The ground source heat pump (and associated paraphernalia) was delivered last Monday. Over a week later and we are struggling to get it working properly.
While it only took 2-3 days to get all of the pipework in place, it has taken the same amount of time again to try to get the air out of the system. If there is an airlock in the ground loops, the fluid will not circulate into the pipework under the field and we won’t be able to extract any heat.
Through rather convoluted process, we managed to get all the air out of the system. This included flushing the ground loops with water to drive the air out, venting the ground loop manifolds and running the ground loop pump with no pressure (allowing the air to work its way out of the system). Once the air was out of the system, we checked the strainer only to find that we had picked up a lot of dirt while flushing the system. I guess this is what strainers are for!
With the strainer removed, you can see the amount of grot that has been captured while the system has been flushed. We thought that this would have been the cause of the “low pressure” alert on the heat pump, but sadly not (or at least, not the entire cause).
Our plan was to run the system with water in the ground loops rather than a mixture of water and anti-freeze. This seems to be our next problem – the temperature of the water is reduced to a point where it will freeze in the heat pump without anti-freeze. Unfortunately to get the anti-freeze into the system, we need to hire a pump. In the meantime, the heat pump displays a “low pressure” alert after 20-30 seconds of the compressor starting. Due to the Christmas break this is going to have to wait until the end of the week.
Top marks to Neil and Ricky from Sol-Air Renewables (www.solairrenewables.co.uk) who have really put some long hours in this week to try to get the heat pump up and running.
In the meantime, we are using the heat pump’s immersion heater to slowly raise the temperature of the water in the underfloor heating. We have put the heat pump into “floor drying mode” and this slowly raises the temperature over a two-week period. Even though the ground loops aren’t working yet, we will be able to dry out the floors.
Hopefully we will get some more progress towards the end of this week (most likely Friday).
The ground source heat pump is the fridge/freezer to camera right, the large round tank is a 500 litre hot water tank and the smaller tank is a 300 litre buffer tank (it stores excess hot water produced by the heat pump). Ricky has done a great job of installing all of the pipework. The guys installing the cast iron gutters at the weekend referred to it as “the engine room on the Titantic”. Mmmm. I might see the funny side of it once it is working!