ULTRAFORCE COMMERCIAL GAS WATER HEATER
SUF 120 thru 400 SERVICE HANDBOOK

State Water Heaters – Technical Traini ng Department 21 Ashland City, Tennessee © 2009

Servicing should onl y be performed by a Qualified Service Agent 198152-002
CONTROL SEQUENCE FLOW CHART
Power on
Control dis plays
model,
temperature
setting and
status
The control
performs inter nal
system checks
and determines
tank temperature
is below set point
If checks are not
passed the
control will
display an error
or warning .
If all checks are
passed and there i s
a call for heat the
blower is energiz ed
for a pre purge
cycle
The control w ill
store an error
history t o show
what fault occurred
and the time
elapsed sinc e the
fault.
When the pre
purge is compl ete
power is appli ed to
the igniter for
Warm-up.
At the concl usion
of the igniter
warm up the gas
valve wi ll open for
4 seconds .
If the c ontrol
senses fl ame the
water heater w ill
fire until the set
point is reac hed.
If the cont rol fails
to see flame t he
blower will continue to
run for a 30 second
Inter purge . There will
be 3 trials for ignition
before a fault is
declared .
At the conc lusion
of the int er purge
the igniter will
warm and the gas
valve wil l open.
At the concl usion
of the heati ng
cycle the blower
will enter a post
purge cycle and
the control wi ll
enter an idle stat e.