2 Thermostat Connections - One Thermostat

[Relsom]

Hi all, this is my first post. I've searched tge webs but haven't found an answer so here goes....My son just bought an old house with a Homart oil fired boiler in tge basement that is functional but needs some of the control wiring sorted out. First - there is no thermostat. The 2 wire tstat cable from the Honeywell R116a controller is ran to the circulator pump relay box, but just hanging there not connected to anything. If shorted, the boiler will fire up and run. Second, the 2 wire tstat cable connected at the circulator pump relay box and balled up, hanging a few joists over will cause the circulator pump to run when shorted. It looks like that cable was pulled down into the basement when the wall above was removed (different topic). So with both of these tstat connections shorted the system runs, max at about 24psi, and the aqua Stat cycles out at 170. My question is ... how do I connect one thermostat to both of these tstat connections? Common sense tells me not to parallel or mix the connections between the R116a and the pump relay. Should I add a double pole relay to turn on both parts of the system together or am I missing something basic here. The pump relay box does not have a spare set of contacts to use to satusfy the R116a thermostat input. I would feel comfortable adding a 110vac operated relay in parallel to the pump which then could satisfy the R116a. Direction here would be most helpful. Thanks.