Grundfos ups3 pump, what speed.?

[Simone]

Hi, recently had a Grundfos ups3 Pump fitted and get a hissing noise out of it and then 2 of the closest radiators start to gargle, I’ve change the speed down to constant 2 as it was on constant 3. Would constant speed 1 be ok as its a bungalow with 8 radiators.? Thank you.

 

[ShaunCorbs]

I would leave it on 2 the noise you heard was probably air have you tried bleeding the radiators?

 

[Simone]

Have bled radiators and there was air in the 2 nearest the boiler, they are the 2 that make the gurgling noise when the pump makes that hissing noise.