Grundfos 15-58fc issue help

jasko

I was wondering if someone can help me with a issue i have. Perhaps i might not be familiar with this. A few days ago my 15-58FC pump was making a squealing noise, talked to my contractor and he said it needs a new pump. I just got back from installing it on my own and it was fairly simple i turned on the heat and the pump didnt seem to circulate the water but i can feel that the impeller and motor is working. after a good minute the motor squeals and i shut it off.
Can anyone shine some light into this issue. my contractor told me it is the pumps that are at fault but from my point in perspective im assuming it is air in the pump. and simply do not know how to prime the pump (if needed) to get the air out from the pump. should i purge the system and if so can someone please shine some light on how to do that. if pictures are needed i can take them, thank you greatly

HomerJSmith

How is the pump oriented. A pic would help. Sometime solder balls stick in the impeller and can rub against the volute.

I would pull it apart and remove the rotor and check for debris in the pump housing.

HVACNUT

It's probably air bound.
Post some pics.

hot_rod

does the motor get really hot, much hotter than the fluid? If so it is air locked, not moving any fluid. The fluid, water, lubricates and cools them motor. It's called a wet rotor design for that reason. I think you have an airlock at the pump or in the piping circuit.

jasko

Thanks so much for the responses

HomerJSmith

You're orientation is fine. I wouldn't suspect an air lock or dry bearings, especially if that zone is heating.

I would take the pump apart and remove the rotor and look at it.
That's what's great about Grundfos pumps, you can take them apart and examine and clean the rotor.

Why would anyone mount these pumps in a backward position, I would want the motor windings housing facing me, so if I needed to take one apart it would be easy.

HVACNUT

The return manifold is behind the supply manifold. It has shut off and drain valves for each zone. Hopefully they correspond to each other.
Turn off all zones except the problem zone.
Raise the heat on the problem zone.
Close that zone's ball valve on the return below the drain valve.
Connect a hose to the drain valve and purge.
You might hear or feel the air through the hose. Purge until it steady water flowing.
Disconnect, put all back the way it was.
Check ALL zones.

hot_rod

All those circa need to have checks installed the FC on the model number indicated flanged and checks. Do you know if the checks are in each circulator?

jasko

Thanks everyone for the reply

HVACNUT said:

The return manifold is behind the supply manifold. It has shut off and drain valves for each zone. Hopefully they correspond to each other.

Turn off all zones except the problem zone.

Raise the heat on the problem zone.

Close that zone's ball valve on the return below the drain valve.

Connect a hose to the drain valve and purge.

You might hear or feel the air through the hose. Purge until it steady water flowing.

Disconnect, put all back the way it was.

Check ALL zones.

I already have tried this, in step by step i isolated (shut off all valves except the one i need to purge) and all i got was a small trickle of water, nothing more, so i tried the other ones and odd enough the same result. am i doing something wrong ??? i would assume there would be pressure on the system to push the water out. I checked the psi and it was around 14 PSI which is good. I did not shut off the furnace while preforming this task, could that be a issue, it has a taco priority zone control system, if that helps.
Again thank you to everyone that has been replying.

GroundUp

Prime example of why one should pay the contractor to do the job they know how to do instead of bothering them for free information and screwing it up yourself. Odds are you have an airlock as has been mentioned, and the method HVACNUT described is the way to purge it. A trickle almost always means you still have air and need to purge more

Zman

GroundUp said:

Prime example of why one should pay the contractor to do the job they know how to do instead of bothering them for free information and screwing it up yourself. Odds are you have an airlock as has been mentioned, and the method HVACNUT described is the way to purge it. A trickle almost always means you still have air and need to purge more

Hmphh, that's not very nice. @jasko posted a very clear and honest question. If you don't have anything nice to say...

jasko

> @GroundUp said:
> Prime example of why one should pay the contractor to do the job they know how to do instead of bothering them for free information and screwing it up yourself. Odds are you have an airlock as has been mentioned, and the method HVACNUT described is the way to purge it. A trickle almost always means you still have air and need to purge more

I'm not here to argue but I rather learn a system I paid several thousand installed. I've worked on similar systems myself and never had a issue like this. Needless to say I'm simply looking for answers since it's better to know than not to. I've waited 1 hour and nothing has come out not its dry as a bone.

GroundUp

If you have 14psi of water on one side of the pump and an open drain that's dry on the other side, you have a large blockage that needs to be pushed through. Odds are, the gauge is faulty and you have zero pressure. I did not say what I said to be rude, but the contractor who suggested you replace the pump could have taken care of this issue at what is likely a fair price. Now you used him for free information and he is not likely to take another call from you. Perhaps the blockage was present previously and that's what caused the pump failure in the first place, but 99% of the time this is simply an airlock following a pump change if the issue did not previously exist. You may need to raise the domestic pressure introduction to the system in order to push the blockage through, assuming all the correct valving has been open and closed for proper purging. Do the circs have a bleed screw? (some do, some don't- it'd be a stainless steel plug with a flathead drive in the butt end of the motor)

rick in Alaska

Bet the old pump is ok....
Rick