Grundfos pump flashing green LED

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I have a Grundfos UPM3 Flex AS pump for my UFH system.

The lights on it are as follows:
LED 1: Flashing green maybe every second
LED 2: off
LED 3: Solid yellow
LED 4: Solid yellow
LED 5: off

I understand the yellow LED's indicate the speed/performance setting it is set to and I can change this by pressing the button on the pump. So it is currently set to medium performance.

What I don't understand is the flashing green LED, I believe this should be solid according to the manual.


Page 2 says the following:
Operation status
– When the operation mode is active, all active LEDs are constantly on in order to differentiate this mode from the select setting mode.
– If the circulator is stopped by an external signal, LED 1 flashes green.

So my understanding of this is that the circulator is stopped in the pump by some external signal.

But what does this actually mean? The floor does heat up but it's not brilliant, the zones were never balanced when it was installed and I wouldn't be surprised if it needs bleeding as well to remove air.

Surely if the circulator is stopped I wouldn't hear the pump running and the floor wouldn't warm up unless my understanding of what a circulator does is wrong.

Next I am unsure what it really means by some external signal. What sort of external signal could be communicating with the pump to stop the circulator and why?

We have a Heatmiser Underfloor Heating Wiring Centre, Heatmiser stats in each room/zone and a Vaillant ecoTec boiler.

The pump LED has been flashing green since we moved in and this property is a new build. I don't have much confidence in the plumbers or electricians that the developer has used and I doubt they will have any clue on this based on my experience with them so far.

Any insight or advice would be greatly appreciated.
 
There are two versions of AS Flex, and the lights mean very different things.

Do you have a photo of yours? Or at least do you know when it was installed?

The change seems to have happened in mid 2020.
 
The newer version of the guide is below. If you have the newer model, the flashing once per second is totally normal, and simply means there is no external controller. The two yellow lights also mean your pump is set to curve 2. Because there is no external controller, the pump will run at the maximum speed for that curve. I can post the curve if you are interested!

1670928885444.png
 
Oh that's helpful thanks. I do not know exactly when it was installed. We moved in March 2022, hard to say exactly when the UFH was installed during development. Maybe sometime in 2021.

Definitely interested in seeing the curve. Do you have a link to the manual for the newer AS Flex model?

Here are a couple of pics:
IMG_20221213_110621_resized_20221213_110701263.jpg
IMG_20221213_110601_resized_20221213_110701647.jpg
 
Oh that's helpful thanks. I do not know exactly when it was installed. We moved in March 2022, hard to say exactly when the UFH was installed during development. Maybe sometime in 2021.

Definitely interested in seeing the curve. Do you have a link to the manual for the newer AS Flex model?

Here are a couple of pics

Yours is definitely the newer model. Link to Grundfos documentation below. Go to page 2 and you probably want Data Booklet (current version), I&O instructions and Flex AS Quick Guide. The first two are generic to the whole UPM3 range. Page 1 has the earlier versions.

https://product-selection.grundfos.com/uk/products/up-oem-north-america/upm3-oem?tab=documentation

Curves below are taken from the manual.

1670930728641.png
 
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