ferroli modena 102 shuts down

[klapaucius]

hello everyone

my boiler is giving me grief again. it used to cycle pretty often and I wasn't able to fix it, even after replacing the DHW sensor. I might be wrong, but it looked like it never modulated the flame.

now it developed a much worse problem. when I turn CH or DHW on, it starts the fan and lights the burner with no problem. but almost immediately (maybe after a second or two of burning) it shuts down with the CH/DHW LED still on and the controller seems "hung". operating the tap or the CH clock doesn't do anything, the LED is constantly on and the boiler does not react to anything. only reset or powercycle helps. the LED number 2 (boiler lock out, crossed flame picture) never lights (!). I don't think I have ever seen that LED on actually.

I checked the fan, the air pressure switch, the cut-off thermostat, temperature sensors. everything seems fine. this problem appeared a couple of days ago, I pulled out and reinserted all connectors and got it working for a day but now nothing helps. it shuts down every time. this might be irrelevant, but the voltage on the air pressure switch is ~40V when the fan is not working, and 0V when it is working. maybe it is not supposed to be 240V after all.

it looks like the PCB is to blame but I would be extermely thankful if someone could suggest additional tests. do these controllers die often ? they cost a fortune. any info is appreciated.

there are some details about the boiler:

Ferroli Modena 102 (gas)
PCB MF03F
problem happens every time DHW or CH is used.
no visible damaged parts anywhere.

thanks very much in advance.

 

[chr15]

I had a very similar problem to this on this model a few years ago-turned out it was the ignition pcb-there are 2 pcb's on this boiler if i remember,main and ignition. Just a thought,have you checked the flame sensor electrode and its lead to make sure they are sound?

 

[klapaucius]

thanks for the quick reply, chr15.

no, this one has only one PCB, which looks like this: http://i8.ebayimg.com/04/i/07/3c/12/30_1_b.JPG

the flame sensor electrode -- how do I check it ? I checked the lead from it to the PCB, no problem. it is quite a thick wire. the sensor itself is inside the chamber but it is just a piece of metal with a ceramic housing, what can be wrong with it ?

what's the voltage on the sensor ? how do I check it ?

 

[geoff@cetltd]

Chr15 - you are a generation behind

the MF03 is a heap of dogs doings - google for a recon one

 

[chr15]

Raden-I never mentioned the MF03,the origional poster did,all I said was that i recalled it having a 2nd ignition pcb on this boiler.

 

[klapaucius]

checked the power supply of the microcontroller - 5V.

raden, are you saying these PCBs are know to fail ? I can't find any cheap reconditioned ones. so far only on eBay for £80.

thanks for replies, guys.
anyone else ?

 

[geoff@cetltd]

Raden-I never mentioned the MF03,the origional poster did,all I said was that i recalled it having a 2nd ignition pcb on this boiler.

Aah but that's the MF02

you're a generation behind there

 

[geoff@cetltd]

checked the power supply of the microcontroller - 5V.

raden, are you saying these PCBs are know to fail ? I can't find any cheap reconditioned ones. so far only on eBay for £80.

thanks for replies, guys.
anyone else ?

FFs - blatant advert

 

[chr15]

So what are you saying-that there are no longer two pcb's on this boiler,or there are still two but spec. and numbers have changed or what?

 

[Gasguru]

Some Modenas have a single board and some have two boards - both usual rubbish design though.

 

[klapaucius]

thanks for the blatant advert, raden. I did not find them myself. this although raises two questions:

1. the part number for the reconditioned part is 805900 and the new ones I found on the net are 807690. which one is correct ? are there different types of boards for the same boiler ?
2. I see many potentiometers on the board. the service manual mentions adjusting them to fit the particular installation and I can't see how I can do that without special tools. this also applies to the brand new part btw.

any advice ?

 

[Gasguru]

The Modena boards cannot simply be swapped as various settings to be adjusted on the board eg ignition burner pressure, heating output whilst monitoring burner gas pressures.

 

[geoff@cetltd]

So what are you saying-that there are no longer two pcb's on this boiler,or there are still two but spec. and numbers have changed or what?

The older version had an MF02 (preceeded by the MF01) and ignition pcb, the later has an MF03 which has all functions on one pcb

 

[klapaucius]

any advice how I can replace the board without special tools ? if I set the potentiometers in the same positions as on the old board, won't it work ? or maybe I can measure certain voltages on connectors and adjust the new board to have the same ?

thanks very much for your help, guys.

 

[bripl]

no need for special tools on the modena just the mi they explain how to set the pots and the pressures req for it.