Viessmann Vitoplex 200 SX2A Service Instructions For Contractors page 15

Adjusting the burner
Rated heating Pressure drop on the hot gas
output side
kW
90
120
150
200
270
350
Partial load operation
Set the minimum heating output for the base load
stage according to the conditions of the flue system.
Note that the flue system must be suitable for the low
flue gas temperatures that may occur.
In the case of frequent cycling in standby mode and for
partial loads below 40 % we recommend the following:
■ Insulate the flue gas collector.
■ Install a motorised flue gas damper.
■ Set the minimum runtime for the boiler to 10 minutes.
Operation with burner load
The minimum boiler water temperature for oil operation
is 50 °C and for gas operation 60 °C.
To protect the boiler, the minimum heating output at
the base load stage is set to 60 % of rated heating out-
put.
Rated heating out- Minimum heating output to
put be set (burner stage 1)
kW
90
120
150
200
270
350
440
560
Operation with burner load
The minimum system temperatures (flow/return) are
60/50 °C for oil operation and 70/60 °C for gas opera-
tion.
(cont.)
Pa mbar
60 0.6
80 0.8
100 1.0
200 2.0
180 1.8
310 3.1
60 %
≥
kW
54
72
90
120
162
210
264
336
40 % and < 60 %
≥
Commissioning, inspection, maintenance
Rated heating Pressure drop on the hot gas
output side
kW
440
560
To protect the system against dew point corrosion,
burner stage 2 (full heating output) must be set to the
rated boiler heating output. It must remain switched on,
even during the summer months (burner stage 2 on
constant standby).
This extends the service life and reduces running
costs.
A minimum flue gas temperature is required for the
base load stage, the value of which is subject to the
design of the flue system.
Pa mbar
280 2.8
400 4.0
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