CODES for a Spa Builders Support Group LX-10 control system on a Sweetwater Spa, what are they?

Can anyone tell me what the numeric codes used on the topside controller mean? So far I've seen from -1 through -8 on the red led display. This topside display has four buttons (temp up, temp down, light on/off, pump lo/hi/off).

-8 seems to be a major fault as the controls freeze and all heat and pump action stops untill the power is turned off and then back on.