Does anybody have an idea how much the Tekmar 062 can modulate boiler temps down from the calculated boiler tempeature based on the heating curve with outdoor reset ? My continuous circ Air handler system runs beautifully on cloudy days and all nights with the current input parameters (115F boiler temp for a 70 deg room temp on a 14F design day). But on sunny days, even though the RTU is in the great room where we have alot of solar load (south facing house with a lot of low-E glass) it seems to not have the range to account for the solar gain and the house overheats.
I've partially solved this by setting the WWSD to 45F and putting the outdoor sensor on the south facing wall of the house. But on a day like today (32F, cloudy) there is still some solar load and the house is creeping up past it's 70F setpoint. When I turn the RTU air sensor off (so now it's just outdoor reset working) the boiler target temperature goes up 5F, so the RTU is pulling that down 5F. Is that it's limit ?
EDIT: The RTU is hooked up to a Tekmar 262. I do have a regular heat/cool thermostat for the cooling system that I could use to turn off the boiler demand on the 262. Seems inelegant given the amount of money that I've put into the system.
[Edited by odcman on 02-16-2006 at 01:02 PM]