Orifice Union
Brass Unions with Orifice are specifically designed for use in the pressure sensing line for fire pump systems. The unions are fitted with 3 /32” orifice which will provide adequate pressure drop into the sensing line without allowing unnecessary pump starts due to major pressure fluctuations that may be indicated in the larger diameter line. The union is only allowed to be used where the water is clear and will not allow sediment to block the hole. Check with pump manufacturer for proper use.
Installation
Install in the pressure sensing line according to the fire pump manufacturers recommendations using appropriate tools and sealants. Make sure excess thread sealants are not introduced inside the union during assembly. Excess sealants will clog the orifice preventing proper sensing line function.