So there I am wondering how to refill the heating circuit of an air source heat pump with antifreeze mix.
I could use the fill and flush rig I own, but this is designed for ground source heat pump collector loops and, as such, is large, heavy and too powerful. I discovered the power issue when I managed to over-pressurise a system and dump many litres of antifreeze mix on the plant room floor a couple of years ago – I will not be making the same mistake again.
I could buy a smaller fill and flush rig, but why would I want two units? Actually, I can justify two units but Fran would, and often does, question my logic… and then the heat pump fairies are brought into the conversation!
I could buy a pump that you fit in a drill, but does that really fit the bill? I could use the 12V fuel transfer pump I have, but I’d need a battery and it has a very low flow rate.
So, not really happy with any of these ideas, I trawl the Internet hoping that someone has thought of the need for a mains-powered transfer pump that is easy to use. That fantastic person does exist, and this is the chemical transfer pump from Tanks Direct that they suggested:
It's a fantastic piece of kit: 230V, forward and reverse switching, really useful when you are filling or emptying the heating system and when you are adjusting the antifreeze concentration.
It is light and, for an additional cost, has its own cage.
When in use, it appears to be producing just over a bar, which is ideal if you are looking to not cause a flood!

For connection pipes, I use clear braided hoses and managed to find some perfect brass hose tails at Easy Irrigation. I needed to stock-check a couple of items with them and they could not have been more helpful – excellent customer service.
To secure the hoses, I used double ear clips from Westfield Fasteners. This company is well worth a visit if you're looking for high-quality fasteners – they generally have what I’m looking for.
I did buy a pair of hose clip pliers from Amazon and found that, while they were OK to start the crimping process, the pliers were too short to gain enough force. I found that using a pair of nail pliers to finish the clip crimping worked really well.
Fran was very happy I didn’t find a reason to buy more tools. I’m lulling her into a false sense of security...
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