I have previously been on site concerning my heat zone valves. I replaced one of the valves, and it seemed like it wouldn't fire up the furnace. I fixed that problem (I thought) but I'm still getting little or no heat in the third zone.

I've tried turning off the other two zones and just heating the one zone, but that doesn't seem to work well. I get a little increase, but nowhere near what I set the thermostat to.

By accident, at one point I disconnected the 2nd valve and it seemed like I got the right amount of heat in the other two zones, but I haven't been able to duplicate that again.

I'm guessing the problem is not the valve, but something else. Of course, my diagnostic skills so far haven't been impressive.

Any suggestions would be appreciated.

 

How's the pressure in the system? If it is less than 15# when hot, try adding some water to get the pressure up to 20# or slightly over. If the problem is air & you don't have a diverter tee system the added pressure might help get the air moving & aid in it's removal.