Russell griffiths

Manifold system versus hot return system

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Quick update. So the consensus on here and the www is 'bronze pump' for the hot return. I didn't want to speculate further so I called Wilo to get some answers.

 

Wilo technical confirmed that it is  the incorrect pump for a hot return circuit and that after time I would get rusty water from the taps and finally a pump failure.

 

Why on earth would the very knowledgable and highly skilled plumber fit the incorrect pump to our hot return circuit? He must have known what he was doing?

The list price of the incorrect fitted pump is £120. The list price for the correct pump is £548. 

 

(That £548 is  the list price for a Wilo SB60, a Wilo SB30 would probably do what is required with ease and can be had for £162)

Edited by Russdl
Added detail regarding SB30 pump.

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37 minutes ago, Russdl said:

Why on earth would the very knowledgable and highly skilled plumber fit the incorrect pump to our hot return circuit? He must have known what he was doing?

Unfortunately he wasn’t as skilled as you may have thought . Cynically he can wait for it to fail and get another call out fee . As many of us have found most trades think they are doing a good/correct job yet they aren’t . In my experience about 75% don’t do it properly ( though it may work ) or cut a corner to save them time .

Edited by pocster

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@Russdl That’s not a cast body - it’s a resin body by the looks of it so I would query the model number on the front as a resin body pump is suitable for potable water instead of a bronze body (and Wilo confirm this)
 

And Hep2O can be used as a hot water return circuit. You have (incorrectly) read the guidance and don’t understand the BS/ EN definitions and I have had this confirmed by Wavin.


For info the below is the definition they (Wavin) use for a hot water return circuit which you don’t meet on 2 of the 3 criteria so you have no issues. 
 

AC5F6F30-3B54-4A33-9F1D-6ECF080416EE.thumb.jpeg.409c2522ea410fbd1174c73ebfd7104b.jpeg

 

 

 

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12 hours ago, Temp said:

Several ebay sellers appear to sell that pump as secondary loop pump but I can't find any info on an RS25/6 on the Wilo website.

 

Says here it a "plastic body...for bronze model". Comes across that it's a valid substitite, as in plastic won't rust etc? Goes on "Can be used for open circuit / potable".

 

https://www.ebay.co.uk/itm/WILO-25-6-1-Plastic-Body-Secondary-Hot-Water-Circulating-Pump-for-Bronze-Model-/292505594621

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13 hours ago, mvincentd said:

I dont recall the rationale now but I was also lead to believe it needs to be a bronze and a rationale was given....

 


doesn’t need to be bronze, just needs to be not cast or steel as the oxygen in the drinking water can corrode steel. 
 

4 hours ago, Russdl said:

Thats from the Wavin site, and Hep2O has been used in our hot return loop. As ours won't be continuously operating I think we're in the clear but it was going to be initially. I didn't really want a hot return circuit but the plumber cajoled me in to agreeing to one and came up with a simple solution to only make it run when the bathrooms are occupied.


it’s a decent solution tbh and one that actually makes sense. Got any photos of the install under the sinks or bath as would be interested if it’s in 15/10 or 10/10 etc. 

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12 minutes ago, Onoff said:

 

Says here it a "plastic body...for bronze model". Comes across that it's a valid substitite, as in plastic won't rust etc? Goes on "Can be used for open circuit / potable".

 

https://www.ebay.co.uk/itm/WILO-25-6-1-Plastic-Body-Secondary-Hot-Water-Circulating-Pump-for-Bronze-Model-/292505594621


Yep that’s the one I’ve found and I think is used in some oil boilers that have hot stores hence why that vendor is selling them. Most likely an OEM pump to Grant or others and resold by them as a spare. 
 

 

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1 hour ago, Russdl said:

Why on earth would the very knowledgable and highly skilled plumber fit the correct pump to our hot return circuit? He must have known what he was doing?

 

 

Presumably to save you £428 😂

 

Wish I had a hot return. Takes a full minute to get warm then at 1m15s it's hot. 

 

If you don't want that pump I'll have it . How's it triggered, occupancy sensor or something?

Edited by Onoff

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It’s not a plastic body. It’s cold and scratches just like any alloy would and there is definitely something ferrous inside (magnet sticks with ease).  I’m minded to stick with the Wilo tech guy on this and not the eBay resellers. Maybe the Wilo guy is wrong but with this conflicting info I’ll stick with him. 
 

Regarding the hot return pipes. I’ve got that wrong. I’ve been reminded that the pipes are plastic coated copper and I agree the solution to turning it on and off is elegant. 
 

 

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9B2ACFB6-DF5C-41A3-8791-C6AE4FAD9EAA.jpeg

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Is it plastic insides maybe?

 

Edit: As in steel coated  maybe?

Edited by Onoff

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@Onoff I’m afraid I have no clue and as information has become conflicting I’ve come down on the side of the Wilo tech guy.
 

Like I said, this all started after three separate commentators told me it was the wrong pump. I wouldn’t have had any idea. 

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11 minutes ago, Russdl said:

@Onoff I’m afraid I have no clue and as information has become conflicting I’ve come down on the side of the Wilo tech guy
 

Like I said, this all started after three separate commentators told me it was the wrong pump.  


you haven’t got the wrong pump. 

 

You are scratching the motor body - that is always alloy. What is the impeller body at the back ..?  

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+1 to @Bitpipe  my circulation pump is the same - not surprising, same plumber!

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40 minutes ago, Bitpipe said:

I have just checked mine (minor panic) on reading this thread.

 

Grundfos UPS 15-50N 130 (p/n 97549426) Selectric Stainless - rated for domestic hot water return, available here for £221 inc. vat.

 

 

So... go back 20 years and for DHW pumps the answer was “bronze pump guv...” and stainless was the realms of process engineering and aggressive fluids and were eye watering in price. Pumps had 60-90W ratings and they were big and noisy. 

 

Around 10 years ago, stainless started to appear in the market mainstream and it’s slowly had uptake but it is still expensive. Pumps got more efficient and electronic control started to appear more in the product set and pumps started to be seen with 40-50W ratings. 
 

Since then, engineering polymers and lightweight materials have become more prevalent, and pumps with eRP A* ratings have appeared with ratings of less 15W.

 

This is simple product evolution. Engineering polymers cost significantly less than bronze as they can be finish moulded, and require limited machining unlike their bronze cousins. The costs have dropped dramatically and sub £100 pumps are commonplace. The downside is they are are an unknown in terms of lifecycle and slightly less durable than their cast predecessors. 
 

Don’t write a product off because your plumber has never seen it, or we are all destined to lead pipes and bathing in front the coal range !!

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So the correct approach is - use a pump rated for DHW return and don't focus on a specific material.

 

However, is the Wilo RS26/6-3 pump featured above compliant or not?

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On 02/01/2021 at 17:47, Russell griffiths said:

Check this out, bit chuffed with this, never used a bender A653D8E5-1AB0-47A2-B8C4-48A7848EF175.thumb.jpeg.382d817181e903994a3c5bd8e9efecec.jpeg

  

 

I just read it as "Check this out, bit chuffed with this, never used a bender".  What over the knee!  "before" was further down the page

 

Very nice

 

 

Edited by Adrian Walker
add more text

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2 hours ago, PeterW said:

you haven’t got the wrong pump. 

 

You are scratching the motor body - that is always alloy. What is the impeller body at the back ..?  


Clearly indicating how little I know about these pumps. The impeller body is black plastic or some such thing.  I understand what your saying but Wilo say it’s not the correct one. All the pumps on the Wilo website that are specifically for domestic hot water recirculating loop have a bronze impeller body.
 

image.jpeg.025d471e2a4c0cb75fd2f308c8bb892e.jpeg

 

The tech guy told me I had the wrong one and I feel obliged to go with that advice. 

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15 minutes ago, Russdl said:

The tech guy told me I had the wrong one and I feel obliged to go with that advice. 

 

I couldn't see where it says that at the link? Is that the tech guys personal opinion or can he back it up with a link to his company's, manufacturer's instructions? 

 

(I've got the hump this afternoon after a big company's so called tech guy gave me a bum steer! 😂).

 

A funny aside, a mate asked me if I'd ever seen a particular busbar system connector. I said yes it's so and so make. No he said I've tried them and they said it's not theirs. So I rang the tech line myself. A very nice young lady confirmed that's no it's not theirs. On the off chance I asked if a particular tech guy, Steve still worked there. We last dealt in 1987 and I had happened across his name in my old filofax. He did amazingly and we chatted about old times. No he confirmed, not their busbar. Yes it is I insisted. He put it to their parent company in the Netherlands and they found a box of 20 in what they refer to as their "museum". Old stock not on the system. My mate bought the lot. I got an email from Steve saying he didn't even remember them so how f***ing old must I be!

 

 

 

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20 minutes ago, Russdl said:


Clearly indicating how little I know about these pumps. The impeller body is black plastic or some such thing.  I understand what your saying but Wilo say it’s not the correct one. All the pumps on the Wilo website that are specifically for domestic hot water recirculating loop have a bronze impeller body.
 

image.jpeg.025d471e2a4c0cb75fd2f308c8bb892e.jpeg

 

The tech guy told me I had the wrong one and I feel obliged to go with that advice. 


So if you were to go with bronze as your choice (not that I agree with Wilo and they have been wrong before...!) then you can switch it if you want but I think you’re spending money you don’t need to.
 

There is nothing ferrous in that plastic bodied pump to rust so it will never fail. 
 

 

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51 minutes ago, PeterW said:

There is nothing ferrous in that plastic bodied pump to rust so it will never fail. 
 

 

Along with plastic pipes. What's to rust in there? I'm lost.

 

Won't any "iron in the water" be picked up anyway by a Magnaclean etc? With the appropriate inhibitors in there it'll last an age. If it does go t!ts up it's not the end of the world, minutes to change on a bad day. 

 

It doesn't run that often either does it. I reckon the biggest win here is the saving you've made of £428 (list 😂).

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12 minutes ago, Onoff said:

Won't any "iron in the water" be picked up anyway by a Magnaclean etc? With the appropriate inhibitors in there it'll last an age. If it does go t!ts up it's not the end of the world, minutes to change on a bad day. 

 

 This is on the potable supply as a hot water circulation pump. But agree about the lack of ferrous in the system. 

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4 hours ago, Onoff said:

I couldn't see where it says that at the link? Is that the tech guys personal opinion or can he back it up with a link to his company's, manufacturer's instructions? 

 

I called up, gave the tech guy the part No. (it seems they call it a Star No?) and asked if it was suitable for a hot return circuit. I  reckon he was punching that part No. into his computer, and computer said 'no'. He told me I needed an SB60, as I explained exactly what it was for he said the much cheaper SB30 would be more than sufficient. I couldn't comment further on his competency or otherwise

 

5 hours ago, PeterW said:

Don’t write a product off because your plumber has never seen it, or we are all destined to lead pipes and bathing in front the coal range !!

 

I wouldn't do that, I was the heretic after a standard light switch in a downstairs WC (not literally). I like change unless there is a good reason not to.

 

I appreciate your explanation as to how things have evolved in the manufacturing process, had I had that information last night I either wouldn't have called Wilo this morning, or if I had I would have been much better informed.

 

4 hours ago, Onoff said:

With the appropriate inhibitors in there it'll last an age

 

As I said and @PeterW highlighted, this is in potable water supply, so trying to minimise use of the inhibitors 😁

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1 minute ago, Russdl said:

I  reckon he was punching that part No. into his computer, and computer said 'no'.


It’s a generic OEM part though - Grant supply them for their boilers under a different product code, and they list them as suitable for potable. Not surprised they told you bronze though as that’s the gold standard - they even spec aluminum in the US but they aren’t used in the UK due to all sorts of other risks ! 

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46 minutes ago, PeterW said:

It’s a generic OEM part though - Grant supply them for their boilers under a different product code, and they list them as suitable for potable.


Again, that shows what I know. I thought Wilo were the manufacture of that pump?

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