New pump is causing problems, hissing, and the room is not heating properly

Hello everyone,

I have a gas boiler and underfloor heating in my house (built in 2005). The flow temperature is about 30 degrees.

I had a pump from Grundfos (I also estimate from 2005), it always made hissing noises, allegedly was not running properly anymore and was replaced by the plumber.

All rooms in my house still got warm.

I now have a new pump from Grundfos again (also Alpha1 25-60/180) and my living room no longer gets warmer than 20 degrees, although 22-23 degrees are set. Behind the pump, 30 degrees are still displayed.

The new pump was installed backwards because the plug otherwise did not fit, see photos. No idea if it might be rotating backwards.

I didn't hear the old pump at all, except for occasional hissing noises. The new pump is very loud, depending on the setting.

I couldn’t make sense of the manual either. There are three settings with three levels each. See photos.

The photos always show the level with the highest setting.

Does anyone maybe have an idea how I should set the settings? Is it normal that the newest pump is the loudest? I have other pumps installed that run without any noise.

You can listen to the hissing noises here: [MEDIA=youtube]ZOalD_niKyg[/MEDIA]

Merry Christmas and thanks in advance

Stephan

Hello, my Grundfos Alpha had to be replaced a few weeks ago after pretty much exactly 13 years due to an electronic defect. If it were running the wrong way around, I don't think your heating would work at all ;)

By the way, mine is whisper quiet...

I also think that the heating controls the pump. I wouldn’t manually adjust anything there (Level I, II, or III).

Grundfos pumps usually come with a "loose" plug! Probably the installer just wanted to use the old cable because he was too lazy to connect the new one? Then it would have fit correctly anyway.

Have you thoroughly bled the system and checked the water pressure? (The heating is usually located downstairs (basement, etc.), and a pump replacement doesn’t necessarily require that, but it could still help). The 23 watts seem a lot to me. I have never seen mine above 18... My heating system also doesn’t run smoothly with too little pressure and air in the system...