Visual Inspection Of Appliance; Gas Pressures And Soundness; Cleanig The Primary Heat Exchanger; Cleanig The Domestic Hot Water Exchanger - Biasi Riva Plus Combi Installation & Operation Instructions

17. Annual Maintenance Cont.
17.8
Empty the central heating system as described in section 17.3 of this chapter and check that
the pressure in the expansion vessel is not less than 1 bar (14.5 psi). See also section 13.2 of
this manual. If the pressure should be lower, take steps to correct the pressure level. To check
the pressure at the venturi device, use the test points (12 on page 11).
• Remove the caps of the pressure test
points and connect a differential pressure
gauge.
• Switch on the boiler
• Compare the value on the gauge with the
minimum values of venturi pressure indi-
cated in the Section 2 on page 9.
Visually inspect all water joints, seals and connections for any evidence of leakage and re-
tighten, grease or replace them as necessary.
Check appliance for gas soundness. Recheck operational pressures and adjust as necessary
as described in Section 15.4 page 37 of this manual.
• Take off the front panel of the case, then the sealed chamber lid and the front panel of the com-
bustion chamber. If you notice dirt on the fi ns of the primary heat exchanger (9 on page 11), cover
the sloping surfaces of the burner (7 on page 11) entirely in a protective layer (sheets of newspa-
per or similar). Brush out the primary heat exchanger (9 on page 11) with a bristle paintbrush.
The descaling of the domestic hot water exchanger will be evaluated by the Authorised Assis-
tance Centre Technician, who will carry out any cleaning, using specifi c products.
To clean the condensate trap:
• Remove the front and right case panels.
• Disconnect the trap from the drain pipe.
• Using pliers, remove the spring D moving
it upwards.
• Disconnect the wirings from the trap.
• Reassemble carrying out the removal op-
erations in reverse order.
The trap should be serviced once a year dur-
ing the annual service.
44 RIVA PLUS COMBI MANUAL
Checking the pressurization in the expansion vessel:
17.9

Visual inspection of appliance:

17.10

Gas pressures and soundness:

17.11 Cleaning the primary heat exchanger:
17.12 Cleaning the domestic hot water exchanger:
17.13

Condensate trap:

Venturi test
points
Figure 17.5
Figure 17.6