Expansion Vessel And Temperature-Pres; Sure Gauge; Function; Checks - Biasi RIVA PLUS HE 24C ERP Service Manual

EXPANSION VESSEL AND TEMPERATURE-PRESSURE GAUGE
13 EXPANSION VESSEL AND TEMPERATURE-
PRESSURE GAUGE

13 .1 Function

The Expansion vessel (D in Figure 12.1 function is to allow for
the volume expansion of the c.h. circuit water due to the tem-
perature rise.

13 .2 Checks

1 Turn off the flow and return isolation valves and empty the
primary circuit of the boiler.
2 Remove the protective cap E (Figure 13.1) from the valve on
the top of the expansion vessel and connect a suitable air
pressure gauge.
E
Figure 13 .1 Rear view of the boiler
3 Check the pre-load pressure and refer to the section Expan-
sion vessel in the User manual and installation instructions
for the correct value.

13 .3 Removal of the expansion vessel

If there is at least 400 mm clearance above the boiler and the
rear exit flue can be easily removed, the expansion vessel can
be changed without removing the boiler.
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent .
1 Remove the front and left hand side panels of the case, turn
off the flow and return isolation valves and empty the primary
circuit.
2 Completely unscrew the connection F, the locknut G (Figure
13.2) and remove the expansion vessel from the top of the
boiler.
Figure 13 .2
3 Re-assemble the parts in reverse order of removal.

13 .4 Removal of the temperature-pressure gauge

1 Remove the front and right hand side panels of the case, turn
off the flow and return isolation valves and empty the primary
circuit.
2 Remove the fork H and the probe holder spring I (Figure
13.3).
3 Squeeze the tabs J to release the temperature-pressure
gauge K and remove it.
4 Re-assemble the parts in reverse order of removal.
Figure 13 .3
G
F
I
H
K
J
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