Control Panel Issues

xskursion

I recently purchased a home that has hydronic floor heating throughout. I noticed that multiple control panels have jumper wires instead of fuses. When I went to install new fuses, they blow immediately, which explains the jumpers. After disconnecting the thermostat wires from the control panel and reconnecting them one at a time, I noticed that only these newer Honeywell model thermostats are causing the fuses to blow. Other rooms have the original Wirsbo thermostats. Does anyone know if these Honeywell thermostats would in some way be incompatible with these older Wirsbo control panels? I can’t figure out what else might be causing these issues, other than maybe bad control panels themselves.