Grundfos UPM3 FLEX AS 25-75 130 AZA

[wiggers42]

Not necessarily. It depends on how long the loops are. Do you know?

The total area is around 30m² and there are two loops.

Increase the flowrates to say 2.5LPM, initially open them up to max flowrate, if you can get > 3.5LPM then the pump is operating with plenty of head.

I increased the flowrate until the third LED came on, around 3l/m.

 

[MNW67]

I increased the flowrate until the third LED came on, around 3l/m.

The third LED should come on when the pump reaches 50% power. Full power is 60W, so this means it has reached 30W.

You have 6L/min flow in total, which is just under 0.4 m3/hour. If you follow up the 0.4 line on the lower graph posted earlier, it intersects Curve 3 at 30 W, so that all ties together.

The total area is around 30m² and there are two loops.

Do you know the actual total length of the pipes in metres?

 

[Johntheo5]

It will be interesting to see what Grundfos inform re the pump curves, if running at a very high head then might cause problems with the thermostatic valve not being able to admit hot water from the boiler if this head is much lower, assumong UFH output of ~ 90W/m2, then 30m2 will emit only 2.5 to 3.0 kw and depending on boiler type gas/oil and modulation then quite likely it will keep cycling rapidly and take a age to heat up if UFH only on. What is the type/model of the boiler and if it feeds rads as well and both are on does the UFH manifold pipework get hot fairly rapidly?.

 

[Johntheo5]

The third LED should come on when the pump reaches 50% power. Full power is 60W, so this means it has reached 30W.

You have 6L/min flow in total, which is just under 0.4 m3/hour. If you follow up the 0.4 line on the lower graph posted earlier, it intersects Curve 3 at 30 W, so that all ties together.

Is this at a 6M head then?.

 

[MNW67]

Is this at a 6M head then?.

Yes, according to the lights on the second level menu on the pump.

Would that be the head you would have chosen?

 

[Johntheo5]

The lowest one to give the required flow and manifold temperature required, most TMVs will not operate properly if the dP is > 1.0 bar?

 

[Johntheo5]

I don't follow the logic of this pump since it has no outside signal, normally one selects one mode and setting and the LEDs reflect this and don't change, the pump will change speed to maintain the selected head (either CP or PP). Can one select any one of the heads??.

 

[MNW67]

The way it's set up, it works like an old fashioned fixed speed pump, with 4 speed/head settings. Although, as you pointed outed, at lower flow rates, the curve is flat like a CP pump.

In the second level "Settings View", you can choose any of the 4 speeds/heads. And currently it's been set to Curve 3.

When it is running, it shows a very basic display of power output in bands. One yellow LED means 0-25% power, two yellow LEDs mean 25-50%, etc.

EDIT: It is very confusing, and I imagine that is why they changed it in 2020. Below is the new version, which is much more obvious.

 

[Johntheo5]

That makes sense, I interpreted the below as reading that the third LED came on when the flowrate was increased via the flow meters
I would set it to one green+one yellow, 4M? and then see if I can get the required flowrates without having to fully open the flowmeters, if not revert to original 5M of one green +two yellow and readjust flowmeters.

I increased the flowrate until the third LED came on, around 3l/m.

 

[MNW67]

I interpreted the below as reading that the third LED came on when the flowrate was increased via the flow meters

That is what is happening. There is a second settings level, which you access by pressing the front button, and this shows different lights. This is where you choose the pump speed/head. Currently the OP's pump is it set to 6m.

Then there is the normal display. This shows the power output, but only in bands, so it is very approximate. So one yellow light means between 0-15W, two yellows 15-30W, three yellows 30-45W, four yellows 45-60W. When the OP increased the flow rate via the flow meters, it required more power, and when the flow in each loop reached about 3l/min, the power band went up from two yellows to three yellows i.e. from the 15-30W band, to the 30-45W band.

 

[wiggers42]

Do you know the actual total length of the pipes in metres?

From the photo, there are about 30 lines of pipes and the length of each is about 6m, so about 180m divided between two loops.

Since I adjusted the flow to around 3l/m, it does seem to warm up quicker and the pump doesn't run for as long. I can't change things too often because the pump and manifold are behind a false panel at the the back of the cupboard where my wife keeps her jam making kit. I have to take all that out to gain access each time!

Thanks for your help. I'll let you know as/when I hear back from Grundfos.

 

[wiggers42]

Grundfos have so far not provided any more information than how to view the current settings.

I had another look today, as I realised I'd left off the red protective caps, and the pump is back to <50% power (two yellows). Seems to have settled down to the new flow rate.

The room is heating up a bit too quickly now, the thermostat is overshooting, so I've reduced the mixer temperature back to 45degC.

 

[wiggers42]

Grundfos have said that it is likely that the pump was supplied with the manifold as a kit. As someone pointed out before, it is an OEM pump. The manifold manufacturers would have specified the pump for the manifold design, so all should be well. Now I've increased the flow rate it is working as expected.