Control Sequence Typical ALL Models | State Industries SUF100150

ULTRAFORCE COMMERCIAL GAS WATER HEATER

SUF 120 thru 400 SERVICE HANDBOOK

CONTROL SEQUENCE (TYPICAL ALL MODELS)

TYPICAL SEQUENCE

1.When the control is powered it should display “waiting for connection” and “UIM v2.06”*. The manufacturer and unit model will be next. The next display will include water temperature, temperature setting and heater status.

* This number may change as software revisions are made.

2. The control performed selected system diagnostic

checks immediately upon power up. This includes

confirming the proper state of the air/gas switches and

ECO limit device and powered anodes.

3. If the control determines that the actual water

temperature inside the tank is below the programmed

temperature set-point less the differential, a call for

heat is activated.

4. If all checks are successfully passed, the

combustion blower is energized for the pre-purge

cycle.

5. When the pre-purge cycle is complete, power is

applied to the igniter element for the igniter warm-up

period.

6. At the conclusion of the igniter warm-up period, the

gas valve will open, allowing gas to enter the burner

chamber.

7. The igniter will remain on for a short predetermined

10.The combustion blower will run for the duration of the post purge cycle to purge the system of all combustion gases. When the post purge cycle is complete, the blower is de-energized and will coast to a stop.

11.The control will now enter the idle state while continuing to monitor the internal tank water temperature and the state of other system devices. If the temperature drops below the set-point value less differential, the control will automatically return to step 2 and repeat the entire operating cycle.

time period, then will be turned off.

8. The control will monitor the flame sense probe to

confirm a flame is present. If a flame is not verified

within predetermined time period, the gas valve will

immediately be closed, and the blower will continue to

run for approximately 30 seconds inter-purge. The

control will try for ignition two more times before

lockout.

9. If a flame is confirmed, the control will enter the

heating mode where it will continue heating the tank

water until the set point temperature plus differential is

reached. At this point, the gas valve is closed and the

control enters the post-purge cycle.

Blow er icon

indicates

pow er to the

blow er

Check mark in the box indicates the blow er proving sw itch contacts are made

Flame icon indicates burner is ignited and that flame has been sensed.

State Water Heaters – Technical Training Department 20

Servicing should only be performed by a Qualified Service Agent

198152-002