Carbon Monoxide beeping

[Jilly]

I have tenant text to say that both of their Carbon monoxide monitors are beeping. 
I’ve told them to turn the boiler off and open all the doors and windows. 

Do I need a plumber to attend?

Is there a way to shut the gas off?

[JohnMo]

Is it beeping because the battery is going flat or in alarm mode, which isn't a beep.

 

If the boiler or stove is off or gas hob then there is no source of CO.

 

You can normally shut gas off at meter I think.

[Temp]

Low battery is usually a single chirp or beep every 15-30 seconds. 

Alarm is full blown, you ain't sleeping through this, continuously sounding and loud.

 

If its a low battery they usually take PP9 / 9V batteries or they have a 10 year battery that you can't replace. If its the latter Screwfix or Toolstation will normally have suitable replacement.

 

If its a real alarm I'd turn off anything that has a flame (boiler, gas oven/ hob, gas fire, candles etc) and I'd get a Gas Safe Registered Engineer (used to be called Corgi) to look at it. If there is more than one possible source perhaps ask the Tennant which they were using when it went off.