Most spray machine problems — a sprayer not building pressure, a leaking cap, a clogged nozzle or a fogger that will not start — can be fixed in minutes with the right steps. Follow the guide below; if the machine still will not work, WhatsApp us a video or bring it to our Karachi shop.
01 · Knapsack or hand compression sprayer
Sprayer not building pressure
Symptoms
The pump handle moves freely with little resistance
Spray is weak or stops after a few seconds
You pump for a long time but the lance only dribbles
Likely causes
Tank filled to the top, leaving no air space to compress
Dry, worn or cracked pump cup / piston seal
Check valve (umbrella or ball valve) at the pump bottom jammed with sand or debris
Loose tank cap or damaged cap gasket letting air escape
Step-by-step fix
Depressurise the sprayer and empty any chemical into its proper container; rinse the tank with clean water.
Refill with clean water only to the fill line, leaving air space at the top — never fill to the brim.
Remove the pump assembly and inspect the pump cup or piston seal. If it is dry, lubricate it with non-water-soluble grease; if it is cracked or flattened, replace it.
Find the check valve at the bottom of the pump chamber. Rinse out sand and grit — unfiltered water is the most common cause — and replace the valve if it is deformed.
Check the tank cap gasket is seated flat and not twisted, then tighten the cap by hand.
Reassemble and test with water only: pump 10–15 strokes and check that pressure builds and holds.
Parts you may need: Pump cup / piston seal, Check valve (umbrella or ball), Cap gasket, Non-water-soluble grease.
Safety: Always depressurise and rinse the sprayer before opening it, and wear gloves if it held chemical.
When to bring it in: If pressure still does not build after replacing the cup and cleaning the valve, the pump cylinder may be scored — bring it to our shop.
Still not working? WhatsApp a video to +92 336 1839537 or bring it to our shop. Send a video
02 · Knapsack or hand compression sprayer
Sprayer loses pressure quickly or leaks at the cap or pump
Symptoms
Hissing from the cap or pump while spraying
Pressure drops within a minute of pumping
Liquid seeps from the pump base or around the cap
Likely causes
O-ring not seated in its groove
Cap gasket twisted, dried out or cracked
Dirt on the relief (safety) valve seat so it does not close fully
Cracked tank or pump chamber
Step-by-step fix
Depressurise, empty and rinse the sprayer.
Remove the cap and check the gasket: it should sit flat and be soft. Replace it if it is hard, cracked or stretched.
Check every O-ring on the pump and hose connections is seated fully in its groove; replace any that are flattened or nicked.
Remove the relief valve, clean the seat and spring with water and a soft brush, and refit it.
Refill with water, pressurise and brush soapy water over joints — bubbles show where air escapes.
Parts you may need: Cap gasket, O-ring kit, Relief valve (if damaged).
Safety: Never disable or tighten down the relief valve — it protects you from over-pressure.
When to bring it in: A cracked tank or pump chamber usually cannot be sealed safely; bring the sprayer in for a replacement part.
Still not working? WhatsApp a video to +92 336 1839537 or bring it to our shop. Send a video
03 · Any sprayer
Nozzle clogged or spraying unevenly
Symptoms
Spray pattern is streaky, one-sided or spitting
Only a thin jet comes out
Flow stops completely
Likely causes
Dried chemical or powder in the nozzle tip
Blocked lance or handle filter
Worn nozzle orifice
Step-by-step fix
Depressurise the sprayer before touching the nozzle.
Unscrew the nozzle and soak it in warm water for 10–15 minutes.
Clear the orifice with a soft brush or by blowing through it — never use a pin or wire, which enlarges the hole and ruins the pattern.
Remove and rinse the filters in the lance and handle.
Refit and test with water; replace the nozzle if the pattern is still uneven.
Parts you may need: Replacement nozzle tip, Lance / handle filter.
Safety: Wear gloves; nozzles and filters hold concentrated chemical residue.
When to bring it in: If the lance itself is blocked or bent, bring it in and we will clear or replace it.
Still not working? WhatsApp a video to +92 336 1839537 or bring it to our shop. Send a video
04 · Knapsack or hand sprayer
Lance or trigger drips when closed
Symptoms
Liquid drips from the nozzle after you release the trigger
Handle feels wet during use
Likely causes
Worn valve seal inside the trigger handle
Debris stuck on the valve seat
Loose handle-to-lance connection
Step-by-step fix
Depressurise and empty the sprayer.
Open the trigger handle following the manufacturer’s layout and remove the valve stem.
Clean the seat and stem; look for a flattened or cut seal.
Fit a new handle seal kit and re-tighten the lance connection with its washer in place.
Test with water under pressure.
Parts you may need: Trigger / handle seal kit, Lance washer.
Safety: A dripping lance puts chemical on your hands and legs — stop using it until it is fixed.
When to bring it in: If the handle body is cracked, bring it in for a replacement handle.
Still not working? WhatsApp a video to +92 336 1839537 or bring it to our shop. Send a video
05 · Motorised knapsack mist blower (2-stroke)
Mist blower won’t start
Symptoms
Engine does not fire when pulled
It fires briefly then stops
Strong smell of fuel (flooded)
Likely causes
Old or wrongly mixed fuel
Choke in the wrong position
Fouled or wrongly gapped spark plug
Clogged air filter
Flooded engine
Step-by-step fix
Drain old fuel and refill with fresh petrol mixed with 2-stroke oil at the ratio in your machine’s manual.
For a cold start, close the choke, pull until the engine fires, then open the choke.
Remove the spark plug, clean off carbon, and set the gap to the manual’s specification; replace it if the electrode is worn.
Clean or replace the air filter.
If flooded: open the choke fully, remove the plug, pull the starter several times to clear fuel, refit the plug and try again with the throttle open.
Parts you may need: Spark plug, Air filter, Fuel filter, Carburettor kit (if needed).
Safety: Refuel only when the engine is cold and away from flames; never start it indoors.
When to bring it in: If there is no spark with a new plug, or it still will not idle, the ignition coil or carburettor needs workshop service.
Still not working? WhatsApp a video to +92 336 1839537 or bring it to our shop. Send a video
06 · Thermal fogger (pulse-jet)
Thermal fogger won’t ignite or stalls
Symptoms
Pump runs but engine does not fire
Engine starts then dies
Irregular running noise
Likely causes
Weak or flat battery
Blocked fuel filter or fuel line
Leaking fuel-tank cap seal (no tank pressure)
Carbon build-up in the combustion chamber or resonator
Step-by-step fix
Charge or replace the battery and check its connections.
Check the fuel is correct for your model and clean the fuel filter.
Inspect the fuel-tank cap seal; a leak stops the tank pressurising, so fuel does not reach the carburettor.
With the machine cold, clean carbon from the combustion chamber and resonator following the manual’s instructions.
Start with the solution tap closed; open it only once the engine is running smoothly.
Parts you may need: Battery, Fuel filter, Tank cap seal, Spark plug (model-dependent).
Safety: Never work on a hot fogger — the resonator stays hot long after shutdown.
When to bring it in: If the engine still will not run smoothly after cleaning, bring it in for a full service.
Still not working? WhatsApp a video to +92 336 1839537 or bring it to our shop. Send a video
07 · Thermal fogger (pulse-jet)
Thermal fogger drips liquid or produces flame
Symptoms
Liquid dripping from the fog tube
Visible flame at the outlet
Wet, heavy fog instead of a fine one
Likely causes
Solution flow too high for the engine
Engine not fully warmed up before the solution tap was opened
Nozzle (dosage jet) too large for the formulation
Step-by-step fix
STOP: close the solution tap immediately and keep the engine running so the fog tube clears.
Let the engine run until it is fully warm and running evenly.
Fit a smaller dosage nozzle suited to your formulation and reopen the solution tap gradually.
Before shutdown, close the solution tap and let the machine run until no fog comes out.
Let the fogger cool completely before refilling — never refill a hot machine.
Parts you may need: Smaller dosage nozzle.
Safety: Flame from a fogger is a fire risk: keep a clear area, never fog near open flames and never refill while hot.
When to bring it in: If it still drips at a small nozzle size, the engine may be running weak — bring it in.
Still not working? WhatsApp a video to +92 336 1839537 or bring it to our shop. Send a video
08 · ULV cold fogger (electric)
ULV fogger runs but no mist comes out
Symptoms
Motor runs but nothing sprays
Mist is intermittent
Droplets are large and wet
Likely causes
Blocked flow line or nozzle
Flow control knob closed or stuck
Blocked tank vent creating a vacuum
Step-by-step fix
Switch off and unplug the machine.
Check the flow control knob is open and turns freely.
Remove the nozzle and flow line and flush them with clean water.
Clear the tank vent so air can replace the liquid being drawn out.
Test with water and adjust the flow knob to get a fine mist.
Parts you may need: Nozzle, Flow line / tubing.
Safety: Unplug before opening; keep water away from the motor housing.
When to bring it in: If the motor hums but the fan does not spin, the motor needs repair.
Still not working? WhatsApp a video to +92 336 1839537 or bring it to our shop. Send a video
09 · Termite injection / HTP power pump
Termite or HTP pump losing prime or pressure
Symptoms
Pressure gauge drops or fluctuates
Pump runs but does not draw liquid
Pulsing flow at the lance
Likely causes
Blocked suction strainer
Air leak on the suction hose or its clamps
Worn valves or piston seals
Low or dirty pump oil
Unloader valve set wrongly
Step-by-step fix
Stop the engine or motor and release pressure.
Clean the suction strainer and check the suction hose for cracks; tighten or replace clamps.
Prime the pump by filling the suction line with water before starting.
Check the oil level and condition; change it if it is milky or low.
Reset the unloader valve to the pressure your job needs, following the manual.
If pressure is still low, inspect the valves and piston seals for wear.
Parts you may need: Suction strainer, Hose clamps, Valve kit, Piston seal kit, Pump oil.
Safety: Release all pressure before opening any fitting; high-pressure jets can inject fluid through skin.
When to bring it in: Worn valves and seals need workshop replacement and pressure testing — bring the pump in.
Still not working? WhatsApp a video to +92 336 1839537 or bring it to our shop. Send a video
10 · Garden sprinkler / water pump
Garden water pump not starting or not pumping water
Symptoms
Motor hums but does not turn
Motor runs but no water comes out
Pump trips or overheats
Likely causes
Failed start capacitor
Impeller stuck after a long idle period
Leaking foot valve losing prime
Air in the suction line
Step-by-step fix
Switch off at the mains before touching the pump.
If it hums but does not turn, the start capacitor is often the fault — have it tested or replaced by a qualified person.
With power off, turn the shaft by hand (through the fan cover slot) to free a stuck impeller.
Prime the pump by filling the pump body and suction pipe with water.
Check the foot valve at the end of the suction pipe; clean it or replace it if it does not hold water.
Parts you may need: Start capacitor, Foot valve, Mechanical seal (if leaking).
Safety: Pumps run on mains power — switch off and unplug before any work.
When to bring it in: Burnt windings or a leaking mechanical seal need workshop repair.
Still not working? WhatsApp a video to +92 336 1839537 or bring it to our shop. Send a video
