We have a Worcester boiler with UFH downstairs and CH upstairs. The CH and DHW run off a Delta Dore Tybox 827 WRF programmable thermostat (all working fine) whilst the UFH off a Tybox 337 programmable thermostat. Both wired into a standard wiring centre.
The 337 keeps "blowing" and failing to turn off the UFH when it hits the target temp - so we come down in the morning and it's up to 24 or 25 degrees! Delta Dore replaced the first two, convinced their products were not at fault(apparently they NEVER fail). Tested in France and each time the capacitor had gone.
Electrician at a loss. Eventually replaced Tybox with simple generic dial thermostat hard-wired in to "test" it. That blew in one evening. Now everyone at a loss as presumably NOT the controller / thermostat.
Everything else fine - no other electrical issues in house, fuses never trip, DHW and CH both working fine off their Delta Dore Tybox, boiler etc fine. Just the UFH keeps killing every controller!
Hope this makes sense - am not in the trade so hopefully explained clearly. Can anyone please help and suggest what the problem might be or how we diagnose it?
The 337 keeps "blowing" and failing to turn off the UFH when it hits the target temp - so we come down in the morning and it's up to 24 or 25 degrees! Delta Dore replaced the first two, convinced their products were not at fault(apparently they NEVER fail). Tested in France and each time the capacitor had gone.
Electrician at a loss. Eventually replaced Tybox with simple generic dial thermostat hard-wired in to "test" it. That blew in one evening. Now everyone at a loss as presumably NOT the controller / thermostat.
Everything else fine - no other electrical issues in house, fuses never trip, DHW and CH both working fine off their Delta Dore Tybox, boiler etc fine. Just the UFH keeps killing every controller!
Hope this makes sense - am not in the trade so hopefully explained clearly. Can anyone please help and suggest what the problem might be or how we diagnose it?
