After problems earlier in the year which has now been very expensively repaired, I am starting to notice that when I am in the bathroom, which is were our boiler is, or, in the adjoining bedroom, there is a noise coming from the boiler. At present the water level in the tank is beow the pump. Lv 7. You’ll notice a slight dribble of water at this point. Leave the screw in this position until the hissing stops. Step 3 - Turn off the water at the shut-off and gat valve. Replaced a rattling Grundfos central heating pump three weeks ago with the modern equivalent (Alpha 2L). This action should "kick start" pump if pump motor windings are OK and pump is not seized. Carefully open the screw until you hear a hissing noise. View online or download Grundfos UPS3 15-50/65 Installation And Operating Instructions Manual Place an old rag or container ready to catch any water. As a renowned pump manufacturer, Grundfos delivers efficient, reliable, and sustainable solutions all … Tighten the screw and restore power. Step 5 - Mop up all the water that trickles out of the pump. Step 4 - Slowly remove the pump bleed screw. When bleeding a pump you must ensure it is cool enough to do so and that the power to it is off. Step 2 - Protect against water damage. Water may dribble out (it will not squirt out) and you may get air first. I have done what I thought was need to prime the pump by filling up the intake line and bleeding air from the pump through the plug on the top. It is not a combi heating system and we still have a working immersion heater/tank. Erika. Step 1 - Turn off the power. Grundfos UPS3 15-50/65 Pdf User Manuals. I have a Grundfos PC22 pump which is attached to a tank to pump water for our house. 4 Answers. I swapped out an old Grundfos pump for the new one. Turn the pump off and loosen the large silver screw in the center of the end plate. there will be an arrow cast into the side of the pump at the pipes end. Gone is the lovely old silver button on the front where you can bleed the pump and now we have more bells and whistles. Remove the large chrome screw from the end cover, replace when water comes out. 1 decade ago. Water will squirt out when the air is bled. Do not install the pump with the vent screw below horizontal. Step 6 - Screw the bleed screw back into place. This indicates that the pump has been completely bled of air. According to the packaging, it’s self-bleeding and has no bleed screw. How do you bleed the air out of a Grundfos pump? The full range supplier of pumps and pump solutions. My central heating boiler pump is a Grundfos. Favorite Answer. 0 1. How do you bleed a Grundfos circulating pump? Step 7 - … Modern pumps such as Grundfos, will have a bleed screw. Relevance. Answer Save. Source(s): S/e electrician 44 years. It's worth a try. Re: GRUNDFOS recirculating pump problem; Author: steve (CA) You could try bleeding it. jayktee96. to bleed a pump , turn off the system, then undo the silver screw in the middle of the motor end of the pump . If capacitor is suspected as being defective, to prove that this is the case, remove bleed screw insert small slotted screwdriver to spin impeller in direction of arrow while power is applied to pump.