Twin Headed Grundfos Pumps?

[ash46]

Has anyone had any dealings with the twin-headed grundfos pumps (heating/dhw)?

A friend of mine has suffered with boiler issues (banging/lock out).

After looking around his system where he has had UFH added to the system and listening to the boiler noise I said that it sounded like air was being trapped, so fitted a couple of auto air valves which has reduced the banging to virtually nothing.

Recently though the boiler on the odd occassion has locked out even when no UFH is on, say in dhw mode.
I noticed he had the twin-headed pumps which In the past I have over heard another plumber saying in the merchants he had issues where these type of pumps were fitted!

can anyone else shed any light on these twin headed pumps?

 

[Gray0689]

Never seen twin head pumps in domestic house??

 

[ecowarm]

google "grundfos pump plan"

 

[SafeGasInstall]

never come a cross them

 

[ecowarm]

info here http://www.grundfos.co.uk/web/HomeU...2dc8670a9673180256888005ec605/$FILE/pplan.pdf

 

[stani]

they were used a lot in domestic heating, but if I remember rightly if the head went you had to make sure you got the correct replacement head i.e. left or right hand side. for different direction. b####y expensive item though.

 

[ecowarm]

I maybe wrong but I think the head is UPS 15-50 130 same both sides ie selectric or super selectric

 

[stani]

dont they go different directions? cant remember properly, just seems something in the back of mind about them, but I might be wrong.

 

[ecowarm]

Me also?

 

[stani]

getting old is c~~p is'nt it. lol

 

[ecowarm]

If you look at the link above and go to the the technical section and zoom in to the pump heads it shows same direction of rotation

 

[stevetheplumber]

its just an update on the old two pump system one for heat one for hot water no motorised valves needed

 

[stani]

If you look at the link above and go to the the technical section and zoom in to the pump heads it shows same direction of rotation

so glad you found that it was starting to do my head in. lol:6:

 

[diamondgas]

Joining in on the 'old' twin pump's thing. They were SMC twin pump systems and there was a couple of none return valve fitted to the flows to stop the heating kicking off when the hot water was on! 1st pump hot water with NTR above followed by C/H pump, NTR after it!

 

[ash46]

One side pumps central heating the other pumps the hot water.

After trying to bleed as much air as possible from the system my mate said that it was a lot better but it still locks out the odd time, just thought after hearing another plumber mention he had hasssle with twin pumps that some of you guys might have had issues?

Have had other ideas like the heat not getting away from the boiler quick enough due to maybe a scaled heat exchanger, even increased the pump speed as it was only on 1 just to see if the boiler was boiling the water and locking out?

My mate seems to be convinced its more to do with the UFH he had installed (before I knew him!!).
I have bled water from the UFH/primaries etc.

Didnt want to do away with the existing pump set up and change it for a more common s-plan set-up if it doesnt cure anything!