First: the "no co" code means "Not Cooling".
Second: 108 VAC is the minimum voltage. It should be in the range of 108 to 132 Volts.
Best case: your line voltage is too low.
Worst case: you have a bad heating element.
Paul
Extra Class Ham Radio operator - K9ERG (since 1956)
Retired Electronics Engineer and Antenna Designer
Was a campground host at IBSP (2006-2010) - now retired.
Single - Full-timer
2005 Four Winds 29Q
2011 2500HD 6.0L GMC Denali (Gasser)