Ravenheat Boiler 85T Cenral Heating not working!

[Ash422]

I have an adopted Ravenheat Boiler HE 85AT unfortunetly! Central Heating is not coming on, although the hot water is working. Any ideas anyone?

The Air pressure switch (at the top) is fine. I have blown through the preceding pipe and it is switching. The fan comes on OK when the hot water is running.

CH Thermistor seems to be in tact. I have moved it around.
Altough the Timer is very noisy. Could that be it?

I assume the diverter is valve is the solid round disc thing in the centre (at the bottom of the boiler where a pipe feed in)...how do I switch that to flow to central heating?

How do I isolate the problem? Any ideas anyone please?
Thanks,

Ash

 

[idealnumber1]

your controls are the problem,have you put the room stat up

 

[howmuchlonger08]

is it a onboard clock? not the most reliable of clocks, is so check the 2 wires that go to the switch.

 

[Ash422]

There is no external room stat. All controls are on the boiler. There are two dial settings. One for hot water HW, and another for HW + CH. Water Setting is at above medium (at the highest effeciency line) for both.

All wires seem to be in tact around the timer (On board). The central heating is not on the timer. I am trying to switch central heating ON manually. In any case, I have reset the timer. No difference.

Three radiators upstairs are not bleeding. I am assuming that is because the heating has not been on for a while, coupled with no pressure in the system.

The boiler is now banging loudly when the central heating is switched ON. Steam bubblles? The flame comes on, when CH is turned ON, there is a loud bang, and the pressure guage fluctuates madly. I have to turn the boiler off at this point in case it blows up!

All this whilst the hot water runs fine....The flame comes on, stays constant, and water runs OK..... strange..?!

 

[Ash422]

OK.. Found the cause. There was no water feeding back into the boiler.
A stop valve was closed. Didn't notice! Simple!?

 

[Ash422]

Lound banging is still occurs occastionally. Metal casing surrounding burner etc is bulging because of this!

Loud bang = noisy ignition
How do you alter the burner pressures and set correctly?

 

[Agile]

I hope that no one is going to give you advise on gas work.

The correct advice is to call a gas registered engineer.

Tony

 

[clf-gas]

Three radiators upstairs are not bleeding. I am assuming that is because the heating has not been on for a while, coupled with no pressure in the system.

and then said.

OK.. Found the cause. There was no water feeding back into the boiler.
A stop valve was closed. Didn't notice! Simple!?

Air in system,,,,SIMPLE,,,,,

 

[Ash422]

No air in the system anymore.
The only problem is occasional internal noise (loud bang).

I will not be doing any gas work myself!
Just trying to understand the problem.

I have already been quoted £80 call out charge + £30 for the first 15 minutes of evaluation!

Will definetly get a registered engineer.

 

[SortedPlumbing]

Your loud bang (and bent combustion chamber) is caused by fan modulating PCB switching your boiler on/off/on/off -

This causes a build up of gas in the combustion chamber!

Seen this on every single one of this boilers !

 

[Ash422]

Seems logical. Its a manufacturing defect then if its common??

Is there a resolution for the problem as yet?
Or is it a case of 'living with it' or getting a new boiler?

 

[Agile]

I have already been quoted £80 call out charge + £30 for the first 15 minutes of evaluation!

Will definetly get a registered engineer.

That seems very expensive as would be £200 for an hours diagnostics.

The boiler fault can be fixed with a new revised fan PCB.

We would charge just a fixed fee of £84 in our local area to diagnose the problem and fit the new PCB which costs about £50-£60 !

Any damage to the casing could need replacement, perhaps expensively.

Tony

 

[Ash422]

OK... Just an update... last week the 'build up of gas' led to a minor internal explosion. I think it has knocked out the air pressure switch. I have ordered an APS and Fan Control Board.

Blowing into the venturi tube (from flue) lights the boiler - therefore it must be either APS or blockage via HE/ venturi tube. The parts are on order so I will see if this resolves the problems.

I can see the combustion chamber now bulging and this might need replacing too. Apparently it needs to be air tight, therefore the boiler might not be lighting because of air gaps (combustion chamber cover).

On the restarting issue (on/off/ on/off) I hope the FCB resolves the problem.

 

[Agile]

Will definetly get a registered engineer.

The problem you now have is as a result of your NOT getting a registered engineer as we always advise.

Hopefully you and others reading this will now be able to see the reasons that we do not advise gas work, which includes opening the combustion chamber, by anyone who is not appropriately trained and experienced.

Tony

 

[Ash422]

I agree. I have Npower visiting this week. You should always get a registered engineer to look at any problems with Gas etc. Which is exactly what I have been doing. But despite that - Ravenheat boilers tend to run for a short period and break down.

You should also be fully informed of problems and do as much as you can to a degree. Otherwise you'll be taken advantage of by a closed industry.

Unfortunelty, Ravenheat boilers are not reliable. Having spoken to the previous owner. This is the second time FCB is being changed. Apparently, the boiler has had checks from 'reputable' engineers in the past.

The venturi tube running past fan impellor is a design defect that Ravenheat should correct.