45. The Heater is now operating at full fire.
Models 989B–2339B
1.The black (hot) wire lead goes directly to the main power switch. This black toggle switch is located at the middle front of the control compartment.
2.When the main power switch is placed in the “ON” position, 120 VAC is applied to the 120 VAC termi- nal block on the circuit board and the 120/24 VAC transformer is powered.
3.120 VAC is waiting at the N.O. contacts of the pump delay relay.
4.Terminals L1 and F1 of the ignition module 1 are powered with 120VAC.
5.120 VAC power is also applied to the control power connector on the circuit board.
6.Terminals L1 and F1 of the ignition module 2 are powered with 120VAC
7.120 VAC power is waiting at relay contacts
8.The 120/24 VAC transformer outputs 24 VAC.
9.24 VAC is sent to power terminal L1 of the low water
10.24 VAC is applied to the red LED safety shutdown light on the front of the unit.
11.24 VAC is applied to the alarm circuit (optional). If the
12.Power is output from terminal
13.Once all safeties have been verified to be closed a 24 VAC signal is sent to pin
14.24 VAC power now leaves pin
15.Power is applied to terminal 24V of the pump delay relay to energize the timing circuit.
16.Relay
17.Terminal
18.The “standby switch” (rocker switch) located at the lower left front of the control compartment is now powered. If the switch is “ON” and there is no call for heat (CFH), the heater is in standby mode.
19.The “standby switch” (rocker switch) located at the lower left front of the control compartment is now powered. If the switch is “ON” and there is no call for heat (CFH), the heater is in standby mode.
20.Power is applied to the coil of
21.After the standby switch is placed into the “ON” position, a 24 VAC signal is sent to the “enable/disable” connection (normally jumpered).
22.24 VAC switched power is applied to the 24VAC terminals on ignition modules 1 and 2.
23.When the “enable/disable” contacts are closed, the 24 VAC signal travels to pin 1 of the stage 1 connection and waits for a CFH.
24.Power is now sent to terminal TRIG of the pump delay relay to energize it.
25.The heater pump is energized.
26.Upon sufficient flow from the heater pump, the flow switch contact will close.
27.A 24 VAC signal is now sent to the “TH” terminal located on ignition module 1 and to the N.O. con- tacts of
28.Once the 24 VAC “TH” signal is received, a 120 VAC signal is sent from F2 on ignition module 1 to
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