I have a Honeywell V8043E zone valve that I need to replace.
Unfortunately, it has the older style seat, so I can't just pull the
motor assembly off. The Honeywell instructions say that I have to
drain the system before I can remove the seat. However, I have also
been told that if I have shut off valves before the zone valves that,
instead, I can shut these off, install the valves and then turn the
water supply back on. When I inquired about air in the system, I was
told that the autovent should take care of this. I do have an autovent
in my heater system.

Whose advice is correct? Any comments would be appreciated.

Thanks;

James M Wiedle