CGi Manual

Part Number 550-142-302/0520
CGi
SERIES 4 — GAS-FIRED WATER BOILER — Boiler Manual
37
Operation — sequence
9a
Department of Energy – Compliance
9
1. Read Operating instructions on page 41. This information
is also located on a label on the inside of the boiler jacket door
panel.
2. Raise room thermostat to call for heat.
a. While attempting to satisfy the heat demand, the
control module monitors the boiler temperature
changes via the water temperature sensor and deter-
mines whether or not the available hot water will
satisfy the demand, only running the circulator.
If additional heat is needed, the sequence continues.
When DHW (if used) calls for heat, sequence above
is bypassed.
3. Circulator energizes. If limit circuit is closed, the inducer
starts. After pressure switch proves proper airflow, control
module initiates 10-second prepurge.
4. Control module sparks the pilot and opens pilot valve in
main gas valve.
a. If pilot does not light within 15 seconds, pilot valve
is closed and spark generator is turned off. Control
module initiates a 15-second postpurge, then starts a
new cycle.
b. If pilot does light and control module senses flame
current, spark generator is turned off and main valve
opens.
5. During main burner operation:
a. Control module monitors pilot flame current. If signal
is lost, main valve closes, spark generator activates and
sequence returns to step 4.
b. If power is interrupted, control system shuts off pilot
and main gas valves and restarts at step 1 when power
is restored.
6. In the event the
limit control shuts down the boiler — The
control module closes the pilot and main gas valves, but keeps
the inducer operating for 15-second postpurge.
This boiler is equipped with a control system that automatically adjusts a time delay period to turn on the boiler
during a call for heat. This is accomplished by circulating available hot water in the system while measuring water
boiler water temperature changes. The control calculates a suitable delay based on temperature measurements
and turns the boiler on only after it determines that the demand for heat cannot be satisfied with the available hot
water.
Due to the wide variety of controls used in boiler installations, this control is also equipped with an adjustment
for the calculated time delay period (ECONOMY ADJUST). In the MIN position, the time delay is zero and the
IMPORTANT notice below must be observed:
IMPORTANT
In accordance with Section 325 (f) (3) of the Energy Policy and Conservation Act, this boiler is equipped with
a feature that saves energy by reducing the boiler water temperature as the heating load decreases. This feature
is equipped with an override which is provided primarily to permit the use of an external energy management
system that serves the same function.
THIS OVERRIDE MUST NOT BE USED UNLESS AT LEAST ONE OF THE FOLLOWING CONDITIONS IS TRUE:
• An external energy management system is installed that reduces the boiler water temperature as the heating load
decreases.
• This boiler is part of a modular or multiple boiler system having a total input of 300,000 BTU/hr or greater.
• This boiler is equipped with a tankless coil.