We've moved into a house with a Vaillant system installed which I'm starting to lose my head over. Is there any obvious things standing out here as I'm very much a novice.
Boiler is a vaillant 618 system, have a unistor cylinder, and I've no idea about what plan this is, aside from two zones (one rads, one ufh) and a unvented cylinder.
When zone 1 (upstairs rads) is working, the underfloor heating (zone 2) works without problem. However when zone 1 is not heating as it has reached its room target temperature, zone 2 (UFH) will not activate the boiler even though the thermostat says it should. I've looked at the thermostat and it shows it should be calling for heat but the boilers radiator indicator does not show and zone 2 cools down until zone 1 fires up again.
Upshot of this is that when the radiators in zone 1 are off eg. during the night with a lower set back temp, the UFH in zone 2 switches off all night (even though the thermostat shows it shouldn't be as day and set back are same) and takes a full day to heat up the next day.
I've also tested having the UFH on a higher temp and as soon as I turn down the zone 1 thermostat (a VR81), the boiler will switch off all central heating.
Do I need to get a heating engineer out?
Thanks for any assistance.
Boiler is a vaillant 618 system, have a unistor cylinder, and I've no idea about what plan this is, aside from two zones (one rads, one ufh) and a unvented cylinder.
When zone 1 (upstairs rads) is working, the underfloor heating (zone 2) works without problem. However when zone 1 is not heating as it has reached its room target temperature, zone 2 (UFH) will not activate the boiler even though the thermostat says it should. I've looked at the thermostat and it shows it should be calling for heat but the boilers radiator indicator does not show and zone 2 cools down until zone 1 fires up again.
Upshot of this is that when the radiators in zone 1 are off eg. during the night with a lower set back temp, the UFH in zone 2 switches off all night (even though the thermostat shows it shouldn't be as day and set back are same) and takes a full day to heat up the next day.
I've also tested having the UFH on a higher temp and as soon as I turn down the zone 1 thermostat (a VR81), the boiler will switch off all central heating.
Do I need to get a heating engineer out?
Thanks for any assistance.
