An outdoor heatpump condensing unit requires a R,Y,C,O,W2. Client originally has an electric heat air handler with an outdoor ac. Now has an indoor air handler with heat strips and an outdoor heatpump condensing unit. The outdoor ac only had 3 wires and now has a heatpump requiring 5 wires. Now way to run new low voltage wiring. Installer wired only C,O,Y. Will work except when defrost is needed. Any brains out there, to resolve this clients issue? Help!