Ralston Instruments QTHP 5000 psi Hand Pump Operation Instructions

Operation Instructions 5000 psi Hand Pump (Model QTHP)





Add Fluid

1. Remove the Vent Plug at the top of the Fluid Chamber

2. Add fluid to the Fluid Chamber

Acceptable fluids: Ralston Calibration Oil, mineral oil, transmission fluid, water, or alcohol.

Remove the vent plug and add around 2 inches of fluid, or enough fluid to keep the bottom of the fluid reservoir covered even when the hand pump is tilted in your hand.



3. Reattach the Vent Plug.


Make your connections

Your goal is to establish leak-proof connections between your pressure source (your hand pump), your reference gauge, and the device or system that is about to be tested.

1. Connect your reference gauge to the top of of the hand pump

The readings on your reference gauge are the source of truth for your test. Your reference gauge should be four times more accurate than the device, or system, under test.

Connect your reference gauge directly to the port at the top of the hand pump, OR if you're using a Quick-test hose: Connect one end to the top of the hand pump the other end to your reference gauge.

2. Connect a Quick-test hose to the outlet port of the pump

The outlet port of the hand pump connects to the device or system you are going to test so that you can apply the desired amount of pressure. 


3. Connect the other end of the Quick-test hose to the Device Under Test.


Prime the Hand Pump

Priming the pump properly will force all air out of the closed system before you begin your test and ensure stability in your readings.

1. Open the Bleed Valve


2. Squeeze the pump handles until no air bubble appear in the fluid 

With the vent valve open, squeeze the pump handles until no air bubbles are visible rising in the fluid from the fluid return hole at the inside-bottom of the fluid reservoir. Squeezing the hand pump handles with the vent valve open will force out all the air in your closed system. Removing all air from your closed system will ensure stable readings during the course of your test.


3. Close the Bleed Valve

Once squeezing the hand pump handles doesn't produce any observable bubbles in the fluid, close off the system by tightening the bleed valve.

Check for leaks in the closed system

1. Squeeze the pump handles until your reference gauge is close to the first target test pressure.

2. Use the fine adjust knob to dial the pressure in until the reference gauge displays the exact pressure you wish to record.


3. Wait one minute. 

If your reference gauge hasn't reflected a loss in pressure after one minute, you can begin your test.





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