Conversion To Natural Gas (Ng) - Viessmann Vitocrossal 200 CM2 400 Service Instructions Manual

Commissioning, Inspection, Maintenance
Steps – Commissioning, Inspection and Maintenance

Conversion to natural gas (NG)

1. Close the gas shut-off valve.
2. Switch OFF the system ON/OFF switch at the boiler
control unit.
3. Switch OFF the main boiler circuit breaker (outside
the boiler room) or the power supply and prevent
unauthorized reconnection.
4. Remove boiler front cover (see page 9).
5. Undo gas supply fitting A.
6. Disconnect compensation tubing G connected
between the venturi tube and the gas valve.
7. Remove four M5 hex nuts (8 mm wrench). Detach the
gas valve from flange E.
8. Remove and dispose of the LPG orifice C and the
rubberized cork gaskets D.
Install a new oriface and rubberized cork gasket (for
model 500 only, see gas orifice table).
Note: Chamfer on the NG orifice must face the
gas valve.
9. Tighten screws M5 x 16 diagonally.
Torque screws diagonally 13.2 lb/in (1.5 Nm).
10. Secure and tighten gas supply fitting A.
14
Vitocrossal 200, CM2 400, 500, 620 and 620 TX Service
(continued)
10.Push compensation hose G on to the gas valve.
11. Apply:
- Partial rating plate above CSA rating plate located
on top panel (behind the boiler control).
- Label indicating that this unit is equipped for NG
over the LPG label located on the gas valve.
- Label indicating that this unit has been converted to NG
from LPG next to the CSA rating plate (on the top panel).
- Fill out and fax conversion report.
12. Check all gas fittings for leaks.
WARNING
Escaping gas leads to a risk of explosion.
Check all fittings for gas leaks.
Note: The use of leak detecting spray can result in
incorrect functions. Leak detecting spray must
not come into contact with electrical components.
Note: For commissioning, see page 12. Switch the burner
to maximum heating output. For this, activate the
emissions test switch at the boiler control unit.
WARNING
Escaping gas leads to a risk of explosion.
Check all fittings for gas leaks.
Note: The use of leak detecting spray can result in
incorrect functions. Leak detecting spray must
not come into contact with electrical components.
Gas orifice dimensions (liquid propane gas) for boiler
models 400, 500, 620 and 620 TX
Boiler Model
400
500 0.85
620
620 TX
Dimension a in. (mm)
NG LPG
-- 0.52 (14.0)
(21.5) 0.58 (14.8)
-- 0.68 (17.2)
-- 0.68 (17.2)