Baxi CPA-BT Serie Instrucciones De Instalación, Montaje Y Funcionamiento página 29

Prevention of condensations
Condensation in boilers is harmful, especially
when they are made of steel. With a combustion
set to 25% excess air, boilers are suitable for
operating with a minimum boiler temperature and
return temperature, showed in the the following
table:
Requirement
1 stage or
Burner
2 stage
operation
65 – 100%
Oil 35°C
Minimum return
Temperature
Gas 39°C
Oil 50°C
Minimum boiler
Temperature
Gas 57°C
When installation requires lower temperatures
than those of the table, it will be necessary to add
a by-pass pump to raise the return temperature
and/or a 3 way mixing valve to have a flow
temperature lower than boiler temperature.
The "Pr" by-pass pump can be calculated for a
water flow about 50% of the main heating pump
of the installation "Pi" and with possibility to
overcome the boiler pressure drop (always less
than 0,1 bar).
Note:
If after following the above recommendations, any
signs of malfunction or failure is detected in the
boiler or installation, please contact with your local
distributor or any authorized After Sales Service.
Attention:
Characteristics and performance qualities are
subject to change without notice.
2 stage Modulating
50 – 100% 35 – 100%
37°C 40°C
40°C 47°C
51°C 53°C
58°C 60°C
Pr Byass pump
C Boiler
Pj Heating pump
Vm Mixing valve
M Mixing valve motor
Sm Flow sensor
Se Outdor sensor
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