Firebird C20 burner

[muv]

Hi,

Anyone familiar with the Firebird C20 oil boiler?

Been away for 3 weeks and I usually switch it off but this time left it on.

Got home Wednesday and the shower had hot water until Saturday morning then went Luke warm, checked the pressure gauge on the boiler and it had dropped just into the red, took the front off and its weeping at the filler joint.

Attached the filler loop and raised the pressure to 1 bar and switched back on but it won't fire up when a hot tap is opened or the heating calls for heat, all I can hear is the two pumps running and no lights showing except the the green LED for water and the Green LED when it calls for heat.

I'm a spark so checked for voltage at the limit stat, all ok, and the pressure switch is seeing pressure and indicating voltage on the the boiler terminal on the PCB. The Riello RDB burner is not showing a red light at the reset button like it normally does although there is voltage at the control box.

Any ideas guys before I have to take Monday off and get someone in to have a look?

 

[Terrywookfit]

Surely as a Sparky you can follow the wiring diagram.

 

[muv]

I have and it took me to the control box.

it has a supply present, I take it the photoresistance looks for the flame so I can disregard that as it's not firing anyway, the oil valve looks to be a solenoid to give the burner oil, a motor for the fan and ignition electrodes. I'm getting low on oil but not that low and I would of thought it would still try to fire even without oil present?

I was hoping for someone that has come across this before, I may be wrong and I've never looked inside a boiler before but thinking it must be something to do with the pressure dropping after not being run for 3 weeks.

 

[Terrywookfit]

Just to clarify.
You have an enviromax combi with an RDB burner fitted.
Is it the MO535 MPF digi box fitted or standard one (No post purge)

 

[muv]

Yes Terry, The enviromax combi with the MO 535 MPF control box fitted.

 

[Terrywookfit]

Have you tried unplugging burner supply to reset the box.
Is there voltage on motor black and blue wires.

 

[muv]

Yes I unplugged the supply to the control box as couldn't get probes on to check voltage.

No voltage going to the motor though.

Control box shagged? Can't see anything else connected to it to tell it to run.

 

[Terrywookfit]

Yes it's fooked!!

 

[muv]

Ok fair enough So are these prone to failure after 3 years? And I take it the drop in pressure was just a coincidence?

 

[Terrywookfit]

Not really I have only changed one.
Have you lifted the lid to check connections or just measured at burner plug

 

[muv]

I lifted the lid on the c/box to check.

Oh well I'll see if I can pick one up tomorrow, back to the kettle filling

Cheers for the help.

 

[Terrywookfit]

Just a thought.
How many wires are in the burner plug. IS IT 5 PIN ??
You have checked that there is switched live AND perm live.
If you have a pressure switch fitted it would explain why pressure loss caused this problem.

I assumed that as you were a Sparky you would have checked.

 

[muv]

Yes there's two lives at the plug. One from the limit stat and the other from the pressure switch.

Pressure loss makes sense, it dropped and disconnected the c/box. When I raised the pressure with filler loop it put power back onto the c/box where I've been checking.

 

[oilhead]

Disconnect the photocell, reset the burner, if it lights then locks out, you have a faulty photocell. Common on these burners.

 

[snb]