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How to Install a Solar Heating System? (A 7-Step Installation Process)

Whether you have built your own DIY solar water heating system and want to know about the next step or just explore the installation process before signing up for the project, stay with us. Below, we are going to discuss how to install a solar water heating system the right way. 

But before we illustrate the installation steps, here are a few things to consider: 

  • Can your roof bear the dead and live load of your heating system? Dead load refers to the system’s weight; live load means additional load—wind and snow loads, etc. As per the Environmental Protection Agency, your roof should support a minimum of 6 pounds of additional dead load. 
  • Do you have shade on your roof, especially on the part where you intend to install your water heating system? 
  • Some heating systems need their storage tanks to be installed on the ground. Do you have a spare room or any other place where the tank can be installed? 
  • Can the plumbing lines for water and a working fluid easily be installed on your roof?  
  • Would you need a backup heater that runs on traditional electricity, and is it already installed, or would it be installed with the solar water heater? 

These things are important to work out before undertaking the installation. Because if your roof is old and needs replacement, you will have to delay the project or will need to find an alternative place for installing your system. If all is worked out, perfect! Let’s move to initiate the process. 

How to install a solar water heating system? 

Solar water heating systems come in at least four popular varieties, and installing one system may be slightly different than another. But the basic steps usually remain the same for each system. In brief, the 7-step installation of solar water heaters looks like this: 

  • Mount solar collectors on your roof. 
  • Install the storage tank and heat exchangers adjacent to your conventional water heater (if it is already installed). 
  • Install the piping system fluid cycle.
  • Do plumbing for water transport. 
  • Install the necessary controls—sensors, valves, etc. 
  • Fill the system and check for leaks. 
  • Insulate the plumbing lines. 

Step 1: Mounting solar collectors on the roof 

You will have to install solar collectors at a certain degree (from 30 to 45 degrees) to allow maximum sunlight exposure. If your roof is flat, you will need a separate frame. But if your roof already has the inclination, only a basic frame to support the system would work. 

Measure your solar collector and the frame—the manufacturer will have already provided both. Remove the shingles and make a few penetrations in your roof—the number of holes depends on the hardware provided by the company (usually, it is four holes, but it may vary). Install the support bases for the frame, seal the holes with silicon, and put the shingles back in their place. Once the support is ready, mount the solar collectors onto the frame and properly screw it. 

Step 2: Installing storage tank and heat exchangers 

Storage tanks are installed in different ways for different systems. In some systems, for example, thermosiphon heating systems, storage tanks are installed adjacent to the solar collector at a height. That would be easy, as the frame has a dedicated place for the tank. You just need to mount it and screw it. 

But in other systems, such as indirect active systems, storage tanks are installed on the ground, in the basement, or in another facility where they are accessible to water and anti-freeze fluid piping. You can install as many storage tanks as you would need. You will also install heat exchangers in this step. 

Heat exchangers are either integral to storage tanks or may come standalone. If it is integral, make the glycol loop connections and hot and cold water connections accessible (glycol is used as the anti-freeze liquid). If the heat exchanger is external to the tank, arrange the piping combination with the tank so that you won’t have to cut the pipes if the tank or exchanger needs replacement. 

This step is just a replacement project if you are replacing your gas-powered or electric heater. Remove that and install the new one. 

Step 3: Installing the piping system and pump fluid cycle

Some systems will not need this step, as they don’t use an anti-freeze liquid. Such systems do not use heat exchangers either. But if you live in a region where water freezes in winter, your system would require a working, non-freezing fluid and heat exchanger for heat transfer. 

You will need two sets of pipes—one to move fluid to the solar collector and one back to the heat exchanger. First, assemble the pipes, measure them, and then cut them—but do not solder them as of now. Dig holes in your roof, run the pipes through the holes, solder them now, and then seal the penetrations with silicon. Install unions at due points so that you won’t have to cut the pipe if it needs replacement in the future. 

Install the pump at the lower side of the piping that leads to the solar collector. A check valve also needs to be installed at the pump’s outlet to stop the backward flow of fluid when the pump is turned off. 

Step 4: Installing piping for water transport 

Your basic system installation is complete. Now is the time to install pipes for water transport. You will need two sets of pipes, usually made of copper. One set would be installed to bring the cold water from your home to the tank, and another set to take the hot water to your plumbing system. 

This step is the simplest of all. You will already have the water piping in place. If your solar heater is to replace your old conventional heater, all you need to do is detach pipes from the old one and attach them to the new one. If you are planning to use that as the backup, keep them that way and run extra pipes to the solar storage tank. 

Step 5: Installing the necessary controls

To make the system function smooth, you must install a control system. Attach one temperature sensor to the solar collector and install another at the storage tank’s base. These sensors should send data about the differential temperature to a central controller, based on which the central controller will guide and regulate the system. Without these sensors, your system would circulate the fluid even when not needed. In some instances, the fluid circulation would cool water instead of heating it. 

You can also install additional controllers. For example, install a bypass valve if you want to keep the conventional water heater in the loop. This valve will decide when the water should pass through the conventional water heater and otherwise. In summer, you may not need a backup heater—that is where the bypass valve proves handy. 

Another helpful addition to the control system could be a tempering valve. This valve adds cold water to the mix when the water is too hot. 

Step 6: Filling the tank  

The hard part is done! Now, run water through the system. You don’t need to run glycol through the fluid piping—mere water would also work. But it is better to run a mix of glycol and water through the glycol loop. 

Give pressure to the system and record it. The pressure should not be more than 30 PSI. Let the system stand for around 8 hours. If the pressure has dropped after 8 hours, there must be a leakage in the system, most likely at points soldered. Repeat the process until the leakage is eliminated. 

Step 7: Insulating the water and glycol piping 

It is the final but important step, as insulation ensures no heat is lost. Insulate each part, including water pipes, glycol pipes, and the external heat exchanger. 

You can insulate water pipes with simple standard foam insulation. However, you would use fiberglass pipe insulation for glycol and heat exchangers. Insulation parts exposed to the sun should be protected with foil wrap or UV-resistant paint. And that was all you needed to install the water heating system. 

That said, note that no two systems are installed the same way. We recommend letting a professional handle the job. That would cost you, but that would also ensure that the system is installed without causing you any inconvenience or malfunction.

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