Okay - I googled Honeywell TH611D - nothing. I am not keen on White Rogers but if it is the only one that will work - I'll try it. I was thinking a Honeywell TH5110D1022 might work if the "y" connection is used for the zone valve. It is generally the lead for the fan relay if you had a forced air furnace. I am asking if this thinking is flawed? If so, I guess I will have no choice but to add the spdt relay or install a new zone valve.
White Rogers 1F80-0471