C.LMT (current limit) – How to govern the controller’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
operating.
The variable heater feature also enable’s 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 effects 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:
MODEL C.LMT (default)
SV2-VH = 15 amp
SV3-VH = 32 amp
SV4-VH = 40 amp
1.LLM (load limit) – how to govern number of loads that operate at once
In some spa installations the amount of available power (amps) for a spa circuit may be limited.
i.e. the recommended power to be supplied to the spa is 32A however only 20A is available at the
property. 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 (please refer previous page). This process
ensures the heater size is governed, however it DOES NOT prevent the combined total power draw
of the jet pumps and blower when running from exceeding the circuit breaker limit.
The power draw (amps) of a jet pump or blower cannot be adjusted. Pump or blower motors are a
certain size and must maintain a certain RPM, so their current draw is fixed. They will always draw
around the same amount of power (amps) when running (assuming voltage and head pressure are fixed). If the
available power (amps) for a spa circuit is limited, the installer must consider how much current
(amps) each jet pump and/or blower will use and where required must adjust the 1.LLM (load
limit) setting to restrict the number of loads that operate at the one time, to keep the total power
draw of the spa within the circuit breaker limits.
Each jet pump and blower is considered a load. The filtration pump is NOT considered a load. The
load limit setting (1.LLM) governs how many loads can be turned on at the same time. (i.e. If
1.LLM= 2, only two loads can operate simultaneously. E.g. 2 x jet pumps could be operated
together OR 1 x jet pump and 1 x blower, but if you tried to turn on 3 x jet pumps or 2 x jet
pumps + blower, the third device would NOT be allowed to turn on to keep the power draw to a
certain limit. One jet pump or blower would have to be turned off before the other load could be
turned on).
A rough guide of the power (amp) draw for equipment running on a spa pool is as follows:
MODEL DESCRIPTION AMPS
XS-3C 250W circulation pump = 1.3A*
XS-10B 700W air blower = 3.3A
XS-30 1850W jet pump = 7.6A
XS-30S 2200W jet pump = 9.0A
* The circulation pump is the filtration pump and is therefore NOT considered a load and will NOT be governed by the
1.LLM (load limit) setting, HOWEVER you must take into account its power draw when calculating how much power the jet
pumps and blower will use. The circ pump will ALWAYS run if a jet pump is operating.
Once you have considered the available power feeding the spa (i.e. 10A/15A/25A/32A/40A/45A)
and how many loads (i.e. jet pumps and blower) can operate together before exceeding the spa
circuit breaker limit you must adjust the load limit (1.LLM) setting. Refer below:
L.SHD (Load Shed Count) – The C.LMT does not control external heat pump operation.
This setting should be used if an external heat pump is installed
This setting determines the load shed behaviour of the heating element or heat pump (if fitted).
Load shedding is governed by the load shed count (1 to 7). Load shed count = number of loads
required to be turned ON for the heater to load shed and turn OFF. The filtration pump is not
counted as a load, the blower and all other pumps are.
Example:
Load Shed Count = 2
When any two loads in addition to the filtration pump are turned ON the heater
load sheds and turns OFF.
The L.SHD setting ranges from 1 to 7.
1 = maximum load shed
7 = load shed disabled (default)
* The circulation pump is the filtration pump and is therefore NOT considered a load and will NOT be governed by the
L.SHD (load shed) setting, HOWEVER you must take into account its power draw when calculating how much power the jet
pumps and blower will use. The circ pump will ALWAYS run if the heat pump is operating.
V.ELE (Variable Element Operation) – Control of electric element operation
Variable element operation allows the SV controller to automatically adjust the heater power level to
match the residual current available when accessory devices (ie pumps and/or blower) are operating. The benifit of this feature is the element can automatically reduce its power level and remain on instead of load shedding and turning off when spa is in manual use and the jet pumps have been activated.
The setting choices are:
VARI variable element enabled (default – May be “ON” in early versions of software)
STEP Controller will choose which element can be turned on without exceeding current limit
OFF variable element disabled
Note: If disabled (OFF) the heating behaviour is the same as a standard element. Load shed settings may need to be configured to esure the spa pack does not exceed its maximum current limit. The controller will not restrcit power draw to the C.LMT value.
V.MAX – Maximum Variable Element Size – How to govern the heater’s power draw
If variable element operation is enabled the installer also has the ability to limit the maximum current the heating
element draws (3A to 25A) via the V.MAX menu item. This enables the installer to reduce the heater current draw
where available power is limited, without the need to replace the heater element or spa pack. The V.MAX setting
ranges from 3A to 25ADefault setting = 23A
This setting is used to limit the power to the spa heater but not limiting it while the consumer is using the spa and
pumps.
e.g. SV3 with approximate power usages
