Q: How many kPa in a Bar?
A: 100kPa = 1 Bar

Q: Why is my gauge pointer off zero?
A: The gauge may have been dropped or over pressured.

Q: Why is my liquid filled gauges pointer off zero?
A: Pressure build up in the cast - to fix relieve pressure by removing and reinserting the rubber bung at the top of the gauge.

Q: My unloader on my pressure switch continuously leaks - Why?
A: Unloader leaks are usually caused by a faulty check valve.

Q: Why are gauges filled with liquid?
A: To avoid early fatigue from vibration or to dampen the indication due to pulsating pressure.

Q: What is the maximum temperature that my gauge can be used at?
A: Gauges should not be exposed to excessive heat or cold, as this may cause them to indicate incorrectly. Working fluids at a temperature above 60°C should not be allowed to enter the gauge. Remember - if a gauge shank cannot be grasped by hand without discomfort, it is working at too high a temperature. (AS1349-1986)

Q: Do you have any Operating and Maintenance instructions for Ametek Lamb Bypass Vacuum Motor?
A: Click Here to download instructions

Q: How do I obtain flow capacities for ASME safety valves?
A: The flow capacity charts for all of our ASME safety valves are shown under the Products section of our web page.

Q: How do I set my LGM, P25 or P25V to my desired pressure settings?
A: Cut-out pressures are adjustable from 60 PSI to 250 PSI with the standard silver spring.  The differential (difference between cut-out and cut-in pressures) is typically set at the factory at roughly 15% of the cut-out pressure.  This is usually a suitable differential and will not normally need to be re-adjusted.  Adjustment Procedure (refer to Figure 1):

  1. Loosen only range screw jam nut

  2. Turn range screw clockwise to raise cut-out and cut-in pressure levels and counter clockwise to decrease cut-out and cut-in levels.

  3. Start compressor and note cut-out and cut-in pressures.  Make adjustments as necessary using range screw and, when acceptable, tighten range screw jam nut.  Proceed as follows, only if it is necessary to make a differential adjustment.

  4. Adjust the cut-in pressure to the desired level per Steps 1 through 3 as above.

  5. Loosen differential screw jam nut and turn differential screw clockwise to raise cut-out pressure and counter clockwise to decrease the cut-out pressure.  Tighten differential screw jam nut when the desired cut-out pressure is set.  Since Step 5 should not change the desired cut-in pressure set in Step 4, the adjustment is now complete.


Q: Which pilot valve or unloader is right for my system?
A: We offer a wide range of pilot valves and unloading valves for many applications:

Pilot Valve
The P25 valve is an adjustable pilot valve with a ¼” NPT inlet and an ¨û” NPT outlet port which can be used to pilot head unloaders or used with a throttle control to slow down the engine during cut-out.  The P25 pilot valve has a 3/8-16 UNC mounting boss, and comes standard with an unloading sleeve for gas engine warm up.  Options include a toggle for one hand unloading, a lock out thumbscrew for dual systems control, and a ¼” nipple for the inlet.  Refer to the Pilot Valve section of our Products web page for details on the cut-in and cut-out ranges.

Venting Pilot Valve
The P25V unloader incorporates all of the P25 options along with a vent valve to unload the compressor discharge after cut-out.  The vent valve on the P25 has a ¼” compression fitting which must be connected to the compressor discharge line.  The P25V offers all of the same options as the P25, except for the mounting boss.

Venting Unloader with Check Valve
We offer a complete line of self-contained Continuous Run Vent unloaders.  These valves incorporate an adjustable pilot valve, vent unloader, and check valve that perform all of the functions required for continuous run compressors.  Options include a ¨û” NPT tapped port for throttle control as a gas engine, a toggle unloading lever for one-hand warm up, and a vent port muffler.  Depending on flow and space requirements, we offer the Mark II, Mark III and Mark IV series of valves.  Visit the Products section of our web site to find out which valve is right for you.

Q: What is the difference between a safety valve and a relief valve?
A: We offer two standard types of pressure relief devices for air:

  • A safety relief valve, or pop-off valve, is set to pre-determined pressure using a spring force to counteract the air pressure force.  When the force created from the air pressure becomes greater than the spring force, the valve 'pops' fully open and vents air to the atmosphere.  Safety relief valves are sized in such a manner that the valve will always have a greater flow capacity than the source creating the air pressure (i.e. an air compressor).  The valve will remain open until a reseat pressure is reached.  This reseat pressure varies with valve type and is usually between 35% to 75% of the set pressure.  Control Devices have eight series of valves that are manufactured in accordance with Section VIII of the ASME Boiler and Pressure Vessel Code.  Control Devices also manufacture a wide range of non-code valves.  See our Products section for information on the valve types.
  • A relief valve is set to a pre-determined pressure with a spring force counteracting the force created by the pressure from the air.  When the force created from the pressure of the air becomes greater than the force of the spring, the valve will start to open and flow to atmosphere.  As the pressure continues to increase, the valve will open further, allowing more flow.  As the pressure decreases, the valve will close near the pressure at which it opened.


Q: What is HACCP    (Hazard Analysis Critical Control Points)

A: After all, you would not cross a busy road without taking adequate precautions for your safety.  A busy road is a hazard; a hazard is the potential to cause harm, therefore we should take the necessary measures to minimise (control) the risk of being run over.  Controlling a risk will not always eliminate it, but it will reduce the chances of someone getting hurt.  If you substitute roads for food you have a similar scenario.

HACCP was originally developed by NASA in the US, for astronauts.  The thought of someone suffering food poisoning symptoms, while travelling in space in weightless conditions confined with others in a small capsule does not bear thinking about.  It was therefore decided that random quality control testing at the end of production was not a sufficiently safe system.

HACCP is a system that was devised to provide quality assurance throughout the process of food manufacture by establishing critical monitoring (control) points.  This system aims to ensure the safety of the food from farm to plate.  Although HACCP in its full form is mainly used in the manufacturing industry, a slightly 'watered down' version called Hazard Analysis, has been set out in the Food Safety (General Food Hygiene) Regulations 1995 and is now a legal requirement for all food businesses.  New regulations will come into force on 1st January 2006 internationally and will require all food businesses to implement a documented HACCP system or a system based on HACCP principles after this date. 

The seven principles of HACCP: 

  1. Conduct a Hazard Analysis - identify the food safety hazards associated with your business, e.g. multiplication of harmful bacteria.

  2. Determine the Critical Control Points - if there is no later stage in the process that will then make the food safe, e.g. cooking, then it is a CCP.  An easy way to do this is to ask the question "What if?"

  3. Establish Critical Limits - temperature limits, below or above which food will not be acceptable.

  4. Monitor and Control the CCPs - if it cannot be monitored or measured, it is not a CCP.  You cannot monitor by sticking a hand in the fridge or looking at a food to say it is OK.

  5. Establish Correct Actions - If a Critical Limit is exceeded, you must have a procedure in place to take remedial action, i.e. increase cooking time, lower fridge temperatures etc.

  6. Establish Verification Procedures - how do you know that your temperatures are OK, unless you regularly calibrate your thermometer?  Just one example of verification. 

  7. Documenting Records and Procedures - having gone through the whole process of HACCP, you will find it difficult to demonstrate your controls, unless you keep records of your actions.

 Q: How do I make an Ice Slurry?
 A: Click here to download instructions

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