Grundfos UPM3 Flex AS - Cant change settings

[jmac88]

I installed this as part of an UFH Manifold circulator. Can press the button to change the speed between three speeds. But I see now that I can change the way it works and it should be in Constant Pressure mode for UFH and it isn't. After reading the manuals, it says to press the button for 2s to g to settings mode. That doesn't work. Nothing changes, just switches to the next speed.
I then found that there is a settings lock and tried holding the button down for 10-15s. But again, nothing changes. It seems that the pump is locked in a mode where I can change the speed and not the mode. Anyone else experienced this. The pump is 2 years old and not used much. Whatever I do, I seem unable to unlock it.

 

[JonathanM]

I think there are two different versions of UPM3 Flex with different instructions. Does your pump look like either of these.

 

[JonathanM]

Having said that, I think the following table shows Flex version doesn't have a Constant Pressure Mode.

 

[jmac88]

mine is not actually identical to either of these but more like the top one.
I finally managed to speak to Grundfos!! Apparently all the UPM versions are what they call OEM and most are not programmable without the digital cable attached and are designed to be controlled fully by the heating control system using pulse modulation. Its just really annoying the way all the literature tells you they can be manually programmed.
I think mine has a constant pressure curve - which is actually PWM A so is designed for UFH but the control system will manage it. I haven't decided yet on what control system to use so have none. There seems to be nothing anywhere that explains the difference between the various pumps and pump families and if you want a fully manageable one then you buy the UPS3 which can be fully configured for whatever purpose.
Problem is that Grundfos still think that all UFH manifolds are sold as a complete solution with the control unit as well and don't seem to have realized that the world has moved on and there are many independent smart heating systems that people want to pair with their UFH manifold and thus need a bit more control and flexibility. In future I will only buy the UPS3 or equivalent.

 

[jmac88]

PS Very helpful and I'm probably still a bit off track. I just like to know and understand all my components and not just have what came with the system!!

 

[JonathanM]

I like to understand all my bits and bobs as well! Also, I have found Grundfos literature is not particularly consumer friendly.

I would be interested to know the mechanism for using a PWM signal to control a UFH pump. I can see that when these UPM3 Flex pumps are installed inside a combi or a system boiler, they can be controlled as a continuously variable pump, using a PWM signal from the boiler. But I just can't envisage how that works to control a UFH system. What sort of device would produce the PWM signal?

 

[jmac88]

Apparently the control system that is shipped with the manifold - according to Grundfos!! But as said, I haven't got one yet!! Just leaving the pump on over the winter with the UHF on as the control system I want is quite expensive and need to hold off buying for a bit - and need to check it can control the pump. Im on Honeywell Evohome currently and so looking at their UFH controller. Rest works really well. But my first issue is to replace my Automatic Bypass valve which I am now 99% certain is faulty and boiler goes on and off without circulating much water as it is skipping the main circuit and going through the bypass and thus the boiler is receiving back hot water and thus switching off. Its been doing that for a while and I have only now really focused on what is wrong. Can turn the setting dial continuously in either direction with no hard stop. Found this when trying to crank up the bypass pressure. So will replace that first then see.