Grainfather Glycol Chiller

A home brewing group I am with has a Grainfather Glycol Chiller.

It has been working fine until yesterday. We turned it on and we had an issue. The pump is working and circulating but the chiller is not. We have checked the connections and made sure we had enough glycol, etc. Yet the chiller doesn't work. We had a batch on a couple of weeks ago and it was working fine.

We thought about cleaning the connectors, which we'll look at this weekend. Also thought about overriding the chiller to see if that forces the chiller to act. Even if it doesn't solve the problem long term it may help to narrow down the cause.

I was wondering if anyone had any similar experience or ideas on what may be causing the issue and what their solution was.

We haven't contacted Grainfather yet but we are based in the UK so I suspect the response won't be the fastest right now.