advice needed, re replacement central heating pump please

[arther dailey]

Hi
gotta replace a grundfoss mk2 pump, its 3 speed, looked on net several grundfoss availaible, what I need to know is 1 1/2" bsp measured on the bore or external thread diam, as the one I have removed is approx 1 7/8" measured on outside of threaded connection.
one I found on the net has the correct width of 130 mm width, but states 1 1/2" bsp pipe connections.

appreciate your advice/help/time. thanks Arther

 

[eddie49]

The number "1 1/2 inch" BSP is a size, not an actual measurement.
From here: https://en.wikipedia.org/wiki/British_Standard_Pipe, the major thread diameter for 1 1/2 BSP is 1.882".
As a decimal, your measurement 1 7/8" is 1.875" which is close enough, so yes, your pump is 1 1/2inch BSP.

 

[brightspark]

good pumps but over priced .theres decent cheaper ones just as good

 

[arther dailey]

The number "1 1/2 inch" BSP is a size, not an actual measurement.
From here: https://en.wikipedia.org/wiki/British_Standard_Pipe, the major thread diameter for 1 1/2 BSP is 1.882".
As a decimal, your measurement 1 7/8" is 1.875" which is close enough, so yes, your pump is 1 1/2inch BSP.

Brilliant, thats a huge help, thankyou

 

[arther dailey]

good pumps but over priced .theres decent cheaper ones just as good

sounds good, could you tell me what make/s you know to be good but better on the wallet,thanks

 

[dobbslc]

Grab one from Screwfix or a proper plumb shop rather than online, you can take it with you then just to be sure its fits.

 

[brightspark]

just looked theres not much difference in prices these days grundfoss have a 5 years warranty on them by the looks some are only 1 year

 

[Kayos]

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/233173744808

Fitted loads without issue, maybe not on a brand new boiler but fine on older systems

 

[arther dailey]

Screw fix and plumbing shop are virtually opposite, just a few miles up the road , so will take old one with me as suggested and see how they compare . cheers guys

 

[dobbslc]

I found that my local shop "Plumbco" were also cheaper then screwfix for a Grundfos pump!

 

[Kayos]

@arther dailey I really really wouldn't over think it, in a domestic setting a pump is a pump is a pump, if it's an old system the modern modulating ones will cause more issues than they solve

 

[arther dailey]

Kavos, appreciate that, the only concern was thread size, and width, I am just after same as nothing fancy, the original only cooked because the system wasnt flushed and impellor got clogged...but after 30 years no ones complaining !!
found a couple new unused grunfoss on the net so will see how they go,other than that new ones just over £100, screw fix are spendy, as are the plumbing shop. never heard about the pulsing jobbies , but there again dont usually get involved with plumbing ! Thanks

I found that my local shop "Plumbco" were also cheaper then screwfix for a Grundfos pump!

Thanks ,will check it out

 

[Kayos]

Just get thr Ebay one I linked, £30 and work spot on