Technical Service Bulletin - Silvan Australia

Technical Service Bulletin

Bulletin TSB-003-06 Category Comet Pump
Number Comet pump diagnosis
Distribution Silvan Account managers,
Subject Date Issued Silvan Dealers,
Silvan Dealer Service
Model All Comet Pumps Department

7/07/2006

Introduction

This bulletin is to assist Dealers understanding of the diagnosis of Comet Pumps

Description

Comet pumps are used on many of the Silvan Sprayers. In order to understand the
diagnosis of faults this service bulletin should be referred to

Action Required

Distribute to all relevant service personnel

Safety

As the pumps are used for spraying particular caution should be adhered to in relation to
cleaning and chemicals used by the Farmer. Proper safety protection such as gloves,
overalls and respirator must be used

Parts List

Refer to the Silvan parts CD for each particular pump parts required

Warranty Detail

Nil
.

Diagnosis

Diagnosis of faults with comet pumps can in most cases be traced to problems within the
spraying system that cause a pump failure. These faults can be traced to areas that can
adversely affect the operation of the pump.

Diagnosis continued

Chemical induction

Author: JR Page 1 6-Jul-06

Technical Service Bulletin

The more common faults of diaphragm failure can often be traced back to the type of
chemical used. As a rule any chemical that has hydrocarbons in its mix can cause
diaphragm failure. This is because hydrocarbons are un burnt petrol and rubber plus
hydrocarbons don’t mix.

There are other sprays that have a high concentration of sulphur again these chemicals are
not kind to rubber diaphragms.

With both of these types of chemicals it is vital that the sprayer is fully flushed when
operation cease for the day as it is not whilst the pump is running that the problem occurs
it is whilst the pump is stopped and the chemicals sit dormant on the diaphragms that the
problem of chemical ingress occurs.

Air Leaks Blocked Filters

Cases of split diaphragms can often be traced to air leaks or blocked filters as the comet
pumps are positive displacement pumps they need to have a clear flow of spray mix at
all times. Blocked filters or air leaks that restrict flow will allow the pump to overstretch
the diaphragms thereby causing tearing or splits this is due to the fact that air is easier to
compress than a solid fluid

Three Point Linkages

With three point linkage sprayers it is very important to ensure that the PTO length is
correct as the pumps can be severely damaged if this is not done. The reason for this is
that the PTO if not set will push on the pump thereby destroying the pump. This can be
seen as the plastic sight glass melts and there is a dark brown marking on the rear of the
crankcase. This can also be caused if the pump is kept running whilst the sprayer is lifted
to maximum height ( refer to operators manual for instruction on PTO shaft length)

Service

Service Of all Comet pumps should be completed after 350 hours of operation. This
includes changing oil using 20w/50 engine oil. Checking and replacing diaphragms as
required. Checking inlet and outlet valves. And general condition of mechanical
components.

Service information for bolt tension and oil quantities can be found in the Silvan Service
Manual

Author: JR Page 2 6-Jul-06

Technical Service Bulletin

Low or no pressure

¾ Split or damage diaphragms
¾ Leaking inlet or outlet valves
¾ Leaking hoses
¾ Blocked Filter
¾ Electrical faults with valves

Diaphragm Damage

¾ Oil contaminated with spray turns to a milky color
¾ Type of spray used
¾ Blocked filters or return lines
¾ Collapsed hoses
¾ Over revving above 540 rpm

High Oil Consumption

¾ Leaking seals
¾ Worn Diaphragms causing oil level drop as diaphragms wear
¾ Lack of service should be serviced every 350 hours

Pump failures TPL sprayers

¾ PTO Length not cut to appropriate length
¾ Running pump with sprayer at highest lift point
¾ Changing Tractors without checking the PTO length

Faults occurring after overhaul

¾ Tension of bolts not set accurately
¾ Diaphragms nor fitted properly bolts not tensioned or seated properly
¾ Wrong type of Diaphragm fitted e.g. Viton where required
¾ Wrong type of oil should be 10w/50 multigrade engine oil
¾ Hoses and fittings not checked prior to pump replacement
¾ Filters not renewed or cleaned on refitting of pump

Technical Support Group Page 3 6-Jul-06
Silvan Australia Pty Ltd
[email protected]
Phone +61 (0)3 9887 2788
Fax +61 (0)3 9800 2304

Author: JR

Technical Service Bulletin

Author: JR Page 4 6-Jul-06