SAFETY NOTICE - 240 VOLT HIGH VOLTAGE - MAKE 110% CERTAIN THE POWER IS SWITCHED OFF BEFORE TESTING.
The electric heater element should come on when there is a call for heat from the temperature sensor, and the Parameters for Hybrid operation are satisfied that allows the element to act as a booster and assist the heat pump during cold weather spells. For the SP3.0 model, here are the settings:
- touch MODE button to indicate the round icon (HY) is on, this allows Heat Pump plus booster Element to work together;
- touch SETTINGS button to view and change Parameters. P03 set from 0 to 1. The defaults for P04 and P05 are OK but may need adaption.
- more details on settings for the SP3.0 are here: https://sunpump.freshdesk.com/solution/articles/6000162174-sp3-0-touch-screen-controller-settings
If the Settings are correct, it is recommended to test the electrical components that act as switches inline between power supply and element.
TEST THE ELECTRIC BOOSTER ELEMENT
SP3.0 6 kW Element Wiring example. Your model may be different.
Test the booster element resistance using a Multi-meter on Ohms
- set to the lowest Ohm value dial setting
- test the resistance between the L1 and L2 power connections at the wire to screw fastener
- the value should be between 8 and 16 Ohms for most elements, in this case 9 is good
- if the value is approximately 0 to 1 that means the element is broken and needs replacement
TEST THE HIGH LIMIT SWITCH
The high limit is a solid state, bi-metal, protection switch that is Normally Closed "NC" and will pop or break the switch to Open when the water reaches 158 F. The Controller will display the message E14 when the high limit trips as a warning. When the tank water cools 30 F lower, the switch automatically returns back to NC and clears the E14 message. SunPump will not continue to operate when the tank is near 158 F. - use some hot water to reduce the overheating.
The High Limit switch is located on the front of the SP3.0 tank a few inched above the electric element, under a square insulation patch.
- Remove the wires from both sides of the switch to isolate the teerminals
- Set the Multi-meter to the lowest Ohms range - or to a continuity beep
- Measure the Ohms, it should read 0 which means it is Normally Closed and good
- A measurement of 1 means the switch is open, broken, or bad and needs replacement
Test the Contactor next, does the Coil make the contacts when energized?
https://sunpump.freshdesk.com/solution/articles/6000163413-contactor-for-2016-2017-sunpumps
Previous SunPump models SP2.2 from 2014-15 also have a Flow Switch. You can find more by a Search or at this article.
Electrical diagrams are in the User Manual and glued to the SP3.0 electrical box for reference. You can find them here:
https://sunpump.freshdesk.com/solution/articles/6000163413-contactor-for-2016-2017-sunpumps