Operating instructions

Fig. 18
detail of setting :
Cut of screw head on - :
Cut of screw head on + :
by pass shut (factory setting)
by pass open
By pass and Pump
The boiler is fitted with a pre-adjusted by pass. Although
adjustment is not normally necessary, the by pass can be
reset by turning screw (17 fig. 18) clockwise to open the by-
pass using the chart below for guidance. It is a l/4 turn from
fully closed to fully open.
If used on a system with thermostatic radiator valves, the
flow rate, through the system, with the thermostatic valves
closed should be at least 100 I/hr.
The chart below indicates the residual head of the pump
available for the system.
mH2
Head
and flow rate available
5
4
3
2
1
0
DCbt
100 100 300
400
500
600 700 BOO
900 1000 h
Fig. 19
“GV - bp -I’ means : Pump in high speed and by-pass closed
“GV - bp +” means : Pump in high speed and by-pass open
“PV - bp -” means : Pump in low speed and by-pass closed
“PV - bp +” means : Pump in low speed and by-pass open
q
chaffoteaux~
-=-AA