Home Automation – LightwaveRF Heating – Testing the System
Conventional System Setup
I needed to check how the new LightwaveRF system would behave in comparison to the old conventional system. So I worked out how the conventional system should work in the main trigger conditions:
Conditions Outcomes Trigger HW Tank Thermostat Programmer Boiler Programmer Triggers HW to Turn On Below Temp On On HW Tank Stat Reaches Temp At/Above Temp On Off Programmer Triggers HW to Turn Off n/a Off Off
Conditions Outcomes Trigger Room Thermostat Programmer Boiler Programmer Triggers HW to Turn On Below Temp On On HW Tank Stat Reaches Temp At/Above Temp On Off Programmer Triggers HW to Turn Off n/a Off Off
Next, to compare it to how the new LightwaveRF system would behave:
Conditions Outcomes Trigger HW Tank Thermostat LW App HW Device LW920 Boiler Switch Boiler Programmer Triggers HW to Turn On Below Temp On On On HW Tank Stat Reaches Temp At/Above Temp On Off Off Programmer Triggers HW to Turn Off n/a Off Off Off
Conditions Outcomes Trigger LW921 Thermostat LW App CH Device LW920 Boiler Switch Boiler Programmer Triggers HW to Turn On Below Temp On On On HW Tank Stat Reaches Temp At/Above Temp On Off Off Programmer Triggers HW to Turn Off n/a Off Off Off
So there's one difference between the two systems. In the conventional system, when the relevant thermostat reaches the target temperature, the light indicating whether the CH or HW is on or not, will remain illuminated. In the new LightwaveRF system, the relevant LW920 Boiler Switch will switch off.
To explain the behavour differences noted above, it's worth comparing the two system components:
HW Component Conventional Setup New LightwaveRF Setup User Switch Programmer LW App On/Off Display Programmer LW App Internal Switching Control Programmer LW920 Boiler Switch Heating Source Boiler Boiler Thermostat HW Tank Thermostat HW Tank Thermostat
CH Component Conventional Setup New LightwaveRF Setup User Switch Programmer LW App/LW921 Thermostat On/Off Display Programmer LW App/LW921 Thermostat Internal Switching Control Programmer LW920 Boiler Switch Heating Source Boiler Boiler Thermostat Room Thermostat LW921 Thermostat
To test the three port valve, I needed to check the scenarios:
Test CH State HW State Three Port Valve Position CH Off, HW Off (default) n/a n/a Port B (HW) CH On, HW Off On Off Port A (CH) CH Off, HW On Off On Port B (HW) CH On, HW On On On Port A/B (mid-position)
As it happens, my 19-year old three port valve is showing its age, and when in CH Off and HW On, the three port valve doesn't reliably switch over to the default Port B position. This leads to some of the radiators remaining on. Time to get the British Gas engineer out!