Well, summer is approaching and we have already had some really hot days. This is the time to maximise your solar hot water savings by ensuring that your electrical element never switches on unnecessarily. You also want to try and prevent the system from going into stagnation (boiling) in the solar collector on your roof. The system is made to withstand stagnation but over long periods of time, it could lead to unnecessary strain on the collector. You can achieve both of these objectives by taking the following steps (look below for your type of controller): We hope you see your electricity consumption significantly reduce over the summer months.
SR868C8 Controller (In use since about December 2010)
If your solar controller and electrical element are on separate circuits, you may want to just switch off the geyser circuit so that the element never switches on. To see if they are on separate circuits, turn the GEYSER switch off on your electrical distribution board. If the controller also turns off you know that the controller and element are on the same and you need to rather set the backup temperatures very low or else set all the timers to the same ON and OFF times to prevent the element from coming on. To adjust these settings donwload the instructions at this link – SR868C8 Quick Setup Guide
If you go away on holiday, be sure to set the ‘Holiday Mode’ on your SR868C8 controller by pressing ‘Holiday’ for about 2 seconds until the little island and palm tree appears.
Geyserwise Controller (In use from about April to December 2010)
On the Geyserwise controller, use the following procedure to ensure the element seldom or never switches on:
- Press the SET button once and a temperature setting will appear. This is the temperature that applies if you have timer settings between 00:01 and 06:00.
- Use the V button to reduce this setting to the minimum of 300C. Should you find that you do not have sufficient hot water you may need to vary this setting, using as low a temperature as possible to ensure you have enough hot water but using as little electricity as possible.
- Press the SET button again and another temperature setting will appear, repeat the above procedure. This one is for 06:01 to 12:00
- Repeat this procedure twice more (12:01 to 18:00 and 18:01 to 24:00). There are 4 temperature settings on the Geyserwise which are for different periods of the day. You may wish to leave the 18:01 to 24:00 setting on a comfortable temperature of about 550C in case of cloudy days.
If you wish to change the timer settings, from the default display, press SET 8 times. Mon to Fri will flash and 1 ON will flash. Adjust the hour setting using V or ?. Press SET and adjust the minute setting. Press SET again and Mon-Fri 1 OFF will flash. Adjust. Repeat for all four Mon-Fri settings and then for the four Sat-Sun timer settings.
If you find that your system is still reaching the maximum tank temperature during the day (75 or 800C), you might want to try leaving it on ‘Holiday Mode’. Push the SET and POWER buttons together. This will circulate the water through the collector at night in order to reduce the tank temperature so that it starts off at a lower temperature the next morning and is less likely to reach stagnation temperature. The screen will go blank except for a small OFF indication. It is particularly important if you go away on holiday to leave the controller on ‘Holiday Mode’ by pressing the SET and POWER buttons simultaneously. The screen will go blank except for a small OFF message.
Full Gauge Microsol II Plus Controller (Up to about March 2010)
The newer Full Gauge controller has a switch on the side that allows you to easily turn off the electrical element. On the Full Gauge controllers without the override switch, use the following procedure to ensure the element seldom or never switches on:
- Press and hold the SET button for about 3 seconds until SEL appears.
- The display will then change to F13 (DO NOT change the F13 setting).
- Press the ^ button once and F16 will appear.
- Press SET once and a temperature will appear. This is the temperature to which the electrical element will take the water if it switches on.
- Press and hold the v button and reduce the temperature. 100C is the minimum setting but you may need to vary this in order to ensure you still have enough hot water.
- Press SET again in order to save the new setting.
An Easy Test to See if Your Solar Water Heating is Working Correctly
It is important to check periodically that your solar water heater is working properly. If the solar heating is working correctly, there should never be more than about a 20 degree C difference between the temperature in the geyser (the default temperture on your controller display), and the collector (unless temporarily caused by a power failure or water supply problem or maximum temperature having been reached in the geyser). This is because when the temperture differential reaches 20 degrees (15 degrees on some models), the pump is turned on to circulate water through the solar collector in order to get the heat into the geyser. The pump continues circulate the water through the collector as long as the temperature differential is more than 4 degrees C. This means that the differential should never be more than about 22 degrees C. i.e. If your geyser temperature is 50 degrees C, the collector should not be higher than about 72 degrees C. A high differential of say 30 to 100 degrees would indicate a possible circulation problem like a stuck valve. In order to check the collector temperature on the different controllers, do the following:
- SR868C8 Controller – press + a couple of times until T1 appears on the top right of the display. T1 will also flash on the system diagram on the left. This displays the collector temperature. Press ESC and it will go back to the default screen.
- Geyserwise Max – Press the v and ^ buttons simultaneously. Ther will now only be one figure on the dispaly, this is the collector temperature. Press the same 2 buttons to go back to the default screen.
- Microsol II Plus – Press the v button 2 or 3 times until t1 appears. After a second a temperature will appear which is the collector temperature. After a few seconds it will automatically revert to the default (T2) temperature.