Lafferty Equipment Manufacturing, Inc.

Installation & Operation Instructions

Model # 925737 · 37.4 Gallon Internal Tank Sprayer


Ready-to-Use Chemical Solution
Compressed Air up to 3 CFM
Minimum Air Supply Line 3/8"
Hose 1/2" ID x 50'
Nozzle 2503 or 2506


Stainless Steel Hose Racks
Large Stainless Steel Hose Rack# 224150
Proportioning / Filling Options
1-Way Ball Valve Mixing Station (4 GPM)# 985100
1-Way Push Lever Mixing Station (4 GPM)# 981100
High Volume Mixing Station (9.9 GPM)# 985835
Alternate Check Valves & Seals (EPDM Standard)
Check Valve, Air, SS, 1/4" MM (Viton / Hast)# 491306
O-Ring, Viton, Tank Lid, 5, 16 & 37 Gallon, ASME# 708513

Weight & Dimensions

Single Package
Shipping Weight201 lbs.
Shipping Dimensions48" x 40" x 54"
Ships on a pallet
Warning! Read All Instructions Before Using Equipment!


The 37.4 Gallon Internal Tank Sprayer is a chemical spray applicator with an all stainless steel cart assembly for applying ready-to-use chemical solutions to a variety of surfaces. Connect compressed air to pressurize the 316L stainless steel ASME rated tank and project the solution through the hose, wand and fan pattern spray nozzle. Includes 2 spray nozzles which provide either 51 or 110 minutes of spraying time depending on the nozzle used.

Safety & Operational Precautions

  • Manufacturer assumes no liability for the use or misuse of this unit.
  • Wear protective clothing, gloves and eye wear when working with chemicals.
  • Always direct the discharge away from people and electrical devices.
  • Carefully follow chemical manufacturer's safe handling instructions and recommended precautions/practices especially when using flammable chemicals.
  • MAXIMUM PRESSURE for air regulator IS 73 PSI. Pop-off valve is set for 75 PSI.
Do Not Use any chemicals that are not compatible with 316L stainless steel, each other or that could off gas. Including hydrochloric (muriatic) acid, hydrofluoric acid, aluminum brighteners, or paint strippers.

To Install (refer to diagram on next page)

  • This unit has been preset and tested. Use as is before making any adjustments.
  • The air regulator controls the tank pressure and is preset at 60 PSI. This is the optimal pressure.MAXIMUM PRESSURE IS 73 PSI. Pop-off valve is set for 75 PSI.
  • Tank pressure can be changed by adjusting this air regulator. Clockwise for more pressure, counter-clockwise for less.
  • Two spray nozzles are provided to control the volume of spray. Try both to see which one is best for your application.. 
  1. Always pull up on the pop-off valve to check for and relieve pressure in the tank before trying to remove the lid!
  2. Pull wire handle up to unlock the tank lid. Then remove the lid from the tank, making sure the "O" ring remains attached to the lid. Fill tank with chemical solution.
  3. Replace the tank lid, making sure the "O" ring seats properly. Lock wire handle in place.
  4. Make sure the discharge ball valve is closed.
  5. Make sure the air ball valve is closed. Connect a compressed air line (3/8" I.D. minimum) to the inlet ball valve.

To Operate

  1. Open the air ball valve. Allow time for pressure to build up.
  2. While firmly holding the wand, point the discharge away from yourself and others. Then, open the discharge ball valve and begin application.
  3. When application is completed, close the discharge ball valve. Return to the unit and close the air ball valve.
  4. Rinse before the spray dries.
  1. Turn off the air supply by closing the air ball valve.
  2. Pull up the ring on the pop-off pressure relief valve and/or open the discharge ball valve to relieve pressure completely.
  3. Refill the tank, when necessary, with chemical solution from optional Mixing Station, using the procedure in "TO PREPARE TO OPERATE" steps 1 - 4.
Troubleshooting Guide
Problem Possible Cause / Solution
A) Weak or no spray coming out
B) Pop-off valve going off continuously
C) Cleaning / application results not acceptable
1, 3, 4, 6
5, 7, 8

Possible Cause / Solution
  1. Air adjustment too low
    • Open air ball valve fully. Adjust air regulator clockwise to a maximum of 70 PSI.
  2. Air pressure too high.
    • Adjust the air regulator to a maximum of 70 PSI.
  3. Lid o-ring not sealing properly
    • Relieve pressure and re-seat o-ring
  4. Chemical concentration too weak
    • Increase chemical concentration
  1. Air regulator clogged or failed
    • Clean or replace air regulator.
  2. Air check valve clogged or failed
    • Clean or replace the air check valve.
  3. Pop-Off Valve clogged or failed
    • Clean or replace
  4. Tank is empty (no solution)
    • Follow refill tank procedure.
  5. Tank o-ring not seated, missing or worn
    • Realign, clean or replace
  6. Soil has hardened on surface
    • Reapplication may be necessary. Always rinse before solution dries.
PREVENTIVE MAINTENANCE: When the unit will be out of service for extended periods, place chemical tube(s) in water and flush the chemical out of the unit to help prevent chemical from drying out and causing build-up. Periodically check and clean chemical strainer and replace if missing.