A Spunding Valve is used to adjust and release pressure on a pressure capable fermenter, such as a Unitank.  It can  also be used to release pressure from a keg while filling or filtering. The relief valve can be adjusted to release pressure from 0-15 psi. 

Caution: This Spunding Valve should never be used as the primary safety pressure relief device. 

Every vessel that is under pressure should have a primary safety relief valve set in accordance with the pressure rating of the vessel. This Spunding valve should only act as a seondary relief that also allows you to adjust the pressure within the safety limits of the vessel or tank.  

How to Adjust: The pressure relief valve is adjusted by unscrewing the very end which reduces pressure on the spring. If tight, and not adjustable by hand, it needs to be loosened with pliers. Wrap a towel around the end piece of the pressure relief valve (about  the last 1/4 in) and loosen with pliers. Then finger tighten or loosen to your desired pressure.  

Gauge reads 0 - 15 psi