help needed.my ravenheat 84e combi will start up in the correct manner ie fan starts, airflow will switch,then pilot ignites burners no problem, but the boiler then cut out after only 5-10 secs. the boiler will then restart itself and the same happens again this will just continue , this problem happens on both hotwater circuit and heating circuit any ideas
ravenheat combi 84e
- Thread starter mrricko
- Start date
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Hello,
Seems like the firing sequence is in working order. If the pilot light goes out after 5-10 secs it would seem the thermocouple is faulty. Does the boiler fire up and the burner ignite then goes out or is it just the pilot light ignites then goes out?
Seems like the firing sequence is in working order. If the pilot light goes out after 5-10 secs it would seem the thermocouple is faulty. Does the boiler fire up and the burner ignite then goes out or is it just the pilot light ignites then goes out?
There is no thermocouple in Raver 84E. It is not a permanent pilot, just comes on briefly to establish flame for main burner.
However there is an ignition flame sensing probe, which could well be where problem is, but this is Corgi territory.
However there is an ignition flame sensing probe, which could well be where problem is, but this is Corgi territory.
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i think it may be the flame rectification device or flame sensor faulty
Yes, if you are very clever you can build a "flame simulator" out of a diode and resistor.
However, if you look closely you would probably find that the boiler is continuing to spark after the flame is established IF the flame sensor was faulty.
The main burner would not light if the flame sensor was faulty because it is the flame established which allows the main burner to come on.
Your problem is much more likely to be associated with the venturi and APS. Since this is CORGI territory I do not want to be seen to be telling you what to do although you seem very sensible, indeed more so than some registered people!
I now expect you will find the fault but please post again to tell us!
Tony Glazier
However, if you look closely you would probably find that the boiler is continuing to spark after the flame is established IF the flame sensor was faulty.
The main burner would not light if the flame sensor was faulty because it is the flame established which allows the main burner to come on.
Your problem is much more likely to be associated with the venturi and APS. Since this is CORGI territory I do not want to be seen to be telling you what to do although you seem very sensible, indeed more so than some registered people!
I now expect you will find the fault but please post again to tell us!
Tony Glazier
today i changed the ignitor/falme sensor and lead with no joy exactly the same problem as before . any one with more ideas the boiler starts up but cuts out after a few seconds. spoke to ravenheat and they suggested the air flow switch may be cause so i opened the chamber and simulated the air flow switch and the burner stayed on for 10 sec not the usual 3 but then cut out even though the air flow was still made correctly. can anyone help
Check that the sensing tubes to the APS are fully intact, some go brittle causing the problem you describe.
Fault finding on any boiler is a bit of an art so the following ideas are based on my experience of common probs. Something you have not told us or something out of the ordinary could send the search for the problem in a different direction
CH thermistors go for fun on these. Ravenheat now specify a 'dry' thermistor [same part number but with 'D' suffix] to replace the wet pocket thermistors which always go wrong unless the system is meticulously flushed. To test try taking the CH thermistor lead off with the boiler set to CH or a tap running for 30 secs to see what happens. Then put it back on. It's low voltage so it wont kill you.
Worth replacing anyway as if you dont have a problem now you probably will do sooner or later and they are cheap as boiler parts go..
What you describe is an ignition problem so the ignition board is a very likely culprit. I concur that you get an expert in if this is the problem.
Check that the flame plays on to the new electrode you have fitted.
If the APS is honeywell then these too are sometimes dodgy but tend to stick rather than have the problem you describe.
CH thermistors go for fun on these. Ravenheat now specify a 'dry' thermistor [same part number but with 'D' suffix] to replace the wet pocket thermistors which always go wrong unless the system is meticulously flushed. To test try taking the CH thermistor lead off with the boiler set to CH or a tap running for 30 secs to see what happens. Then put it back on. It's low voltage so it wont kill you.
Worth replacing anyway as if you dont have a problem now you probably will do sooner or later and they are cheap as boiler parts go..
What you describe is an ignition problem so the ignition board is a very likely culprit. I concur that you get an expert in if this is the problem.
Check that the flame plays on to the new electrode you have fitted.
If the APS is honeywell then these too are sometimes dodgy but tend to stick rather than have the problem you describe.
Your 5th Aug 2005 posting seems to be at varience with the advice I gave you before.
I think I will retract what I was think about your understanding on how the boiler operates.
You should concentrate on the venturi and APS. You need to dynamically simulate the APS taking the timing into account NOT just the final outcome.
I dont think the temperature sensor is faulty but if you wanted to pursue this then replace it with a 6 K resistor if it measures about 13 k cold.
Tony
I think I will retract what I was think about your understanding on how the boiler operates.
You should concentrate on the venturi and APS. You need to dynamically simulate the APS taking the timing into account NOT just the final outcome.
I dont think the temperature sensor is faulty but if you wanted to pursue this then replace it with a 6 K resistor if it measures about 13 k cold.
Tony
Slugbabydotcom said:
They changed the set up on these so that what I said there applies to earlier models only.
If the pcb has 2 fuses its the earlier one
If it has only one fuse its the later one. It will also have a separate flame sensing electrode.
Replacing with a resistor about 12k as suggested would simulate a working thermistor in either case
Test APS from ignition pcb. Theres a diagram in there but this might save u from squinting
5 = NC
6 = NO
7 = Common
11 = N
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