York Rooftop Unit Heater

[lkanago]

I am looking at a york rooftop unit for a school here in Illinois York model # DAPB - F048AB. There is a 15kw electric heat accessory so the system is sized right for the 1,000 sf room but the administration is complaining that the system is not heating the room in the winter times. It is only one system out of five that is acting this way. Any ideas on what the problem may be? or has anyone experienced the same problem with york units? my best guess might be that the economizer settings were not set correctly for that unit.

Thanks,

Laurent K

[frigman]

check the economiser to make sure its at minimum position,and verify blower fan speed is set for proper cfm.do a temp rise for unit and see if its in spec

[SigGuy]

Check and make sure the installer installed the economizer relief damper correctly. I found one that the installer installed the damper to open inside the unit instead of opening out with air pressure. The damper would continuously open and let cold air in.

SG

[lkanago]

thanks for the quick reply. I talked it over with our HVAC guy and he said the same as you two said. As we found out, the school had a problem with all five york units. The system was not sized/balanced right and the dampers probably weren't set correctly. Thanks again. We will be contacting the HVAC designers soon.