Swap Danfoss oilpump with Suntec?

[muckymick]

Hi all,

Back again with oil pump problems (yawn). Anyway since last post it sounds like the last pump I fitted which was a Danfoss BFP 41 L3 is sounding quite angry. I would think it wont last the weekend as it sounds very noisy and to the touch when running isn't smooth I have a replacement but at this stage a new oil pump every three weeks isn't really feasible.

You were all very helpful last time round but the gist I got was, is that there are problems at the moment with the Danfoss pumps. I am thinking of replacing the pump with a Suntec OIL PUMP AS47C-7451 according to the Worcester Bosch installation sheet I think that is compatible with the Electro Oil B9B Burner.

Does this sound like a good idea, am at a loss as the pump that is failing is clear of debris in the filter and there is no detectable water in the tank from last dip with kolor Kut.

probably a daft question too, but is it normal for the oil pump to run hot? I assume so but if you don't know for sure it would be good to know that is normal.

Any advice much appreciated as always.

cheers

Mick

 

[CombustionGuy]

I would be asking why are you replacing a pump every 3 weeks.... How does the motor sound if you remove the oil pump, as the motor bearing could
Be shot and causing distress on the oil pump shaft thus causing that to fail.. Also after installing the oil pump did you line it up correctly and set the pressure and test the flue gases afterwards to ensure it was burning correctly..

 

[Burnerman]

Motor bearing howl is quite a common issue...6202zz bearings needed.
As Norfolk said, if the BFP pump is having such a short life there are other issues.
As for the alignment, there's a small plastic coupling between motor and pump, so check that, and don't over tighten the Allen screws that holds the pump onto the motor.
John

 

[muckymick]

Hello there,

thanks for the reply, Yes I totally agree, why an oil pump would fail so regularly is becoming a headache especially in the absence of foreign bodies and water. Hence my querying is it an issue with Danfoss pumps at the moment or could it be something else in the boiler setup that is as you say putting distress on the pump.

As far as I know the burner motor is fine, it's very quiet in normal operation and although I swapped the last pump ( as it was -1 outside and the WB engineer couldnt get over to me for a week) but the pump fitted prior to that one which lasted less than two weeks was fitted by the WB engineer. He also fitted the burner motor new in april of last year, so he discounted that as a source of the problem. He initially suspected Water in the oil at that stage, that has since been ruled out.

as for lining it up and setting pressure yes that has been done, the lining up seems pretty straight forward and the pressure was set to 100psi as per a recommendation from both the WB engineer and an engineer from this site on my last post.

Flues gases I have no way of checking I did however check the baffles which aren't sooty, that will have to wait unfortunately until next service. Although I would hope that replacing a pump and setting it to an acceptable pressure wouldnt cause the boiler to burn that inefficiently.

 

[muckymick]

Thanks John,

Interesting about the Allen screws i'll ease them off, and the coupler at the time appeared keyed into place but i'll double check it. If I take the pump off and give the fan a spin would that be enough to detect a bearing issue?

cheers

Mick

 

[Burnerman]

If you have had a new motor recently Mick I'd be very surprised if the bearings were shot already.....they do run as hot as hell though, and usually drone if the bearings are past it.
The coupling between motor and pump is just a plastic keyed affair - I've never had one of those fail though, but I don't over tighten the pump Allen screws.
The 41 pump has an excellent cartridge filter inside - that should stop any crap but not water of course.
To check for water, I run a sample of kero into a clean container and wait for it to settle.....I can't comment on the water detecting stuff you use - never come across it!
Be lucky
John

 

[muckymick]

Thanks John,

Well I have ordered a bearing anyway, was only a few quid so just in case, it's there if i need it. Yeah the paste is this stuff http://www.oilybits.com/water-removal/kolor-kut-water-finding-paste/prod_149.html I had a sample of oil from changing the filter so I tested that, no change in the paste I added a little water to the oil let it settle then tested again, the paste goes vividly bright red. so having dipped both ends of the tank and no change in the paste I am convinced there is no water present and yes the filter on the pump is clean as. Also the last pumped that failed i stripped down no sign of rusting at all. To be honest it's a bit of a mystery when i get in this evening I am going to slacken the Allen screws and see if that helps cut the grindy noisy sound coming from the burner housing, and more than likely i'll get the yearly service brought forward a couple of months. I have emailed Danfoss to see if they will contact me and possibly offer any insight as to why this would happen. Sods law, boiler was on all summer for the hot water, not a moments bother!

 

[Burnerman]

The fan isn't catching somewhere, is it?
John

 

[muckymick]

Could be, will open the access point for it this evening and see if it goes round freely and quietly. fingers crossed it may just be that making the noise