I'm trying to model two different water heaters in the same loop. The first water heater use solar collector to heating with a bypass. The second water heater use a heat pump air to water as a backup heater. But no matter how I model this system I end up with the same error:

** Severe  ** Plant Component WaterHeater:HeatPump:PumpedCondenser called "HEATPUMPCONDENSER" was not found on any plant loops.
**   ~~~   ** Looking for matching inlet Node="HPH INLET NODE".
**  Fatal  ** InitWaterThermalTank: Program terminated due to previous condition(s).

Is there some different way to model this problem? Is it possible to model this way and is something I don't see? If you have any insights I can send my IDF file!