Checking The Ventilation Air Apertures In The Installation Room; Matching The Control Unit To The Heating System; Adjusting Heating Curves - Viessmann VITOCROSSAL Service Instructions Manual

Checking the combustion quality
Selecting the upper/lower heating output
Weather-compensated control unit
Service menu
1. Press OK and simultaneously for approx. 4 s.
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2. "Actuator test"
3. Select the lower heating output:
Select "Base load OFF". Then "Base load ON"
appears and the burner runs at its lower heating
output.
4. Select the upper heating output:
Select "Full load OFF". Then "Full load ON"
appears and the burner runs at its upper heating
output.
5. End output selection:
Press .
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Checking the ventilation air apertures in the installation room (only for
open flue operation)

Matching the control unit to the heating system

The control unit must be matched to the system equip-
ment level. Various system components are recog-
nised automatically by the control unit and the relevant
codes are set automatically.

Adjusting heating curves

Only for weather-compensated control units
The heating curves illustrate the relationship between
the outside temperature and the boiler water or flow
temperature.
To put it simply, the lower the outside temperature, the
higher the boiler water or flow temperature.
The boiler water or flow temperature in turn affects the
room temperature.
Settings in the delivered condition:
■ Slope = 1.4
■ Level = 0
Commissioning, inspection, maintenance
(cont.)
Constant temperature control unit
Service menu
1. Press OK and simultaneously for approx. 4 s.
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2. Use to select " " and confirm with OK.
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The display shows "I" and "ON" flashes.
3. Select the lower heating output:
Press OK, "ON" will be displayed constantly.
4. Select the upper heating output:
Press .
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5. Select "2" with , "ON" flashes.
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6. Press OK, "ON" will be displayed constantly.
7. End output selection:
Press .
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■ For individual coding steps, see page 36.
Note
If the heating system includes heating circuits with mix-
ers, then the flow temperature of the heating circuit
without mixer is higher by a selected differential (8 K in
the delivered condition) than the flow temperature of
the heating circuits with mixers.
The differential temperature is adjustable via coding
address "9F" in the "General" group.
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