help please - no heating

heating24

so we've had Tado for several years, we had whatever version it was where you could pay a one off amount to upgrade - I think we had V3 and upgraded to V3+ but I'm not 100% on if those are the right numbers or whether it makes any difference to this. Tado has worked well ever since, we have a wired wall thermostat and loads of smart radiator valves. We didn't get an extension kit for the hot water because that would have limited how many rooms we could have set up with the radiator valves. We have a boiler in our utility with an old school Honeywell control panel, which we leave in the continuous position for the hot water and the heating, and then we have a hot water tank in our airing cupboard. Yesterday morning the fuse switch for the Honeywell panel blew. We replaced the fuse and it blew again. We had no hot water or heating yesterday. Today a man came out and established that the zone valve in our airing cupboard was faulty and it was kicking out sparks, which was blowing the fuse. He has replaced this with a new valve box. But whilst this has resolved the hot water side of things, we still have no heating. The Tado app thinks that everything is working fine, it's showing all the rooms calling for heat, but the wall thermostat is not turning the boiler on. The man checked that there is power going in and out of the wired connection to the wall thermostat and that there is power coming into the zone vale from the wall thermostat. So the wired connection is fine. I've taken out the batteries to the wall thermostat and then put them back in, and I've held the button on the wall thermostat down for 10 seconds to reset it. I've tried turning all the radiators off in the app, and then turning them all back on again. But nothing is working. The only thing that worked briefly earlier is that he used a lever on the top of the valve to manually lock it into a open position, which meant that whilst the hot water was on, the radiators had heat going to them too. But whilst we initially thought the heating had continued to work after the hot water got hot, we were wrong and so then the radiators cooled down, and we are back to a freezing house. Does anyone have any idea on what could be causing the wall thermostat to not work and control turning on this valve, when we know that there is nothing wrong between the wired connection between them? if I alter a set temperature for the wall thermostat, it quickly shows on its display, so the bridge is working fine, we can hear the valves making the noise as they open the radiator valves to call for heat, but the wall thermostat just isn't sending the signal through the relay switch to get the zone valve to work so that the pump and then boiler will kick in.

wateroakley

@heating24 Hello. For users to help, you'll need to describe the details for your heating system and controls more succinctly.

• Boiler make/model?
• Y-Plan or S-pLan zone valve, make/model?.
• Honeywell 'control panel' model?
• The wiring box?
• Tado thermostat?
• Pictures will help, easiest posted from web browser..

Faullty zone valves or wiring can cause other control components to fail before the 3A fuse blows. E.g. multiple failures of Honeywell programmer, semi-smart wired thermostat, and blown 2A (20mm) fuse in a Honeywell wiring box. If you have blown a couple of main 3A fuses, or used a 13A fuse, all the more likely.

Please post the details of you heating system, and users will try to help.