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

[snb]

I think you are probably going round in circles.

Until you have primed the pump don't try to look at anything else.

For all your efforts it might just be quicker and leave you with some sanity and get an engineer out to prime the system.

If you keep trying all you will succeed in doing is damaging the pump if you havn't already. They don't like being turned when dry. You may be lucky but often the pumps will only last a few days before they start to fail.

 

[Agile]

If you think the motor is not turning then you have to establish if its mechanically free.

If not try oiling.

If it is free, then measure capacitance if you can but for the sake of a £3 capacitor just change it.

As stated, pumps are lubricated by the oil so running then dry is NOT a good idea hence my suggestion of filling the Tiger loop.

Tony

 

[pjmallinson]

If you think the motor is not turning then you have to establish if its mechanically free.
If not try oiling.
If it is free, then measure capacitance if you can but for the sake of a £3 capacitor just change it...

Thanks for that Agile. Am just off to investigate the motor but certainly by turning the fan (slowly, as it's difficult to reach of course) it is fairly free. Not the same as spinning it fast on the bench I know. I'll certainly change the capacitor if it's so cheap rather than mess about. Where do I get bits? Seems NU Way keeps being referred to? As to filling the tigerloop, this has puzzled me. I have tried connecting a small header tank of oil to it for this very purpose but to my amazement it doesn't fill. I tried all three inlets too. There must be something I don't know. Thanks. PeterM

 

[Agile]

Your boiler does not fill !

Your Tiger Loop does not fill !

Has somebody put an antigravity jinx on you ?


As a capacitor, the cost would be about £3 but when sold as a boiler spare part the manufacturer adds a lot and then the parts merchant adds a further lot.

As a boiler spare its probably about £11 !

If you have mentioned the burner model then the oilies will be able to give you a better idea of the cost and where to get them easiest.

Tony

 

[pjmallinson]

If you think the motor is not turning then you have to establish if its mechanically free....

Eureka! Although I'm nervous of even saying it. Removed motor. The fan spun perfectly freely and the bearings seemed fine so it seemed logical to see if it would run... perfect. Obviously the problem must be in the pump. And there was the answer. The bearing is clearly knackered but until I had it in my hand it wasn't so obvious. It seemed a little stiff and would spin over after a fashion but then it would completely jam in certain positions. The gears all look fine and there's no sign of any serious wear so I'm assuming it's the bearing.
I'm sure I could just replace the bearing but sod's law says something would befall the pump in the depths of winter. So I'm very keen to just fit a new pump and be done with it, after all this one is probably of pensionable age at maybe 25 years. And maintenance costs in the past 10 years or so have been negligible too so it does seem fair.
I checked the type and it's a Suntec AS47C 7451. I Google it and found there was a potential supplier not far away so phoned them up. To cut a long story short They were extremely helpful and pointed out that whilst they could probably get one it might be better to just fit the Danfoss equivalent, a 21L3, which is apparently very universally used now and remarkably cheap at about £45 inlcuding lead. This seems too good to be true and to boot if I take the burner in he'll fit it free!! It seems like a no-brainer but do any of you have any views on this? I.e. perhaps there are 'things' I don't know. I look forward to your comments.
[/list]

 

[MANDATE]

Hi! PJ. All I can say is that my Suntec AS47C7451 is of good quality in my opinion. I fitted it in 1996 and no problem whatsoever.
I had to wait 2 days but was offered a alternative which I declined because it involved plastic gears and/or body.
I see the Suntec site has drawings and details of the AS pump.
Don't forget you'll need a oil pressure gauge to adjust the pressure to the specification requirements, although I think mine was in fact set to 100psi which was correct for my set up.
Are you going to treat the burner to a new clean nozzle?.
I also recall having to obtain an adaptor in order to fit the pressure gauge.
Hope you soon have it up and running.

 

[pjmallinson]

Hi! PJ. All I can say is that my Suntec AS47C7451 is of good quality in my opinion. I fitted it in 1996 and no problem whatsoever...

Thanks Mandate for thoughts on AS47C etc. If the Danfoss is inferior quality I'm with you and will certainly stick to Suntec though I gather it will be at least twice the price! I'll check the spec. Thanks also for reminding me about setting pressure. I'd temporarily forgotten about that. Probably can borrow gauge of someone or maybe they're not expensive to buy. Yes, I already have a new nozzle ready to go in. Which reminds me I need to find out the correct positioning and gap etc of the electrodes relative to the nozzle and the air ring. I'll post a photo in case you are familiar with it. And then there's the air control adjustment too. Although it has all worked okay I can't be sure it's all set up optimally. Perhaps I would need specialist equipment though?
It better give trouble free service for at least another ten years after all this! Thanks again. PeterM

 

[Agile]

What type is the failed bearing?

Tony

 

[pjmallinson]

What type is the failed bearing?

Morning Tony. In checking the bearing type I now discover it's not that simple! When I removed the pump gears leaving just the spindle in the pump body I discovered it didn't feel as knackered as I thought. In fact it seemed perfectly smooth if slightly tight. Anyway, I removed the circlip which I assumed held in a roller bearing and lo and behold it turns out it's just retaining an oil seal. There IS NO separate bearing. It's simply a plain bearing, ie the spindle directly into the pump casting which of course logically it would be as it makes it more robust. BUT this means the 'failed bearing' like symptoms I felt must emanate from the gear assembly on the shaft. This is now a puzzle as there is no obvious wear or damage. My only observation was that the crescent shaped insert which fits between the gears is only located by one (tiny) pin even though there are drillings for a second. However, as there is no evidence of a broken pin I assume this is correct anyway. I expect I need to talk to an expert on the design of these pumps unless you know the answer. The implication is that if there is no obvious explanation all I can do is replace the whole pump. Cheers, Peter

 

[MANDATE]

Hi PM.
Had a look at your photos.
I don't think your burner is a D42, everything looks like mine except the bit between the fan housing and the pump. Mine is open and I can get fingers in there to feel and turn the fan.
Regarding the pump, the crescent should have a dowel pin in each hole. Without the 2nd pin it could be loose and foul on one of the gears and affect performance.(That's where the actual pumping takes place, between crescent and gear teeth)
My oil pressure gauge cost £11 +vat, but that was 1996, make sure you get an adaptor so it will fit to pump.
I did not worry too much about air control, kept mine where is was. (to test it would be expensive) I did however check neighbours boiler to verify the setting was OK.
Electrode gap is 3mm on mine and positioned 6mm back from the front face of nozzle.
Don't think the suntec pump is that more expensive than others, I reckon around £50.

 

[pjmallinson]

Hi PM.
Had a look at your photos....

Hi Mandate. Thanks for the above. Electrode setting info very helpful. Always wondered. Yes it's a mystery about the crescent pin. Difficult to imagine how it could come out and even if it did it's almost more difficult to think it wouldn't jam up and destroy the gears. Anyway I'm off to Worcester tomorrow to get a Danfoss fitted and everything set up including pressure. I checked it wasn't plastic or in any way inferior. I too found various sources of the Suntec around the £50-60 mark but all things considered, not the least of which is the time factor, I plumped for this solution.
I'm actually quite glad to be taking the whole burner to someone who can check everything. After all this hassle I'm now pretty paranoid about it breaking down in a few weeks time for some other reason I should have spotted. If it did I think I'd end up in an asylum! I'm just assuming the original 'priming' problem will be a non event when it comes to it, just like it's always been in the past. So not quite home and dry yet. Thanks again. Peter

 

[casius66]

Just double check the flexi hoses are the right way around when you connect up or you'll get a frothy tiger loop and no "flame on" - as I said previously you can cheat the photocell with a torch to keep the pump going until the tiger loop is primed.
I'm led to believe that the Danfoss pumps (which are good) can be run dry for up to 5mins but I've never had to run them dry for that long.

 

[MANDATE]

Hi! PJ How have you progressed with your burner? Do I take it, that it's all up and running again.

 

[pjmallinson]

Hi! PJ How have you progressed with your burner? Do I take it, that it's all up and running again.

Hi Mandate. More or less up and running. It wasn't the end of the story though. I located excellent chap in Worcester and took whole burner to him to fit new Danfoss pump and set up everything. However, discovered the motor bearings dodgey and were intermittently seizing so easy to miss the fault. In the end because fitting a new motor was not going to be straight forward, unlike pump, I decided it was time to fit complete new burner as he had a new surplus stock burner he let me have for £130. Amazing. It was a no-brainer to work out this might spare me from even thinking about central heating boilers for years to come as I can certainly think of just a few million things I'd rather be doing with my time (and I'm no spring chicken!). The only thing I haven't done is an air adjustment/ flue gas analysis as of course I don't have a meter. Still thinking about that one. I'ts also a joy that it fires up so quietly. No problem priming the the oil line etc either after doing the recommended trick with the input flexies into a small pot of oil. Still got my fingers crossed though. Thanks a million for all your help. Can't be sure I shan't tap your brains again one day as I do have another house with an old oil boiler so beware!! Regards, Peter