Rielo RDB burner strange problem

[cjb1971]

Boiler fires up and sounds like its strugling for fuel,cleaned out filters,checked oil pump and all ok.The voltage going to solenoid coil varys wildly between 0v and 210v which probably causing the solenoid to keep restricting the flow of oil causing the problem.
I have tried a new control box,new photocell and even tried a new capacitor on the motor,the voltage going into the control box stays stable at 220v.Any body got an idew what can be causing this problem? the only electrical thing i have not tried replacing is the actual motor which seems to be running fine,could this be drawing too much current causing the problem with the solenoid coil???

 

[Agile]

That does sound like a strange problem and from what you have described might be a wiring problem?

Have you tried powering the solenoid from a seperate source to see if that cures the fault?

Tony

 

[Tipper]

IIRC the control voltage for the control box is derived from the motor windings on some Riello burners. Therefore it could be the motor failing to produce the correct volts for the controls and so leading to problems with the solenoid.

See if you can check the volts from the motor at the control box terminals, white wires I think.

 

[cjb1971]

When i return with the motor in hand ill try them 2 things,motor had 3 wires black blue and white i think so will check the white wire voltage,dont work on many of these burners and just my luck there was nobody in at riello to answer phones today,thanks for the info,sounds like it could be the motor after all then.The only wiring going into the control box is L N E,which tests ok.

 

[MANDATE]

My first thoughts were 'dirty nozzle maybe'.
Then I thought 'how was the pump checked and found to be ok' I recall having problems and did not know how poor my pump was until I purchased a pressure gauge. Spec stated 100 psi and all I could achieve was 20psi.

The 0 volts on solinoid suggests to me a bad connection or broken wire.
Can't you remove it and bench test it to simulate functioning.

 

[oilman]

Boiler fires up and sounds like its strugling for fuel,

Perhaps it is.

The voltage going to solenoid coil varys wildly between 0v and 210v

How have you determined this?

which probably causing the solenoid to keep restricting the flow of oil causing the problem.

A bit of guesswork.

I have tried a new control box,new photocell and even tried a new capacitor on the motor,the voltage going into the control box stays stable at 220v.

It would be better to diagnose the fault.

Any body got an idew what can be causing this problem? the only electrical thing i have not tried replacing is the actual motor which seems to be running fine,could this be drawing too much current causing the problem with the solenoid coil???

What measurements have you made to justify taking an action?

 

[cjb1971]

Boiler fires up and sounds like its strugling for fuel,

Perhaps it is.

The voltage going to solenoid coil varys wildly between 0v and 210v

How have you determined this?

which probably causing the solenoid to keep restricting the flow of oil causing the problem.

A bit of guesswork.

I have tried a new control box,new photocell and even tried a new capacitor on the motor,the voltage going into the control box stays stable at 220v.

It would be better to diagnose the fault.

Any body got an idew what can be causing this problem? the only electrical thing i have not tried replacing is the actual motor which seems to be running fine,could this be drawing too much current causing the problem with the solenoid coil???

What measurements have you made to justify taking an action?

Not struggling for fuel as it is only 6ft from tank and all filetrs are clean and the oil comes out the pipe boiler end at a good flow rate.
I determined the voltage going to the coil by disconnecting the wires coil end and connecting them to a multimeter,and believe it or........looked at the display on the meter...........
Not guesswork,if the coil is opening/closing all the time then fuel would be restricted to the burner
I have diagnosed the fault as an electrical probelm so tried swapping out the various electrical components,the only one i didnt have was the motor.
Perhaps from the symptoms you could give me your diagnosis of the problem?

 

[oilman]

What pressure is the oil pump set to give?

I determined the voltage going to the coil by disconnecting the wires coil end and connecting them to a multimeter,and believe it or........looked at the display on the meter...........

Is this a digital multimeter by any chance?

 

[cjb1971]

Had no manuals to check it was correct but pump was giving a steady 150psi,Its an auto ranging digital multimeter that i use,and showed a steady 220v on control box input connections.

 

[Tipper]

If it turns out not to be electrical then it may be as simple as water in the oil. Change the nozzle to clear it fully after bleeding/flushing through the system.

(On one call-out I did the children of the household had played at 'filling the tank' with a watering can! Another had the whole top of the tank rusted out and the tank about 1/4 full of rain water And finally boiler problems after a student party......smelt like pee in the tank to me!)

 

[ajstoneservices]

You need 50v on the white wire from the motor.

 

[stumpydick]

solenoid closes at 36v dc, then holds at 12v dc approx.[according to riello]

 

[oilman]

Had no manuals to check it was correct but pump was giving a steady 150psi,Its an auto ranging digital multimeter that i use,and showed a steady 220v on control box input connections.

10 bar is HIGH!! This could indicate the combustion will be so far out the flame will not establish.

Trying to measure short pulses using an autoranging meter is near meaningless, whatever the reading says.

The spark is present, and the solenoid open for a second or so.

 

[ajstoneservices]

 

[cjb1971]

Tested the motor and it was giving 50v through the white wire!Fitted the replacement and low and behold worked a treat!
Pressure was just below 10 bar,cust had found out the manual,presure should of been 9.8 bar,so left as it was,just one of them hard to explain breakdowns i guess