cpenn Report post Posted January 2, 2020 Roof a/c fan and compressor will not engage...Same result when on heat pump setting...When starting there is a humming sound but the compressor or fan will not start...Would appreciate a diagnosis if anyone knows the problem. Duo-Therm Penguin roof top a/c and heat pump Model #630516.321 Share this post Link to post Share on other sites
wolfe10 Report post Posted January 2, 2020 Have you checked voltage to the unit? Same on generator or shore power (to help rule out power issue)? Next would be to check the capacitors (roof access)-- they help start the fan and compressor. Share this post Link to post Share on other sites
rayin Report post Posted January 2, 2020 I agree with Brett, start capacitor may be bad. Note: if you are unfamiliar with handling and testing capacitors, be sure to short between terminals FIRST before handling! They are capable of giving severe shocks and burns. Share this post Link to post Share on other sites
manholt Report post Posted January 2, 2020 What year is your unit? Share this post Link to post Share on other sites
