Installation Instructions

Connecting a two-port zone valve
Figure 7 Connecting a
two port zone valve
G/Y: Green/Yellow
Earth wire
BL: Blue Motor Neutral
BR: Brown Motor Live
GR: Grey End switch (if
used) Permanent Live
O: Orange End switch (If
used). In wired system
this typically feeds
the boiler. When a
wireless boiler relay is
fitted the end switch
is not required
Opentherm bridge
Opentherm input on the boiler ONLY.
Do not connect to the room thermostat
terminals
Opentherm bridge
Opentherm equipped boiler
Figure 8
230V
50-60Hz
<5A
N L L
BDR91
V4043H
A-B:5(3)A
A-C:5(3)A
A B C
L
N
BL BR
M
GR O
G / Y
45evohome Installation Guide