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Central heating / circulation pumps

idris

idris

Member
Joined
3 Jan 2011
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821
Location
Herts
I know there used to be someone who sold adaptor kits to run Grundfos central heating pumps as aquarium circulation pumps, but they don't seem to be available any more.

Does anyone have any current knowledge of these, or know of a good (cheap) alternative?
 
I'm not sure there's much cost saving in using a converted Grundfos pump over the Aqua Medic DC Runner range.
 
Darrel. Thanks. Last time I looked they seemed to be no longer available.
Webworm, by my reckoning, the Grundfos has around 100 advantages (Sterling) over the Aqua Medic. 😉
 
Ok, now you've got my interest, is the based on the price of a new pump, if so can you point me in the right direction
 
The threads on the Grunfos pumps is British standard pipe thread. They come off factory with a swivel and a seal as showen in the pic bellow. Depending on the pump size 3/4" or up. However you want to connect them, ridgid pipe or hose, no special addapter kits required.

$_35.jpg

Standard PVC threaded fittings are also BSP thread. The only thing that could be is the thread in the pumps swivel is Tapered and the PVC threaded fittings are parallel. But that shouldn't be a problem. Jus don't jank 'm in all the way if the swivel is indeed tapered thread...
 
zozo said:
What is it actualy for?.. Reducing the amount of metal in the impeler housing?.
Click to expand...
Corrosion prevention. These mods have been done for years, my mate had a reef tank in late 80's and he used Gundfoss central heating pumps along with the plastic replacement end as his main circulation pumps. The clever thing is the impellor is magnetically coupled thus no sealed rotating bearing shafts are needed, which gives a life time of 10's of years for these pumps. My mates 30 year boiler was replaced recently (as spares no longer available) including replacing the original 30 year old Grundfoss pump.

Still available on Ebay for £12.
 
ian_m said:
Corrosion prevention. These mods have been done for years, my mate had a reef tank in late 80's and he used Gundfoss central heating pumps along with the plastic replacement end as his main circulation pumps. The clever thing is the impellor is magnetically coupled thus no sealed rotating bearing shafts are needed, which gives a life time of 10's of years for these pumps. My mates 30 year boiler was replaced recently (as spares no longer available) including replacing the original 30 year old Grundfoss pump.

Still available on Ebay for £12.
Click to expand...

That's what i thought.. 🙂 Tho it's only good for 50% of the total surface, the other half at the motor housing side stays cast iron including the impeller.
I wonder, with all the todays new coating technologies, if a simple epoxy coating inside the housing could be as sufficient. 🙂

But honnestly don't know, have no experience with these pumps as aqaurium hobyist.. Only as plumber replaced and trashed quite a few.. I know their longlivity can be decades.
 
Now if there was a 0-10v speed controllable heating pump that you could modify......
 
webworm said:
Now if there was a 0-10v speed controllable heating pump that you could modify......
Click to expand...

Than you could search for DC voltage pumps, DC voltage is controllable with Puls Width Modulation.

https://www.ebay.com/sch/i.html?_fr...A0.H0.TRS0&_nkw=pwm+motor+controller&_sacat=0

In a way, any AC pump, also simply is an AC Electro motor.. AC Motors in generaly can be controled best with Variac = Variable Alternating Current.
Widely used in the Air conditioning industry to regulate AC fan motors. From a technical view point it doesn't make much of a difference, moving air or moving water with an electro motor. 😉.

<Google for Variac and you'll find the old type>

Google for AC motor controller you'll find the modern electronic types, step down AC voltage converter
https://nl.banggood.com/AC-220V-400...eed-Fan-Control-Controller-RA-p-1419606.html?

🙂

There are nowadays AC 220 volt PWM controlers on the market.. Yet not figured out how they exactly work.. Google for example for the TC423

Anyway whats most important, find or test the motor specs at minimum startup voltage.
That's the limiting factor..
 
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The Grundfos pumps at my last couple of houses were both 3 speed versions. The old pumps used to have a dial but the new ones seem to have gone all push button. 🙂 Some of them now seem to be available with SS housings.
 
The Aquaturn conversion are very good indeed, there are many benefits.
I have installed dozens of them on fish ponds, marine tanks and my own tanks, the latest versions are made from clear plastic (polythene) and are self sealing connection.
I have had them running continuously for over 20 years.
I use the three speed grundfoss pump, they are not low watt pumps, I think the lower setting is 40w, but offer high pressure performance.
Their advertising is not permanent on eBay , sometimes they are for sale and sometimes not!
 
The way I look at is this...
A second hand central heating pump is £15 ( inc P&P), as is the Aquaturn kit.
An Aqua Medic pump is about £130 (inc P&P).
The CH pump might need a bloody good clean, but my hobby time is free.
Even if a s/h CH pump lasts a year, that's around d a decade of pumps for the sane cost.
Ok. You may not get the fine controlability on flow rate, but you can fit a £5 inline tap to cover that ... though I can't adjust that from my phone.
 
The pumps are very heavy and cost more to run that many low pressure pumps but on the first two settings, there is very little noise or vibration.
In fact on the first setting the pump is virtually silent.
You can just see the kit on this vid and notice just how quiet the pump can be considering the camera is along side it.
 
You do need to consider running cost as central heating pumps are not that efficient in terms of water volume pumped per watt power consumed.

So for my electric @ 17p / KWhr, yearly running cost for a 2400l/hr central heating pump, consuming 48Watts is 365 * 24 * 0.17 * 48/1000 -> £71.

For an equivalent Aquamedic pump (2200l/hr) only consumes 20W, so cost is -> 365 * 24 * 0.17 * 20/1000 -> £30, thus £40 per year cheaper to run.

So £30 for you CH pump and adapter kit, total cost first year £100, 2nd year £170, 3rd year £240, £310 4th year

A £110 Aquamedic pump costs £150 first year, £180 2nd year, £210 3rd year, £240 4th year.

So a proper aquarium pump will have paid for itself in savings after only 3 years. :cigar:. Also Aquamedic has a speed control as standard.

CH pumps were once the money saving way of doing things, maybe 20-30years ago, but today I am not convinced.
 
Aqua sobriquet said:
You make a compelling argument Ian. 😉
Click to expand...
Thank you. In this day and expensive age it is worth spending a little time checking these things out. I don't mind paying a little more in the beginning if its cheaper in the long run.

My JBLe1501 filter @1400l/hr is only 23W which compared to older JBL models, and other manufacturers older models, @ 50W odd, despite a higher initial cost ends up being cheaper.
 
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