Solar Thermal Controllers

Solar Thermal Controllers

My sensor cable is only 4 feet long. How do I wire it from the controller all the way to the collectors?

My sensor cable is only 4 feet long. How do I wire it from the controller all the way to the collectors? First off, when wiring to the collectors, make sure you use the high temp sensor (usually black or red). One end of the sensor cable has the sensor, which needs to be at the hot end of the collector array, and the other end has crimped wires that fit easily and securely into controller slots. So, the best thing to do is cut the sensor cable in half, and use each half where it is meant to be used. How do you bridge the gap? Well, SunMaxx pre-insulated line set (corrugated stainless steel pipe) has a 2-strand wire cable embedded inside it just for that purpose. Use the wire in the return line from the collectors to connect the two halves of your sensor. Wire connections should be soldered and shrink wrapped. The SunMaxx “Sensor to Wire Connections” installation guide shows the step-by-step process.

How do I get my SmartMaxx DHWPlus controller from Celcius to Farenheit?

How do I get my SmartMaxx DHWPlus controller from Celcius to Farenheit? Push the "+" button until you move to end of the main menu (time). Press the "+" button continuously for about 3 seconds to get into the adjustment submenu. You should see "Arr." Temperature scale choice is near the end of the submenu, so keep pushing the "+" button until you see "UNIT." When you get there, press the "OK" button once. "SET" will start blinking on the screen. Press the "+" button once, and Celcius will change to Farenheit. Push the "OK" button again to make the change permanent.

What is involved in setting the drainback option (ODB) on my SmartMaxx-DHWPlus controller?

What is involved in setting the drainback option (ODB) on my SmartMaxx-DHWPlus controller? In the submenu, switch ODB from “OFF” to “ON.” Four new items will appear in the submenu: tDTO, tFill, tSTB, and OBST. Some experimentation may be necessary to get these settings correct for your system.
  • tDTO (time period switch-on) is the amount of time the DT O must be met before the controller will turn the pump on. The factory setting is 60 seconds. The collector/tank temperature differential must be met for 60 seconds straight before the controller will trigger the pump.
  • tFill (filling time) is the amount of time the pump runs at 100% to push the heat transfer fluid up and over the top of the system piping. The factory setting is 5 minutes.
  • tSTB (stabilization time) is the amount of time the controller will ignore the DT F after it changes over to minimum pump speed. The factory setting is 2 minutes. This time is set aside because running the pump at 100% may cool the collectors below the “off” temperature differential. So, instead of shutting the system down as soon as it comes on, tSTB allows a time period for the collectors to stabilize at the minimum pump speed.
  • OBST (booster option) can be turned on if you have a second pump plumbed in series with the first. The second pump will then only come on during the filling time (tFill).
Turning on ODB will also automatically trigger the following changes:
  • The EM setting will be set to a fixed value of 200°F.
  • DT O will be set to a fixed value of 20°F.
  • DT F will be set to a fixed value of 8°F.
  • DT S will be set to a fixed value of 30°F.

How do I get into the adjustment submenu on my SmartMaxx-DHWPlus controller?

How do I get into the adjustment submenu on my SmartMaxx-DHWPlus controller? Press the “+” button to move through the main menu (Display Channels) until you reach the last item in the main menu. Then press the “+” for about 3 seconds straight until you access the submenu (Adjustment Channels). The first code displayed will be “Arr.”

How Do I Get My SmartMaxxDHWPlus Controller from German to English?

How do I get my SmartMaxxDHWPlus controller from German to English? With the controller plugged in, push the “+” button until you reach the end of the main menu. You will see the time displayed under the German “ZEIT.” Then push the “+” button for about 3 seconds straight until the controller goes to the submenu. “ANL” is the first German code in the submenu. Once you have accessed the submenu, press the “+” button until you reach the end of the submenu (a version number). Then press the “-“ button three times to go back to language (German “SPR”). Press the “OK’ button. While “SET” is blinking, press the “-“ button once to go from “dE” (German) to “En” (English). Press the “OK” button again. The code displayed now should be “LANG” which means you are back to English.

Setting your solar thermal system differential temperature setpoint.

Q:What is the most appropriate differential temperature for my solar thermal system? A: The factory setting on our controllers is 12 Degrees. This will work fine but for northern climates it is better to have a delta T of 17 Degrees. This will allow the collector to heat up sufficiently so as to not turn the pump on and off early in the cold mornings. In warmer climates, say mid-latitude and below you can keep the factory setting at 12 deg F.