GRUNDFOS Pump Failure.....suggestions

[dishman]

Hello

I have read some similar old posts on this topic but wanted to check a few things with a fresh one.

Came back from holiday to find no central heating and no noise from the pump. Boiler 35+ year old glowworm fires up fine otherwise and heats hot water.

So I suspect pump failure of some sort.

I have checked a few guides and unscrewed the cap of the front of the pump. Water weeps out as I took the cap off (slow drip) and I span the pump manually with a screwdriver. The pump span freely when spinning it with a screwdriver. Gave it a tap here and there...still no joy when reconnected.

So it could be just a complete failure or maybe the capacitor. Not keen about messing with electrics though, seems a bit of a long shot. Is it?

Any other "repair" ideas...?

So last option is replacement. The model is GRUNDFOS TYPE UPS 15-50x18.

Which from what I have read is a very old model (so has done well to last so long). Grundfos suggest replacement with an Alpha 2 15-50 but rather than 18 has the rating of 130? What does the "130" represent. Will I have any problems by replacing it with a 15-50 130? (the guide below does say the 15/50x18 has a "port" of 130...so does that essentially mean it is the same?)

I got that information from this Grundfos guide

http://cbs.grundfos.com/export/site...s/Final_Pump_Replacement_Guide_A5_0610_lr.pdf

Page 4 near the bottom.....

Finally, replacement looks to be simple. Isolate the valves, remove pump, attach new pump, release valves, and all go?

Is it that easy?

 

[Boilerman2]

Before ripping out your pump, have you checked that there is voltage at the pump (230vac) between the L & N connections on the pump measured using a multimeter???

 

[dishman]

No,

But are you implying that the fuse may have gone?

If so, the Pump is conected to the same power socket as the timer switch and that powers up fine.

If not, what would this test reveal?

 

[twgas]

Testing with a meter would tell you if there's an electrical fault "before" the pump. Just because the timer appears ok does not mean there is power to the pump. From your questions I would suggest you get someone in who understands the issue as you are clearly not competant - no disrespect, but electricity is dangerous stuff.

 

[dishman]

I agree, what I am trying to do is just identify the basic problem first. If I determine that it is beyond my diy skills then I will get someone out. I have not reached that point yet.

I cannot (though do not discount it) see how there could suddenly be a problem between the socket and the pump. The wiring has been protected by a cover for a very long time. the flex is in very good condition and is only 30cm in length from socket to pump. As I said , the socket itself works fine.

Back to my original query, from what I have read, the 15 50x18 should be compatible with a 15x50 130....is this correct?

Regardless of whether I do the work or not, I'd rather get the part myself (good second hand or "new" ebay stock) rather than getting a brand new part costing £150. I intend to replace this whole system next year anyway.

Hence my questions....

But, as you recommend, if I have exhausted simple ways to indentify the problem, I will most ccertainlyget someone out.

 

[Dan Robinson]

If you're not going to listen to or follow the advise given by people who do this for a living why bother asking for advise FFS.

 

[dishman]

I am not ignoring the advice....

I clearly said I do not discount it being the problem.......and would get a professional to check the electrics.

I have followed other guides advice quite easily about turning the pump manually to "free" it up etc. No joy, so it could easily be the internal electrics, the connection as suggested, or mechanical pump failure....

I already stated in my initial post I did not want to start messing with the electrics.....

Therefore.....

All I was asking is:

1) Are there any other simple things to try/check...other than the electrics.

2) Confirmation that the 15 50x18 is compatible with the 130. So If I do need to replace the pump I can source a cheap part myself....

 

[Tibbot]

Are there any other simple things to try/check...other than the electrics.

It works by electricity. If it doesn't appear to work, the only way to establish a fault is to find out first if it's getting power. You can't see electricity, so it's proper tools or test it the painful way.

 

[Terry lambert]

The capacitor is what starts the pump, the idea of manually spinning the pump with a screw driver is to do the capacitors Job, therefore proving whether that is the fault.

You state that you spun the pump, then reconnected

Call for heat then remove the cap and spin the impeller, if the pump then works, then the capacitor is kaput.

You've been given good advice to check for power at the pump

 

[Agile]

Its not clear to me if you are just trying to save money or something else.

Many professionals would charge about £80 to visit you and identify the fault and most would usually have a serviceable used pump which they would fit for you for perhaps an extra £30.

You can probably buy just the pump head on its own for about £100 new.

Tony

 

[D_Hailsham]

What does the "130" represent. Will I have any problems by replacing it with a 15-50 130?

The 18 (or 180) and 130 denote the distance between the inlet and outlet of the pump. You would need an adaptor, available from plumbers merchants, to fill in the 50mm gap.

You mention a socket. Is the pump plugged into the socket with a standard 3-pin plug? If so, have you tried changing the fuse (3A) in the plug?

If you hold a screwdriver against the pump and put the handle against your ear, can you hear the pump whirring. If you change the pump speed, does the sound change?