monoflame cut out after lighting

[twentytwentyman]

I have a monoflame 50/70 on a Calfire oil boiler which starts and runs then after 1-5 mins cuts out. It sounds if the flame goes out and I guess the photocell cuts it off.

Restting cut out and it starts runs and cuts out again after the same time.

Oil flow is good and tank full.

It started after being swtiched off for the summer.

I have cleaned photo cell, fan and motor are working well, I have read posts on this site and boiler instruction book and think it is either the solenoid on pump or control box.
Am I on the right track?
If it is solenoid how do you get it off. It is a Danfoss pump?

 

[Agile]

Are you sure its not overheating? That time cycle is just right for an overheat problem!

Is the pump really pumping?

Tony

 

[twentytwentyman]

The pump is running and there is the sound of water running round the pipes so I had assumed it was. I will go and investigate further.

 

[twentytwentyman]

Yes pump is working well and is pumping water round system as can feel radiators just starting to warm up.

Took the thermostat out of the front of the boiler (it is a boiler house model with no covers) and placed in cold water, started boiler again and it cuts out after same time as before so am thinking it is not that.

Tank stat set at 50 degrees and should only switch off three way valve if at temp. Have both CH and HW on.

Hope this helps

Mark

 

[Nixt]

Is the burner locking out and not o/heat stat. If so problem is burner related as any boiler or system fault simply cuts power to burner with no lock-out.

 

[twentytwentyman]

Yes the boiler is locking out and the reset light on the control box has to be pressed.

 

[chr15]

Yes the boiler is locking out and the reset light on the control box has to be pressed.

Do you have a tigerloop (de-aerator) on the fuel line or is it a single pipe fuel line? And have you got good fuel flow right up to the pump?

 

[Nixt]

If it runs for 5 mins each time then Control box, photocell, motor, capacitor, nozzle and transformer are maybe OK. The fuel pump may have a tight spot or the drive coupling worn. Also coil may have intermittent fault - not one I've experienced but others on here have. You can narrow things down if you put a combined manifold/pressure gauge on the pump and check it 'till lock-out.

 

[wilhelm]

after taking the precaution there is good flow of oil p£ssin out of the flex,
I would then change the pump. I agrree it could be just the coil, but I aint bothered.

 

[twentytwentyman]

OK thanks for those thoughts from you all, I will go and investigate further.

Mark

 

[MANDATE]

I think you are on the right lines. I've come across a coil recently that worked ok while cool but failed after about 1 to 2 mins. Heat generated must be causing it to go open circuit.
I think you may have to remove the wires from control box and power it up through a separate switched supply. I think you should hear it if and when it fails. Or with a suitable amp meter in the circuit you would have visual proof.
don't know if this helps.