Curtis RU-150 Service Manual page 11

1. Remove pilot adjustment cap. Adjust pilot
key, allowing flame to completely envelop the
end ⅜" of the Thermocouple.
The Unitrol thermostat is built to the most ex-
acting standards and is a precision instrument
which should never need re-calibration. However
through tampering, misuse or other reasons, if
the thermostat is found to be more than 10º from
normal, a re-calibration may be performed by a
qualified service technician. The following are the
steps for this procedure:
1. Turn the thermostat to OFF to allow the unit to
cool down.
2. When the water temperature is room temper-
ature, turn the thermostat dial until the main
burner ignites.
3. Slowly, turn the thermostat dial counterclock-
wise until the flame on the burner goes out.
4. Place a thermometer into the water jacket to
determine the temperature of the water.
5. Pull off the thermostat dial and lift off the out-
side cover.
PROCEDURE FOR ADJUSTING PILOT
TO RE-CALIBRATE THE THERMOSTAT
2. Adjust pilot burner air shutter (if provided) to
obtain a soft blue flame.
6. Turn the temperature stop to correspond to
the actual water temperature. Mark the loca-
tion of the stop for reference.
7. Turn the stop slowly until the control snaps
off. Holding the stop to prevent rotation,
carefully loosen the stop adjustment nut (see
illustration above).
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