Heatpump with hotwater boiler backup

TommyRay

Up North you guys have probably run into this set up. But we're down South and this is out of the norm. We installed a brand new Heatpump that works great. The customer did not want backup electric strip heat. When it drops to 30* outside he wants to cut the heatpump off and bring on his hotwater boiler that supplys radiators which We've accomplished. Problem: we cant get the indoor fan to turn off when running the boiler. We are using a TH632OU2008 (Honeywell) with outside thermostat. The TH632 only gives us 3 fan options: On, Auto or circulate. What are we missing? Do we need to add a relay or the fossil fuel kit.

pecmsg

Change in set up to gas or oil furnace