Raypak VERSA IC, Installation & Operating Instructions Manual

Page: 49 / 80

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11. The VERSA IC
®
Control will turn on the system,
boiler and/or DHW pump as necessary to address
the call-for-heat. This is dependent on the Mode
of operation selected. The pumps will proceed
through their purge period before the control will
move into a Trial for Ignition (TFI). For systems
with CWP enabled, the MIX output is sent to the
MIX MIN % value.
12. The VERSA
®
Control Board and PIM™ check the
safety circuit and will stop from going into a trial for
ignition if any of the safety devices is in an
error/fault condition.
13. If no fault condition is found, the air pressure
switch (if present) is verified to be in the open posi-
tion before the blower is energized.
14. The blower(s) are energized and set to pre-purge
speed (if modulating).
15. The air pressure switch is verified to close within
60 seconds to prove air flow.
16. Once the air pressure switch closes (or the blower
speed is acknowledged as operating at the pre-
purge speed by the tachometer output), the blower
proceeds to pre-purge for the specified duration.
17. The voltage level of the 24VAC supply input is
confirmed to be above 18.0VAC – if not, a Low
Voltage fault will be recorded and the heater will
go into a soft lockout condition until the voltage
rises above 18.0VAC consistently.
18. If all checks have passed, the system proceeds to
ignition.
19. The PIM™ re-initializes the ignition counter to the
configured number of trials (typically 1 or 3).
20. The Hi Limit sensor is confirmed to read below the
Hi Limit setpoint.
21. The blower light-off RPM speed (modulating blow-
ers only) is verified.
22. The gas valve relay contacts are verified open – if
closed, a fault code will be issued and the heater
will post-purge and go into a hard lockout condi-
tion.
23. On heaters equipped with a Hot Surface Igniter:
a. The control turns on the HSI and the HSI prov-
ing current is verified to be above the
configured value.
b. The configured heat-up delay takes place to
allow the HSI element to reach ignition tem-
perature.
c. The gas valve output is energized for the trial-
for-ignition time to light the burner.
d. The HSI is de-energized during the last sec-
ond of the trial-for-ignition period to sense for
the burner flame.
e. The flame sense is checked for successful
lighting of the burner. If a valid flame is detect-
ed, the main gas valve, operating pumps and
blower relay remain energized and the PIM™
proceeds to the Heating mode. For systems
with CWP enabled, the MIX output is released
to its control point based on distance from Inlet
temperature target
24. On heaters equipped with a Direct Spark Igniter:
a. The DSI igniter (high voltage spark output) is
energized.
b. The gas valve output is energized for the trial-
for-ignition time to light the burner.
c. The flame sense is checked for successful
lighting of the burner. If a valid flame is detect-
ed, the sparking is terminated, the main gas
valve, operating pumps and blower relay
remain energized and the PIM™ proceeds to
the Heating mode. For systems with CWP
enabled, the MIX output is released to its con-
trol point based on distance from Inlet
temperature target
25. If flame is not detected during the trial-for-ignition
period, the gas valve output is disabled immedi-
ately and the blower goes to a post-purge.
26. On single trial-for-ignition models, the PIM™
enters ignition lockout and the LED on the PIM™
indicates the fault code for ignition lockout. The
VERSA IC
®
Display should also state Ignition
Lockout.
27. On multi-trial-for-ignition models, the control goes
through an interpurge delay before additional igni-
tion attempts are started. If no flame is detected
after the final trial-for-ignition, the PIM™ enters
ignition lockout and the LED on the PIM™ indi-
cates the fault code for ignition lockout. The
VERSA IC
®
Display should also state Ignition
Lockout.