Dosing-units.com Frequently asked questions:
Q Do I need to fit a foot valve and strainer on the pump inlet ?
A If the pump is fitted in a suction lift situation (not flooded suction) then a foot valve should be fitted. Ensure that the maximum lift for the pump stated on the technical data is not exceeded.
Q Should I install a pressure keeping (loading) valve in my system ?
A To ensure efficient pump valve operation the pump should work against a positive pressure of a general minimum 0.5 bar. Fit loading valve if less. Additionally if the design of the pipe work layout is such that a siphoning is possible a loading valve should be fitted to prevent this.
Q What about possible pump and pipe work overpressure ?
A To protect pump and pipe work against damaging excessive pressure fit in line relief valve or purchase pump fitted with integral pressure relief valve. This is particularly crucial if a shut off valve is fitted in the discharge line which could be inadvertently closed.
Q Can I use threaded fittings and PTFE tape on the pump valve connections ?
A Definitely no, only the appropriate union pipe connections supplied with the pump or fitting should be used. Never use PTFE tape or similar or B.S.P fittings as damage to the connection thread or pump head may result. The seal is made with 'O' rings supplied with the pump or fitting. If necessary replace with new ones.
Q Why is the pump not providing the correct capacity ?
A Most common cause of poor output is blocked or dirty valve gear. Carefully remove the inlet and outlet assemblies and check for blockages, rinse as necessary. Take care not to lose the 'O' rings, replace them if required.