The video above outlines the process in more detail. As our Gas instructor Sam goes through how to properly check the working pressure of a gas appliance, in this case a cooker. Below we have structed the steps in easy to follow parts.
What is working pressure?
Working pressure is the normal operating pressure to which a component is designed to operate continuously with a safe margin below the point at which the material will yield or burst. Also called design working pressure or maximum working pressure.
The first step is to connect a zeroed gas test gauge to the test nipple on the meter! A test point nipple is used to test gas pressures on a gas supply pipe. It's also used to test the tightness of the gas installation (leak test).
The next step as our instructor Sam demonstrates is to turn the gas supply on slowly, then take a reading from the gauge. When reading a gas test gauge, make sure that you look at both columns; the reading on both should be the same. If they a different, even slightly, reset the gauge by adjusting the zero adjuster or average the readings by adding them together and dividing them by two.
Now in this example we are using a household cooker to demonstrate this topic. On a cooker you should be testing the three biggest rings, so the next step is to light those up on the cooker itself. All other appliances will have their maximum rate determined by the manufacturer.
Next, check the reading on the gauge, the measurement will be in millibar which is a unit of air pressure in the metric system. In this example our instructor Sam gets a reading of 22.5 millibar for the working pressure.
Okay so now you have a reading from the Gas meter itself, you will turn off the appliance, turn the gas supply of slowly and then remove your testing equipment. As it is now time to check the working pressure from the appliance itself. The two reading should be similar, there's a small margin there to work with but no more than +1 or -1 on the reading.
Next, you will want to locate the testing point on the appliance. In this example, the cooker has only one test point located on the back side of the appliance. You'll want to remove the test nipple from this point and connect your test gauge.
Finally, you will want to turn your gas supply on at the meter and turn back on the appliance, in this case the three largest burners on the cooker. Once again, take a reading and ensure to check both sides, Sam gets a reading that is only 0.5 millibar different from the meter and the appliance, meaning that it is an acceptable pressure drop.
That's it, job done! You have now checked the working pressure at both points and can turn the appliance off, turn the gas supply down slowly and remove the test gauge. You can now place the test nipple back on and as Sam shows in the video check for any leaks.
Remember that conducting gas work without being registered with the Gas Safe Register is illegal. These tutorial videos are mainly for our training students as an extra resource to refer to whilst they continue on their training journey with us. If you would like some more information about the varies Gas training courses that we offer call us on 01322 280 202!