small leak above zone valve?

[tommyo]

I have a small leak above one zone valve, (2 are on system) I am assuming this has to drained before any attempt to solder(suggestions) will this do anything to the zone valve ?, and should I use map gas or propane seeng as when doing this. When drained and refilling is ther anything else I should be cautious about, and how would I bleed air after completion, thanks for any advice.

 

[NHmaster]

Yes, water needs to be drained
Yes too much heat will damage the valve