WIKA mw series User Manual

INSTRUCTION MANUAL
NI-221WE
Rev. 5 12/16
7 of 9
15 TROUBLESHOOTING
IMPORTANT NOTE: operations involving replacement of essential components must be carried out at our workshop, especially
for instruments with flameproof certificate; this is to guarantee the user the total and correct restoration of the product original
characteristics.
MALFUNCTION PROBABLE CAUSE REMEDY
Set point shift
 Permanent deformation of the sensitive element due
to fatigue or non-tolerated overages.
 Variation of the elastic features of the sensitive ele-
ment due to its chemical corrosion.
 O-ring wear (only MWH and MAH)
 Recalibrate or replace the sensitive element.
 Recalibrate or replace the sensitive element with
another made of a suitable material. If necessary
apply a fluid separator.
 Replace the piston subgroup and recalibrate.
Poor repeatability
 O-ring wear (only MWH and MAH)
 Air bubbles or condensation (only for types with pres-
sure <1 bar).
 Replace the piston subgroup and recalibrate.
 Drain the process connection line and if necessary
modify it.
Slow response
 Clogged or obstructed connection line.
 Root valve partially closed.
 Too viscous fluid.
 Check and clean line.
 Open valve.
 Provide instrument with suitable fluid separator.
No actuation or
undue actuation
 Root valve closed.
 Microswitch contacts damaged.
 Loosened electrical joints.
 Interrupted or short-circuited electrical line.
 Open the valve.
 Replace the Microswitch.
 Check all electrical joints.
 Check the conditions of the electrical line.
Undue actuation
 Accidental shocks or excessive mechanical vibra-
tions.
 Modify the mounting.
Fig. 17 – Mounting of the brackets for 2” pipe and possible position
Model MW, version MWB Model MW (not for version MWB)
Model MA
A – Process connection B – Electrical connection

WIKA mw series Specifications

General

Brand	WIKA
Model	mw series
Category	Switch
Language	English