[rheavn]

I went out and looked at my heater shut off valves today. It appears to me that these valves are two piece--much like the AquaHot mixing valves. If so disassembling the manifold and disconnecting the heater hoses would be unnecessary. It appears to me by removing the handles, one could remove each valve guts with a deep socket. If you had the valve part ready coolant loss could be held to only a small amount. Might have to buy the whole valve, but only use the valve guts. I attached a picture. See if your valves are like mine.