| 摘要 |
A swimming pool or spa heater unit (10) having a heat exchanger manifold (28) designed to permit the use of direct plastic piping connections to the manifold header (33). The manifold is principally characterized by a header end having an inlet port (36) and outlet port (37) located on a level below the manifold inlets and outlets (32) communicating with the heat exchanger (34). The inverted arrangement of the header ports (36, 37) relative to the manifold inlets (32) and outlets (32) to the heat exchanger (34) permits unreturned water in the unit heated by residual heat from the heater (10) to form a temperature gradient therebetween which prevents the temperature of the water at the header connection from reaching a level incompatible with the use of direct plastic piping connections. The manifold is also integrally provided with weirs (40, 41) which serve to provide dry-fire protection for the heater. |
