Very noisey boiler plus pressure too low or high

[northernmonkeyz]

Hi,
I hope someone can advise me!
We are in rented accommodation which has an old Ravenheat RSF 820/20.
Last winter our gas bill was extremely high (£1200 from Oct to Feb)....almost 3/4 more than previous winters despite the house being the same size as the previous one.
The boiler is making a lot of noise and seems to be struggling. The pressure is always half a bar when cold and 3.5 bars when the heating is on.
When the heating is on it’s almost impossible to touch the radiators regardless of how low we have the heating thermostat.
Does anyone have any ideas what could be done to fix the noise, pressure and also the fact it’s too hot?
Could these things be the reason for the really high gas bills?

Thanks in advance,
Al

[DEEARR2]

Excess pressure when hot would indicate the pressure vessel in the boiler should be checked. With the pressure at 3.5 bar the boiler pressure refief valve should be lifting and discharging to outside. This may be accounting for the noise from the boiler. No control of the boiler temperature would require the controls to be checked.
These conditions would render the boiler as being dangerous and I would advise it be shut down immediately. Notify your landlord and have it checked by a REGISTERED ENGINEER.