Central Heating Pump

[SlackAlice]

I think my pump is showing signs of going on the blink. It's a Grundfoss 3 speed 15-50 pump, been fitted about 10yrs. Very often when the C/H switches on it fails to start running unless I give it a thump with the heel of my hand. Once it's running it's fine.

You recommended a Grundfoss Alpha 2 as a replacement on another thread. Looking at the Alpha 2 raises a question. It appears to have a 'plug in' for the wiring connection, does this come with the pump or is it a separate cable to buy? Any advantage in fitting the 15-60 version over the 15-50?

[SlackAlice]

Replace 'You' with 'buildersmate'
Apologies ☺

[buildersmate]

The difference between the two is the delivery head - 5m and 6m respectively. For a normal house using a boiler of perhaps 30kW, I would have thought that adequate.
Pumps needing a whack I reckon is a sign it is going to fail soon - and I remember changing a Grundfos for another when it got unreliable at around 10 years. If you think about what you are expecting it to do, it's not bad really.
The Alpha 2 runs my underfloor heating so is on almost continuously for 15 hours per day, quietly humming away. It is 8 years old now and still going strong.
The Builder will no doubt have something to say on this.

[SlackAlice]

Thank you buildersmate for you comments. I quite agree I've had my moneys worth out of the old pump. Grundfos are top pumps and I'd have no qualms about fitting one, it's just the electrical connection looks a bit different to their standard pumps.

I'll wait and see what The Builder says before I finally decide.

[The Builder]

I've been following this with interest since it's a new one on me. Automatic operation with variable flow. It seems you can set it to match the system you have, rather than just plugging it in.
It has its own special plug which comes with it, complete with lead. It should be earthed, so it's just a matter of connecting to a standard supply.

[SlackAlice]

OK thanks The Builder.
Nothing complicated then, think I'll go for it ☺
Let you what happens.

[SlackAlice]

oops again

Let you 'know' what happens.
Now, how can I do 'Best Answer' x 2

[SlackAlice]

Update.
Since writing this thread and looking around to get the cheapest prices for the pump, the old pump has been performing faultlessly!!!!

Job postponed ☺