Problems with Hydro Smart boiler

[tcabinets]

I installed a Hydro Smart boiler in my shop/garage and it works great except that once in a while it will start to "growl" and make noise in what seems to be the top of the boiler. I found that adjusting/ increasing the pressure seems to fix it temporarily.
The system has 3 zones that I switch on and off depending on the area where I'm working.
Any suggestions.

 

[custom1]

Welcome.
First guess would be trapped air. Give us some more details and maybe a picture. How long has it been in service and has it done that the whole time?

 

[mygarageone]

You should has some dip switches for exhaust fan speed based on elevation , try setting your elevating dip switch for the next higher elevation.
I believe that will cure your growling issue.

 

[JackDiddly]

make sure its not happening when you open a zone that has been closed and cold for awhile. I am not at all familiar with the brand you mentioned, but with the copper fin tube style of heat exchanger dumping cold water into your hot heat exchanger will make some noise and cause some damage, if that were to be the prob you could pipe in a bypass from supply to return to help keep the boiler temp up while operating.