Gas and Oil Home Heating Furnaces - Hot water circulation problem

I have a three zone hot water system with a Burnham boiler. Zone-1 for the main house first floor, Zone-2 main house second floor, Zone-3 addition(1 - 10 ft baseboard). Zone-1 & 2 work fine it's Zone-3 that's the problem. The thermostat will open the vale when on and I can manually open the value but the water just doesn't circulate. If one of the other Zones are on and circulating then then Zone 3 get's the circulated water since it's valve is open. Not sure what is going on here. Is this a bad pump of some sort or is the baseboard too small to trigger the circulation of the water? Obviously with these questions I've proven my ignornace Please Help.:confused:

Almost sounds like the pump isn't wired to that zone when it calls for heat.

Check to make sure all wires are hooked up on that zone valve, and trace it back to the relay box.

If you have a meter, check to see if you are getting power from that zone to the pump relay.

Im like jay. If the tstat calls for heat and opened the valve why didnt it turn on the pump. Dont see how its a bad pump,bad wire or relay more like it.;) ED

What brand are the zone valves?