I have been to my friends new house and there is what looks like a bypass (gate valve operated) on his Y plan system.
I thought Y plans did not need a bypass and the valve is stuck solid so I cannot mess with it. Any ideas what it could be? I assume it is open as both sides of the pipes are red hot. The plumbing goes from the pump to a T connector that splits to the to the gate valve and the the inlet for mid position valve. The rest is under the floorboards
Adam