How much refrigerant should I put in?

We recommend using a pressure gauge to determine an accurate fill. Interdynamics’ color-coded gauges indicate whether you should continue filling (charging) or not. If you have just retrofitted from an R-12 system and had all the R-12 refrigerant removed, you should fill a system with R-134a at 80-85% of the original R-12 Volume. (Consult your owners manual or sticker under the hood for original R-12 volume).