TMG -HW41T Product Manual page 26

PROBLEM
Very low or no flow
Unloader will not unload
Unloader (flow) cycles
with system under
pressure
Unloader (flow) cycles
with system in bypass
Unloader (pressure)
produces smooth flow &
low volume
Unloader (flow) produces
smooth flow & lowvolume
WW W . T M G I ND U S T R I A L . C O M
FLUID SYSTEM DIAGNOSTICS - Unloader
POSSIBLE CAUSE
Unloader stuck in bypass
Debris in unloader
Sever leak on the outlet of unit
Improper flow
Nozzle to small
Nozzle clogged
Improper unloader orifice
Unloader orifice clogged
Injector orifice clogged
Other downstream restriction
Pump not delivering the rated
pressure
High water supply pressure
No restrictions on the unloader
Downstream leakage (excessive)
Accumulator downstream (option)
Unloader adjusted too low
Spray nozzle clogged
Spray nozzle too small
Injector orifice blocked
System not delivering rated flow
Unloader adjusted too low
Unloader valve stuck inbypass
Restriction in system
SOLUTION
Isolate the flow problem. If it occurs before the unloader
discharge point, check the piston
assembly to see if it is fouled or stuck in bypass mode.
Take bottom nut off unloader, identify ball, spring and
seat. Clean out any debris and
Check for leaks and repair.
Any variation in flow form what the orifice is sized can
cause cycling. System must produce the
rated flowconstantly.
A nozzle that is too small can cause the flow to be
reduced.
A distorted spray pattern indicates a clogged nozzle.
The systems rated output should indicate the proper
sized orifice for your system.
Check the orifice for clogs and clear out any debris.
If the system has a Venturi injector downstream of the
unloader, check the orifice for clogs.
Scale buildup can restrict flow. Check; controls, valves,
switches, trigger gun, and lance.
Descale as necessary and begin preventive maintenance
program for scale prevention.
See low pressure or low flow diagnostics.
Check inlet water supply for excessive pressure.
Check unloader bypass port to see if a flow restrictor is
properly installed. Install one if none is present.
Causes the unloader to since a continuing flow and divert
it to the closed gun. Repair or replace.
Remove the accumulator from the system.
Adjust the unloader using the pressure gauge for the
correct pressure.
A distorted spray pattern indicates a clogged nozzle.
A small nozzle causes a reduced flow and cycling may
result.
If the system has a Venturi injector downstream of the
unloader, check the orifice for clogs.
See flowdiagnostics.
Adjust unloader and regulator until proper pressure is
achieved.
If unloader is sticking, repair or replace as necessary.
Downstream restrictions can cause a reduction in flow.
Check; controls, valves, switches, trigger gun, and lance.
Descale as necessary and begin preventive maintenance
program for scale prevention.
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