Crown Boiler MWC116ENL - Manual (Page 68)

66
XV. Troubleshooting
WARNING
Turn off power to boiler before replacing fuses or working on wiring.
Figure 15.2: Fuse Location
Line Voltage Connections
Fuse
Table 15.1: No Error Code Displayed
CONDITION POSSIBLE CAUSES
Boiler does not run, no lights are on or fl ashing
• No 120VAC Power at boiler. Check breaker and wiring
between breaker panel and boiler
• Fuse on main PCB is blown (Figure 15.2). Check for short in
boiler wiring, then replace with an idenitcal 4.0A fuse.
Lamp 1 fl ashes every two seconds, but boiler does not
respond to a call for heat.
• Problem with thermostat or zone wiring
Combi boiler does not respond to a call for domestic hot water
(DWH).
• Domestic draw less than 0.5GPM
• Defective fl ow switch (LED inside fl ow switch will glow red
when it resonds to a call for DHW).
• Inlet and outlet connections reversed.
Combi boiler responds to a call for DHW, but hot water output
is inadequate.
• Draw rate is in excess of that shown in Table 2.2
• Inlet and/or manifold pressures incorrect (see Start-up
Section).
• Plate heat exchanger is fouled.
• DHW fi lter is dirty
Boiler responds to a call for heat, but room temperature never
gets high enough to satisfy room thermostat
• Air in radiation
• Inlet and/or manifold pressures incorrect (see Start-up
Section).
• No fl ow, or insuffi ent fl ow, through system.
• Boiler is undersized.
• Insuffi cient radiation
Boiler short cycles AND heat (or DHW) output is inadequate
• Flue gas recirculation into combustion air
• See causes for inadequate heat or DHW above