40p an hour. I'm not familiar or used to the settings(as they are quite complicated with curves and offsets) but I need to know how to set it correctly. We have underfloor downstairs and rads upstairs. It also produces the hot water for the house.
The meter goes down to about 6/7p an hour when the compressor in the heat pump stops so I'm guessing that it's the culprit and it's running far too much.

Any help would be massively helpful.

Thanks Ian

neilball

We need some more info before being able to offer any advice. What size compressor have you got installed? Is your heating circuit a single zone serving underfloor and radiators or two zones plus hot water? What target flow temperatures are you using for your heating and hot water? What controls do you have wired back to the heat pump? What is your electricity unit cost?

Iannyboy

Thanks for replying and sorry it's taken so long to get back. Getting really frustrated with it all. It's. NIBE 10k heatpump so not sure what size compressor. It is supplying us with underfloor, radiators and hot water. The temperature for hot water is 50 degrees and room temp we are looking for is around 20. We have electronic room stats controlling the actuators for the underfloor and thermostats on the radiators open fully. Our tariff is 13.08p. There are so many settings on the heat pump (degree minutes and heating curves and offsets) that it's hard to know how to set it to its most efficient. Any help is welcomed. And I'd like to understand the degree mins to know how to calculate and set it accordingly.
Thanks Ian

neilball

Without knowing if you have 2 different heating zones (one for radiators, one for UFH) on the heatpump or a single heat zone feeding both then it's hard to say. Where is your Nibe installer and what have they done to get the system going?

My Nibe unit only has a single heating zone feeding my system (underfloor heating throughout) and I run my heating circuit at a fixed target temperature of 38 degrees when a manifold needs heat and 10 degrees when no heat is needed (i.e. the heating circuit shuts down).

One thing to watch out for is that your immersion heaters are not switching in unnecessarily. They will operate if you are asking for too high a flow temperature for your rads - hopefully your plumber has significantly oversized your rads so they work at a much lower flow temperature.

Iannyboy

Yes I have 2 different heating zones. Since my last post I have realised that the scheduling has been causing the problems. It had been set to reduce the rad temperature during the night. By doing this it has been requiring additional heat (immerser) in the mornings etc to boost heat.

I have switched the scheduling off and we are going to fit a time clock on rad supply so that it can be cool during the night and have a full buffer tank for the rads in the morning.

Also ther rads are indeed oversized and calculations were done by my installers.

Hopefully this is a solution.

Out of curiosity how should I decide on what the degree minutes should be set to? This is something I'm finding difficult to understand.