I have a Grundfos A2 pump in c/h system and my system has got very hot water in my expansion tank. I either need to flush out the stem or turn down the speed of the pump but the pump doesn't seem to have the facility to turn the speed down. Any suggestions.
When you say A2 did you mean the alpha 2? https://uk.grundfos.com/products/find-product/alpha2.html If you did you just press the arrow on the front until you get the desired speed up. But these pumps are designed to modulate so you should need to set it on the first or second setting. Should you choose to go to the manual settings it the bar symbols that you will need. Also the F&E tank is designed to house hot water its from the expansion of the water in your system unless it is actually pumping over (coming out of the open vent)