Raypak WH & P L W - Manual (Page 37)

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9. 24 VAC is sent to the low water cut-off (optional)
and the red power light is energized.
10. 24 VAC is applied to the blue power light located
on the diagnostic display board.
11. 24 VAC is also applied to the red LED safety shut-
down light on the front diagnostic board.
12. 24 VAC is applied to the alarm circuit (optional). If
the E-5 sales option (Alarm) is included a 5 sec-
ond time delay relay will not allow the alarm to
sound unless the circuit stays energized for more
than 5 seconds.
13. Power is applied to terminal P1-1 of the Universal
Diagnostics Board. All safeties are verified to
ensure that it is safe to operate the heater. The
safety components wired into the diagnostic board
are: low water cut-off (optional), blocked vent
switch, manual vent temp switch (optional), manu-
al reset high limit, low gas pressure switch (option-
al), high gas pressure switches (optional), and
auto-reset high limit (optional).
14. Power is applied to terminal TP-1 of the
Economaster II pump delay to energize the circuit
board.
15. Once all safeties have been verified to be closed,
a 24 VAC signal is output from pin P3-16 of the
Universal Diagnostic Board.
16. Relay K-1 (N.C.) will now be energized, and opens
the N.C. contacts to disable the alarm (optional)
and turn off the red safety shutdown light.
17. Pin P1-4 on the diagnostic board will now output a
24 VAC signal to pin 1 of the “standby switch”.
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. Power is applied to the coil of K-3. (If an ignition
lockout occurs, ignition module 1 closes contacts
allowing the 24VAC from K-3 to go to ground and
the K-3 contacts close to allow the unit to fire at
stage 3.)
20. After the standby switch is placed into the “ON”
position, a 24 VAC signal is sent to the
“enable/disable” connection (normally jumpered).
21. 24 VAC switched power is applied to the S24V ter-
minal on ignition modules 1 and 2.
22. 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.
23. When a CFH occurs, a 24 VAC signal is sent to the
CFH light on the diagnostics panel located on the
lower left front of the control compartment.
24. Power is now sent to terminal TP4 of the
Economaster II to energize the relay and close the
pump contacts.
25. The heater pump is energized.
26. Upon sufficient flow from the heater pump, the
flow switch contacts will close.
27. The flow light is energized; located on the diag-
nostics panel.
28. A 24 VAC signal is also sent to the “TH” terminal
located on ignition module 1 and to the N.O. con-
tacts of K-2 and K-3.
29. Once the 24 VAC “TH” signal is received, a 120
VAC signal is sent from F2 on ignition module 1 to
the 120 VAC pilot duty terminals, located at J-14
on the circuit board.
30. The 120 VAC signal continues to the coil of relay
K-4 (N.O.).
31. The 120 VAC signal continues to the 120 VAC
safety terminals located at J-13 on the circuit
board.
32. When the coil on relay K-4 (N.O.) is powered, the
relay contacts (K-4) close and energize the blow-
ers from the J-8 connections on the CPW board.
33. After proper air pressure is received in the air
plenum, the air pressure switches will close.
34. A 24 VAC signal is now sent to the blower LED’s
on the diagnostics board.
35. Power is applied to the optional equipment inter-
lock connection (normally jumpered).
36. The 24 VAC signal is then sent to the 24 VAC safe-
ty connector.