10
Installation instructions 0020140122_04
12
230 V~ 0 ...24 V
12f
VR 66
NTC
BUS
- +
2 1
DHW OFF
N L
DHW ON
N L
CH1
N L
230V~
N L
230 V~
230 V~
CYL
2 1
CH2
CYL
CH1
DHW ON
DHW OFF / CH2
BUS
NTC
1
1
M
9b
M M
9e
M
DHW
230 V~
230 V~ 0 ...24 V
L
N
X1
230 V~
X12
L
N
24V=
RT
Burn.
L
off
N
BUS
- +
X13
Opt.2
X16
Opt.1
X100
X41
X40 X51
X35
X31
X32
0( )
0( )
DCF
RF
AF
FB
1
ecoTEC plus
X36
38
12q
BUS
PWR
LAN
VR 921
230 V~
b
38 If a thermostat shall be used, instead of the DHW tempera-
ture sensor; remove the DHW temperature sensor, mount
the thermostat, and connect the thermostat on clamp ‘CYL’.
3.2.5 Multizone operation mode
The Multizone operation mode is compatible with:
– VRT 350
(using rotary switch position 0) or
– VRT 380 and VR 92 (using rotary switch position 2)
– system, combi and open vent boiler
The information about the heating or hot water demand is
sent by the room thermostat via the control centre to the
boiler. The VR 66/2 then decides if the hot water demand
needs to be fulfilled and drives the valves.
In this way, the boiler can store different target tempera-
tures for heating and hot water modes.
i
The multizone mode is only compatible with
VRT 350
or VRT 380 combined with VR 92. No
other room thermostats are compatible.
The multizone mode will NOT support weather
compensation and cannot be used on Y plan
systems with three port motorised valves.
The standard installation for multizone mode is character-
ised by:
– 2 port valves for zoning,
– 2 VRT 350 programmable wired room thermostats or
– 1 VRT 380 room thermosthat combined with 1 VR 92,
– heating zones and DHW cylinder cannot operate in par-
allel.
Priorities are defined as follows:
Priority levels
Function
1
Domestic hot water
2
Central heating
