How to re-prime Worcester Danesmoor 20/25 oil system?

[pjmallinson]

The boiler has been working fine for years but I have recently had to re-route the oil feed line from the tank. I took the opportunity to do the service on the boiler and replace filter etc. I now have the situation where there is no oil in any of the pipework, the tigerloop or presumably even the pump. I have tried priming the system by running the start process from lockout about five times but unsurprisingly no oil is raised.
How do I bleed/purge the pump etc to get things going again. I notice there are a couple of large hex nuts on the side of the pump and also what looks like a bleed nipple which looks relevant?
The burner is a Selectos and the pump is a Sundstrand. I can supply photos for ID if necessary.
Thanks for your help in advance!

 

[Agile]

Is the tank ABOVE the inlet level of the pump?

If so does oil appear at the inlet to the pump?

Stupid but have you left isolating valve at tank off?

Tony

 

[pjmallinson]

Is the tank ABOVE the inlet level of the pump?

Thanks for swift reply Tony. No, It's a tiger loop system because the tank outlet is about 1.5m below pump, and about 25m away. Good obvious question about isolator valve but I can confirm it is open]. The system is and has been working fine for years. nothing has been re sited, it's only the pipewok changes that have created this situation. oh, and just to eliminate another of those blindingly obvious gaffes; the tank is full!

 

[Agile]

Others will be able to advise better but I have never understood what is so special about a Tiger Loop that should enable to to be fitted with a tank below the boiler inlet level. They are stated to be self priming!

I can only assume they just rely on the boiler pump to suck the oil? But then why shouldn't other methods?

Obviously if there are any air leaks in the new pipework that will defeat the suction effect as would the air vent being still open.

Maybe clutching at straws but is it possible to fill the chamber with oil and see if that helps it?

Tony

 

[holty]

has the tiger loop just been fitted. if so has the 2 pipe bypass screw been fitted.was the tank shut off valve the circle type.if so could be worth cracking the nut afterwards, with a bucket underneath.to see if oil is being passed.

 

[MANDATE]

The bleed screw is like a blanking plug about 12mm across flats. The one with large hex nut behind has a screwdriver slot behind the plug for adjusting pump pressure.
I would not try it with plug full removed, unless you fit pipe into container.
You could try it with plug loosened.
I recall it took 6 or 7 attempts on mine.

 

[pjmallinson]

Thanks all of you for your suggestions...

Tony; I'll try filling the chamber. Sounds sensible.

Holty of Cornwall; no, tiger loop isn't new. It has been working fine for years. Not sure about 'circle' type shut off valve but oil is definitely flowing.

Mandate; I'll try the 12mm hex nut bleed as you suggest and try start up 6/7 times. Do you concur with Tony that it might also help to fill the tigerloop chamber to its normal working level, ie 20mm or so?

Thanks all of you. Peter M[/b]

 

[APHSLTD]

Others will be able to advise better but I have never understood what is so special about a Tiger Loop that should enable to to be fitted with a tank below the boiler inlet level. They are stated to be self priming!

I can only assume they just rely on the boiler pump to suck the oil? But then why shouldn't other methods?

Obviously if there are any air leaks in the new pipework that will defeat the suction effect as would the air vent being still open.

Maybe clutching at straws but is it possible to fill the chamber with oil and see if that helps it?

Tony

A tiger loop is a deaeration device, you are right in that the oil pump is what lifts the oil. When the pump switches off the theory is that the oil will flow back to the tank allowing air into the system which the tiger loop ten eliminates.

I dont fit them, I prefer to fit a NRV although MI's tend to ask for them.

The should be self priming but you sometimes have to also vent the oil pump.

 

[AlanE]

With that lift and 25 metres of pipe you might have to call in the services of an oil boiler engineer who would have a fuel suction pump to get fuel to boiler.

With the amount of air in the pipe it will take ages using the boiler pump as they dont run long before going to lockout.

 

[APHSLTD]

Thanks all of you for your suggestions...

Do you concur with Tony that it might also help to fill the tigerloop chamber to its normal working level, ie 20mm or so?

Thanks all of you. Peter M[/b]

If you visit the worcester website http://www.worcester-bosch.co.uk/installer/products/oil-boilers/greenstar-camray-1825/literature

download the installation instructions (second link down) and an explanation of how to prime a tiger loop is on page 36

 

[MANDATE]

Another method I have used is with the system closed down, remove control box and remove wiring for motor/pump. Re wire motor/pump from independent switched source ( switched extension lead) You can then run motor/pump without any lockouts until you achieve oil at the nozzle.
I do also have another solution which I have not yet needed since I changed tank. It involves inserting 10mm tee junction just after tank gate valve, 10mm pipe to a 10mm valve and more pipe to a small tank (plastic paint canister) about 3ft higher than tank. So close gate valve, open 10mm valve, oil in canister now flows down to pump, easy to purge and start.
Applied this method for a few days when I changed tanks.

 

[casius66]

Recheck your new joints (and any joints you've disturbed) fitting the new oil line, just give 'em a nip up and try to run the burner 4 or 5 times.

You can cheat the photocell with a torch to prevent it going to lock out (but don't overdo it)...

 

[cjb1971]

I use a suction pump i had from screwfix which self contains the oil it sucks through,made an attatchment up to fit a flexi oil line for it,attatch it,give it a few pumps u hear the air and oil come through,reconnect and fire up no probs!no mess and works 100% first time every time no matter how far away and what level the oil tank is,but for this problem have you made sure that the non return valve on the oil line is working properly?

 

[MANDATE]

Would that be the 'oil suction gun' approx £7-50. Looks ideal for the job.

 

[pjmallinson]

Wow, many thanks to all of you for the incredibly helpful suggestions. too many to thank you all in person. I especially like your suggestion 'Mandate' about fitting a tee at the tank so a false head of oil can be created, plus by-passing the control box to avoid lockout. Brilliantly simple and logical. Am disappointed to think I didn't suss that out myself! May not need it of course but I'll certainly do that if I can't get it to lift without. However, I did get it going when I first installed it all without any trouble but it must be at least ten years ago and unfortunately the memory isn't what it used to be! Anyway, armed with all that I'll be itching to crack on with it tomorrow with renewed enthusiasm. Thanks again all. Peter M