Worcester 12/18 danesmoor oil schmelly when operating

[dovski]

Well, title self explanatory really. I checked the balanced flue sealing, the heat exch.s are clear aside a little soot. Gaskets both good. I pulled the burner (foam gasket good) and there was a little evidence of burnt oil down the face of the nozzle and around the upstream side of the burner plate. I replaced the nozzle and the two burner o-rings but its still smelling bad, no signs of external leaks. Been all over it 2 or 3 times from the tiger loop (GS PROFI-3) to the RIELLO pump inlet/outlet..nothing..can the pump be leaking? not sure where to go next..

 

[oilhead]

Riello pumps are notorious for leaking from the shaft seal when running. This creates a smell, but the heat of the pump and motor evaporates any leaks. disconnect and remove the pump to check.

 

[dovski]

Thanks for your reply, I ran it outside and there is 50v at the coil on startup, ignition is immediate with no priming, but on shutdown, flame out occurs without any dripping from the nozzle for a second or two, then a jet of oil is ejected from the nozzle for around 2 seconds, I dont know what causing this unless the pump solenoid isnt sealing..??

 

[dovski]

Replaced the pump, more cost effective in the long run. fuel still ejects from the nozzle on shutdown, a jet for a second or so, not a dribble.. see what its like tomorrow.

 

[dovski]

I know its been a while but we've had a hot summer and no boiler use.. Filled the tank and had a weep at a union prior to the de-aireator which was without the pump running. Cured that and decide to fit a pressure regulator before to offload any excess pressure from the full tank, 1800ltr.
Fitted a new pump as mentioned above and set 110psi per manual info. Have the same symptom of fuel smell on shutdown after firing.
Is there a valve external to pump for stopping supply to the nozzle or is just the pump/motor stopping that ceases supply to the jet/nozzle? Nozzle been replaced already.
I'll order some new face and cover seals in the meantime..any ideas

 

[Stuart981]

Could be air in the oil. When the solenoid shuts off the fuel, any air entrained in the fuel between the valve and nozzle expands and a squirt of oil is ejected.

 

[dovski]

Been reading about afterdrip, seems trapped air may cause this and one post I uncovered suggested a dual line de-aireated system will suffer indefinately!?

AFTER DRIP QUESTION

I have never found any device, OSV, Solenoid, Check valve etc that will stop after-drip.

forum.heatinghelp.com

I have a dual line feed and return from the burner to the GOK de-aireator.... single line feed to it, with press reg inline mounted correctly horizontally inline. I'm about to bleed the pump and GOK again, see whats what..

 

[dovski]

What the thoughts on de-aireators? get rid?? and fit a filter in its place...?

 

[Stuart981]

Is the tank outlet below the level of the boiler?

 

[muggles]

If you've got so much pressure from the tank that you need a pressure regulator then the deaerator is totally unnecessary

 

[dovski]

Thanks, The tank bottom is approx level with burner.. I think I'll try it without the burner. I did get a slug of air from the pressure test port extension which I guess would have caused the compression or hydraulicing effect.. trying it again for an hour or so..

 

[Johntheo5]

Riello solenoid valves are actually shut when firing and open during the pre purge period, and when the burner is shut down, can you monitor the "wash" pressure during the pre purge period and for a few seconds after the burner shuts down, might show up something.

Not sure when using a Tiger Loop or similar but the Bypass blanking screw is removed if using a single pipe system and in place with a two pipe system where the second pipe recirculates the oil back to the tank, My 20 year old Riello G5X came with its screw taped to the front of the instruction manual, where it remains today.

"During pre purge you have oil being circulated around the return line. Pumps take in a set capacity each second, during pre purge the oil is going around the circuit and back through link between return and inlet. This capacity generates the wash pressure on Riellos (some Suntecs work the same). When the usually NO coil energises it closes the the return port, which in turn takes on more oil from the inlet and raises pressure. When the pressure set by regulating spool is achieved it opens the regulating spool allowing flow to nozzle, any unwanted excess oil is circulated back to return. At no point during pre purge should the oil pressure be enough to open spool and go through to nozzle.
Pre purge is 14 seconds yes (varies on different control boxes) and the wash pressure on Riello is about 2 bar for RDB and up to 5 on old Riello's"

 

[Stuart981]

Sometimes you can have a leak that is nothing more than a stain that only appears when the burner is running and evaporates as soon as it forms. Might be worth applying some coloured blotting paper to joints downstream of the pump when the boiler is running.

 

[dovski]

Stripped the burner apart last night again, the staining was all around the nozzle/nozzle holder and blast tube, suspected a cracked feed pipe but no stock locally, took the nozzle out and remembered I's sealed the thread with ptfe, took that off cleaned up the nozzle and put reassembled with heltite sealant. I took the de-aireator (GOK) off and converted back to single pipe and the smells gone 99% this morning...Hopefully its fixed. I'd like to have had the time to test after one thing at a time but wanted to hit it with the biggest hammer i have..hence all the fixes at once. I'l come back in a few days..

 

[Johntheo5]

No way should thread tape or any form of sealant be used when installing a new nozzle.