Riello Array AR 2000 Installation And Operation Manual page 58

APPENDIX
APPENDIX SHUTDOWN
− Disconnect the multimeter and reconnect the wires, as
shown in the picture below.
−
1 (NC)
2 (NO)
Fig. 72 Wired pressure switch
− Test the pressure switch on the other side of the boiler
(module 4 or 8); repeat the process from Fig. 69 through
Fig. 72.
If the multimeter shows "0" (or any other symbol confirming the
electrical continuity between 1 (NC) and 3 (COM) of the condensate
pressure switches), the error on the boiler is due to a water pressure
lower than 7.5psi (or a failure of the pressure switch itself).
If on the condensate pressure switch the multimeter shows the
circuit between 1 (NC) and 3 (COM) is open, there is a blockage
downstream of the relevant condensate trap (or a failure of the
pressure switch itself).
2. For Array AR 1000, AR 1500 and AR 2000: "LWCO/Air inlet block"
error message on TS Boiler screen.
− This message shows on touchscreen as a result of two
possible errors:
− Boiler water level below the LWCO probe on the Supply
header.
− Differential between air pressure inside the boiler cabinet
and air pressure of the boiler room higher than 1.4" wc.
In order to discriminate between those two causes, it is suggested
to access the differential air pressure switch inside the boiler
cabinet (left side).
− This pressure switch is also normally closed (NC). Confirm it
is wired correctly, with connections on 1 (NC) and 3 (COM),
see picture below.
1 (NC)
2 (NO)
Fig. 73 Wired pressure switch
− Follow the steps from Fig. 69 through Fig. 72.
3 (COM)
3 (COM)
If the multimeter shows "0" (or any other symbol confirming the
electrical continuity between 1 (NC) and 3 (COM) of the air pressure
switch), the error on the boiler is due to a lack of water on the
hydraulic circuit (or a failure of the pressure switch itself).
− If the multimeter shows the air pressure switch circuit
between 1 (NC) and 3 (COM) is open, the error is due to an
air pressure differential between boiler cabinet and boiler
room higher than 1.4"wc (or a failure of the pressure switch
itself).
The root cause is most likely an obstruction/blockage on
combustion air inlet.
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