Grundfos UPS 25-40-180 pump failure: it breaks and drowned!

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Grundfos UPS 25-40-180 pump failure: it breaks and drowned!




by Christophe » 06/01/19, 18:58

My Grundfos UPS circulator took the water and drowned before yesterday blew the differential as soon as it was turned on ...

At first I thought it was only the capacitor that was faulty (this is the 1er test that I did: it was still good) but in disassembling it I quickly understood that the failure was much more important.

Indeed; the rotor remained "stuck" to the frame (hydraulic side) and water was present at the stator!

The turbine is now well seized in the stainless steel part: it turns again but must force to turn it.

View rust present, I do not think the leak was recent ... probably a few weeks or months? It is a circulator that I use only a few dozen hours in the year (additional heating).

The evening before the breakdown I heard that the circulator was making an abnormal noise and in the morning the circuit breaker 300 main MA had jumped.

All this to show you the inside of a Grundfos circulator. The circulators are visibly brushless motors (2000 start manufacturing I think) but I'm not a specialist in electric motor technology ...

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The body of this circulator was replaced by another old UPS that I had in stock (compatible hydraulic side)
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Re: Grundfos UPS 25-40-180 pump failure: it breaks and drowned!




by Christophe » 06/01/19, 19:10

If you ask, can I try to dissect it a little more? : Cheesy:
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Re: Grundfos UPS 25-40-180 pump failure: it breaks and drowned!




by Forhorse » 06/01/19, 19:26

Historically, heating circulator motors are single-phase asynchronous motors. I do not know if recent has changed? I think it is mainly control electronics that has changed (addition of a frequency converter?)

To vary the speed of a single-phase asynchronous motor there are now specific frequency inverters which are responsible for supplying the main winding and the secondary winding with a phase shift of 90 ° (it becomes a sort of two-phase motor. ..)
It is more precise and more energy efficient than the old condo phase shift and the selector that reduces the engine torque and thus increase its slip to reduce its speed.
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Re: Grundfos UPS 25-40-180 pump failure: it breaks and drowned!




by izentrop » 06/01/19, 20:27

Hello,
Already disassemble and clean and change the defective seals and can be the bearings if they are removable.
See if there is a repair kit? https://fr.grundfos.com/service-support ... ndees.html
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Re: Grundfos UPS 25-40-180 pump failure: it breaks and drowned!




by Christophe » 07/01/19, 09:17

Forhorse wrote:It is more precise and more energy efficient than the old condo phase shift and the selector that reduces the engine torque and thus increase its slip to reduce its speed.


It is this technology which is used in this case and which is still used in most new "1st price" circulators ... A range of grundfos has been continuously adjustable for a few years between 1 and 100% which must use, I think, an integrated frequency converter (these ciculators are sold 300 € instead of 100 € ... and I'm not sure they are as reliable: the one I just replaced was going to be 20 years old)

Otherwise, I had estimated a few years ago the thermal power that a circulator of X watts could transmit in an average installation (with therefore "average" pressure drops) and the result is simple, it is X kW .. .which allows you to easily adjust your circulator by knowing its thermal power!
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Re: Grundfos UPS 25-40-180 pump failure: it breaks and drowned!




by Christophe » 07/01/19, 09:24

izentrop wrote:Hello,
Already disassemble and clean and change the defective seals and can be the bearings if they are removable.
See if there is a repair kit? https://fr.grundfos.com/service-support ... ndees.html


Uh thank you but no: given the state of the circulator (rotor seized, stator in course circuit ...) I will not attempt to fix it, I already replaced by a similar model lying in a corner 8)
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Re: Grundfos UPS 25-40-180 pump failure: it breaks and drowned!




by Gaston » 07/01/19, 12:15

Forhorse wrote:It is more precise and more energy efficient than the old condo phase shift and the selector that reduces the engine torque and thus increase its slip to reduce its speed.
Often, when we move to an electronic control, we also move to a real three-phase.
We can then control more easily and at will speed and torque.
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Re: Grundfos UPS 25-40-180 pump failure: it breaks and drowned!




by Forhorse » 07/01/19, 20:28

It would be more relevant to switch to a true three-phase stator yes. But is it necessarily the choice of circulator manufacturers?
this forces us to produce 2 type of stator: single-phase with winding at 90 ° for low-end models with capacitor, and three-phase for the high-end inverter.
I would be manufacturing a circulator, I would produce only one type of stator that fits 2 ranges.
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Re: Grundfos UPS 25-40-180 pump failure: it breaks and drowned!




by Forhorse » 07/01/19, 20:42

Christophe wrote:A range of grundfos has been in continuous adjustment for a few years between 1 and 100% which should use, I think, a built-in frequency converter (these ciculators are sold 300 € instead of 100 € ... and I'm not sure that they are also reliable: the one I just replaced was going on his 20 years)


When we want to make reliable electronics we can do it very well.
Just as one can make a basic circulator first price very unreliable that will not hold 20 years ... a Chinese capacitor of very poor quality that will give up after a few years will put the circulator down almost programmed without electronics complex.
In addition as the plumber / heating engineer will not bother to diagnose and replace the condo HS (component that costs between € 5 and 10) they will replace the pump without asking any question the client again the heating, plumber has sold a circulator on which he takes a good margin plus a technical service purely in his area of ​​expertise and the circulator manufacturer sells circulators ... everyone is happy.
In contrast, a very well-designed drive with quality components will still work perfectly in 35 years, with all the additional functions of torque monitoring, blocking, current leakage, etc ... that can very well contribute to this entire circulator remains reliable for many years.

In short, it is not a question of electronics, but of will manufacturers to produce reliable or not (programmed obsolescence, coughs ...)
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Re: Grundfos UPS 25-40-180 pump failure: it breaks and drowned!




by Christophe » 07/01/19, 22:28

Precisely: I strongly doubt that "general public" circulators, even top of the range, are designed to last 35 years ... for the reason you mention because not everyone would be happy if that was the case! : Cheesy: : Mrgreen:

A few years ago I had inquired to buy a drive for a single phase asynchronous motor 650W: this is only found in the industry equipment and it cost in the 1000 € 4 is the price of the only engine .. I chose the solution of the rheostat at 50 € : Cheesy: There is one subject above for those interested: electrical-electronic-computer / controller-to-power-speed-to-asynchronous-motor-t5240.html

I doubt that the drives of the new circulators (sold in the 250-300 € it seems to me) are so reliable that it ...

The Grundfos Alpha range is even connected to your smartphone: https://be.grundfos.com/content/dam/GBL ... FR_Web.pdf : Mrgreen:

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But then, she no longer has the ability to unclamp the turbine with a simple screwdriver ... so we can not stop the pump completely for many months without being able to easily untap (which was my case with the circulator that has made the soul, I had not used it since 2 years on and some and can be 3 years ... unlocked before returning to service).

Only the Alpha1 L retains this famous screw!

In the end, over a year, not sure that energy savings (electrical) are real! It's like home automation: if the consumption of watch / control is greater than the savings they allow, the interest is negative! But it helps to show off a little ...

For the savings (thermal) achieved by the AutoAdapt technology, I am curious to have figures!

After a quick search, it turns out that the old models Grundfos (3 basic speed selector) are still new and are sold ... bin at the same price see more expensive Alpha range stuffed with electronics... Then, I wonder why! Hint: everyone will be happy! : Cheesy:
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