C.LMT (current limit) how to govern the heater’s power draw

This article is designed to provide all the information you need to govern the heater’s power draw.


Every SV controller features a variable heater so the amount of power supplied to the heater can be adjusted. This is particularly helpful because it enables the SV controller to automatically
reduce the size (kW) of the heater when the pumps and/or blower are running, so that the spa’s
power draw stays within the limits of the circuit breaker feeding the spa, but also ensures the
maximum amount of heating input to the spa whilst in use. Traditionally spa heaters were a fixed
size (kW) and would usually be “load shed” and turned OFF completely when pumps/blowers were

The variable heater feature also enables the heater size to be governed to a certain limit if the
available power (amps) feeding the spa is limited. PLEASE NOTE: The C.LMT (current limit)
setting ONLY affects the power draw from the heater. It does not govern or restrict the
amount of power that the pumps or blower use.

The default C.LMT (current limit) settings for the SV controller models are:

In some spa installations the amount of available power (amps) for a spa circuit may be limited.
In this case the installer should adjust the C.LMT setting to match the rating of the circuit breaker feeding the spa. i.e. adjust C.LMT=20A i.e. the recommended power to be supplied to the spa is 32A however only 20A is available at the property.

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