Ruud heating/ac unit blowing only cold air in...

Question

Ruud model# URGG-07N48JKR mfd in 03/89 is blowing only cold air when in heat mode. Is this a single phase heat pump? I changed t-stat (Hunter model# 44360) and believe I wired correctly. 4 wires:
1) T1 to T1
2) G to G
3) RH and RC jumpered together
4) W1 on old t-stat to W/B on new t-stat

Switches on back set to HP(believing I have a heat pump) and HG (fan works fine in HG)

Still only cold air blows when in heat mode. Any advice??
thank you!