Riello Array AR 1000 - Page 56

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SHUTDOWN
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APPENDIX
APPENDIX
− Disconnect the multimeter and reconnect the wires, as
shown in the picture below.
−
1 (NC)
2 (NO)
3 (COM)
Fig. 76 Wired pressure switch
− Test the pressure switch on the other side of the boiler
(module 4 or 8); repeat the process from Fig. 73 through
Fig. 76.
If the multimeter shows “0” (or any other symbol conrming 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 three 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.
− Gas pressure above 13.5” wc (33.6 mbar) or below 4” wc
(10.0 mbar);
In order to discriminate between those three 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). Conrm it is wired
correctly, with connections on 1 (NC) and 3 (COM), see picture below.
1 (NC)
2 (NO)
3 (COM)
Fig. 77 Wired pressure switch
− Follow the steps from Fig. 73 through Fig. 76.
If the multimeter shows “0” (or any other symbol conrming the
electrical continuity between 1 (NC) and 3 (COM) of the air pressure
switch), the error on the boiler is due to one of the possible causes:
− lack of water on the hydraulic circuit
− failure of the air pressure switch itself
− tripping of either high gas pressure switch or low gas
pressure switch.
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.