Having a problem when modeling a VAV with Reheat System. No matter what changes I make to the Heating coil leaving temperature for my system I am getting results saying that the Supply dry bulb is anywhere from 5000 to 13000 deg F. And the Space Air Flow for heating is coming out to 0 cfm. I expect that the VAV minumum value would be the expected space cfm value when the system is heating but the temperature at the main heating coils(terminal unit reheat coils) is excessive.
All rooms are using the same thermostat template 75F cooling set point and 70F heating set point. No schedule is used.
In the same file I have Multizone Systems modeled and all the results are coming out with reasonable numbers...77 def F Supply DB and valid CFM.
If I change one of the VAV with Reheat Systems in my model to a Multizone System then the Heating Loads appear to calculate correctly.
Any suggestions as to what I a missing in my model that's causing these results?
Thanks,
Cletus
I really have no idea, but are there clues in any of the reports as to what may be going on? Maybe something in the bottom of the system checksum where it reviews the coil selection? How about in the engineering checks? Also, did you scan for errors?
Otherwise, call CDS.
Or, have you tried making it a new file using the new file based on? This has fixed "buggy" files for me in the past.
It turned out to be an issue with the schedules. The schedule for heating appeared to operate backwards, heating was turned off when it schedule showed it as available, so in order to meet the room heating set point the heating leaving temp was increased.