Possible to replace Wilo warm water circulation pump?

Hello,
Our gas central heating boiler also provides hot water via a hot tank, loca ted in the cellar. Becaue of the distance from the hot tank to the rest of the house, the hot water pipes are looped through the house to the kitchen and bathroom, and is driven by a circulation pump. This pump has now comple telp seized.
I tested it, using the very helpful guide here:
http://www.youtube.com/watch?v
LQr3Z1pFk The pump is a Wilo Z25, which I have now discoverd is very expensive. The c heapest online I've found is about £400. As far as I can tell, this also includes the brass flanges that connect the pump to the rest of the hot wat er system.
Is it possible to buy the motor, without having to buy the brass flange?
The Wilo Z25 pump is about 13 years old, and looking at the Wilo website, i t seems that the following pumps are available: Z25/2, Z25/5, Z25/6 and Z25 /10. I believ that the one I need is the Z25/2, because its power rating is about the same (~50W, single phase) as the old one I have.
Many thanks, Paul
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cated in the cellar. Becaue of the distance from the hot tank to the rest o f the house, the hot water pipes are looped through the house to the kitche n and bathroom, and is driven by a circulation pump. This pump has now comp letelp seized.

ch?vLQr3Z1pFk

cheapest online I've found is about £400.
Looks like a bog standard CH pump to me. Search ebay for ch pump. The first one I saw was 2 months old and at the moment is £15.00 That's fifteen.
Allan
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On 09/02/2013 14:35, Allan Mac wrote:

located in the cellar. Becaue of the distance from the hot tank to the rest of the house, the hot water pipes are looped through the house to the kitchen and bathroom, and is driven by a circulation pump. This pump has now completelp seized.

I don't think you can use a bog standard CH pump in a (secondary) HW system because the water is always changing - and you'll get corrosion and/or contamination of the water. Don't you need one with bronze innards, or somesuch? A CH pump is designed to circulate the *same* water all the time in the primary circuit.
To the OP: What did your tests reveal? What you you mean by seized? Does the impeller refuse to turn when you dismantle the pump, or does it look like an electrical failure.
If, for example, the windings have burned out but the mechanical bits are ok, you *may* be able to replace the electrics with those from a cheaper pump. But if the mechanical bits are seized, you *will* need to use components suitable for domestic hot water circulation.
--
Cheers,
Roger
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Roger Mills wrote:

You can't normally swap the guts as the impeller needs to be bronze and that is part of the motor. toolstation part number 42168 should be similar to your original pump.
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On 09/02/2013 17:29, Bob Minchin wrote:

I don't think I've ever dismantled one, but the video which the OP cited appeared to show all the mechanical bits (impeller, shaft and shaft case) coming out from the centre of the windings.
--
Cheers,
Roger
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cated in the cellar. Becaue of the distance from the hot tank to the rest o f the house, the hot water pipes are looped through the house to the kitche n and bathroom, and is driven by a circulation pump. This pump has now comp letelp seized.

ch?vLQr3Z1pFk

cheapest online I've found is about £400. As far as I can tell, this als o includes the brass flanges that connect the pump to the rest of the hot w ater system.

it seems that the following pumps are available: Z25/2, Z25/5, Z25/6 and Z 25/10. I believ that the one I need is the Z25/2, because its power rating is about the same (~50W, single phase) as the old one I have.

You can't use a CH pump for domestic hot water, they just corrode up. The real McCoy is made of bronze or stainless steel hence expensive. Most manufacturers make one.
It is costing you lots of lost energy too. Maybe time for a re- organisation.
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How powerful does your pump need to be? As far as I'm aware you don't need (or want) to circulate the water quickly. Would this pump do?
http://www.anchorpumps.com/grundfos-up-15-14b-80-comfort-hot-water-circulator-240v
Tim
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Thanks all for the quick replies. Much appreciated.
The impeller has completely seized. I opened the venting screw on the front and tried using a screwdriver to coax some movement back into the impeller . No go. I then unscrewed the pump housing from the brass flange, and the i mpeller is completely seized.
The original idea behind the pump was to circulate water in the hot water c ircuit in the early morning and meal times, to avoid having to waste water when waiting for the hot water to "arrive". Silly enough, I never used the pump for the last 10 years, and only decided to start using it again when I noticed my water bill.
As far as I know, the pump doesn't need to actually deliver hot water, only to circulate it in the circuit just before use. So, I suppose it doesn't h ave to work very hard to do its job :<)
I suppose I have to use another Wilo pump with matching flange dimensions, as a drop-in replacement for the original.
I noticed a huge difference in prices (two from the UK, and one on Ebay in Germany): http://www.pumpstock.co.uk/wilo-pumps-wilo-star-star-z-25-series.html http://www.mytub.co.uk/product_information.php?productS1577 http://www.benl.ebay.be/itm/Wilo-Star-Z-25-2-Zirkulationspumpe-230-Volt-180 -mm-Wasserpumpe-NEU-P286-13-/111008035150?pt=Systemkomponenten_Heizung&ha sh=item19d898314e
Is it possible that the last one on Ebay is a fake?
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Water bill?
Do you mean water consumption bill? Okay, I suppose you waste a bit of water running the taps waiting for your hot water but I would guess that this will be less than the heat and power you waste by circulating your hot water.
Tim
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Hi Tim,
I'm sure you're right, but my wife pushing to reduce the water bill. So, I thought, circulate the hot water in the morning 15 minutes before we get up to have our showers, and there shouldn't be too much wasted energy.
Certainly if I have to fork out £200 for a new pump, I probably wouldn't recuperate that outlay in my lifetime. On the other hand, I can see her poi nt. Here in Belgium it seems the average water usage per person is about 10 0 litres per day, and ours is about 170. I even measured it recently: for a 10 minute shower and shave afterwards I use 130 litres.
P.

ot

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On Sat, 09 Feb 2013 14:48:56 -0800, ppmoore wrote:

It's clear where you are wasting water...
Try fitting a flow restrictor to your shower, it's simply a screw-on device. I reduced our showers here from 12 l/m to 8 l/m with no noticeable difference in showering performance, but 6 /pm proved inadequate. Yours is 13 l/m.
Something like this:
http://www.eco-builder.co.uk/water-saving-devices/flow-restrictors/
If you both have a 10 minute shower a day, that's 260 litres of water; with a flow restrictor in place that would come down to 160 litres, saving 100 litres a day or 3 cu metres a month. Taking shorter showers would save even more.
Doing that alone, for little outlay and no inconvenience, would drop you way below the average consumption.
As for 'wasted' water, collect the cold that runs first and use it for other purposes, such as watering the garden or washing cars. We store ours in 100-litre butts.
Replacing your pump seems like a costly idea that has no real benefit.
--
Terry Fields

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On 10/02/2013 10:17, Terry Fields wrote:

Much as the rest makes sense, I wonder about the collecting. How many people here are set up to divert (by any means) the cold water that runs first into a butt?
Can't help thinking that the materials and effort would rarely be worth it. At least, beyond the trivial such as using the first bit to sluice down the draining board or wash the spiders out of the bath... :-)
--
Rod

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On Sun, 10 Feb 2013 10:24:58 +0000, polygonum wrote:

It takes 1 minute before the shower flow temperature stabilises, and we collect that water in a 10-litre plastic container. We simply take these outside and empty them into the butts.
Collecting 20 litres a day for the period of March to September saves about £25 in water costs (see below).

Ah, well, paying a combined cost of ~£6:50 a cubic meter for water and sewerage concentrates the mind on water-saving measures...
The two of us here average 7.8 cu m a month, or about £650 a year including standing charges; most of that goes in showers and toilet flushes. Any fewer toilet flushes and the system blocks due to inadequate flow at a junction in the pipework.
--
Terry Fields

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On 10/02/2013 10:40, Terry Fields wrote:

If you both have a 10 minute shower a day, that's 260 litres of water;

Having finally got our water leak issues fully resolved (not much thanks to a major water company that services much of London), I had a scribble calculation of the amount lost. I am convinced it is well north of half a million litres - and that is only considering the time since we realised there was a leak. A lower level of leakage could have been going on for years.
Luckily no meter. :-)
But the idea of carrying a 10 l bucket (or whatever) downstairs and out in the freezing cold is extremely unappealing. Indeed, my partner could not physically do it. Sure I could do it when I am around but still not easy. Our small bathroom, for example, really has nowhere to keep a suitable container.
--
Rod

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On Sun, 10 Feb 2013 11:04:23 +0000, polygonum wrote:

Stay that way!

We don't collect shower water over the Autumn to Spring periods, there's enough rainfall to fill buckets, etc.
The place to keep the 10-litre container is in the bath/shower. Lift it out when the water gets to temperature, and take it outside to empty into the butts on the next journey outside.
As I said, water/sewerage at £650 a year for two careful users concentrates the mind!
--
Terry Fields

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On 09/02/2013 22:48, ppmoore wrote:

recuperate that outlay in my lifetime. On the other hand, I can see her point. Here in Belgium it seems the average water usage per person is about 100 litres per day, and ours is about 170. I even measured it recently: for a 10 minute shower and shave afterwards I use 130 litres.

How long is the pipe between hot water cylinder and shower? Even if it's 22mm pipe, you will only use about 1 litre per 3 metres of pipe waiting for it to get hot - so that's unlikely to be your problem.
Your problem is clearly profligate waste of water! *No-one* needs the shower on full blast for 10 minutes in order to get a decent shower! Try turning it on to wet yourself and then turn it off while you soap yourself, and then back on to wash the soap off. I would struggle to make the whole process last more than *five* minutes - if that.
Oh, and fit a flow restrictor - as others have suggested.
Just replacing your circulation pump will achieve diddly squat!
--
Cheers,
Roger
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nt and tried using a screwdriver to coax some movement back into the impell er. No go. I then unscrewed the pump housing from the brass flange, and the impeller is completely seized.

circuit in the early morning and meal times, to avoid having to waste wate r when waiting for the hot water to "arrive". Silly enough, I never used th e pump for the last 10 years, and only decided to start using it again when I noticed my water bill.

ly to circulate it in the circuit just before use. So, I suppose it doesn't have to work very hard to do its job :<)

, as a drop-in replacement for the original.

n Germany):http://www.pumpstock.co.uk/wilo-pumps-wilo-star-star-z-25-series .htmlhttp://www.mytub.co.uk/product_information.php?productS1577http:// www.benl.ebay.be/itm/Wilo-Star-Z-25-2-Zirkulationspumpe-230-Vo...

Circulating domestic hot water is normally only necessary in large commercial buildings. Only enough water needs to be circulated to make up for the heat losses from the pipework. This depends on the size and length of the pipework and how well insulated it is. But the pump is very small. For a house, the smallest you can lay your hands on.
Intermittant operation is a bad idea. Water that has been heated and allowed to cool is very prone to bacterial contamination because the chlorine (put in by the supplier) has been driven out, This is how people get leggionaire's disease for example.
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Where's the chlorine going to go if the water is always inside the pipe work?
Tim
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harry wrote:

How does this differ from the HW water left in the pipework between the water cylinder and the tap that cools down in a normal HW setup?
--
Adam



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There's more of it. It's not all washed away by running the tap for a while.
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