Polytherm UFH system, zones not working

kelbal

Hi,

I have a house with multiple UFH zones downstairs, each controlled by its own thermostat. Three of the zones aren't working when the thermostat is telling the oil fired heating to come on. I've confirmed the heating is working fine on other zones. The plumbing from these 3 zones all comes back to a manifold under the stairs. There's some sort of electrical junction box there with the pipes, and there's a few pumps in a wardrobe upstairs. It sounds like an electrical issue to me, the fact that the thermostat is trying to activate the heating, but there isn't a sign of life at the boiler. It's a fairly complex system, and I'm only recently moved into the house. I'll get a plumber out alright, but first just trying to get to grips with what could be going on, there's hardly a simple enough solution ?

Thanks in advance