The initial installation was done by non-qualified installers. The system did not work. A qualified HVAC man came in and got the system going, but it soon failed, again. I contacted Hawaii Sheet Metal & Mechanical. Their crew found two leaks and repaired them. The system then worked in two rooms or if all rooms were engaged. It failed once again when only one of two guest rooms was activated. Hawaii Sheet Metal & Mechanical sent a technician out; but he failed to remediate the issue. I did troubleshooting, myself, and discovered that the electrical leads from our two guest rooms were reversed. I switched the leads, and all is well.