11
FERtech 25 OV
Cod. 3540U431 - 11/2009 (Rev. 00)
fig. 10
2.3 Boiler water connections
The heating capacity of the unit should be previously established by
calculating the building’s heat requirement according to current regu-
lations. For good operation and long life of the boiler, the plumbing
system must be well proportioned and always complete with all those
accessories that guarantee regular operation and running, room ther-
mostat, trv’s etc. The flow and return must be a minimum diameter of
22mm for the first 3 metres from the appliance.
If the flow and return pipes follow a path where air pockets could form
in certain places, it is essential to install vent valves at these points.
Also, install type “A” drain cock device at the lowest points in the
system to allow complete draining.
The temperature differential between the flow manifold and the return
to the boiler should not exceed 20° C.
A minimum flow of 6 litres/min is required through the heat exchan-
ger, calibrated on site. An automatic by-pass must be fitted to the
system.
Do not use the water system pipes to earth electrical applian-
ces.
Before installation, carefully flush all the pipes of the heating system
to remove residues or impurities that could affect the unit’s operation
(BS 7593 Building regs Doc L).
Make the connections to the appliance as shown in fig. 10.
Key
1
System flow (22 mm compression union)
3
Gas inlet (22 mm with isolation valve fitted)
5
System return - 22 mm compression union)
Make the boiler connection in such a way that its internal pipes are free of stress.
400
45
50
213
187
135
630
80
120
45 25
144
35
1 5
120
3
