I have a heat pump that uses the water heater to run I had to replace the waterheater now I only have hot water when the heater is on please help

By heat pump do you mean hot water recirculating system? Gas or electric hot water heater?
I only have hot water when the heater is on the heater is automatic and should be on all the time. Please explain. Can you furnish more details? Back to you, Tom

It is a gas water heater and an aqua therm heat pump the water heater only gives hot water when we turnn the heat on .if heat is not on there is no hot water .

It is a gas water heater and an aqua therm heat pump the water heater only gives hot water when we turnn the heat on .if heat is not on there is no hot water .