Rev 8/2014
PrecisionTemp, Inc • 11 Sunnybrook Drive • Cincinnati, Ohio, 45237 • 1-800-934-9690 •
fax 513-641-0733 20
PT-200FT (Flow Through) and PT-200OR
Design and Sequence of Operation
The PT-200 tankless gas booster heater is designed as an on-demand water heater that
ignites the burner when the ware washer rinse solenoid opens and water flows through
the booster.
The PT-200FT is designed to be installed close to the dish machine. The National
Sanitation Foundation stipulates that if a booster heater that is located further than five
feet from the dishmachine, then it requires a recirculation system be fitted. This system
recirculates the water between the outlet of the booster and the inlet to the dishmachine
to prevent temperature loss below the required 180°F. For further information, see the
page titled “PT-200RC (Recirculation) Design and Sequence of Operation”.
The sequence of operation is as follows:
•
Power is on, the power switch glows, and green LED on the control board flashes. The
digital temperature readout is not displaying.
•
The rinse solenoid of the warewasher opens and water flows through booster heater.
Note:
The next steps take place in 3-5 seconds.
•
The flow meter senses the water flow & sends a flow signal to the green control board.
•
The green control board sends 12v DC through the brown wire to the pressure differential
switch and on to the black solid-state relay that powers the power vent blower.
•
The relay closes the 110v AC contacts to start the blower.
•
Fluing is proofed by the clear vacuum tube that runs from the blower to the pressure
differential switch.
•
The pressure differential switch contacts close, sending 12v DC to the spark ignition
module via the grey wire.
•
The ignition module simultaneously affects a spark through the heavy yellow wire to the
spark ignition probe over the burner and sends 12v DC to the combination gas valve via
the blue wire. Ignition attempts lasts up to 5.5 seconds. The digital temperature read-out
displays the outlet temperature.
•
Ignition of the burner’s center element is effected and the flame is proofed and monitored
through the same yellow wire by the spark ignition module.
•
The green control board sends DC voltage to the modulating gas valve for one second to
effect flame cross-over to all burners.
•
The micro-processor on the green control board monitors water flow with the flow meter
and temperature with the three thermisters twice per second and varies voltage 0 – 22v
DC to the gas modulating valve, varying gas flow to burner in order to maintain constant
temperature output.
•
Burner remains lit as long as the rinse solenoid is open, but if flame is extinguished for
any reason, the gas valve will shut off in less than 1 second. Re-ignition will be
attempted.
•
When warewasher rinse solenoid closes and booster heater no longer senses flow, the
booster heater reverts to standby mode and digital temperature readout turns off.
