TMG TMG-HW28, Product Manual

Page: 26 / 41

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