Service; Sequence Of Operations - Honeywell WV4460E Installation Instructions Manual

WV4460E POWER VENT WATER HEATER CONTROLS
4. Dusty, wet, or corrosive environment. Since these
environments can cause the control to deteriorate
more rapidly, the system should be checked more
often.
The system should be replaced if:
a. It does not perform properly on checkout or
troubleshooting.
b. The control is likely to have operated for more
than 100,000 cycles.
c. The control has been flooded.
Sequence
1 Start-up
2 Flammable Vapor Check
0 Idle
1 Heat demand
2 Open pressure switch
3 Energize draft motor
4 Close Pressure switch
5 Energize pilot and spark igniter
6 De-energize spark igniter
7 Energize main gas valve
8 Wait 3 seconds to stabilize flame
9 Temperature reaches setpoint
10 De-energize the main and pilot gas valves The gas valves are de-energized.
11 Monitor Flame
12 De-energize draft motor
69-1872EF—01
Table 4. WV4460E Sequence of Operation.
Mode
Power Up
Heating Sequence

SERVICE

WARNING
Fire or Explosion Hazard
Can cause severe injury, death, or property
damage.
Do not disassemble the water heater control; it
contains no replaceable components. Attempted
disassembly or repair can damage the control.

Sequence of Operations

1. Follow the sequence of operation as shown in
Table 4.
Description
Upon Power up, the control runs a safe-start check of
RAM, ROM, and I/O with a typical start-up delay of 1-2
seconds.
To insure no outputs are energized if flammable vapors
are present, the control pre-loads a condition indicating
flammable vapors are present. If no vapors are really
present, then the control resumes normal operation with
no perceptible delays. If vapors are present, the control
will immediately perform the flammable vapor lockout.
Normal operation
The control receives a demand for heat (the temperature
is less than set point minus differential).
The control checks the pressure switch to insure that it is
open.
The induced draft motor is energized.
The control monitors the pressure switch until it closes.
The pilot valve and spark igniter are energized (after the
Prepurge time).
The igniter is de-energized (when flame is proved above
the "Igniter Off" level).
The main valve is energized (when flame is proved above
the "RUN" level).
Flame and Pressure Switch signals are ignored for 3
seconds after the main valve is energized (Flame
Stabilization Period).
The demand for heat is satisfied (temperature reaches
set point).
Flame is monitored until flame signal drops below Flame
Lost level.
The induced draft motor is de-energized (after the
Postpurge time).
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