Technical information

5
2
Control Overview—External Controls Connections
BMS Connections—External Disable/Mixing Valve Close [143]
Applicable for Vitocontrol-S, MW1 (CT3/VD2/RS/VB2)
1
3
1 Boiler control.
2 Plug 143 used to interconnect
control devices with boiler
control. Ensure plug [143] is
plugged into the correct socket
found in the boiler control.
3 Field supplied interconnection
wire between plug [143] and
control device.
4 Field supplied relay:
24VAC
120VAC
24VDC
5 Field supplied control relay.
When coil energized, dry
contact switch is made and
disable or close mixing valves
demand takes place.
6 Instead of relays, it may be
possible to use simple switches
to provide similar control
functionality.
External Disable/Close Mixing Valves:
Dry contact to [143] plug.
Primary Consideration(s):
There is no frost protection during external disable or close mixing
valves demand. No minimum boiler water temperature is maintained
during the contact closure.
Configurations:
Dry contact to [143] plug is connected to terminals 2 and 3.
Coding address 99 allows selection of operation between disable and
mixing valve close demand.
SW
143
146
143
R
4
OR
6
IMPORTANT
Ensure that all field wiring conforms
to local codes and regulations.
IMPORTANT
No minimum boiler water
temperature or freeze-up protection
when control is disabled.
Section 4.3
Section 4
1 2 3
Connection Overview
5346540 v1.0 09/2006 Technical information subject to change without notice
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