B
buttonmoon
Hi guys
I was asked to have a look at a central heating fault on what appears to be a S plan system. Plumber had already had a look and told them that it was an electrical fault.
Gas boiler, immersion, 2 zone valves, honeywell wireless room thermostat, ST9400C Honeywell controller.
They say that the heating hasn't come on since they came back from holiday about a week ago.
The controller seems OK so I open the main junction box to see what's what.
So the first thing I notice other than the mess of poorly terminated wires is that the controller only has three+cpc cores which are connected to incoming line, neutral and the cylinder stat. Then I look at the receiver for the wireless room stat and its connected to to the live feed as well. OK I see what they've done here I think. The CH is being controlled by the thermostat and the controller is having nothing to do with it. Then I discover a live cable stuffed behind the immersion which is connected to Line in, neutral and cpc??
At this point the client tells me she has had the thermostat replaced recently so perhaps this was something to do with the old one but still wired incorrectly. Anyway to get back to the actual fault I now test for voltage with the room stat turned up to max on the core which goes from the stat to the zone valve. The little green light comes on on the receiver to indicate it has registered the change in the state of the wireless thermostat but I get no voltage on either that point or the point where the two orange wires meet. I have checked inside the receiver for loose connections and at the main junction box and I'm thinking that its a faulty receiver.
I'm sorry if this is a really obvious thing but I don't have a lot of experience when it comes to central heating systems and what with the system not being exactly a standard s plan, I thought I'd just run it by you guys for a second opinion.
All thoughts sensible or not appreciated
I was asked to have a look at a central heating fault on what appears to be a S plan system. Plumber had already had a look and told them that it was an electrical fault.
Gas boiler, immersion, 2 zone valves, honeywell wireless room thermostat, ST9400C Honeywell controller.
They say that the heating hasn't come on since they came back from holiday about a week ago.
The controller seems OK so I open the main junction box to see what's what.
So the first thing I notice other than the mess of poorly terminated wires is that the controller only has three+cpc cores which are connected to incoming line, neutral and the cylinder stat. Then I look at the receiver for the wireless room stat and its connected to to the live feed as well. OK I see what they've done here I think. The CH is being controlled by the thermostat and the controller is having nothing to do with it. Then I discover a live cable stuffed behind the immersion which is connected to Line in, neutral and cpc??
At this point the client tells me she has had the thermostat replaced recently so perhaps this was something to do with the old one but still wired incorrectly. Anyway to get back to the actual fault I now test for voltage with the room stat turned up to max on the core which goes from the stat to the zone valve. The little green light comes on on the receiver to indicate it has registered the change in the state of the wireless thermostat but I get no voltage on either that point or the point where the two orange wires meet. I have checked inside the receiver for loose connections and at the main junction box and I'm thinking that its a faulty receiver.
I'm sorry if this is a really obvious thing but I don't have a lot of experience when it comes to central heating systems and what with the system not being exactly a standard s plan, I thought I'd just run it by you guys for a second opinion.
All thoughts sensible or not appreciated
