replacing central heating circualtion pump

[marctiga]

hiya

my dinosaur heating circulation pump as finaly died on me after many years of good service its a smc cadet "s" circulation pump (yes its old! lol)

ive been looking on ebay fora replacement and found most are grundfos 15/50 or 15/60 type pumps but i've measured the length of my smc pump and it seems longer than 130mm (where do i measure it from? end of flange threads or just the body?) as i presume now is the standard length for these type of pumps is 130mm?

i was wondering if im rite in sayin that the grundfos pump wud not be a st8 forward take out put in pump to replace my smc cadet one because of the length of it?

any advice please or where i cud get a replacement pump? or even a second hand smc cadet (yes i know im hoping lol)

thank you

 

[EliteHeat]

You would be better off draining the system and modifying the pipework to suit the new (and every other) pump. Replace the valves whilst you're at it - not that they would budge now I expect.

 

[Nige F]

hiya

my dinosaur heating circulation pump as finaly died on me after many years of good service its a smc cadet "s" circulation pump (yes its old! lol)




thank you

That`s Unbelievably old

 

[khaitken]

Hi!

I've just been going through a similar exercise: pump hasn't packed in as yet but not getting a lot of heat upstairs. Went under the floor to adjust the speed control - just keeps turning and no improvement. So, having recently drained/flushed the system to no avail, a new pump! Went back under the floor to measure up and discovered, like you did, 160mm port to port and all modern-day pumps are 130mm. Under the floor again today to find out the make of pump (as the Grundfos website has a replacement pump finder), put "SMC Cadet 's'" into Google and came up with your post.

So it looks like drain down again and modify the pipework as EliteHeat suggests!

The Grundfos site recommends an Alpha pump as a replacement as opposed to the 15/50 or 15/60. Not sure what the differences/benefits are - anyone got any thoughts on the subject?

(I've got 16 radiators covering about 200 sq m on two floors with a relatively new Potterton Profile 80 EL boiler).

Thanks

Ken

 

[namsag]

No need to alter pipework there is a simple fitting called a pump adaptor that makes up the difference in size

 

[bab]

get a 15-60 unless uv money to burn. alphas may be clever but i find clever lasts less. time will tell. The pump extensions come in different sizes. Get extra rubber washers if gona use extension as the fibre can be a b1tch to seal if access is poor. ya new grundfoss will come with 2 new rubber washers.

 

[gas4you]

Last Alpha I fitted new took took out the boiler pcb

I haven't dared try another since

 

[khaitken]

Thanks everyone for the really useful advice. I'll go hunt down pump adaptors and a 15-60 pump!

Ken

 

[twgas]

i Find fibre washers better between pump and extension piece as they dont splay out when tightened. rubber at the valves though.

 

[ollski]

i Find fibre washers better between pump and extension piece as they dont splay out when tightened. rubber at the valves though.

Ditto that, we probably use different adaptors but the ones I use won't seal with rubber washers, they just chew em up.

 

[namsag]

Rubber washers a complete waste of time on adaptors just ok at pump end even some of fibre washers supplied are garbage. The thick walled fibre ones are ideal.
And why do people not use rubber washers on straight change pump to pump valve so much easier to change pump in future

 

[marctiga]

oh so i can get a pump adaptor so i dont have to fiddle with modifyng the pipe work and then i can put a grundfos pump in? which grundfos pump would you suggest 15/50 or 15/60?

any ideas where i can get the adpators from anyone?

many thanks

 

[Terrywookfit]

You could try a plumbers merchant!!

 

[khaitken]

I found adaptors at:

http://www.heating-parts.co.uk/ProductByGroup.asp?PrGrp=69

and

http://www.bes.co.uk/products/105.asp

but haven't decided what I need as they don't give sizes!

I presume the Cadet has 1 1/2" ports but haven't confirmed this - another trip under the floor!

 

[namsag]

ON first link get 1 each of parts that end in numbers 929 and 107 one of those will do it. Also get a couple of extra washers at same time or as they call them gaskets