Ideal Isar m30100 cuts out error LF when hot tap turned off
The Ideal Isar m30100 which cuts out with error code LF whenever a hot tap is turned OFF.
A week ago the flame detection electrode was replaced but the problem remains.
The central heating is functioning ok, and when the DHW is running plenty of hot water flows from the hot tap.
When the hot tap is turned off the display goes from d with steady green LED to d with flashing green LED.
After 10 flashes there is a click and then the display shows LF.
On pressing the reset button the boiler fires up and will again supply central heating water and DHW.....until a hot tap is used and then switched off....which causes the cut out again.
Thank you,
member Sun Dial
tininho, UK, Joined: 27 Feb 2010, Posts: 15, Location: Glasgow,
Sun Feb 28, 2010 8:21 pm
Hi,
The LF fault is an ignition fault, or flame failure....
My First port of call would be a fan or flue fault.... When running in H/W mode, the fan works at a higher rate than in CH mode, so that the gas/air ratio is higher, thus alowing maximum heat output.... If the fan is sluggish it is possible that the gas/air ratio is out and causing poor combustion and in turn causing the flame failure.... This could also on occasion give an L8 fault code
Other causes of LF faults are: choked condensate trap, faulty PCB and (on occasion), fault with burner or ionisation probe......
The reason the boiler runs through the night (seemingly with no demand) is that the Isar has a built in hot water pre-heat system. In effect, it keeps a small store of domestic hot water constantly....
By the way... is it noisy when in operation????......
Hope this helps,
Martin
member
Hi Martin, Thank you for the information. To answer your question, no, it is not noisy, it does not bang when the gas lights, and no rattles or grinding come from fan or pump, they all seem ok.
To me the significant factor is that it is only when the hot water tap is turned off that the cut out occurs. We can run a bath or long shower with no problem, until the tap is turned off.
After the 10 LED flashes it always cuts out at that point.
Thank you for helping with this.
member, Sun Dial
tininho
It's certainly a strange one..... In theory there is no reason why this should be specific to H/W, other than the fact that the boiler burns at maximum output on H/W op's, but generally doesn't on C/H...... Could be a fault with the Printed Circuit Board.... Difficult to prove the fault in this kind of situation....
Martin
The Ideal Isar m30100 which cuts out with error code LF whenever a hot tap is turned OFF.
A week ago the flame detection electrode was replaced but the problem remains.
The central heating is functioning ok, and when the DHW is running plenty of hot water flows from the hot tap.
When the hot tap is turned off the display goes from d with steady green LED to d with flashing green LED.
After 10 flashes there is a click and then the display shows LF.
On pressing the reset button the boiler fires up and will again supply central heating water and DHW.....until a hot tap is used and then switched off....which causes the cut out again.
Thank you,
member Sun Dial
tininho, UK, Joined: 27 Feb 2010, Posts: 15, Location: Glasgow,
Sun Feb 28, 2010 8:21 pm
Hi,
The LF fault is an ignition fault, or flame failure....
My First port of call would be a fan or flue fault.... When running in H/W mode, the fan works at a higher rate than in CH mode, so that the gas/air ratio is higher, thus alowing maximum heat output.... If the fan is sluggish it is possible that the gas/air ratio is out and causing poor combustion and in turn causing the flame failure.... This could also on occasion give an L8 fault code
Other causes of LF faults are: choked condensate trap, faulty PCB and (on occasion), fault with burner or ionisation probe......
The reason the boiler runs through the night (seemingly with no demand) is that the Isar has a built in hot water pre-heat system. In effect, it keeps a small store of domestic hot water constantly....
By the way... is it noisy when in operation????......
Hope this helps,
Martin
member
Hi Martin, Thank you for the information. To answer your question, no, it is not noisy, it does not bang when the gas lights, and no rattles or grinding come from fan or pump, they all seem ok.
To me the significant factor is that it is only when the hot water tap is turned off that the cut out occurs. We can run a bath or long shower with no problem, until the tap is turned off.
After the 10 LED flashes it always cuts out at that point.
Thank you for helping with this.
member, Sun Dial
tininho
It's certainly a strange one..... In theory there is no reason why this should be specific to H/W, other than the fact that the boiler burns at maximum output on H/W op's, but generally doesn't on C/H...... Could be a fault with the Printed Circuit Board.... Difficult to prove the fault in this kind of situation....
Martin
