Danfoss Fuel Pump

[Johntheo5]

This pump has started to leak from the PLASTIC blank plug (one pipe system), had been installed (with boiler) from new as far as I know a number of years ago.
Should a steel blanking plug have been used, and if so, why was the pump apparently supplied with this (plastic one) since it came configured as a one pipe system with the horseshoe washer pre installed?
Its located just to the right of the pump inlet braided hose.

 

[Exedon]

As you can imagine that should always have been a metal plug!

 

[Johntheo5]

Possible, I suppose that it did come with the metal blanking plug installed in the pump inlet, if threads are the same, and was jusr discarded when removed to install the inlet pipe?

 

[Exedon]

Really odd they always come with return port metal plug inlet port plastic plug.
Can't think I have any danfoss 1/4 plugs kicking about certainly have some riello ones lol.