Multiport and bubbles

[frogkick]

Every time I switch the setting on my multiport - say to drain or backwash, and then back to filter, there are bubbles coming out of the jets for maybe the first 20 or so seconds. Is this a normal part of it or is it something I should be investigating?

 

[Homebrewale]

It's possible you have a small leak in one of your pipe. Each time you switch the setting on the MPV, you need to turn off the pump. That is when air could enter if everything isn't sealed tight. Do you hear any water draining from pipes when the pump is turned off?

 

[frogkick]

The pump is turned off when I switch. I'll have to listen for water draining when I move it next time.