Replacement pump (I think) advice

[wifflebat]

Hi everyone.
I'm a noob to the forum and to plumbing, though I have learnt a great deal recently during some home improvements!

I have an unvented central heating system with a wood pellet boiler (Kunzel) that has been in for about 5 years or so now. Recently I've been having some problems with the circulator pump which is a DAB VA 55/130 EVO. Basically I think it has been sticking as it isn't circulating when it should be. The voltage to the pump is fine.
Usually I just turn off the power to the pump, close the valves around it and poke about a bit with the propeller shaft via the brass access screw thing and sometimes it runs again. Tonight I got a bit fed up with it and decided to take it off. The propeller itself moves very freely in and out about 6mm which I'm pretty sure isn't right :/
You can see this in the pics.
I ran the pump disconnected like this for a few seconds and, although it runs in both of these positions, it sounds a little rougher in the outer position (not by much though).

I guess what I'd like to know is
a) it shouldn't move like that, should it?! and
b) what sort of replacement pump can I use? ie what are the essential specs from this pump that I will need to get something that will do the job. I don't want to underpower the system (if anything I'd like to up the power) and I'll need to head out tomorrow to try to get one.

I had a quick look on screwfix direct to see if any of the part codes looked familiar but they didn't.

All advice very gratefully received!

Many thanks

https://www.dropbox.com/s/rjlp6kg8e8r41ba/image.jpeg

https://www.dropbox.com/s/k196jj9pjyqr4bk/image[1].jpeg

https://www.dropbox.com/s/b3umxs72kyzk6ca/image[2].jpeg

 

[AWheating]

Take it to your local plumbers merchant and see what they have as a replacement.

What is the water condition in the system? At 5 years old it should be clear.

 

[wifflebat]

Hi
thanks for the reply. The water is pretty black and has been for as long as I can remember. Tbh this system has given nothing but heartache since it went in. I do t think the bloke that installed it really knew what he was at.

 

[oz-plumber]

Sounds like the pump capacitor to me.

Not sure where you are going to get one from.

It might be best just to change the pump.

 

[PhoenixServices]

Change the pump. Then get the system power flushed by a recommended local engineer. And dose with inhibitor.

 

[PhoenixServices]

Plus get the whole system looked over at the same time to check it is all tickity boo.
Will cost a little bit but will save you money in wood/maintenance in the long run.

 

[PhoenixServices]

One more thing for the new pump get either a grundfos alpha 2 25-40 130 or a wilo yonos pico 25/1-4 130 (that's if the pump that was originally in there is correctly sized)

 

[Ermintrude]

Get the wilo.

 

[missplumb]

get the grundfos in my opinion

 

[SimonG]

Dont use the grundfos alpha, absolutely pants.

Get some cleaner in the system and flushed out, then a filter of some sort (centramag for me) and inhibitor.

 

[wifflebat]

Hi folks
Thanks for all the replies and advice. In the end I went down to my local (and very friendly) plumbers merchant and went with what he had. I upgraded from a 5m to 6m head as I wanted something a bit beefier. Drained the system down, plonked in some rust inhibitor and filled it up.
Had a dodgy Thermomix valve too so I've also learnt a bit about them as well as I got taking that apart too (thanks to this forum as well!).
Seems to be going ok at present but I think I might get someone in next spring/summer to repipe the whole thing as I'm not convinced it's as efficient as it should be. The distributor of the pellet boiler I have looked pretty disgusted when he called shortly after it went in!

Thanks again!

 

[doitmyself]

Dont use the grundfos alpha, absolutely pants.

Why do you say that?

 

[SimonG]

Too clever for there own good.

 

[happyflyer]

Too clever for there own good.

I agree with you Simon, there are two many pumps out there try to take over control, what the hell is going on with the industry, commercial are the same you need a Degree in F & C to set them up, keep it simple that's what I say.

 

[missplumb]

the magna 3's are perfect for commercial systems. just put them into auto adapt and away it goes. The problems we have with Wilo pumps is that itdoesnt have a complete auto adapt like the grundfos - it will only adapy on the power curve you set it to. This doenst allow our systems to work quite how we want them to.

 

[doitmyself]

Too clever for there own good.

Do you mean that the average installer doesn't know how to commission a system with an Alpha installed?

 

[mike76]

Wilo pump is fine! Black water in system sounds like a bit of a leak ! New pump see if there is a leak and clean the system! Make sure you find out why system is getting so dirty!