SmartMaxx™ Solar Hot Water Controller for Domestic Hot Water & Space Heating with 3 Relays

Our pump station’s fill valve has GHT hose threads on the outside. You can easily make an adaptor using the following three fittings, which can be purchased at your local hardware store or plumbing supply.

• Schrader valve x ¼” male NPT
• Reducing Bushing, ½” NPT Male x ¼” NPT Female
• Hose fitting, ½” NPT male x ¾” swivel GHT female

Use Teflon tape on the NPT threads of the Schrader valve and bushing in constructing the adaptor. When attaching the adaptor to the pump station, be sure to use two tools: one to hold the fill valve in place, and one to tighten the adaptor. That way, you won’t create leaks in the pump station itself while testing.

Take a deep breath and let all your air out… of your Solar thermal system One of the biggest issues with a successful commissioning is air removal. Any time you spend with this detail will be time well spent. Air pockets become entrained within your HTF and like to find places to hide. Air pockets can form between your HTF and the inner wall of piping (especially with flexible piping) and can only be removed through persistence and time. Here are a few things you can do to help this process. First, be sure that your air purger is located on the high and hot side of your collector series. The hotter the fluid the less the ability for dissolved gasses to stay in solution and the higher the air vent, the more likely you will effectively remove trapped air that, due to its buoyancy, will rise to the top. Once you feel most of the air has been removed this way, you can shut that air eliminator off or remove it all together. If you install a Titan Power Plus collector, you will have a manual air bleeder permanently installed in your line set connections. If you install a ThermoPower collector, you will include an air vent that should be isolated and de-commissioned at this point. Now, down to the pump station. The UniMaxx pump stations have an integral air eliminator with a scoop that will allow entrained air to collect and be bled off manually by opening the valve up to a full turn until HTF comes out. This can be done each day for the first few days or periodically checked. Smaller systems will take much less time removing the air. Another way of enabling the removal of air is to run the pump at maximum speed during commissioning, this will help to break the friction that holds the bubbles to the inner wall thus forcing the bubble through and out. After words, you should adjust your pump speed accordingly. If air persists in your system, it will inevitably find its way to the suction side of your pump and cause cavitation and eventual pump failure. If your pump appears to be not pumping, it is likely that although it is receiving 115v, it cannot pump because of air pockets. Simply unplug your pump and manual override and give it a few minutes. Air will work its way out, pump can run and then you need to go back to the air purging steps. Please view our SunMaxx technical manual (linked) for further instruction in effective system commissioning.

To check the temperature sensor you can use the digital multimeter tool and check the resistance of the sensor.

A simple steps which allow to check the temperature sensor:

1. Turn the system off (electricity) – safety us the most important
2. Open the controller box
3. Check if the connection is not loose
   • If loose fix the connection by pushing the sensor wire inside the terminal
   • Close the controller box and check if that fixed the issue
4. Check the sensor wire resistance with multimeter (turn the multimeter switch to the resistance measurement) – reading should be around 1.101 kOhm at room temperature and around 1.250 kOhm for hot water
   • If readings are different sensor might need replacement

This short advice should help you to solve the problem.

The SmartMaxx™ controllers work similar like thermistors but there is a little difference in the way of measuring the temperature. The Pt1000 sensors (type of sensor which are using our systems) are also called RTDs. The resistance temperature probe is based on the resistance of metal in our case Platinum. The resistance of this metal depends on the temperature. Basically there are two types of thermistors PTC (the resistance is increasing due to temperature growth) and NTC (an increase in temperature causes the resistance to decrease) – the value of resistance depends on temperature. These type of sensors are more sensitive than basic type of controllers.