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- 27 Jan 2018
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Well well well, Vaillant do like to make it fuzzy on use of VR66 without a ebus VRC programmer, and both zone valves connected to it.
It's totally possible, for monozone only though, you will need a full VRC for multizone.
Your programmer needs to trigger the boiler input on CH room stat demand, the boiler will tell the VR66 to open the CH zone valve before it fires up.
For HW you do the same but you wire it to pin 1 on the VR66 cyl plug, pin 2 is a perm live, you do not need that if you are getting live from the programmer but if you are not then you may need it, it's good if you are using a relay to drive it for any reason. When pin 1 goes live it signals to boiler to start up and opens valve.
One nice feature of the VR66 is that it leaves the zone valve open after the end of firing for the pump overrun so that it dumps any remaining heat into the CH/HW and cools down the HE much quicker as return water starts to drop temp, good idea if you have a very short ABV loop, you still need the ABV as the pump may start before the zone valve is open if you have slow valves.
Anyway so now I do not get s53 as there is always HW priority so no large variation in flown temps and faster CH recovery as flow temp is higher.
It's totally possible, for monozone only though, you will need a full VRC for multizone.
Your programmer needs to trigger the boiler input on CH room stat demand, the boiler will tell the VR66 to open the CH zone valve before it fires up.
For HW you do the same but you wire it to pin 1 on the VR66 cyl plug, pin 2 is a perm live, you do not need that if you are getting live from the programmer but if you are not then you may need it, it's good if you are using a relay to drive it for any reason. When pin 1 goes live it signals to boiler to start up and opens valve.
One nice feature of the VR66 is that it leaves the zone valve open after the end of firing for the pump overrun so that it dumps any remaining heat into the CH/HW and cools down the HE much quicker as return water starts to drop temp, good idea if you have a very short ABV loop, you still need the ABV as the pump may start before the zone valve is open if you have slow valves.
Anyway so now I do not get s53 as there is always HW priority so no large variation in flown temps and faster CH recovery as flow temp is higher.