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Grundfos circulating pump troubleshooting

This answer was rated:

How do I know if the circulating pump is bad on my boiler? It is a Grundfos UP-26-64F

Already Tried:
The pilot lights, The flame sensor senses the flame and turns on the burner. It starts to heat up and then you hear the water making popping sounds and then jerking sounds form the water inside the place where it gets heated up. Also what book would you recommend on how to diagnose and fix my boiler?

Sorry you're having trouble...

Does your pump have a chrome cap on the end with a slot in it?
What kind of boiler do you have?
JACUSTOMER-32r76mac- :

Yes, it does! They call that a drain plug, right?

Up above there is another slotted copper plug on the pipe right above the flange.
Tom :

Ok...well..it's not really a drain plug...

The slot in the copper flange is a shut off valve in case you have to replace your pump.
If you remove the plug on the end of the motor...you'll get a little water out of it....not alot...
JACUSTOMER-32r76mac- :

It is a HYTECH brand Boiler

Yep just a little bit of water came out.
Tom :

The end of the pump shaft is slotted. Sometimes these motors stick..especially after sitting all summer. Try turning it with a screwdriver and see it the rotor is stuck..

JACUSTOMER-32r76mac- :

It was running for a 2 days without any problem and then all of a sudden this happened.

Tom :

IF there is air in the pipes it can be a real killer of the Grundfos pump. The rotor and bearings are water lubricated...They don't like air. It can chew up the bearing surface pretty fast sometimes..

If there is up and down (in and out doens't matter so much) play in the shaft it is done for.
You can test this by wedging a tiny screwdriver under the shaft and gently lift up and down to see if there is play.
JACUSTOMER-32r76mac- :

The pump is not making any noise at all.

Tom :

You need to make sure there is power to it.. Next pull the electrical cover off (with power off) and see if it has fried a wire terminal or a capacitor.

Truly...no matter what you find..(other than stuck)...there really isn't any repair to these pumps. It's pull it out and replace it.
JACUSTOMER-32r76mac- :

I could never tell if this pump was on even when it was working lol

Tom :

That's a good feature..nice and quiet....

I use them alot...
JACUSTOMER-32r76mac- :

I found a replacement online for $236

How do I tell if it is working?
Tom :

Try turning it on with the plug out of the end and see if the shaft spins.

It'll spit a little water but nothing to be alarmed about.
JACUSTOMER-32r76mac- :

I am going to check that now.

The pump is not spinning.
I stuck a screw driver in side that slot on the pump and could freely turn the pump back and forth.
Tom :

You'll want to check and make sure the relay that energizes the pump is good. On the box there on the wall....do you hear it click if you turn the power off and on?

JACUSTOMER-32r76mac- :

It definitely clicks on. You can feel it and hear it Model 8494-101

Tom :

Do you own a volt meter?

JACUSTOMER-32r76mac- :

yes I do

Tom :

Take the plastic cover off the electrical box on the pump and see if you're getting 120 volts to it...

There should be screw terminals where the wire terminates...pretty easy to test.
JACUSTOMER-32r76mac- :

Yes, it does have power going to it 122.8 volts

Tom :

You can pretty much assume a faulty winding in the pump motor. Looks like it's time for a new one. Sorry..

JACUSTOMER-32r76mac- :

One of the pipes also has al small leak :( That must be what caused it to break.

Tom :

Truly..probably a coincidence...

JACUSTOMER-32r76mac- :

Its one of the pipes with a flange fitting like a brake line on a car. To of them come together on the bottom inside of the boiler into a big valve.

Tom :

A small leak shouldn't hurt it unless there was so much air in the system you were not getting any flow.

Unfortunately..I've never seen a Hytech boiler where I'm from and a quick internet search didn't turn up much.
JACUSTOMER-32r76mac- :

I know!

Tom :

Sorry...do you think you'll be able to fix the leak??

Just make sure your make-up water valve is in good working order to replenish any system water lost due to the leak.
JACUSTOMER-32r76mac- :

Yes I will. It will be easy to fix. Is there any trick to changing the pump I should know?

I am getting a book from the Library called Heating Boiler Operator's Manual.
Tom :

Well....not really...you have a valve on the top..but it doesn't look like the bottom flange had one is that correct?

JACUSTOMER-32r76mac- :

The pipe that is leaking is under the boiler cover. I should not have used the word valve. It is a big coupler with 5 different connections right in the center of the boiler.

Tom :

Going back to the pump...

the brass flange with the slot is an isolation valve for the pump...but I don't think there is one right under the pump...
Or....here is another way to do it IF you get the identical pump....
JACUSTOMER-32r76mac- :
Leaking pipe from water tank to Grundfos boiler
Full Size Image
The leak is the grey colored pipe on the left coming down from the water tank of the boiler.
Tom :

Shut off the makeup water...and drain enough water so that the pressure is at 0. Shut that flange valve off over the pump...Take your new pump apart...(4 allen head screws)...pull just the motor assembly out.....remove the 4 screws holding the old motor on the pump housing....remove the old one and quickly stick the new one in....make sure the rubber 'O'ring stays in place...

Not as hard as it sounds and saves a lot of time and loss of water. Yes you'll get some water loss...but if you're quick you don't lose much..IF you are uncomfortable with this...Don't Try it!!

JACUSTOMER-32r76mac- :

What does the isolation valve do?

Tom :

OK...looks like you may be draining the whole system to fix that anyway!!

It just shuts off water to the pump.
Usually you put one above and below so pump changes are a snap.
The screw driver slot indicates the valve position...in line with the pipe being open.
JACUSTOMER-32r76mac- :

How do you get it to turn? it moves slightly left right and pushes in?

Tom :

No...big screwdriver....turn hard...

It's basically a ball valve without a handle.
JACUSTOMER-32r76mac- :

There is not one under the pump.

Tom :

Rats.

The SAFE way is to make sure boiler is cold and drain the system.
Make sure the make up water is off so it doesn't start adding as you're draining!
JACUSTOMER-32r76mac- :

I have drained it before. I know it is a pain to get it to circulate properly again :(

Around what psi should the water preasure be?
I will. Thanks
10-12
Tom :

Is there another hose bib anywhere besides the one by the floor?

JACUSTOMER-32r76mac- :

No just that one. I replaced it about 3 years ago same with the presure relief valve.

Tom :

Ok...sorry...about having to drain it.

JACUSTOMER-32r76mac- :

You have been a great help! :) I will be using your service in the future! Thanks for your help!

Tom :

Check ebay for your pump...I think you can save some$$$

I did a quick search for Grundfos 26 64 and it returned a few results..
JACUSTOMER-32r76mac- :

Good idea! Thanks

Tom :

You're welcome...anything else I can do for you?

JACUSTOMER-32r76mac- :

Not today. I will most likely be contacting you when I try to install the pump. :)

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