Central heating not circulating - even after pump replacement

[hanvyj]

The Grundfos ups3 has to be the worst pump on the market when trying to get air out & circulate. Had nothing but bother with them on open & sealed systems.
We've actually removed & refitted the old style pumps on boiler installs, removed the manual bleed screw & had systems back up & running within minutes ,
The auto venting just doesn't work.
We've lost multiple hours trying to vent systems , sometimes retuning to the job the following day , hoping that's its managed to clear the air.
worst design ever ,
Just give us back a pump with a manual bleed screw

Yeah, I suspect the system was designed with a pump as a bleed point? I'm thinking it might be worth adding a bleed valve to the boiler pipework if I next do any work on it - though I'm not sure where I'd squeeze it in. Replacing the pump with something that cant be manually bled just causes a host of trouble.

What model WILO did you install? and what mode and setting??
And what is the power and flow?? How many rads?

I installed the PICO 6m head version. I think I just set it to fixed power setting 2 just to be happy it's working while testing. We've got 13 radiators (9 downstairs), and the water heater so I set the pump, so I'll probably set it between the low and medium setting:

Thanks for all the help everyone

 

[Johntheo5]

Yeah, I suspect the system was designed with a pump as a bleed point? I'm thinking it might be worth adding a bleed valve to the boiler pipework if I next do any work on it - though I'm not sure where I'd squeeze it in. Replacing the pump with something that cant be manually bled just causes a host of trouble.


I installed the PICO 6m head version. I think I just set it to fixed power setting 2 just to be happy it's working while testing. We've got 13 radiators (9 downstairs), and the water heater so I set the pump, so I'll probably set it between the low and medium setting:
View attachment 344030
Thanks for all the help everyone

Fixed speed II, C2, is a pretty good choice on that pump at 3.8M, (the UPS3 even on fixed speed I is still 4.2M). If/when you do set it to PP mode, note the power with all rads on and with a cold system, then keep adjusting the PP setting until you get the same power, the selected PP head will flash for a few seconds after each adjustment, you will probably see it at ~ 4.8M ish, you can then, later, make any fine adjustments as required.