Workshop Fan Coil Unit Blowing Cold Air - Boiler Has Beckett HeatManager

NTL1991

Happy New Year!



I'm trying to work out an issue with my fan coil unit in my basement workshop that doesn't always provide adequate heating.



The boiler is an oil-fired Utica, rated at 175 MBH. I have 5 zones running off the boiler: main level, upper level, a large patio room, a 40-gallon BoilerMate, and this Beacon Morris 18k BTU hydronic fan coil in the basement.



The boiler has always had a Beckett HeatManager fuel economizer installed.



The fan coil has it's own zone valve, triggered by a White Rogers thermostat, and the fan motor on the unit is triggered by a Honeywell L6006C aquastat, set at ~160 degrees if I remember correctly.



The boiler has a L8148A High-Limit Aquastat, set at 200 degrees. The problem seems to be that the HeatManager is allowing the boiler to "economize" and drop well below the minimum operating temperature of the fan coil, causing the zone valve and pump the stay energized for almost 20 minutes before the burner kicks on and reaches high limit. The HeatManager thinks it's doing a swell job economizing all that time, but in reality, it's just pushing 140-160 degree water through the fan coil zone, which isn't nearly hot enough to trigger the L6006C.



My question is: Is there a way to wire the fan coil zone to bypass the HeatManager, so that when the zone calls, the boiler actually stays within the 180-200 degree range that the aquastat is set for? (As an aside, shouldn't the indirect already be wired this way, too!?) Once the zone is no longer calling, then the baseboard zones (main floor, upper floor, patio room) can make their call through the HeatManager?



Or I can just flip the switch on the HeatManager altogether, which I'd rather not do as it does provide some savings for this mostly oversized boiler.



Thanks,

Nick

Paul S_3

why

Dont you just lower the aquastat setting on the fan coil, so the fan turns on at a lower temp, instead of 160f....Paul S

NTL1991

If

If I lower the temperature on the fan coil aquastat, I'll get even more cold air blowing from it. The issue is that the boiler is staying below 160F for too long.



-Nick