AW Gear Meters ZHM Series User Manual

ZHM Series Flow Meter Maintenance Guide

Cleaning, inspecting or repairing a ZHM Series gear flow meter is easily accomplished
by following the procedures below.

- Remove the Pickup (12) from the flow meter body (6). (The
model HESK1 sensor is shown here) Some models have a dual

sensor, IGO6HD-XX, which has 2 built-in pickups, and is
attached by two sunken, hex-head screws.

- Note index marks (14). If symbols are absent, mark the body positions.

- Loosen the hex bolts (7) with a 5 mm key wrench - ZHM-04/8mm,
ZHM 05+06/10mm, ZHM 07/14mm. Remove the bolts except for two
opposing bolts (7)which should remain engaged by a few threads to
avoid damaging the shaft when the 2 flow meter housings separate.

- Holding the upper housing (6), gently tap the opposing bolts (7) to
separate the lower housing (1). Do not use chisels or screwdrivers

to split or pry apart the housings - this may damage the carbide
parts.

- After separation, remove and inspect the gears (4) & shafts (3).
Clean with solvent and a small brush. The gears should revolve
freely on the shafts.

- After cleaning all parts completely, the gears & shafts can be
reinserted. Check for free and easy rotation.

- Replace the O-ring (5) if deformed.

- Keep meter housings parallel during reassembly. Both locating
pins must be in place (2). Align index marks (14).

- Replace hex bolts as follows:

ZHM 01-03 - 15 Nm. *(This is hand tight).
ZHM 04 - 75 Nm.
ZHM 05/06 -130 Nm.
ZHM 07 -300 Nm.

- Over tightening will not cause damage but may restrict
operation if internal surfaces are not completely clean.

- After reassembly - a brief air blast will spin the gears.
This should be clearly audible given a moderate
background noise level.

- Clean any debris from the pickup port, insert Hall Sensor
all the way, and then back off 1/4 revolution and tighten
lock nut. * Do not over tighten *

- With the dual sensor, the electrical connector should
point in the flow direction after reassembly. The sensor should
fit flush on the meter body with good hex screw alignment.

- Optional PTFE space fillers (10) are available to fill
space behind the conversion fittings when multi-colored
materials are being metered.

AW Gear Meters 8809 Industrial Drive, Franksville, WI 53126  web: www.awgearmeters.com

 Tel: [phone]  Fax: [phone]  Email: [e-mail]

REV. 03/09 ZHM.DOC

Cross Reference Guide for ZHM Series Spare Parts for ZHM Meters

1 - Lower Housing (303 Stainless Steel)* Pt.# LH-**

2 - Stainless Steel Locating Pins Pt.# LP
3 - Tungsten Carbide Shafts Pt.# ST-**
4 - Stainless Steel Gear* Pt.# GR-**
5 - O-ring

Pt.# COV-** Black FKM O-ring
COT-** White PTFE O-ring

6 - Upper Housing (303 Stainless Steel)*

Pt.# UH-**
7 - HEX Socket Cap Screw* Pt.# SC-**
8 - Port Adaptor/Conversion Fitting

Pt.# NPT-ZHM 01-03 12mm to 1/4" NPT

GRA-ZHM 01-03 12mm to 3/8" NPT

HEC-ZHM 01-03 12mm to 1/2" NPT

SAE-01-03 12mm to 3/4" SAE

NPT-ZHM 04 20mm to 3/4" NPT
NPT-ZHM 05 33mm to 1.0" NPT

9 - Crushable Aluminum Washer

Pt.# WAL-ZHM
10 - Teflon Space Filler

Pt.# SF-ZHM 01

SF-ZHM 02/1-03
11 - Lock Nut for Hall Sensor Pickup Pt.# LN
12 - Hall Sensor Pickup

Pt.# HESKS1 (For ZHM 01-04)

HESLS1 (For ZHM 04 & up)

HDSXS1 (Double Effect Sensor)
13 - 5 Pin Connector for HES & HD Sensors

Pt.# AMP-HES
14 - Index Marks that appear on the Upper and Lower

Housings. This is not a spare part.

* Standard material is 303 stainless steel. A special 316TI

alloy is available and is indicated after the part number as
follows: ZHM 02TI or GR 02TI.

** Indicates ZHM Series Flow Meter Size

AW Gear Meters 8809 Industrial Drive, Franksville, WI 53126  web: www.awgearmeters.com

 Tel: [phone]  Fax: [phone]  Email: [e-mail]

REV. 03/09 ZHM.DOC