Question on Grundfos Pump

[Amovida]

Hello and hope everyone is staying warm this winter!

I have 2 Grundfos circ pumps (1 per zone) on an old Triangle Tube Prestige 110 boiler on a house we purchased relatively recently. One of the pumps appears to not be circulating as that zone is not warming.

First I checked voltage to the pump and I am getting 120V when the thermostat calls for heat.

I pulled the large silver screw from the back of the pump housing and you can see the end of what I assume is the impeller. It has some marks on it as if it were meant to be turned with phillips or a screwdriver. When I put pressure on the end of the impeller it begins to turn under power from the motor. When you back of the pressure with the edge of the screwdriver it stops turning.

Said in another way it the impeller only begins to turn when there is moderate pressure on it. I understand that when you replace the silver end cap it will create some pressure on the end of the impeller.

I guess my question is...is this by design or is this a pump that is wearing out and needs replacement?

 

[Fitter30]

What's the model of pump? Pump needs to be replaced

 

[Sponsor]

 

[Amovida]

Good morning and thanks for the reply. The circ pump is a 1/25hp Grundfos pump. I don’t have the pump in front of me at the moment but I’m pretty sure the model number is UP 15-10F.

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[Jeff H Young]

bad pump is a bad pump regardless of make, model

 

[Amovida]

What I am wondering is why does the impeller spin...once you've put a bit of pressure on it via a screwdriver? Does anyone have any direct experience with this with Grundfos pumps?

I imagine the phillips/screwdriver fitting on the end of the impeller is there so that if the impeller gets bound up with any debris you can remove the cap and manually move the impeller to clear the debris.

Any thoughts as to whether this is normal operation (the part where it begins to spin with a little pressure) or not would be appreciated. Thanks and enjoy your Sunday!

 

[Jeff H Young]

not understanding the question Not an expert on this pump but the impeller should turn with cap removed

 

[Amovida]

Rereading what I wrote I see where what I said may not be clear. Let me give it another shot.

When you remove the silver slotted end cap that is about the size of a quarter it exposes the end of the impeller. This impeller/pump is getting power but the motor power does not spin the impeller until you push it in with a flat screw driver blade. Then the motor power takes over and it spins under the pressure of the screwdriver as long as the you hold the screwdriver in a way it does not catch on the slots on the end of the impeller. For whatever reason it only begins to spin under this pressure. Looking at the cap it seems to force the impeller in this position when it’s put back in its place by threading it on. I’m wondering if this is normal operation or if this is a sign of a malfunction. Thanks to anyone who helps with this…and I hope everyone is staying warm!

 

[Jeff H Young]

I dont know if its normal I cant remember attempting to run pump with cap removed