As well as generating heat for the house, we also now have a full tank of hot water.
Although it is going to take a few days to get the property up to full temperature, we haven’t done too badly in the last 20 hours or so. Below is an update on the internal temperature graph from our weather station.
Inside temperature after the ground source heat pump was turned on about 4pm yesterday afternoon.
It looks as if the problem with the ground source heat pump has finally been fixed (although it would appear that there was no problem to be fixed). It is going to take a few days for the house to get up to temperature, but at least it is a start.
The heat pump has been throwing LP (Low Pressure) alerts for the past couple of weeks. The ground loops were flushed. But there was no air in the system. All of the strainers on the ground loops were checked. Again, no problem. The circulation pump for the ground loops was replaced. But the same problem persisted. The software on the heat pump was updated. No difference.
The Nibe engineer spent 5 hours on site and finally struck on the idea that the temperature of internal underfloor heating was too low. Apparently, there needs to be a significant temperature difference between the ground loops and the underfloor heating otherwise the low temperature in the underfloor heating will reduce the temperature (and thus the pressure) on the ground loops.
The answer appears to be to use the internal immersion heater to raise the temperature of the underfloor heating. Then the ground source heat pump could be engaged and, voila, it all works as it should.
We restarted the heat pump about 6 hours ago (around 4pm this afternoon) after engaging the immersion heater for a while. The good news is that it is still running (and generating heat). Fingers crossed.
Here’s the graph for the internal temperature from our weather station. You can see where the heat pump was turned on around 4pm. Hopefully, the graph overnight will look just as good. Fingers crossed.
The ground source heat pump worked well for about 2 weeks and then started shutting down with a low pressure alarm. This is normally due to an issue with circulation of fluid in the ground loops. Last Friday, we had to give up and turn the unit off altogether. We have now been without heating and hot water for the last week.
Initially, it was thought that it was dirt in the system, but there was no dirt in any of the strainers and the system was flushed to prove the point. Then it was thought that it was the pump that pumps the antifreeze around the ground loops. This was replaced, but the fault still persisted.
Neither the installer or NuHeat have been able to resolve the problem despite their best efforts. This issue now resides with Nibe who are the manufacturer of the ground source heat pump unit itself. Unfortunately, this means further delays as we have to wait for an appointment for the engineer to come out.
When the heat pump is back up and working, it will take 2-3 days at least for the property to get back up to full temperature. We are just gratefully that it hasn’t been too cold yet this winter!
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