Sequence Of Events - Rheem TRITON Service And Training Manual

Sequence of Events

Call for heat occurs when tank
temperature is below the set point by
the differential amount
E Does a heat
demand exist
Yes
Is the proof
of fan switch
open?
Yes
Is flame
Current ≥0.5µA
Detected?
No
Start the blower and
ramp up to purge
speed
Is the proof
of fan pressure
switch closed
Pre-purge
Yes
Pre ppurge is
17seconds
D Apply spark for 2
seconds
Open gas valve for
3.5 seconds
A
No
Set A008 – PoF
No Switch/Blower
mismatch
Set A027 – Flame
present before heating
Yes
(Requires power cycle
to reset)
Set A005 – PoF error
No
during pre-purge
When the ignition control opens the gas valve it first closes Gas
Valve Relay#1. If it does not sense the relay closed it will set T035
– Gas Relay #1 Stuck Open. The control will continue to try and
close this relay to satisfy heat demand. Gas Valve Relay #1 must
close before closure of Gas Valve Relay #2 is attempted. The T035
Alert will not prevent the combustion system from operating. Any
other Gas Valve Relay alarms (A036, A037, A038) will cause a
Fault condition and prevent combustion system operation
The Triton ignition control periodically run self check routines for hardware faults.
Any detected fault will lock out the unit and prevent combustion. It will check every
ours and if the condition clears it will return to normal operation. A power cycle may
also clear the condition. Hardware faults are detailed in the use and care manual
The presence of any "A0– series fault will prevent operation. If in a heating cycle
when the alarm occurs combustion will be stopped and the unit will lock out until the
condition is resolved.
The inlet pressure switch and the exhaust (flue) pressure switches are normally
closed switches. If either switch opens (>4 seconds) at any time the ignition
control will close the gas valve and stop combustion and set the appropriate alarm
code (A003 – Intake Switch Open and A007 – Exhaust Switch Open). The
blower will then run for 30 seconds. If the switch has closed the ignition control
will initiate a call for heat (unless heat demand was satisfied). If the switch is still
open after 30 seconds the blower is secured. If the switch closes and a heat
demand exists the control will initiate a call for heat. All pressure switch
operations require a 4 second persistency to be recognized by the control. The
proof of fan pressure switch is ignored by the control during ignition
Concerning the proof of fan switch behavior, if the pressure switch remains open
after the inducer has run 60 seconds, the control will de-energize the inducer for
30 seconds. After 30 seconds, the control verifies the pressure switch remains
open and re-energizes the inducer. If the pressure switch was found closed, the
control changes the fault code to stuck closed switch (A008) and waits indefinitely
for the pressure switch to open. This 60 second run / 30 second off shall continue
as long as a call for heat exists until the pressure switch is proven.
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