Sealing iron plumbing fitting to brass?

[Roger Moss]

My central heating pump has just packed up (I think it froze in cold weather) and I'm busy replacing it. Looking at the fittings I built it with about a year ago I find there has been some weepage between the iron pump fittings and the brass end-fittings for the copper tube system. I had used PTFE tape here - is this "the best"?

In the past I have tried Boss white (or green) and hate the stuff, though admittedly I haven't tried it with hemp. I also have Atmos sealant (a type of grease), Loctite 55 cord, and EverBuild pipe seal (a liquid perspex type of setting sealant). Before I fill the system and add all the inhibitor - any suggestions as to which is best?

Thanks

Roger

[John Rumm]

It should be fine, but sounds like you needed a good deal more of it.

Fernox LSX jointing compound is also worth trying - a silicone type of material that does a good job.