Would you replace this pump?

[Ben Lumley]

Hello,

Hoping you with more knowledge + experience can help with a quick query.... please

One of the pump valves started to drip badly this week from the spindle, so I've got them out to replace, so have the pump out.

Pump is a Grundfos UPS 15 50x18 Model C No U748 MKII - see picture of the label.

Guessing it's pretty old? It looks old and all the pipes around it looked very undisturbed, caked in scale, dust etc (must have leaked a bit at some point) - so presumably been there a while.

It's more than a tad noisy from time to time - can hear/feel it all through the house. Especially if you turn it up to 3 (2 seems to work fine and is much quieter). Makes me wonder whether it's seen better days? Or are they just noisy?

It quite scaled too - quite a lot of black rubbish was caked into the inlet/outlet and washed out when I ran water through it + prodded a bit. The ports (is that the name?) look like they'll need a bit of a clean before they'll seal (remnants of old rubber washer + scale all over them). Sure all that can be cleaned up though.

What would you lot with infinitely more experience than me recommend? Replace whilst system is all in pieces anyway? Or clean it up and refit?

I'm erring towards thinking a new pump might be the safest bet and hopefully be a bit quieter too? But no experience to base this on - so I'm all ears if you reckon this is normal and it's got years left and I should keep my money till I need to spend it.

Thankyou!

 

[Hugh Jaleak]

Personal opinion, if it works, don't fix it. Grundfos probably the best on the market at the time, and still are IMO.

 

[Agile]

You should only be using it on the setting "2".

No need to replace it.

Who is the "them" you got out to replace it?

Tony

 

[Steelmasons]

You should only be using it on the setting "2".

How did you deduce that???

 

[Ben Lumley]

You should only be using it on the setting "2".

No need to replace it.

Who is the "them" you got out to replace it?

Tony

No them, just me. That's why I'm seeking a bit of more experienced input here - looking like consensus is keep the pump, so worth my while dropping by!

 

[Agile]

Replace pump valves with proper gate type.

Smear silicone grease on the seals.

Then you can easily replace the pump at any time in the future if you needed to.

Tony

 

[Terrywookfit]

Replace pump valves with proper gate type.

Smear silicone grease on the seals.

Then you can easily replace the pump at any time in the future if you needed to.

Tony

Why would you put grease on the rubber seal??

 

[ollski]

How did you deduce that???

I did some course on grunnies years ago and they said 1 on a clean system 2 on dirty and 3 only for bleeding the system. Nothing winds me up more than people setting speed 3 on a restricted system as if it was a pressure pump and pulling air in.

 

[oilboffin]

Yes but if the system is properly done eg positive pressure then you can run the pump on 2 or 3
I was also told to bleed the system at rest eg. everything off.

 

[Terrywookfit]

Surely the speed should be selected to suit system requirements.

 

[Steelmasons]

I did some course on grunnies years ago and they said 1 on a clean system 2 on dirty and 3 only for bleeding the system. Nothing winds me up more than people setting speed 3 on a restricted system as if it was a pressure pump and pulling air in.

What course was that then???..Never heard so much tosh in all my life...I do hope you've wised up since attending that Micky Mouse "course"

So why would you select speed 3 when "bleeding" the system if it pulls air in?..a tad contradictory.
So on a clean system you recommend speed 1?...would that not be dependant on the resistance through the heat exchanger coupled with index circuit resistance?
Do boiler manufacturers select speed 1 for their integral pumps (circulators)??
Jeez I've heard it all now......then we have Agile recommending speed 2 when he knows nothing whatsoever regarding the system in question nor does he have a clue on the required flow rate.
It's embarrassing.

 

[misterdubya]

Cutting to the chase here. If it's working properly don't change it. If it's not then change it. Talk about making a mountain out of a molehill.

 

[Steelmasons]

Why would you put grease on the rubber seal??

No reason whatsoever.

 

[denso13]

You should only be using it on the setting "2"

Why? (I know it's already been asked but no answer yet)

 

[Steelmasons]

Why? (I know it's already been asked but no answer yet)

He won't comment due to not having an answer......