arrived on site to check right Carter Hoffmann holding cabinet. (from the front, right unit) checked and found high limit tripped. reset high limit. found cooling fan extremely dirty. cleaned for now, but should be replaced. checked operation. unit now heating. heated to set point of 150° and cycled off. display reading 152°. cabinet cycled back on at 148°. cabinet heating and blower operational. cabinet in service. 1/17/2020 arrived at location with part, put in new cooling fan in unit, cooling fan is running, unit heats in service