HVACComponent ZoneHVACUnitHeater_Impl::heatingCoil() const 
 {
   boost::optional<HVACComponent> value = optionalHeatingCoil();
   if (!value) 
 {
     LOG_AND_THROW(briefDescription() << " does not have an Heating Coil attached.");
   }
   return value.get();
 }
  std::vector<ModelObject> ZoneHVACLowTempRadiantConstFlow_Impl::children() const
 {
   std::vector<ModelObject> result;
   if (OptionalHVACComponent intermediate = optionalHeatingCoil()) {
     result.push_back(*intermediate);
   }
   if (OptionalHVACComponent intermediate = optionalCoolingCoil()) {
     result.push_back(*intermediate);
   }
   return result;
 }
 std::vector<ModelObject> ZoneHVACUnitHeater_Impl::children() const
 {
   std::vector<ModelObject> result;
   if (OptionalHVACComponent intermediate = optionalSupplyAirFan()) 
 {
   result.push_back(*intermediate);
 }
   if (OptionalHVACComponent intermediate = optionalHeatingCoil()) 
 {
     result.push_back(*intermediate);
   }
   return result;
 }
 HVACComponent ZoneHVACLowTempRadiantVarFlow_Impl::heatingCoil() const 
 {
   boost::optional<HVACComponent> coil = optionalHeatingCoil();
   OS_ASSERT(coil);
   return coil.get();
 }