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Chapter 8. Service and Unit Replacement
The only component which calls for service is the pilot relay. When malfunctioning of the
pilot relay is suspected, service it as described below. If the pilot relay is found to be defective,
replace it with a new one.
If the meter body requires to be modified due to a specification change, application change
or due to failure contact your Azbil Corporation agent. If it is required that modifications
be done by yourself, order service tools and the service manual SM2-5220-0000 “PREX3000
KF-B Liquid Level Meters Detector Replacement Procedure”.
8-1. To replace the pilot relay
Remove the pilot relay by removing the three screws shown in Fig. 8-1.
If the gasket has deteriorated or has been damaged, replace it also when replacing the pilot
relay.
To install the pilot relay, place the gasket in the correct position, set the pilot relay on the
manifold by setting the guide pin at the bottom of the pilot relay to the guide hole, and tighten
the screws evenly.
8-2. To service the pilot relay
Remove the pilot relay as described in 1 above, service it as described below, and then install it
in its original position.
(a) Remove the three assembly screws (1) and nuts (19). (See Fig. 3-5.)
(b) Parts (3) to (17) will separate in sequence. It is not necessary to separate parts (2) to (6)
unless they are to be replaced.
(c) Clean metal parts with an approved solvent such as petroleum naphtha or Clorothene.
Depress the valve stem (2) against the conical spring (5) to allow the solvent to penetrate
through the seat which touches the port section of the valve stem.
(d) Examine the inner exhaust ring (13) and valve stem (2). If dirty, clean them with a clean
cloth. Do not use any solvent to clean them.
(e) Dry all parts thoroughly with clean compressed air.
(f) Replace diaphragm (16) and (11) if worn or damaged.
(g) Reassemble the pilot relay by rejoining all parts in order with assembly screws (1), and
nuts (19). Tighten the screws uniformly.
