GA124 Gauge Fickering

CGeorge

We have a new install of a Buderus GA124 and Im not a professional boiler tech . 
Whats happening with this primary / secondary loop system is some boiler flashing thats causing the gauge to flicker. 
The only way Ive been able to help this issue is to replace the primary loop circ or increase the antifreeze concentration as in past we only ran about 25% . But after a couple days it comes back . I even went from a 007 to 008 and same thing happened .System pressure is always at 18-20 lbs. 
Thank you in advance

No the circ is not controlled by logic and
does not have a post time set up

neilc

post a picture of your setup,
sounds like something isn't piped correctly,
how new is new and where is your contractor ?

hot_rod

Some air trapped in the boiler passageways?

Does that boiler require an aluminum specific glycol?  It’s rare to need more than 35- 40% glycol