My gas supply is disrupted
What to check if no gas is coming from your gas supply
There are a few simple checks to carry out which allow you to determine and possibly correct the problem. Please carry them out in the order listed. While this section is based on LPG tanks, the procedure for a cylinder supply is similar. Before you continue, make sure that you have turned off all burners that do not have flame-failure devices fitted - in particular, make sure all cooker and grill taps are in the off position.
1) Check that the tank is not empty
On the vast majority of tanks, the contents gauge is on the top of the tank facing upwards (do not confuse it with the other gauge on the tank, a pressure gauge, which is screwed into the valve that your gas supply pipe is connected to and is shown in the next photo). The contents gauge is graduated in percentages, and 5% or less means that it is empty.
If, instead of a bulk tank, you have cylinders connected to an automatic changeover regulator, the regulator will usually display a red indicator if the bank of cylinders is empty. They have a knob which you can turn to get it to operate from the reserve bank - if it also shows red in this position, you are out of gas (or the cylinders are turned off).
2) Check that the isolation valves are not turned off
There are usually two, one is at the tank - your gas supply pipe is screwed into this valve. It works similarly to an ordinary water tap - turn it clockwise to turn it off and anticlockwise to turn it on. The picture shows a service valve with a pressure gauge (which is usually but not always fitted).
There is usually a second valve on the outside of your premises, close to where the gas supply pipe enters your building - this is a quarter-turn valve, make sure it is also in the on position (the photo shows it in the on position, when it is in the off position the handle is perpendicular to the pipe).
Cylinder installations often have an isolation valve on the pipework between the cylinders and where the pipe enters the house, in addition to the cylinder valves, which operate similar to a tank service valve.
3) Check that the excess-flow valve in the tank is not engaged
This should not normally happen, but it may arise if (a) the tank was empty and then filled or (b) an isolation valve was turned off for an extended period or to carry out work on the pipework. The service valve on the tank (to which the pipework is connected) has an internal safety device called an excess-flow valve which reduces the supply to a trickle if there is a sudden surge of gas. This prevents a large leak if, for example, the pipework is broken by vandals. To check and reset it:
- Turn off all gas appliances. It is usually impossible to re-pressurise the system if there are appliances trying to draw gas from the system.
- Turn the service valve off and wait 15 seconds. If you hear a small click sound, this is the excess-flow valve releasing itself into the open position, so continue with the rest of this procedure. If you do not hear a click, then this was not your problem, so open the service valve fully and check for another problem.
- Open the valve one sixth of a turn - you should hear gas flowing through the system. Wait until the gas has pressurised (filled up) the system, when the flow will stop. If you hear a small click and/or the flow stopping during this, it is the excess flow valve shutting off again - repeat the procedure from the start, but do not open the valve quite so much the next time.
- When the flow stops, indicating that the gas has fully pressurised the system, slowly open the service valve fully.
Some cylinder installations have similar excess flow valves located in the ends of the hoses. To get these to open, turn off all appliances and wait about 15 minutes for the valves to open.
Note that these excess-flow valves will usually open themselves anyway if they are left for long enough, because they incorporate a small bleed hole which should eventually re-pressurise the system.
4) Check that the regulator is not locked out
Some systems are fitted with low and/or high pressure lockout devices as part of one of the regulators (typically domestic central heating systems and small domestric/industrial systems). These typically lock out if the tank is allowed to go empty.
5) I still have a problem
Make sure you really have a gas supply problem and not an appliance problem - if you have more than one appliance and one or more are operating satisfactorily, the problem is most likely with the appliance. If you only have a problem at high demand (i.e. each appliance operates fine on it's own but you get problems when all are running simultaneously) you may have a problem due to the pipework being too small, an undersized regulator, or too small / too few tanks or cylinders. Contact your installer.