![I have a Potterton puma boiler. It has recently been hissing out of the top and sometimes sounded like a steam train. I have a Potterton puma boiler. It has recently been hissing out of the top and sometimes sounded like a steam train.](https://f01.justanswer.com/JACUSTOMER0zaiofhy/2012-04-22_002321_photo_copy.jpg)
I have a Potterton puma boiler. It has recently been hissing out of the top and sometimes sounded like a steam train.
![Combi boiler pressure refill, low pressure fault, fix lockout, potterton puma combination repair - YouTube Combi boiler pressure refill, low pressure fault, fix lockout, potterton puma combination repair - YouTube](https://i.ytimg.com/vi/fuXaSZd06w0/maxresdefault.jpg)
Combi boiler pressure refill, low pressure fault, fix lockout, potterton puma combination repair - YouTube
Installation & Service Instructions Puma 100 & 100e Wall Mounted, Fanned, Room Sealed Combination Boiler
![Combi boiler pressure refill, low pressure fault, fix lockout, potterton puma combination repair - YouTube Combi boiler pressure refill, low pressure fault, fix lockout, potterton puma combination repair - YouTube](https://i.ytimg.com/vi/2RGLZDik1Lw/maxresdefault.jpg)