grundfos pumps

[doityourselfido]

what is the difference in grundfos pumps can a 15-60 replace a 15-50x 18 which is unatainable..

 

[45yearsagasman]

What's it off? Is it a boilermate thermal store?

 

[matt1e]

replace with a selectric 15-50 (direct swap) or an ALPHA2/2L 15-50 whitch is also a direct swap but more economical, a better pump and of course much more expensive

the numbers refer to bore size (15) and head the pump produces (50= 5 metres) BTW

 

[wibbit]

replace with a selectric 15-50 (direct swap) or an ALPHA2/2L 15-50 whitch is also a direct swap but more economical, a better pump and of course much more expensive

the numbers refer to bore size (15) and head the pump produces (50= 5 metres) BTW

Can I just say, I've probably spent the last 2+ hours trying to work out what those number mean.

The 50 was easy to find (5m head hight), however I've really struggled to find what the 15 meant!

In case you can answer my other question, what's the last number for

E.G.
ALPHA3 15-80 130 v's ALPHA3 25-80 180

So, we have 15 = bore size
80 = 8M head hight.

Whats the 130/180 for?

Resurrecting a rather old thread, as it seems some what pertinent.

 

[wibbit]

Never mind, 130 vs 180 = Port to Port length (basically the distance between the input/output)

 

[Johntheo5]

You shouldn't need a 8M (80) pump replacing a 5M or 6M pump but most 5/6M pumps are 130mm port to port.

 

[wibbit]

You shouldn't need a 8M (80) pump replacing a 5M or 6M pump but most 5/6M pumps are 130mm port to port.

Thanks John I'm looking at the 8M as we've had a loft extension done, and from the pump/boiler to the top of the highest radiator is around 7m

 

[JonathanM]

Thanks John I'm looking at the 8M as we've had a loft extension done, and from the pump/boiler to the top of the highest radiator is around 7m

I don't know how much the pump head required (in metres) depends on the actual physical height of your system. I think it's more to do with the resistance in the system. I think the pressure to push the water to high radiators comes from the pressure vessel, more than the pump. Hopefully, somebody else will weigh in to say where the balance lies.

 

[wibbit]

I don't know how much the pump head required (in metres) depends on the actual physical height of your system. I think it's more to do with the resistance in the system. I think the pressure to push the water to high radiators comes from the pressure vessel, more than the pump. Hopefully, somebody else will weigh in to say where the balance lies.

I've got another thread open specifically about the pump replacement, this was more the meaning around the numbers.

Interesting about the head required, and the issue vessel.

I suppose at the end of the day, the water being pumped up, also has water coming back down again, so not quite the same as simply pushing water straight up.

I'd not thought about that, however as you say, hopefully some one with with a better understanding than me will speak up

 

[Johntheo5]

The height (elevation) theoretically makes no difference to the pump head required as its a U tube whether via a header tank or if sealed via a E.vessel with a cold pressure = or > the elevation In practice, depending on the piping diameter, then the head required will be a little higher but if piping is 22mm or greater then no real worries. The head required as stated above depends on the system pressure loss due to the boiler Hx (heat exchanger) loss, rad loss and valve & pipework losses etc. Gas boiler Hx losses can be quite substantial, up to ~ 3.5M at say 20LPM flow, oil fired boiler Hxs have practically no losses.

A " 6M"UPS3 would IMO be a good replacement as this pump is way more powerful than most other 6M pumps, my main "crib" about them is that they don't display the power in watts which can be very useful when/if problems ever arise.

 

[wibbit]

Thanks for the details.

We have quite a bit of underfloor heating, however they have their own pumps, so the boiler pump is only driving the water to the mixer valves and the 6 or so radiators, the bulk of the under floor heating is fed by 28mm pipe (about a meter from the boiler all the way up to the mixer valve).

I was considering the grundfos alpha3, largely due to the Bluetooth connection, and my geeky side wanting to go out up to home assistant.

I'm assuming the 15/60 would be a perfectly suitable replacement?

 

[JonathanM]

I think you said on the other post that the radiators in the living room don't get hot?

 

[wibbit]

I think you said on the other post that the radiators in the living room don't get hot?

That is correct.

Though, I don't know if that is due to the current pump falling out not.

I have wondered also weather the 28mm for return to the bulk of the underfloor heating was sufficiently "easy" that the water is simply following around that loop, and avoiding the radiators in the living room.

If I turn off that underfloor heating (which closes the valve) then they start to warn up, but excruciatingly slowly

 

[wibbit]

Would it be better to move this discussion to that thread?

 

[Johntheo5]

Yes, probably better on the other thread, can you then say how many UFH manifolds and pumps, loops etc and when all on together the total flow by adding all the flow meters and the manifold(s) flow&return temperatures.