Vaillant turbomax 824 HW ok No CH & Pressure stays at 3

[aseru]

Hi I have a Vaillant turbomax 824 which is not sending hot water to the Central heating system but the Tap hot water is fine.
The problem started when I went to turn the CH on and as I did I noticed that the pressure was very Low about 0.5 so I turned the key under neath to allow the pressure to increase but as I did this the key fell out into a crack in the floor, the prerssure continued to rise and as it got close to 3.0 I turned the boiler off at the main power switch. I then retrieved the key and turned it back to the default postion hoping the pressure would slowly lower but it stayed at 3. I then noticed the radiator was not getting hot.
I've tried emptying one of the radiators of water hoping this would lower the pressure which did seem to lower it to about 2.8 but it soon went back up and still no CH.
I have noticed that a couple of times the pipe to the radiator gets quite hot but It never gets as far as the radiator and on other occasions the C.H Flow pipe gets hot at the top but further down it is cold.
The display gets as far as s.07 Water Pump Over Run.

Any Help Appreciated

Thanks Abe

 

[diamondgas]

aseru ... get yourself a gas safe engineer out. Sounds like you may have a diverter problem. Are all the external controls working? Time clock, room thermostat turned to max? Regards the pressure you will need to get it back down to around 1ish otherwise you could find the safety blow-off valve opens!

 

[Patchie]

HI as above get an engeineer in, but to me sounds like there is an air lock or a blockage, i would try draining down system some were there will be a drain cock down stairs rad near door is a good place to start. then re fill slowly venting all rads of air starting from ground floor and working upwards keep topping up as you go then level presure off at 1 to 1.5 bar then try it. you should also add inhibutor to system when you refill.

 

[RusClarke10]

The pressure on the boiler needs to be set at 1.5, when you make a demand on the heating the boiler pressure rises. If the boiler pressure gets to high it will cut the boiler out. You need to bleed the radiator until the pressure reads 1.5 when cold. If the pressure still rises once this is done to 3 bar, then you would need to call a heating engineer as this would be a problem within the boiler.