Resolved VR33 module in Vaillant Eco Tec Plus Tado X
Vaillant ecotec plus 837
From Tado Starter Kit I used both bridge wires to short terminals (7+8) (3+4)..My previous wireless Honeywell thermostat was connected to (3+4)
Connected VR33 module to X31.
Removed bridge supplied with New VR33 module and replaced with 2 wire connection to Opentherm terminals to Tado X receiver paying attention to polarity. (dont know if important or not)
After installing the VR33 module the boiler worked but I had following issues.
1.Boiler would cycle without request for heat from Tado X receiver and continued to cycle even when heating off over night.
2. On occasions, temperature control of boiler output would be available in Tado app but then disappear.
3. Values in app using the temperature scroll wheel would change sometimes maximum adjustable temperature being 55° then on another occasion being up to 75°.
4. Boiler temperature still needed to be controlled manually using dials on front of boiler.
The fix was to remove the now obsolete Timer module from front of boiler!
Now I have control of both Hot water and central heating flow temperature via Tado app.
The Dials on boiler only set maximum temperature now, so Ive set central heating to max 75C and hot water to 64C (max without initiating vaillants "C" comfort setting)
Now I have full temperature range control via app.
Most importantly boiler only fires up when heat requested.
Hope this is useful.
Dont get ripped off on eBay
I paid £84.99 euros including postage & Tax to UK
PS I have now range rated boiler to minimum 12KW to reduce anti cycling.. boiler is much quieter now.
Range rating down has also reduced the rad expansion squeaking and clicking even at higher flow temperatures : ) (-2C this morning in Sunny Brentwood)
