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NOTE
The boiler / water heater
is equipped with a Frost
Protection feature. This
feature will operate the boiler
pump and the burner to help
protect the boiler / water
heater from freezing. If the
boiler / water heater is in
a hard lock-out condition
the burner will not operate,
however the boiler / water
heater pump will operate.
IBC is not responsible for
damages to the boiler, and/
or related components,
nor property damages that
may result from freezing
conditions.
2-6
DC SERIES BOILERS / WATER HEATERS DC 15-95, DC 15-96, DC 20-125, DC 33-160
2.7
SEQUENCE OF OPERATION
The boiler / water heater will operate in a similar way for both a space heating
and a domestic hot water call for heat. When the boiler / water heater is powered
up the controller enters a self diagnostic mode and displays 2 in the Service
Display.
The Sequence of Operation is as follows:
The boiler / water heater receives a call for heat from closing terminals X4.6
1.
and X4.7 (24 volts). The boiler / water heater can also receive a call from
Domestic Hot Water heating from the internal flow sensor, or from a 10KΩ
sensor or aquastat (X4.9 and X4.10 in 24V terminal).
2.
The boiler / water heater does a safety check and energizes the fan for a pre-
purge (Service Display = 3)
Once the 5 second pre-purge is compete, the boiler / water heater enters a 5
3.
second trial for ignition (Service Display = 4). If the boiler / water heater fails
to ignite, the boiler / water heater will compete a 5 second inter-purge then
another 5 second trial for ignition. This is repeated 4 times before a hard lock
out occurs. The Reset button
and allow for another attempt.
Once the burner is lit and flame has been proven the boiler / water heater
4.
operates as it is programmed (Service Display = 5 for Space Heating or 6 for
Domestic Hot Water)
If the boiler / water heater reaches its target temperature and there is still a
5.
call for heat or hot water. (Service Display = 1)
After the call for heat is satisfied, the boiler / water heater pump will operate
6.
for an adjustable amount of time (Service Display = 0)
7.
If the burner is on to maintain the heat exchanger temperature for DHW
Comfort mode or for Freeze Protection mode (Service Display = 7)
If the burner is on for Frost Protection (Service Display = 9)
8.
MAIN
DISPLAY
[Pressure
e.g., 14 P]
(blank)
XXX
XXX
XXX
XXX
XXX
XXX
XXX
XXX
Table 9: Operating Display and Service Display Codes.
must be pressed to reset the controller
SERVICE
DESCRIPTION
DISPLAY
-
The boiler / water heater is OFF. Press the On/Off
button to turn on the boiler
(blank)
No Call for Heat - Standby
0
Boiler / water heater pump running – pump post purge
1
Boiler / water heater water temperature reached target –
boiler / water heater pump is energized, call for heat still
present
2
Self-test – When power is applied to the boiler / water
heater the controller enters a self diagnostic mode for 5
seconds
3
Fan Pre-purge , Inter-purge and Post-purge
4
Trial for Ignition and Flame Proving
5
Heating – Space Heating
6
Heating – DHW
7
Burner on for Comfort mode or Freeze Protection mode
INSTALLATION AND OPERATION INSTRUCTIONS
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