Troubleshooting; Introduction; Testing Electronic Unit; Testing Sensing Element - Ametek Z-tron III Installation And Operating Istructions

Section 5:

Troubleshooting

5.1

Introduction

5.2

Testing Electronic Unit

5.3

Testing Sensing Element

The Z-tron III Level Control is a solid-state device with
no moving parts other than its relays, and requires no
maintenance or adjustments. The units are designed to give
years of unattended service.
A spare electronic chassis is recommended for every 10 units
so that, in case of a failed unit, a critical application will not
be delayed while the unit is returned to the factory for repair.
Use the following troubleshooting procedures to check out the
Z-tron III Level Control. If attempts to locate the difficulty
fail, notify your local Drexelbrook representative, or call the
factory direct at 1-800-527-6297 (US and Canada) or
+1 215-674-1234 (International).
It is recommended to begin with Electronic Unit:
1. Verify that voltage is reaching unit.
2. Change fail-safe selector switch (Fig 3-1). If LED does
not change state along with relays, Electronic Unit has
failed.
3. Remove power from unit, loosen hold-down screws , then
remove unit. Remove Blue screw from top of sensing
element & disconnect Red spade lug connector. SAFELY
reapply power.
4. As in Section 3.1, start with setpoint adjustment
in extreme counterclockwise (CCW) position, turn
screwdriver clockwise (CW) until relay just operates.
5. Rotate setpoint adjustment back and forth about this
point, observing travel of screwdriver between relay
pull-in and relay drop-out. If properly operating,
screwdriver should travel less than ¼ turn to operate
the relay. If not, Electric Unit has failed.
Be sure to first test Electronic Unit. Then:
1. Remove Electric Unit, as above, but do not apply power.
2. Use an analog ohmmeter
scale. Measure the resistances between each pair of
sensing element connections. See Figure 5-1.
Center Conductor to Housing
Center Conductor to Red Lug
Red Lug to Housing
13
Troubleshooting
that is set to the R x 1K ohm
1
__________ohms
__________ohms
__________ohms