Two-Port Zone Valve; Connecting An Opentherm Bridge - Honeywell Evohome Installation Manual

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
relay box is fitted the end
switch is not required.
!
If connecting a two
port zone valve with
an unvented cylinder
connection for a high
limit thermostat, the 'L'
permanent live feed must
be broken when high limit
cutout activates on the
insertion thermostat.
Figure 8 Wiring an
OpenTherm Bridge to
an OpenTherm boiler.
evohome Installation Guide

Two-port zone valve

BDR91
230V
N L L
50-60Hz
<5A
L
N

Connecting an Opentherm bridge

Opentherm bridge
A-B:5(3)A
A-C:5(3)A
A B C
G/Y BL BR GR O
M
V4043H
Opentherm equipped boiler
Opentherm input on the boiler ONLY.
Do not connect to the room thermostat
terminals
45