Changed My Water Pump but it always needs bleeding?

[dannyo]

I installed a new grundfos grundfos 15-60 water pump a week ago.

Trouble is my heating does not work until I bleed it? I have bled it two or three times a day for the alst week. It works great after I bleed it but next day air seems to back in system.

My boiler is down stairs and pump upsatirs next to water tank.
Is this normal after changing a pump? Can anyone advise?

 

[cross thread]

what speed is it on? and the 15/60 is the bigger output is it sucking in air,due to low head/pipework

 

[HarrogateGas]

I suspect you may have put the pump in the wrong way.

 

[dannyo]

I am pretty sure its the right way round. It has an arrow on the pump which is the same way round as on the old one ie pointing otwards the 3 port valve.

I did drain the system down when I changed the pump.

How many times would the pump normally need bleeding on a typical system drain down? Can anyone give me a rough idea?

Pump is currently on speed 3 ie max as I live in a 3 storey house and the pump is on the top floor!

 

[dannyo]

it is still doing if anyone has any suggestions I would be grateful?

 

[Rob]

as gordon said it may be sucking air down the open vent pipe when it first kicks in, try turning the speed down.

 

[dannyo]

Wow. turned speed to mimnimum last night and system worked great with litttle or noise from pump and piping hot central heating!

Worked this morning fine also!

I will let you know if it starts to happen again but I am pretty sure it has solved it!

Thanks for everyones help!

 

[dannyo]

Help - air in pump again after running on lowest speed for a few days?
Once air is bled from pump and vent pipe above the pump the system works great?
Is there anything I can do to the system to stop the air getting getting into the pump?