ideal classic

[markinaark]

been to a service on a ideal classic nf . sequence all normal all fires up lovely , then as expected when reaches temp, (burner flame out.fan off etc), then immediatly tryes to ignite pilot, sparks up pilot on for 1/2 seconds and then repeats this cycle till boiler drops in temperature then fires up as normal and repeats this over and over.

first thoughts replace pcb ,
but surely a board could not skip a range of safety checks ie fan aps stats etc to go directly to ignition .

any thoughs or suggestions appreciated.

 

[hammers4spanner]

Checked all wiring connestions??

 

[markinaark]

the sequence at the start , confirms everthing as should be,
but when reaches temp. should really go to stanby until system cools and stat kicks back in. has me a wee bit baffled at the minute..
but it will attempt to ignite , and opens pilot valve for 1/2 seconds then off and then back on. and continues till stat takes over.,

 

[Nostrum]

I had a similar problem although not quite as odd recently, the fan would run for a second then turn off etc which was the potentiometer, but I would say board in your case as like you say something has to be a miss for it to skip through the sequence.

Does the APS close when the fan goes off?

 

[markinaark]

would assume board checks aps for nc position , to confirm before activates fan, if aps was stuck .shouldnt go to next stage. boiler seems to have a mind of its own .
fan only starts after the stat kicks back in.

 

[arran197]

That's a strange one. Would say board, but never changed one and I look after a few of these. Normally very reliable, with the fan being the most common fault.

 

[SimonJohns]

I would say fan is dirty. Aps very sensitive on this boiler

 

[Backboiler]

Faulty thermostat?