... source heat pump water heater 1) titanium heater exchanger. 2) galvanized steel shell airsourceheatpumpwaterheaterfactory air source heat pump water heater vs series ... ,13kw,17.5kw,21.5kw,25.5kw. *.Titanium Heater exchanger PVC. *.Eco-friendly gas R410A *.Lower noise ... available. * CE&RoHS approval.air source heat pump water heater vs series spec: Model No. Unit VS130RVS180R VS220RVS250RHeating ...