Peltier Module Installation Guide

Surfaces And Flatness

Our modules are supplied flat to ±0.05 mm, with a height tolerance of ±0.2 mm. Your mating surfaces should be at least as good. A gap between the module and the plate is a thermal resistance in the worst possible place.

Clean both surfaces before assembly. Machining oil, fingerprints and swarf all add resistance and none of them are visible once the assembly is closed.

Thermal Interface Material

Apply a thin, even layer to both faces of the module. Thermal grease is a conductor compared with air but an insulator compared with metal, so more is not better. A thick line of grease is a thermal resistance you paid for.

Graphite sheet is the better choice for volume production because thickness is set by the sheet rather than by the operator, it does not pump out under thermal cycling, and it keeps the line clean.

Clamping Force

The maximum compressive load is 1 MPa. That limit applies over the module area, so on a small module it is very easy to exceed with a normal screwdriver.

Distribute the force across the whole module, not through two corner screws. A clamping plate that bows will load the module edges and leave the centre unsupported.

If your assembly cannot guarantee even clamping, an aluminium substrate module is much more forgiving than a ceramic one, because it is metallic and breakage free.

Leads And Polarity

Lead wire is 150 mm as standard, red positive and black negative. Other lengths, gauges and terminations are available on request.

Confirm polarity before powering. Reversed polarity does not damage the module, but it makes the intended cold face hot, which will surprise a test rig and can damage whatever you are trying to cool.

Strain relieve the leads. Repeated flexing at the solder joint is a common assembly induced failure.

Sealing And Condensation

Silicone gel sealing is applied by default. Specify if you do not want the module sealed.

Sealing protects the module, but the surrounding assembly still needs a plan. Any surface below the local dew point will condense water. The three practical options are to hold the set point above dew point, to seal the cold volume, or to purge it with dry gas.

Condensation is the most common cause of a thermoelectric assembly failing weeks after it was commissioned successfully.

Commissioning Sequence

Power up at low current first and confirm the cold side falls while the hot side rises. Then check the hot side temperature under full load. If it keeps climbing, the sink is undersized and no adjustment to the module will fix it.

Fit the thermistor on the surface you actually want to control, close the loop, and tune for a stable set point rather than the fastest possible pull down. Hard cycling shortens module life.