FER Falcon

[bewsh]

FER Falcon, exactly the same as a Ferroli Modena 102.

Customer has been having the c/h randomly come on with no demand.

Checked continuity for room stat and it's in OL. Physically disconnected one of the wires for the room stat and still randomly comes on, checked resistance between the 2 wires going to the room stat to make sure they aren't touching somewhere under the floor boards, all ok and in OL. And when it randomly comes on, the h/w doesn't work, doesn't even register the h/w demand. Just the c/h demand light on, boiler fires for a few seconds, and goes off. But when it's not doing this fault, the h/w works fine.

The thermistors have been replaced - as the c/h thermistor also doubles as a frost stat.
PCB has been replaced.
Timer linked out and room stat disconnected.

Anyone else ever had this? Or any other suggestions??

 

[Billy Bob Bob]

as far as i remember its not the same as a 102 its similar to a 77ff ,does it have a thermocouple?when where the ntc,s replaced and what reading are you getting from them when cold,also is a timer fitted?

 

[Ermintrude]

Sounds like a wet connection. Frost stat short?

 

[bewsh]

Nah it's not the one with the thermocouple. Electronic ignition, looks very much like the Modena, I think the only difference is the PRV manifold.

Well at the time, the system was hot, and I measured the temperature and it was about 60, and I was getting about 2kohms, can't quite remember. But, I cross referenced them with the book and they were about right. But they were replaced a couple of weeks back.

But as the fault was intermittent, the customer monitored it and it happened again.

There was an integral clock, but I linked that out as the customer only uses the room stat to control heating anyway.

Spoke to Ferroli who advised PCB, so replaced PCB, and it's still the same.

 

[Ermintrude]

They always say pcb. Is the flow switch vertical one at base of boiler?

 

[bewsh]

Ye, I do find they always blame the PCB. I try not to ring them, if I can help it.

The flow switch is the one at the base of the boiler.

 

[Billy Bob Bob]

Nah it's not the one with the thermocouple. Electronic ignition, looks very much like the Modena, I think the only difference is the PRV manifold.

Well at the time, the system was hot, and I measured the temperature and it was about 60, and I was getting about 2kohms, can't quite remember. But, I cross referenced them with the book and they were about right. But they were replaced a couple of weeks back.

But as the fault was intermittent, the customer monitored it and it happened again.

There was an integral clock, but I linked that out as the customer only uses the room stat to control heating anyway.

Spoke to Ferroli who advised PCB, so replaced PCB, and it's still the same.

if its got a thermocouple its got the green ntc,s?this is more 77 than modena,had one years ago doing something similar however look at the top of the main hex,should be 2 stats ones o/h others frost ASFIK primary ntc is not a frost stat as well on this one,if theres 2 stats on the main hex ones frost and they can either fail or the heat sink compound drys out making it think its too cold ,also be caerfull removing the door and checking the combustion seal there positive pressured casings

 

[bewsh]

Nah, it's definitely the modena type boiler. It's got the clear ntc's, and no thermocouple. Read the book, the frost stat is built in to the c/h ntc.

 

[bewsh]

If the falcon is the 77ff, it may be the falcon II

 

[Billy Bob Bob]

Nah, it's definitely the modena type boiler. It's got the clear ntc's, and no thermocouple. Read the book, the frost stat is built in to the c/h ntc.

mis read your post,thought it had a t/c would look for water going where its not designed too

 

[Ermintrude]

Flow switch probably stuck. It's a plastic ball bearing. Take it out and clear it easy. Or replacment 19 . Ch is a clock / switch possibly frost but DHW will override frost

 

[Ollieg]

check the connections to the pcb for the CH ntc. Could be loose or poor connection causing frost stat type operation.
Glowworm compacts are having this problem.

 

[bewsh]

Ye, that's what I don't understand, why would the h/w fault only when the c/h comes on with no demand? As you said, the h/w should override the frost stat. I'll take the flow switch out and have a look, going back on Monday.