Solar Lord Tank Sensor HWC1 and HWC2 models


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Solar Lord Tank Sensor that suits Solar Lord solar hot water controller HWC1 and HWC 2 models

The Solar Lord Controller and the tank sensor for this controller is no longer available. 

The best way to fix this system is to install a new Senztek 1-2 Controller which will separate the booster from the solar.

Controller includes:

    FREE Thermal heat paste for roof sensor installation

    1 x 20 roof sensor

    1 x 2.5m tank sensor

The Senztek controllers come pre-programmed with all leads and plugs fitted for easy plug and play use. 

There are many different types of controllers that use different types of sensors. If you are unsure, email us a photo of your controller and we can guide you to the correct sensor.


The image above is of the original sensor. The actual product supplied may differ to this but is an appropriate replacement part for your system. Images of the solar hot water controllers and original sensors are included in the description of products to assist you to find the appropriate product for your system (controller is not included in sale price).

Solar Hot Water Parts has the complete solar hot water replacement range. We are continually extending our solar hot water spare parts catalogue to give you the best selection of solar hot water replacement parts to choose from.

We sell the widest range of spare parts to suit any solar hot water service, whether it be a flat plate panel or evacuated tube solar collector. The Solar Hot Water Parts range is now online and ready to order, with complete tech specs to ensure your seamless selection.

If you're unsure which part suits, simply contact us - click here



*Please note solar Lord Roof sensors cannot be joined easily. Their polarity needs to be kept intact. Replace the entire cable from the roof down.

HWC-2 Customer Information

INPUT 240 VAC 50Hz 10A 2400W - OUTPUT MAX LOAD 10A 2400W - IP33
Approval Certificate No. 0060411

The HWC-2 is a Micro Processor driven Differential Controller that utilises highly accurate digital thermostats to maximise solar gain.

When the roof top collector reaches a predetermined temperature above the storage tank temperature power is supplied to a small low power circulating pump which in­ turn circulates the cooler tank water to the hotter roof and the hot roof water back to the storage tank.

If the roof top collector temperature is approaching freezing the small circulator pump will be switched on momentarily to circulate warmer water to the roof top collector protecting it from freezing.

Each Controller has a full range of built in self diagnosis and if an error occurs an alarm will sound on and off. Under normal operation L1 and L4 Red indicators will flash alternatively & if the circulating pump is on L1 and L4 will double flash alternatively.

If the alarm is heard, then check all wiring as per the installer instructions, if the alarm continues to sound then switch the unit off and call the Authorised Installer for service.

HWC-2 Installer Instructions

INPUT 240 VAC 50Hz 10A 2400W - OUTPUT MAX LOAD 10A 2400W - IP33
Approval Certificate No. 0060411

The controller enclosure must be firmly attached to the storage tank or nearby solid fixture by either the two mounting lugs or direct attachment though the controller. If mounting through the controller ensure the power cord is disconnected from the mains supply then remove the enclosure front cover by turning the four corner locks so each arrow points to the 'O' marked on the front cover. Insert two mounting screws diagonally through the oval holes in the enclosure, refit front cover and turn the four corner locks to the 'I' position.

All sensor wires should be fixed in a manner that they are not under tension or attached to the hot water return pipe. Conduit should be used if wire can not be easily pulled or if under ground. Do not run sensor cables parallel to mains power cable. Any additional cable should not be coiled; it should be shortened ensuring lead ends are tinned (soldered) and refitted to terminal plugs.

Each Controller has a full range of built-in self diagnosis. An alarm will sound on and off every 30 seconds if a fault is detected. The number of beeps in a row determines the fault which is also displayed inside the enclosure by the corresponding fault light.

L4 blinking & 4 Beeps indicate wrong polarity Tank connection or short-circuited cable or sensor.
L3 blinking & 3 Beeps indicate wrong polarity Collector connection or short­ circuited cable or sensor.
L2 blinking & 2 Beeps indicate a broken or disconnected Tank sensor cable or open circuit sensor.
L1 blinking & 1 Beep indicates a broken or disconnected Collector sensor cable or open circuit sensor.

If the led indication is for an open circuit sensor (either tank or collector), check that secure connection has been made into the terminal plug by gently pulling on each lead. If the connections are secure then check for any breaks, untinned wire ends or bad joins in the cable for whichever sensor was indicated, plugging in a spare sensor can help confirm that a sensor is at fault. If a roof sensor requires replacement due to actual sensor failure the sensor end only need be replaced by soldering on a replacement end and ensuring a water tight joint by using the appropriate heat shrink.

If a short circuit or reverse sensor is indicated follow the above instructions,and check for a reverse connection for whichever sensor and if the fault indication still remains check for any damage or bad joins in the cable. If no obvious fault is found then replace the sensor.

Most sensor error indications are caused by damage to cables, incorrect polarity should they be removed and then re-installed or poor connections. Any cable joins must be soldered and this includes where the cable enters the terminal plug which is inserted into the sensor socket.

lf the sensor cable has a black and white lead, the white lead is positive and the black is negative and if each wire is the same colour, the one with the thin trace is the positive and the solid colour the negative. If the cable is to be extended with non genuine cable then a size of 14/020 should be used. If the sensors have been fitted correctly and no beeps are heard and LED's L1 & L4 alternate then the controller is functioning properly.

TEST BUTTON: This button is internal to the unit and when pushed will start the circulating pump, briefly sound a beep and turns the 4 LED's on. The LED's then turn off and will indicate roof and tank temperatures. The Number of times LED L1 flashes indicates tens of degrees at the collector, followed by the number of time L2 flashes for single degrees at the collector. L3 is for tank tens of degrees, and L4 is for tank single degrees, (e.g. L1= 5 flashes, L2=no flash, L3=4 flashes,

L4= 1 flash means the collector is 50°C and the tank is 41°C)

Please note #
Large power surges and lightning can cause damage to sensors and microprocessors. If by changing sensors the symptom continues there is likely damage to the main controller which will require replacement at the customer's expense, household insurance may cover this.