Capicitor wiring for a Grundfos CH Pump

[dsb0118]

My central heating pump isn't working. It goes round but you have to flick the rotor with a screwdriver each time to get it to start. Following advice from other posts on this group I thought it might be the capacitor but the problem is the pump is hard to get at and when I levered the capacitor out, it came out wires and all before I could see where the wires came from.

The pump is a Grundfos UPS15-50x18. There seem to be eight holes numbered 1 to 8 which you can push a wire into. Nos. 1 and 2 are already joined by a wire link so I'm guessing it's not those but which of the other six do I use?

All advice gratefully received.

Also. Does any one know where to get a replacement capacitor from? I live in the Reading area.

[Andrew Gabriel]

Test the capacitor by connecting it in series with a 40W lightbulb. The lamp should come on dimmer than normal. If it doesn't come on at all, the capacitor has gone open- circuit, and if it comes on full brightness, the capacitor has gone short-circuit.

You could try "The Shop on the Bridge", an electrical shop in Oxford Road just after the Dixons/Halfords/MFI/PizzaHut shopping centre as you drive out of Reading. Check the rating you need in µF, and ask them for a fluorescent lamp power factor correction capacitor with the nearest rating (value isn't very critical). I haven't been in there for a long time, but they used to do these when they were still in Kings Road some time ago.

If you have a fluorescent fitting somewhere in the house, you could even steal the power factor correction capacitor out of it (unless it was a cheap Wickes one or similar, in which case they never bother fitting them in the first place;-)

[Richard Sterry]

[snip]

[snip]

Cor, nostalgia! I spent many a happy hour in there as a schoolboy in the mid to late 60's. I thought it must have closed years ago, and was therefore very surprised to see it at its new location on Oxford Rd recently, while visiting my Mum in the Battle Hospital. I meant to go inside and have a poke around the shop, but never got around to it. Must do so, one day!

Rick

[Andrew Gabriel]

Likewise;-) My grandparents knew the Milne's who ran it originally. It was the retail shop which hung off M.J.Milne electrical wholesaler. I think it's now run by one of their sons, and if the older Mr Milne is still around, he'd probably be over 100 by now.

The real shop on the bridge became a wine bar come nightclub, and they moved to the current premises, which are sadly only a tiny fraction of the size. Same sort of thing in there, just not as much of it, and I don't know if the wholesale business still exists (which used to occupy several former shop presises in Kings road just along from the original shop). I don't go into Reading very often now (parking ticket due to badly worded parking restriction designed as a cash earner for the council put me off the place), so I haven't been in there for 2-3 years.

One thing that amused me in the old shop was when it reorganised on one occasion and they built a separate cash kiosk where you paid. They wallpapered the front of the kiosk with all the bounced cheques they'd had returned over the years -- it made for quite interesting reading whilst you were in the queue to pay.

[James Salisbury]

Whilst in Reading you may wish to check out Drews the Ironmongers, close-ish to the station. I got a nice big plastic tool box there a couple of years ago, and took it home on the train. Stood a little too far away from it on the platform and got the question, is this your box sir???????

[Andrew Gabriel]

I haven't been in there for ages. I recall buying a 4 foot length of M10 studding there in 1979 and I've been in a few times since. My recollection is they were quite expensive, but did have some of the rather more obscure things. At weekends, they used to be only open on Saturday mornings, which usually meant they were shut whenever I would think of using them.

Given my previous posting, this is almost too corny to mention, but my parents knew Mrs Drew a few years ago -- she was a neighbour, but moved away and I don't think they are in touch anymore. I presumed Mr Drew, who originally owned Drews, had already passed away -- at least he wasn't around at that time and I never saw him.

There was another independant store I recall in Reading in my youth, Sargents (or Sergents?). They originally had a large store on Oxford Road in the middle of Reading opposite the Butts shopping centre [forgotten what that got renamed to]. Then they moved out to Richfield Avenue which is an industrial estate and had only a tiny showroom no longer suitable for browsing around. ISTR they had vanished when I passed by sometime later.

[MikeS]

Gabriel, Doesn't a capacitor conduct electricity whilst its charging when its charge no electricity is conducted this is when it a dc current but of course if its a/c current then it will charge and discharge to the frequency of the a/c current. MikeS

[Andrew Gabriel]

Yes. So with AC, it continuously charges and discharges, which means an AC current flows through it, and the lamp will light. The current will actually be slightly out of phase with the mains voltage waveform -- for a capacitor it will be leading the voltage waveform. The capacitor will present an impedance which will drop the effective voltage to the lamp (like a resistor, but with no power loss) which is why the lamp will be dimmer, if the capacitor is working.

[raden]

In message , dsb0118 writes

Third time I've said it in a month ... I've just thrown a load out

The capacitor goes between holes 4 and 8

I might have some still lying around

ring me tomorrow

[raden]

In message , Andrew Gabriel writes

2uF / 400v~ (older ones 2.2uF)

it's printed on the capacitor

[raden]

In message , MikeS writes

It's an ac motor, and it's a motor start capacitor

please go on ...

[MikeS]

When testing a capacitor it is safer using a mulitmeter using low voltage DC than using mains with a lamp in series. Hence my rhetorical question re the characteristics of a capacitor. I know its an AC drive motor. Safety first.

A friend of mine who had a good education, unlike me, wired up his mothers iron he connected the positive to the positive terminal likewise the neg to neg but for some reason only known to him he shared the earth connection with the pos and neg terminals. and blew the company fuse. This is why I don't take for granted the level of understanding when it comes to electricity.

You have only to see the fatility figures for the building industy to get a clear idear how reckless some building workers are. Also see the post where the plasterer kept doing his job whilst getting eletrical shocks very macho! MikeS

[Peter]

I've been caught by Reading's badly worded parking zone signs. Everyone I asked agreed with my interpatation of the signage as well...

I wrote an appeal letter pointing out my findings and quoting British and EU laws requiring clarity of public signs etc... They replied stating that the signs had been approved and that I still had to pay up.

I think Reading is in the top three councils making a profit from parking schemes.

What makes it worse is that I live in a Reading Residents parking zone yet the useless council refuse to give me a permit.

-- Peter D

[raden]

In message , MikeS writes

How so?

How are you going to test a capacitor properly with a multimeter?

If the capacitor has lost some of it's capacitance (common fault in CH pump capacitors), it will still show as being a capacitor but might not have enough oomph (technical term) to start the motor

Also, it might work perfectly well at low voltages but fail at mains.

Especially as it's extremely unlikely that you'd get an iron working on DC. There is no positive or negative, only live and neutral (+ earth)

Sounds like he didn't have much of a clue

We're not on about reckless building workers, are we ?

[Rod Hewitt]

Peter wrote in news:1PCdnboQHq [e-mail]:

Many years ago, when I worked in Reading, 'they' changed the direction of some one way streets. During the day. With cars parked along them.

Police were less than impressed when they had to spend hours stopping traffic to enable people to turn their cars round. More fun watching.

[MikeS]

[Jeff]

replying to raden, Jeff wrote: Hi Geoff I appreciate this is a very old thread,but am hoping someone can help.Ive had the same issue,and would like to thank you for answering the original question. Could I just ask as with mine the wires just seem to be slid into holes 4 and 8. Should they be soldered in or is there a screw type mechanism under where they sit,or is just sliding them in good enough.mine maybe the older version as there are no numbers to the hole,that I can see,it's in situ and hard to get a great look at it. I thank you in advance and hope this post is still read

[John Rumm]

Geoff has not been reading the group for some time now.

However to answer your question, the wires just push into the holes - there is no screw to tighten or any soldering required. If you have no numbering there will normally be a wire link between 1 & 2. So you cap goes into the last hole at the other end, and one after the hold adjacent to the link.

See:

or a better view: