... 4. R22, R410a,R407c,R134a Heat pump heat exchangers are made of top quality titanium pipes using advance PVC ... chemical and medical industries.Outward can be made of 3 kinds of material: PVC-U ,PP-R, stainless ... PP-R, stainless steelExcellent PVC plasticCompact design with high heat transfer ability.Suitable for R22, R134a, R410a,, R407cWorking ... water/antifreeze 10.5kw Spa pool heat pump heat exchanger