How to Solder Copper on a Heat Pump

A heat pump is an energy-efficient system for heating a home using compression and expansion. It operates on the same principle as an air-conditioner, except in reverse. The heat pump has a loop of tubing where the refrigerant circulates in the system. Typically, this tubing is made of copper, since copper has very high thermal conductivity and is resistant to corrosion. Soldering the joints shut is the best way to seal the system and prevent leaks.

Heat pump with copper joints
Steel wool
Gloves
Copper flux
Copper solder
Blow torch (typically propane or butane)

Instructions

- 1
  Separate the two sides of the joint and thoroughly clean the joint area with the steel wool. The copper will be really shinny once it is clean.
- 2
  Put on the gloves and apply flux around the outside of the male side of the joint and the inside of the female side. The male side sits on the inside of the female side when the two pieces are joined together.
- 3
  Connect the joint together.
- 4
  Turn on the blow torch and begin heating the outside of the female side of the joint, about 1 inch down the tubing from the joint. Slowly work the torch around the tubing, keeping the flame perpendicular to the tubing, while moving closer to the end of the tube. Stop once you get to where the male and female portions meet.
- 5
  Touch the solder to the joint and slowly move it round the circumference of the joint as it melts. If the solder does not melt, heat the tubing some more and try again until the solder melts.
- 6
  Heat the tubing a little more. Then add more solder and allow the joint to fully cool at room temperature.

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