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Hello, I have a 30 amp Aga 4-oven cooker that isn't charging fully and I suspect it's the controller board.
***Symptoms***
This is a night storage range cooker that charges up a heat store to 700 degrees on cheap rate electricity (via a programmable timer switch) and distributes it to four ovens and two hotplates by a circulating fan over the following day. I've had it a dozen years and it operates almost flawlessly.
Recently it has not been getting up to its full temperature. The ovens are at 210 degrees C, not the normal circa 240 degrees. The indicative thermometer on it suggests its cooler too and it takes longer to cook stuff. It's at maybe 80% or so of normal temperature.
Also - it has a function whereby if it is significantly below normal temp it will override the timer switch controlled supply and call for power. This switches off when it gets to about 80% of normal max temperature. Recently this function has been triggering at about 80% max temp and switching off a little while later - ie triggering much earlier and at higher temperature than it should.
There is an oven vent switch on a daughter board. Activating this will extinguish the faulty call for power - which is odd.
I suspect a faulty temp sensing function, or perhaps the controller board is not fully powering the charging circuit - ie sending enough voltage to the relays. Sometimes although the charging LED is lit on the Aga control panel, the current draw is minimal (as judged by rate of flash on my electricity meter).
***Repairs so far***
The mk3/4 control board costs upwards of £1000, and a repair is about £250. So it is worth attempting some repairs first.
I have replaced the core circulating fan (as the bearings had gone and this is often the cause of a cooler aga) - No impact.
I have tested the three banks of heating elements for continuity and resistance - all normal.
I have replaced the core thermo-couple - No impact.
When the charging circuit is first activated it pulls 20 amps when measured with a clamp at the switched incoming supply at the wall (normal range is 19-21 amps).
So this suggests to me that the charging circuit is providing enough charge - just not for long enough - ie it is switching off early or perhaps not powering the relays fully (I think there are three relays - presumably one for each element?). There's no audible repeated clicking suggesting a faulty relay.
The only things remaining are the oven thermocouple and the main controller board.
Any one have any ideas on what I can test next or what to look for/likely faults? How would I test that the correct current is reaching each heating element?
I'm tempted just to chuck 250 quid at it - but other threads on here have suggested that it may be a simple component or two on the control board and very cheap to remove/replace and resolder. One thread (slightly different symptoms) suggested a MOSFET. I'm wondering about the relays.
I've attached some generic internet pics of the main control board and the relay board, along with my (dusty!) main board. I've not been able to find any schematics for them though.
Many thanks for any help/advice.
Robin
***Symptoms***
This is a night storage range cooker that charges up a heat store to 700 degrees on cheap rate electricity (via a programmable timer switch) and distributes it to four ovens and two hotplates by a circulating fan over the following day. I've had it a dozen years and it operates almost flawlessly.
Recently it has not been getting up to its full temperature. The ovens are at 210 degrees C, not the normal circa 240 degrees. The indicative thermometer on it suggests its cooler too and it takes longer to cook stuff. It's at maybe 80% or so of normal temperature.
Also - it has a function whereby if it is significantly below normal temp it will override the timer switch controlled supply and call for power. This switches off when it gets to about 80% of normal max temperature. Recently this function has been triggering at about 80% max temp and switching off a little while later - ie triggering much earlier and at higher temperature than it should.
There is an oven vent switch on a daughter board. Activating this will extinguish the faulty call for power - which is odd.
I suspect a faulty temp sensing function, or perhaps the controller board is not fully powering the charging circuit - ie sending enough voltage to the relays. Sometimes although the charging LED is lit on the Aga control panel, the current draw is minimal (as judged by rate of flash on my electricity meter).
***Repairs so far***
The mk3/4 control board costs upwards of £1000, and a repair is about £250. So it is worth attempting some repairs first.
I have replaced the core circulating fan (as the bearings had gone and this is often the cause of a cooler aga) - No impact.
I have tested the three banks of heating elements for continuity and resistance - all normal.
I have replaced the core thermo-couple - No impact.
When the charging circuit is first activated it pulls 20 amps when measured with a clamp at the switched incoming supply at the wall (normal range is 19-21 amps).
So this suggests to me that the charging circuit is providing enough charge - just not for long enough - ie it is switching off early or perhaps not powering the relays fully (I think there are three relays - presumably one for each element?). There's no audible repeated clicking suggesting a faulty relay.
The only things remaining are the oven thermocouple and the main controller board.
Any one have any ideas on what I can test next or what to look for/likely faults? How would I test that the correct current is reaching each heating element?
I'm tempted just to chuck 250 quid at it - but other threads on here have suggested that it may be a simple component or two on the control board and very cheap to remove/replace and resolder. One thread (slightly different symptoms) suggested a MOSFET. I'm wondering about the relays.
I've attached some generic internet pics of the main control board and the relay board, along with my (dusty!) main board. I've not been able to find any schematics for them though.
Many thanks for any help/advice.
Robin
