documentations
Coldwright OEM Coil Specifications
Copper Tubes
Seamless copper tubes mechanically expanded into the fins to produce a permanent metal to metal contact for optimum heat transfer.
Tubes are staggered in order to allow maximum exposure of all tubes to air flow.
| Tube OD | Wall Thickness | Vertical Pitch | Horizontal Pitch |
| 3/8″ (9.35mm) | 0.41 | 25.4 | 22 |
| 3/8″ (9.35mm) | 0.71 | 25.4 | 22 |
| 1/2″ (12.7mm) | 0.41 | 31.75 | 27.6 |
| 1/2″ (12.7mm) | 0.71 | 31.75 | 27.6 |
| 5/8″ (15.88mm) | 0.45 | 38.1 | 33 |
| 5/8″ (15.88mm) | 0.91 | 38.1 | 33 |
Fin Options
We offer two types of fins: Plain Aluminium fins and Precoated Epoxy Aluminium fins with fin thickness of 0.15mm.
We can manufacture common standard coils with a wide ranges of fins spacing from 5 fins per inch (PFI) or 158 fins per meter (FPM) up to 16 PFI or 630 FPM.
For special Evaporator coils which are required larger fin spacing, we can also do from 2 FPI or 79 FPM to 4 FPI or 157 FPM
Brazing
All joints are hand brazed with 15% Silver solder (DX and steam coils) and 5% Silver solder (water coils).
Circuiting
All our coils are built with the most efficient counter-flow circuiting. In counter-flow setup, water or refrigerant are travelling along the heat exchanger in opposite direction of air-flow.
Coil Frame
Material Options: Galvanized steel, Aluminium, Brass or Stainless steel.
Stainless steel tube plates have a 2mm Aluminium insert between the copper tubes to prevent chaffing.
All tube holes in the tube plates have die formed collars to prevent chaffing.
Flange size options: we can do flange size from 25mm – 40mm.
Testing
Coils are pressurized to 2400kPa with dry nitrogen and then leak tested by submergence in water. Coils are dispatched sealed with 700kPa pressure.
Booster coils are dispatched without pressure. Ends sealed with plastic caps.
Test certificates are available on application.
Distributors
Venturi Type Distributors will be used on all our DX Coils
Water Coils
Vents and Drains on all coils except Booster type coils