Biasi 24S ...Pump problem?

[Agile]

Forgot to add that the pump does not start even when separate power supply connected to it

With a crescendo of drums and cymbals!


"I think its reasonable to assume the pump is NOT working!"


I wonder why I suspect you have not read what I have already said! ( Pearls before swine )


Tony

 

[chrishutt]

Although I got it to work on the bench with a seperate power supply

Forgot to add that the pump does not start even when separate power supply connected to it

So which is it? If it doesn't work with a separate power supply then it's clearly faulty.

As for replacing the pump, if the existing pump body is a standard one (130mm long, 1.5" threaded unions at each end, etc.) you can replace the whole pump with any brand with the same length and threads (which are standard fr small domestic pumps) and the same "head" (either 5 metre or 6 metre).

 

[Agile]

Ah, if only life was so simple!

This boiler has a complicated plastic unit backing the pump which contains the AAV, pressure gauge connection and interface to the hydraulic block.

Only the exact type of pump head will fit !

Tony

 

[Tunni56]

Didn't know you were a drummer Tony! For the sake of clarification...

i) The pump operated perfectly whilst on my workbench connected to a seperate power supply

ii) It did not operate when connected to the boiler either on its own power supply OR with an independent supply

Therefore I suspect (as stated in my original post) that the ingress of water appears to be the problem. BUT this issue became 'clouded' by the discussions concerning the water 'leaking' from the vent screw ie was it an abnormal ammount or not etc etc. and as a result of spurting vs trickling was the pump 'shot'

The amount acording to Tony's description seems normal therefore with regard to this symptom, the pump was OK.

That's why I posted this next bit:

Can anyone confirm that the likely ingress of water into the pump housing is as a result of wear and nothing to do with the two rubber seals (as these seem to be OK! Or could seals that appear OK be faulty.

I read carefully, however the fact is that I dont have the answer to the above question yet is it wear and tear or just leaking seals?

Further to that I'm happy just to replace the pump (if it's not too expensive, just to eliminate it from the equation) That's why I posted the model number and asked if anyone knew the price. The logical thing is to replace just the pump head (ie where it bolts to the plastic housing

So in summing up a) if the pump is worn (not the seals) would that allow water into the main housing or is it the seals
b) how much for the pump (hey Tony didn't you have a old one lying around that I noticed on another post)

Oh and the full quotation is:

"Give not that which is holy unto the dogs, neither cast ye your pearls before swine, lest they trample them under their feet" Matthew 7:6

 

[Agile]

The only reason the pump would not work on the boiler is if the impeller is not turning. But you can test that by rotating the shaft.

Do you tighten the pump screws bit by bit? Is the big seal in good condition?

There are two water seals, the large one and a small one under the screw. Is the one under the screw in good condition?

Most unlikely to be the can leaking but it can do!

New manufacturer's pump head is about £120 inc.

But it has to be the correct one for your boiler.

Are you quite sure your pump is the original as factory fitted?

Tony

 

[Tunni56]

OK Thanks for everyones help. The pump WAS faulty. The fault was as I indicated in my very first post (nothing to do with wear as such) but water had somehow found it's way into the housing.

I went to B & Q and discovered that their cheapest pump was virtually identical (the impeller was slightly different) BUT as my pump impellor was perfect with no wear) I just swapped them and now the pump works OK. But the boiler will not now light..it indicates a flue problem. I'm going to start a new post for that!!!

Oops! When I checked the APS several days ago I left a spade connector off! Just remembered.

Now boiler working! Big thanks to Agile (Tony) and all the other regular contributors!

Phil

PS my new pump cost £34!!

PPS I know you can unscrew the actual nylon wheel of the impellor on some pumps. BUT can you do that on a Wilo. It appears that the only way to unscrew the wheel would be to insert a screw driver in the end of the shaft then physically turn the nylon wheel (opposite way to normal as the threads are usually reversed?) Anyone done this?

 

[chrishutt]

their cheapest pump was virtually identical (the impeller was slightly different) BUT as my pump impellor was perfect with no wear) I just swapped them

How did you swap the impellers? do you mean you swapped the pump heads, or the shaft/rotor/bearing/impeller assemblies?

I think you've misunderstood the pump fault. It is normal for the housing of the shaft and rotor to be full of water. The part that should not have water in is the housing of the stator windings. There is a kind of can separating the two, hence the expression canned rotor when describing this design of pump.

Your fault was that the bearing had failed, resulting in the rotor jamming against the inside of the can. When you opened the screw cap at the end a lot of water leaked out because the bearing was so worn - it would normally only allow a small amount of water to pass.

Now why didn't I tell you all this before? Well, I did, in a way, but you didn't notice. I described the same fault in my recent thread (I had this same problem on a Biasi pump) where you posted about your problem. Still, better late than never.

 

[Agile]

As far as I know, all current pumps have the impellers pressed onto the metal shaft and they are not removable.

I must assume that he was able to swap the cans over. That however does not support Chris H's theory that the bearing was badly worn.

There is also the discrepancy that he said it "worked on the bench" but then it "did not work in the boiler".

Pumps are very simple compared with other boiler parts but there are still several pitfalls unless you have a good knowledge of the products.

Well at least he eventually got his boiler working so he is very happy. I would never be allowed to take so long on a repair! An hour on site is the absolute maximum!

Tony

 

[chrishutt]

I must assume that he was able to swap the cans over. That however does not support Chris H's theory that the bearing was badly worn.

That is true. The can itself stays with the stator. It's the shaft/rotor/bearing plate/impeller assembly that can be prised/lifted out, but then he'd have transferred a defective bearing to the new pump if my theory was right. So I guess it must be wrong.

 

[Agile]

On the earlier Wilos before about 2002/3 the rotor could be removed from the can.

On the later ones from about that date the rotor and can come out together.

I think that he swapped the whole can/rotor but the bearing was not that worn!

Different design but the ARGI day at Grunfoss was very good"

Tony