75
D. Two basic types of errors codes are shown on the
display:
1. Soft Lockout Codes – When a soft lockout occurs,
the boiler will shut down and the display will
alternate between the number “9” and the letter
“b” followed by a two digit service code. A list of
these codes, and their meanings, is shown in Table
29 in Section XIV Troubleshooting. The boiler will
automatically restart once the condition that caused
the lockout is corrected.
2. Hard Lockout Codes – When a hard lockout occurs,
the boiler will shut down and the display will ash
the letter “E” followed by a two digit service code.
A list of these codes, and their meanings, is shown
in Table 30 in Section XIV Troubleshooting. Once
the condition that caused the lockout is corrected,
the boiler will need to be manually reset using the
RESET button on the display.
Table 23: Boiler Status
First
Digit Boiler Status
0Burner off - No call for heat or DHW
1 Pre-purge or post-purge
2 Ignition
3 Burner responding to call for heat
4Burner responding to call for DHW
5 Checking air pressure switch
6 Burner off - Set point temperature has been reached
7 Call for heat ended. 10s heating post pump period
8Call for DHW ended. 10s DHW post pump period
9 and b
Flashing Burner off - on soft lockout. See Troubleshooting Section to
determine meaning of error code.
A Boiler responding to call from heating zone
HBurner on - Held in high re
LBurner on - Held in low re
E. If an outdoor sensor is installed, the boiler will
automatically adjust the heating zone set point
temperature based on the outdoor reset curve in Figure
51. The maximum set point is dened by parameter
4 (factory set to 180°F) when the outdoor temperature
is 0°F or below. The minimum set point temperature
shown is 100°F when the outdoor temperature is 60°F
or above. As the outdoor temperature falls the supply
water target temperature increases. For example,
if the outdoor air temperature is 30°F, the set point
temperature for the supply water is 140°F.
F. An indirect water heater thermostat can be connected
between terminals 2 and 4 on the terminal strip. When
this thermostat closes, the central heating circulator will
be turned off and the DHW circulator will be turned on.
G. An external limit control can be installed between
terminals 5 and 6 on the terminal strip. Be sure to
remove the jumper between terminals 5 and 6 when
adding an external limit control to the system. If the
external limit opens, the boiler will shut down and error
code “b 26” will be displayed. If the limit installed is
a manual reset type, it will need to be reset before the
boiler will operate.
H. The sequence of operation for a Alpine Series boiler
on a call for heat from a thermostat is as described
below:
1. When power is rst turned on, 120V is provided
to the MCBA, the combustion fan and the LWCO
transformer. A separate 50VA transformer,
connected directly to the MCBA, powers all other
low voltage circuits.
2. For the rst few seconds after power-up the control
module goes through a self check.
3. When there is a call for heat, the control module
checks to make sure the air pressure switch is
open. If it is, the combustion fan will be energized
and will ramp up to ignition speed. When the air
pressure switch closes, a 10 second prepurge is
activated.
4. After the prepurge, the control module energizes
the gas control valve and the spark for 4.5 seconds.
If a ame is established and proved, the control
allows the ame to stabilize for 5 seconds at the
combustion fan ignition speed setting. If the ame
fails to prove, the control module will attempt to
light the burner 4 more times. If a ame is still not
established, the control will lockout.
5. Once the ame stabilization period has ended,
the MCBA allows the burner to modulate. The
actual ring rate is dependent upon the measured
current and recent differences between the set point
temperature and the supply temperature. If an
outdoor sensor is connected to the control module
and the boiler is responding to a call for heat, the set
point temperature will be determined by the outdoor
reset curve shown in Figure 51.
6. Once the set point temperature is reached, the
MCBA will turn the burner off and allow the
combustion fan to operate in postpurge for 30
seconds before it turns off.
7. The central heating pump will continue to operate
until the room thermostat has been satised.
8. A demand for domestic hot water (DHW) is given
priority on Alpine Series boilers. If a call for DHW
is received while the boiler is responding to a call
for heat, the heating circulator is de-energized until
the call for DHW is satised.