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Hot Water Circulating Pump problem.

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john1

Active Member
Hi,

I have obtained a central heating water pump with its external wiring
damaged. The damage is minimal, its the small box on the side of the
pump which has been wrenched off, the small box contains a capacitor
and a small rotary switch labelled 1,2,3.
I have the small plastic box which was attached to the side of the
pump, and although it is a little damaged the capacitor looks Ok, and
the small rotary switch looks Ok. The screw holes are damaged but the
connecting wires are not damaged.

The connecting wires were attached with baby spade connectors, these
have pulled away without any damage.

Unfortunately there are six of them, and i don't know where they go.

Well, i know they go back to the six spade connections, but i don't
know which goes where.

I want to put this unit back into working order, so i will need some
help to try and figure out how the pump windings are connected.

Briefly:
Six wires coming from the pump/motor appear to be from three windings.
One of about 180 Ohms, and two of about 70 Ohms.
The windings are electrically independant of each other.
The capacitor is (i think) 2.5 Mfd, 1000 V. Wkg.

It is my guess that the higher impedance winding would be the shadow
and would go in series with the capacitor, unless someone thinks
otherwise ... ...

And that the two lower impedance windings would go to the switch to
be the 1,2,3 settings.
Presumably high medium and low.

The unit is only for 240 V mains, the windings are not for supply
voltage such as 110.

I will try to get some photos up and posted and maybe someone will
actually recognise the unit ... you never know.

Any help in sorting out these six wires would be much appreciated,
Regards, John :)
 
Sounds like a pump that is fitted in lots of domestic heating systems.

As you suggest, post a picture or some of the detail, (eg, make and model) and mabye we can compare, like for like.
 
It's a heating pump alright.

The capacitor is a motor run capacitor, it goes in series with the start winding which is difficult to know without the datasheet.

I take it that you're in a 110V area, well it's desinged to be connected between the two hots on a split phase system.
 
Hi Joe McGiver, Hi Hero999,

Joe, yes it is indeed a pump that is fitted into many domestic heating
systems.
I have taken a few photos, and i will try to post them here.
It is a Celsia Multi-head made by Potterton, i have not managed to
find any details on the internet yet.

Hero, yes it's a central heating pump alright. I removed it from the
discarded system myself. The capacitor is supposed to go in series
with one of the three windings, to provide phase shift for starting
and running the motor.

I'm not in a 110 volt area, the unit is made for 240 volts, and i
think the two lower impedance windings are for the 'Multi-head'
control, which are marked 1, 2, and 3.
How this is achieved i don't know, so far i am just guessing.

**************

The switch part seems very simple, just a three way rotary with one
common. Doesn't seem enough connections to make a parallel with the
two low impedance windings, i dunno. I may have to draw it out to
see how it could be wired.

I shall now try to post a picture or two.
Regards, John :)
 
Heres a pic of the front of it, the motor part is about 90 mm dia,
the pump part is at the base and is about 95 mm square,
the flat part on the left is where the plastic box sits with the
capacitor and the 'head' control.

John :)
 

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another pic
 

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another pic
 

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I have managed to get all the background in focus.
Pity about the white object.

However you can make out the baby spade terminals,
three across the top of the rotary switch,
the one on the right did not have a spade fitting on it,
it has a wire soldered on,
the other two had spade fittings on them, from the motor.

The one at middle bottom of the rotary switch
had a spade fitting on it, from the motor.

The six conections shown on the left are actually
three connections each with two connectors showing.
The bottom pair are both the live connection.
The middle pair are both the neutral connection.
The top pair are both the earth connection.

The middle double connector is the supply neutral and has a wire to the
capacitor, and a spade fitting on it, from the motor.
The bottom double connector is the supply live and has a wire to the
rotary switch, and a spade fitting on it, from the motor.

There are two white wires from the capacitor,
one goes to the middle pair of connections, neutral
the other goes to a connection marked '5' which is a
double connection with two spade fittings on it.
This connection marked '5' also had a motor wire fitting on it.

So from that i could draw up a 'sort-of' schematic,
but it would be pretty vague ....

John :)
 

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A 'sort-of' diagram.

I will have to look again at that rotary switch,
something doesn't look right there.

I may draw it out properly,
to see if i can figure how the motor is to be wired.

Ive put the motor wires as an 'M'
there are six of them.

Any help with this would be appreciated.
Regards, John :)
 

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Checked out the switch.
That is how its laid out.

John :)
 
Hi,

I hope i've traced this right.
but i dont see how to connect the motor.

Maybe someone else could see it ...

John :)
 

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That looks about right but I can't help you connect the motor because I know as much as you.

Have you tried Googling for the datasheet?
 
Hi Joe, Hi Hero,

I have PM'd Hotwaterwizard.
i am hoping that this will be a piece of cake for him :)

Maybe this pump will be running soon.

John :)
 
(and yes, i have tried Google, many times, with many variations,
but i have not found anything)
 
john1 said:
Hi Joe, Hi Hero,

I have PM'd Hotwaterwizard.
i am hoping that this will be a piece of cake for him :)

Maybe this pump will be running soon.

John :)
If he is able to help you could you please post the answer on the forum so that others can benifit from it.
 
I have asked Hotwater wizard to visit this thread,
so any outcome will be shown here.

I have been pondering this obscure problem on and off
for two days now, and i am no nearer to figuring out
the wiring on this pump.

John :)
 
I have looked at my spare pump and taken some ohm readings which are tabulated below
I've used arbitrary numbers 1 to 8 on the connectors. The connection box is plugged to body of pump.
Readings were taken with a DMM set to 200 ohms range

Switch readings were taken at each of the 3 positions (I would take the ohms readings with salt)

readings were done in sequence: 1-2, 1-3, 1-4 etc, then 2-3, 2-4, 2-5; 3-4, 3-5 ... and so on to 6-7.

Make: GRUNDFOS
Type: UPS15-50x18
Model: C
No: U740
.
.
Motor Coil Resistances
.
---- 1 ------ 2 ------ 3 ------ 4 ------ 5 ------ ------ 7 ------ 8
.
.......1------------------- -165 ohms -------------------7
.
...................2 --- 135 ohms ---4
.
...............................3--- 132 ohms --5
.
---- 1 ------ 2 ------ 3 ------ 4 ------ 5 ------ ------ 7 ------ 8
.
.
Junction Box and Switch
.
Connections
.
---- 1 ------ 2 ------ 3 ------ 4 ------ 5 ------ ------ 7 ------ 8.
.
.......1 Neutral
.
.................. 2 Live
.
..............................3 -Link- 4
.
..... 1 --- 2.5 micro Farads 400Vac ----5
.
---- 1 ------ 2 ------ 3 ------ 4 ------ 5 ------ ------ 7 ------ 8.

.
Switch Position
---- 1 ------ 2 ------ 3 ------ 4 ------ 5 ------- ------- 7 ------ 8.
.
one..................................................5 --- 55 ohms --- 7
.
two......................................4 ------ 65 ohms --------- 7
.
three.............2 ----------------- 30 ohms ---------------- 7
.
---- 1 ------ 2 ------ 3 ------ 4 ------ 5 ------- ------- 7 ------ 8
.
.
.
Potterton are makers of boilers. I doubt if the pump was made by them.
I would take a guess that it was made by someone like Grundfos and rebadged.
(Similarly when makers of boilers have their names on controls, valves are often rebadged Honeywell)

Edit - formatting
 
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Hi Cheapslider,

Thank you very much for taking those readings,
and noting them down carefully.
This is very much appreciated.

I am perusing your post and looking for similarities
to the pump assembly that i have here.

Regards, John :)
 
Hi John
I hope you are not sitting in the cold while the pump is not working.

I work with a guy who does motor rewinds and this should be a doddle for him. Only thing is, I wont see him until tommorow.

I will try to have an answer for you then, hope that is OK.

JMcG
 
Thank you Joe,

No, i'm not sitting in the cold.
I intend to use this pump to pump out an area by my front door,
which floods-up like a deep puddle every time we get heavy rain.

I had a similar water circulating pump for this job before,
i would just turn it on when i needed it.
They are (usually) quiet running, they don't have much of a pressure
output, but they shift quite a lot of water so long as it moves easily.

My path by my front door is a little lower than the immediate area
around, and when it rains heavily it soon gets a few inches deep in
water. I have tried soakaways, but they don't last long. So i was
using one of these circulating pumps as i don't need to lift the
water very high at all to get it to run off elsewhere.

Occasionally the pump i had would clog and stop, that is easy to fix
with this type, they run the rotor via a thin sheet of stainless.
But i foolishly tried to clear out a screw-hole on the pump i had.
I don't know why i bothered to clear out this screw hole in the body
of the pump i had. It had been left dirt filled for years, and had
never been any trouble. But on this day i had to clear the pump, and
i noticed a screw-hole full of dirt. So i poked at it with a nail.
I wiggled the nail, and i blew in the hole. I shoved the nail in and
out, and i wiggled it some more. I blew in the hole again, and i
thought - there, now thats a nice clear screw-hole.
The screw hole wasn't even in the pump bit of the unit, i just got
carried away.

Well, after re-assembly the pump didn't work.
Upon examination i found that someone had damaged the internal coils
by poking at them with something, possibly a nail, right under the
now free and clear screw hole.
That put me in something of a bad mood for a while, then i tried to
repair it. I made a special copper part for my iron, found all the
damaged ends, soldered them back as far as i could see alright.
It wasn't alright. That pump never ran again.

So i was quite pleased to come across this one, still attached to
the 'Ideal' boiler unit that was discarded outside a house where an
extension had prompted a central heating re-fit. I removed it, and
also took the small electrical box that sits on the side of the pump
which was dangling nearby, having come adrift during the upheaval.
I thought it would be no trouble to re-attach the pump connections,
as they are little baby spade connectors, and they had pulled away
with no damage, except to the plastic box which is rather broken up.

When i had a good look, i see that this pump has six wires to
re-connect. So, thats the story so far.

Cheers, John :)
 
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