Auxiliary Low Gas Pressure Switch - Viessmann Vitocrossal 200 CM2 186 Service Instruction

Vitocrossal 200 CM2 186 to 311 Service

Auxiliary Low Gas Pressure Switch

Legend
1 Low gas pressure switch cable
Legend
A DIN rail (junction box)
B Auxiliary low gas pressure switch or external shut-off (dry contact)
Commissioning, Inspection, Maintenance
Installation steps
1. Disconnect boiler power supply.
2. If the boiler has already been installed, shut off main
gas supply to the boiler and disconnect gas supply
piping.
3. Supply and install gas piping components as required
(see illustration).
4. Route cable beneath the top rail 1 as shown.
Secure using plug-in cable retainers as shown.
5. Make electrical connections as shown below.
6. Set the low gas pressure switch to 4.5" wc.
7. Open gas supply to the burner.
Note: The setting must be higher then the GW1
pressure switch (4" w.c.) located on the gas
valve. If a 4" w.c. setting is required then the
GW1 pressure switch must be set below 4"w.c.
8. Using an approved gas leak detector, check gas line
and low gas pressure switch.
9. Reconnect power to the boiler.
Note: External vent line is not required. If necessary the
d" NPT vent opening on the Honeywell low
gas pressure switch can be used.
CM2 Boiler Low pressure gas
connection switch connection
G
26 (L) COM
27 (L)
Operation
When sufficient gas pressure is available, the low gas
pressure switch contact terminals 3(COM) and 2(NO)
will close. The burner control is then energized and the
system will operate normally.
When sufficient gas pressure is no longer available, the
low gas pressure switch contact terminals 3(COM) and
2(NO) will open. The burner control will stop operating
and generate a fault C1 at the boiler control.
To restart the boiler, press the low gas pressure switch
reset button (only once) and reset the boiler control fault.
If the fault persists, verify the gas supply pressure. There
should be a minimum operating pressure of 4.5" w.c., if
not contact your local gas company.
Wire color
Green

White
NO Black
27