I.C.E. HTDM Food Process Unit User Manual

Page 23

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VI. Tachometer Test Procedure

Old Style Tachometer Test (Pre 2000 units)

1. Insure that the sensor will be no further than ¼ “ from the

magnet when aligned

2. With magnet NOT aligned with the tachometer verify 5VDC between

red and black wires.

3. With magnet NOT aligned with the tachometer verify 5VDC between

white and black wires.

4. Rotate blower wheel until magnet is aligned with Tachometer


5. Verify 5VDC between red and black wires.
6. Verify 0VDC between white and black wires.

The tachometer sensor is polarity sensitive. Improper operation
can be caused from improper orientation of the magnet. If
problems continue remove and reverse the magnet and repeat the
above procedure

New Style Tachometer Test (Equipped on unit built in 2000-present)

Disconnect power to the combustion blower. Engage a heat cycle so
that the board locks out on an air proving error.

Verify approximately 5 VDC between terminals J2-17 and J2-18.

If voltage is not present disconnect all tachometer leads
from the board and recheck. If power is now present replace
the tachometer and verify wiring is correct. If power is

still absent replace the ICECON II controller and verify

Ensure that the magnet is not aligned with the end of the

tachometer. Approximately 5Vdc should be between J2-18 and

Rotate the combustion blower wheel until the magnet is

aligned with the tachometer. The voltage between J2-18 and
J2-16 should now be zero. If this is not the case check the
distance from the tachometer and the magnet. This space
should not exceed 1/8


of an inch. If required adjust to the

correct spacing. If the systems remain the same the magnet
will have to be remove and reversed as the tachometer is

polarity sensitive.