telford copper cylinders - tristor main pressure thermal store

[Viper Gas]

Hi Guys,

anyone come across one of these before? pics to come!

Although it produces hot water very nicely the customer is complaining about a whistling noise coming from the top of the cylinder after it has been on for a couple of hours. I noted that the auto fill light was not blinking as it says it should.

Any ideas why its not flashing?
Any ideas why its whistling?

thanks

DD368