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Author Topic: Does anyone else have one of these A-rated circulation pumps?  (Read 726 times)
woodstove
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« on: September 09, 2017, 06:34:25 PM »

If you have a pump that looks like this, can you please confirm if it works correctly on Auto?

I've recently fitted one and it appears to be faulty banghead as the Auto setting runs at 31 watts all the time and does not appear to have adapted to my system.


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« Last Edit: September 09, 2017, 07:05:56 PM by woodstove » Logged
Antman
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« Reply #1 on: September 09, 2017, 07:11:56 PM »

If anything like Grundfos Alpha 2L it depends on what system you have.
They can be completely screwed by bypass valve setting. You also have to be careful to maintain enough flow through a condensing boiler heat exchanger otherwise kettling can result when the pump shuts down low (as the bypass valve will not work). Potentially this could damage the HE and any possible energy saving pales into insignificance!
I gave up on my system - long pipe runs in a large bungalow - and reverted to constant speed (constant curve) mode as it caused too many (and various) issues in auto modes - and believe me I experimented for some time  banghead  In my case it was a waste to pay the extra although it did not cost me as much as it might have if not in the trade.
Antman
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woodstove
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« Reply #2 on: September 09, 2017, 08:24:01 PM »

Thanks Antman

I think I'm going to arrive at the same conclusion shortly, but need to understand exactly why it's not working correctly first.

On my pump, all other modes also run at 31 watts, except constant speed 1, which is 9 watts.
I had expected constant speed 2 to have used somewhere between 31 watts and 9 watts.
The power graph from the users manual says it should be 24 watts, which makes me think my pump is faulty.

Does your Grundfos pump display a different power use for each constant speed setting?












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Antman
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« Reply #3 on: September 10, 2017, 10:31:08 AM »

I went for the cheaper 2L version without the power display - glad I did given the unsuitability for my system. There's no point in the electronic gizmos if you only end up running it as a standard circulator on one of the fixed speeds.
I really feel that the 'energy saving' bug is going too far on standard domestic kit that has to perform a set function - bit like paying an extra 500 for a fridge that tells you that you are running low on milk. I know that cos I just emptied the bleedin bottle  hysteria
Such items will not last as long due to the complexities and reliabilty of the inherent electronics plus limited manufacturer support and thus will end up costing far more in CO2 due to shortened lifespan, recycle and transport costs etc.

There is a place for these pumps in the right system but I am not convinced that they actually save anything in the long term. A bit like smart meters - a government con to make you think you are saving energy when in truth you need the same kWh input to heat the oven for 30mins whether you are watching the smart meter or not.

The other thing is, with my boiler (Remeha Avanta), it runs a pump purge cycle every time the power is cycled - a function you cannot disable  banghead  So after a power cut (annoyingly we've had quite a few this year) it rapidly turns the pump on and off for 3 mins. That is not good for any electronics and certainly not for that which is powered direct from the mains supply, as the increased start-up surge power dissipation shortens the life of the PSU components significantly. If I am home I isolate the pump using the service isolator until the purge cycle ends (easy for me as I have two service isolators on the boiler due to the solar heat dump being linked to CH pump).
Antman
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« Reply #4 on: September 10, 2017, 10:36:18 AM »

I should also mention that system balancing will affect the posh pumps too - far more noticeably that a standard pump. I have seen systems where the lockshields are all cranked open to max. Whilst it may work, it means the system flows and back-pressure on the pump (that is sensed to control the 'speed') will be all wrong even with TRVs.
Antman
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20 x 47mm, 172 l cylinder, Heat Dump, 15 x Sanyo HIT-H250E, SB4000TL,  Nestor Martin IQ13 WBS
DIY Solar System Support at http://www.handyantman.co.uk/antman.html
All support is voluntary and free of charge. I'm not employed by Navitron so responses may not be same-day
biff
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« Reply #5 on: September 10, 2017, 11:27:15 AM »

Good interesting posts Ant,
                    I have been studying these C/H pumps for a while, I promised myself i would get a posh A rated one but then Steve,(ebadger) happened to say something about his having to be reset each times he has outage or any little glitch in the power supply. We did discuss a small UPS back up that would keep the PC alive during outage but for some reason that was not a viable proposition.
  So it looks like i will be exchanging for the bog standard pump connected to our expansion pipe stat. We found out the hard way why the present pump was cheap,,It eats the juice.
                                                           Biff
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« Reply #6 on: September 10, 2017, 03:05:01 PM »

I second all that Antman says, I have at least 6 or 7 dead "smart" pumps in the garage waiting to be offed to the scrappy, but also tellingly about 15 or so standard pumps that are still working fine after years of service only to have be replaced while converting a Y or S plan system to a combi, make of that what you will.  Sadly I think the makers are on a band waggon here, stick a few bits of electronics in the thing, call it "smart" and triple the price facepalm
In reality they will only save a few kWhrs if you are lucky, provided the system is balanced correctly a standard 15/50 only uses 40 Watts or so.

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« Reply #7 on: September 10, 2017, 05:03:38 PM »

yes Desp, I've seen commercial boilerhouses littered with dead Grundfos (and others) inverter pumps, its a total con,the electronics fail before the pump, the direct online types just keep going till they wear out.
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woodstove
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« Reply #8 on: September 10, 2017, 08:04:23 PM »

Thanks all ....... it appears the designers and manufactures still have some work to do on these 'smart' pumps  banghead
Also, it's worth noting that nobody has had anything good to say about them onpatrol

My quest for a smart pump started here:

https://www.navitron.org.uk/forum/index.php/topic,27876.0.html

So far the pump I've fitted is not working as planned. So I've ordered another pump which I think is same as the one eabadger is currently using.
I hope it performs better, we'll see hysteria
  
 



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« Last Edit: September 10, 2017, 08:32:12 PM by woodstove » Logged
eabadger
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« Reply #9 on: September 12, 2017, 03:00:56 PM »

i bought the first one of these about two years ago and works fine, have since updated all pumps to same make.
i did have one brand new eco Grundfoss pump, but have removed it due to what i see is a design error.
as we live off grid we time some circuits off at 00:00, internet (much to kids annoyance) and heating controls, what i found was the Grundfoss always reverts to auto, which was not what i wanted, the ones i have now remember the state you set them to so work fine, the watt hour display is accurate enough as tested with a fluke.

i have nothing to do with the seller or maker but would recommend completely.

steve
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26kw wood stove back boiler to underfloor heating and dhw
woodstove
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« Reply #10 on: September 12, 2017, 07:41:19 PM »

Thanks Steve, that's good news Grin

The new pump arrived yesterday and will be installed when I find a suitable magnetic filter ..... there's way too many to choose from  banghead

When I removed the original Wilo pump and Myson 2 port valve, they were dirty inside and the valve sealing plates were scored, this was causing my unwanted heat leak into the radiator circuit. The wood stove boiler is now 9 years old and has never been flushed, so it's probably time to get it cleaned out and kept clean.

Do you have a magnetic filter installed?

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Philip R
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« Reply #11 on: September 12, 2017, 10:27:19 PM »

Plenty of debate on the shortcomings of these pumps.

How does the pump detect change of flow, is it change of speed as the flow changes or do they have built in diff pressure transducer, are the sensing lines if fitted get blocked up.
I Have recently flushed out 3 heating sytems full of black muck. 2 were all on systems with cast iron heat exchanger shod boilers and open vented. the latter a sealed system with aluminium boiler Heatex.

When the cast iron heat exchangers oxide and spall, they release iron oxide and graphite into the system, the rads provide iron oxide only.

Difference between a conventional circulator and newer HE electronically controlled one is that the former only magnetises ( a little)  when its induction motor is  powerred up. the Latter with its permanent magnets is always magnetised. It acts as a great magnetic system filter and attracts all the muck to the impellor and space in the can betwwen the rotor and stator. wrecks its performance, efficiency and then the pump.

In my garage, I have a nice collection of servicable Grundfos UPS 15-50s and 15-60s from combis I have replaced with new boilers. fitted with PM motors.

I powerflush with a Kamco magnetic filter on my flushing pump on standards radiator plumbing.
If a small bore system. Every radiator, removed to garden and using a hose and some help, I agitate the rads and rinse till clean. Hard work. Then rinse out the small bore pipes. Pain in the back. Both methods are time consuming if done thorughly.

Magnetic filters I like the fernox TF1s and the news TF1 Omegas in nickel plated brass. I have never had one leak and the valves are good quality.
Adey Magnacleans, Cleaned them out, they work well, but I detest the valve layout and crappy cheap leaking valve spindles. I had one snap off in may hand 2 years ago and flooded a garage, water just missed the dis board. Nearly had brown trousers. sh*tfan So dont like them although the newer ones have a more robust plastic housing , still avoid fitting them.
Sentinel centrifuge type, fitted a few. Good valves, dont leak. As I fitted them the new or cleaned system, I have not seen much muck come out of one on repeat service visits.
Spirotech MB2. fitted a few. compact, not sure  now as to their efficacy at catching/ holding dirt due to small magnet inside.
Later MB3, external magnets, not that big, similar concerns.
Cheapo ones from screwfix, magnets too small / weak to hold decent inventory of magnetite without letting it go again.
Eclipse magnetics, fantastic magnet inside. No on sells stocks them in CW1/ CW5 area.

I think your pumps will work better if it is water you are pumping, not water with suspended Magnetite or worse Haematite, (Yellow ochre suspension).
BTW I Use a buildcert approved inhibitor too
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woodstove
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« Reply #12 on: September 13, 2017, 09:27:54 AM »

Thanks Philp.

I think the Fernox TF1 Total filter will be the one I fit, when I can find one at an acceptable price  banghead,
Do you have any experiences with the Fernox TF1 Compact?

Also, it would be helpful if someone here could strip a few of these failed pumps, so we can better understand how they work and fail?
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Antman
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« Reply #13 on: September 13, 2017, 09:51:07 AM »

Philip
I suspect the pumps work by sensing the coil current. This will increase with back pressure/lower flow as TRVs shut down. So with clever alogorithms in the drive electronics the current can be translated into flow rate or pressure depending on setting. The Auto adapt modes will presumably compensate better for varying fluid viscosity.

In my case, newly flushed clean system so no issues with magnetite etc.

My guess is that failures are likely to be smt capcitors that dry out in the inherent heat within the enclosed backbox on the pumps. Mains power and smt electronics in enclosed spaces do not make good companions in terms of reliability. For lengevity you need to keep the electronics ambient temp down below 40degC - which will never happen with a solid lump of metal at 65+ deg sitting directly behind the pcb  wackoold
Antman
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20 x 47mm, 172 l cylinder, Heat Dump, 15 x Sanyo HIT-H250E, SB4000TL,  Nestor Martin IQ13 WBS
DIY Solar System Support at http://www.handyantman.co.uk/antman.html
All support is voluntary and free of charge. I'm not employed by Navitron so responses may not be same-day
eabadger
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« Reply #14 on: September 13, 2017, 04:14:53 PM »

yes i have a fernox tf1 magnetic filter, as we run wood heating and now wet ASHP to the dhw and underfloor and upstairs radiators, i have to make some changes soon and system has been in two years so plan to do a flush and new inhibitor when done.
i seemed to have made a mistake in putting pump on return on wood heating as well, as the negative pressure drops the third floor rads down.
we also have aldin self bleeds on all rads and the floor manifold, but as neat as they look they do seem to fail on a regular basis, the less aesthetic french ones seem to be bullet proof and will swap out soon.

steve
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1600w PV main array at 24v, excide 2v 1000a forklift cells now x 2, 320w PV secondary array at 12v. Enfield 1944 ex RAF 5.6kw diesel genset (now in pieces, big ends gone), Petter AC1 28v diesel charging set at 2.8kw.
1kw wind turbine.
26kw wood stove back boiler to underfloor heating and dhw
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