Supply Pressure For Ng And Lpg; Checking The Rotary Damper Setting - Viessmann Vitocrossal 200 CM2 400 Service Instructions Manual

Vitocrossal 200, CM2 400, 500, 620 and 620 TX Service
Steps – Commissioning, Inspection and Maintenance

Supply pressure for NG and LPG.

1. Start the burner
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.
2. Measure the supply pressure (running pressure). Use
suitable measuring instruments calibrated with a
minimum resolution of 0.04 "w.c. for measuring the
supply pressure.
Value must be:
Supply pressure with:
Natural gas Liquid propane gas
under 4"w.c. under 10"w.c.
4 to 14"w.c. 10 to 14"w.c.
over 14"w.c over 14"w.c.
Commissioning, Inspection, Maintenance
Note: The supply pressure should be between 4"w.c.
3. Record the actual value in the report (on page 67).
4. Close the gas shut-off valve.
5. Remove the pressure tester and close test nipple A
(shown on page 16).
Corrective action
Do not attempt adjustment. Call local gas utility
Start up boiler.
Do not attempt adjustment. Call local gas utility to decrease pressure.
Boiler valve must not be exposed to pressure over 14 "w.c.

Checking the Rotary Damper Setting

The electro-mechanical inlet air damper reduces the
amount of air during ignition timing, for a smoother
ignition of the burner.
1. Open the gas shut-off valve.
2. Check the position of the rotary damper in burner
idle mode. The rotary damper windows B must be
completely open and the graduated collar D on the
air damper motor must be set to "0" relative to mark C.
3. Check whether compensation tubing A has been
connected between the gas valve and venturi mixing
pipe.
4. Start the burner.
5. Check the position of the rotary damper during the
start-up phase. The rotary damper windows B must
be almost closed for approximately 5 seconds, during
which time the graduated collar D is set as follows:
Boiler Models
400
500
620
620 TX
(continued)
and 14"w.c. The gas pressure switch for the inlet
pressure test/check is factory set to 4"w.c.
Never alter this setting.
Rotary damper setting in °
30 (close) / 0 (open)
20 (close) / 0 (open)
20 (close) / 0 (open)
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