Vokera Flowmatic boiler fault help

[suluki]

Hi all,

Have a problem with a Vokera flowmatic combi boiler.

Symptoms are:

Rad needs bleeding on a regular basis and boiler is now making loud banging noises when calling for heat and hot water. Both hot water and heating are still working but water temperature is scalding hot so due to the loud noises from the boiler it has has now been turned off.

Anyone know what might be the problem, many thanks

 

[DP]

Good chance that this excellent model has not seen a proper service for many moons.

Boiler will be about 10 years old with plenty guts to do the same again BUT, it MUST be looked after. By looking after it I do not mean 'look at it and call it a service'.

What pressure are you running the boiler at. Tells you below the pressure gauge that the pressure should be 1.5 bar

 

[suluki]

its running at 1.5 bar but i dont have the manual to it dont soppose any one has one on here they could email me have they. thanks.

cant understand why it should be overheating unless the overheat stat is nackered.
thanks for the reply DP

 

[DP]

Boiler will reach 85 degrees when CH stats is at max, 70 when in CH mode. If boiler overheating, pilot will go out. If overheat stat is knacked, you get no pilot.

 

[croydoncorgi]

Rad needs bleeding on a regular basis

- how regular? With a sealed system there should be no opportunity for air to get into system. Is it air that is coming out of the rad(s). Keep the curtains out of the way and see if the jet of gas coming out of the bleedscrew lights! It might be hydrogen - which leads to a whole new set of possibilities.
Banging from the boiler followed by overheat and lockout implies that its short of water. If you're also getting (lots of) air in the rads, these could be symptoms of the same underlying problem. Quite possibly, there may be nothing at all wrong with the boiler itself - the safety devices are doing their job.

 

[suluki]

Going to see if thier are any gases in rads if there is what will cause this build up of hydrogen.

 

[kevplumb]

electrolytic corrosion the steel rads and copper pipework brass fittings etc are reacting with each other

 

[suluki]

Thanks for the kind replies