Heliatos RH/BH Solar Water Heating System Installation Instructions

General System Layout Sketch

The diagram illustrates the RH/BH solar water heating system layout. It shows two SW-38 Solar Panels connected in series. These panels are part of a loop that includes a Heat Exchanger, which heats water in an RV Water Heater (specifically one without a built-in heat exchanger). A separate glycol loop circulates through the solar panels and the heat exchanger. This loop includes an Expansion Tank and a Glycol Fill Valve. A Water Pump circulates the water, and a Glycol Pump circulates the glycol. The diagram indicates flow directions for Hot Water, Cold Water, and Glycol.

Introduction

This document describes how to install a Heliatos RH type solar water heating system. These systems use SW-38 Solar Water Heating Panels in combination with a Stainless Steel Heat Exchanger. The circulation loop contains a freeze resistant non-toxic fluid. As a result there is no danger of the panels freezing and being damaged. The level of freeze protection can be selected by the dilution of the antifreeze fluid. Heliatos recommends using Propylene Glycol based RV antifreeze.

The SW series panels are designed to be easily installed on any flat surface. They are equipped with 3/8" compression fittings, making reliable tight connections between panels and to included 3/8" PEX tubing easy and fast. No soldering or special tools are required.

It is the installer's responsibility to assure that the panels themselves, as well as the method and place of installation, are in full compliance with all applicable regulations. Please consult the datasheet for the panels you are considering and assure that they are permissible and appropriate for your application.

Surface Preparation and PV Panel Location

In general, the surface you are planning to use for your installation should be fairly flat. The panels can accommodate a base that is up to 1/4" uneven under each panel. Because of the special polycarbonate glazing, they can flex a small amount without damage. The panels are equipped with four "feet". Each foot has a hole sized for a #8 deck screw. If mounting the panels to a surface suitable for exterior deck screws, they are ready to install out of the box. However, if bigger bolts are required, the holes will have to be enlarged with a drill.

If using a rack to tilt your panels towards the sun, please ensure the feet rest flat on the rack's surfaces and are securely fastened. Rack-mounted panels can be subject to large wind forces.

The PV (electric) panel that powers the pumps should be installed to receive the same sun as the water heating panels to ensure pumping power and heating are balanced. The two pumps are connected to the PV panel with the included wire. They are not interchangeable, so follow instructions closely when installing the pumps. The panels themselves are strong enough to remain outside the RV at highway speeds; however, the installer must ensure the mounting can support the very large forces present due to air flow.

Step 1: Panel Unpacking and Layout

Unpack the panels from the box and lay them on the installation surface next to each other. Each panel is connected to the next with a compression union. The compression nuts, pre-installed onto the tube in the panels, thread onto the two ends of these unions.

Diagram: Shows two solar panels positioned side-by-side, with a compression union fitting between them, ready for connection.

Step 2: Connecting Panels

This step applies if you have more than one panel. Connect the panels to each other using the included compression unions. First, apply sealant to the union. Put a ring of sealant around the inside lip of both sides of the union as shown in the illustration.

Diagram: Shows a close-up of a compression union fitting with an arrow indicating where to apply sealant around the fitting edge.

Start threading the union into the nuts on one panel and hand-tighten only to allow flexibility when lining up the panels. Bring the panels close to each other so the nuts on the second panel can be threaded onto the union, hand-tighten. Slightly tighten the nuts on both sides. Not much torque is needed to form a tight seal. Once all panels are connected, further tighten each nut by about 1 turn.

Diagram: Illustrates the process of connecting two panels using compression fittings, showing the nuts being threaded onto the union.

Step 3: Completing Panel Array Connections

This installation manual assumes you have a Connection Fittings kit. These kits contain all necessary fittings. Since components use standard fittings, parts may also be obtainable at a local home improvement center or plumbing supply.

The direction of flow through the array of panels does not matter; it can go from left to right or the other way around. First, thread one 3/8" compression union into the nuts on the two end panels (left and right) and hand-tighten. Apply sealant as in step 2.

Diagram: Shows a "3/8" Compression Union" with an arrow indicating the direction of threading.

Next, slide a compression nut onto both tubes, followed by a nylon ferrule (ring). Insert a brass insert into the end of the PEX tubing to provide extra strength for a good seal with compression fittings. Finally, push the tubes into the 3/8" compression unions and thread the compression nuts onto the union. Hand-tighten and then tighten an additional turn.

Diagrams: Show the components of a compression fitting (insert, ferrule, nut) and how they are assembled onto the PEX tubing and then connected to the union. One diagram shows "Hold Adapter Body while tightening Compression Nut".

Step 4: Securing the Panel Array

The panel array must be securely tied down, especially if mounted on a rack or rails where wind can catch the panels from below. The manual shows deck screws, but follow directions provided with your mounting hardware. Panels are light, so do not rely on their weight to hold them in place.

Diagrams: Show panels being mounted with screws to a surface and also mounted on rails.

Mounting directly on a flat surface, as well as on racks or rails, is accomplished similarly. To achieve full wind loading capability, attach all tabs securely to your mounting system.

Step 5: Insulating Fittings and Pipes

Exposed fittings and pipes must be insulated. This can be done by surrounding each joint with a foam or fiberglass sleeve. If using plastic foam, wrap it with aluminum adhesive tape to prevent rapid UV degradation. Install a foam sleeve over every fitting between panels and at the ends of the panel array.

Diagrams: Show a foam sleeve being placed over a fitting and aluminum clad foam tape being applied over the foam sleeve.

Diagram: Shows a completed installation of three solar panels mounted in a row on rails.

Before You Begin: Heat Exchanger Assembly

There are three sections left to complete the installation: Heat Exchanger, Glycol Fill Valve, and Expansion Tank. Familiarize yourself with all three before proceeding to ensure the plumbing installation fits all components cleanly.

It is important to install the respective parts on the correct ports. Crossing ports will prevent the glycol and water loops from separating and can contaminate your domestic water supply with glycol. Thread the two brass elbows onto the heat exchanger using plumbing sealant. If holding the heat exchanger facing you with the red dot on the bottom right, the elbows go on the two left side ports. Thread hex couplings onto the ports on the right, then thread street elbows into the couplings using plumbing sealant on both.

Diagram: Shows the heat exchanger with labels indicating where "Brass Elbows go here" (left side ports) and "Hex Couplings and Street Elbows" (right side ports).

This kit includes 2 pumps. One is a TopsFlo TD5 pump with a full stainless body. The second is a Heliatos HS-21 pump with an all black Ryton body.

Pump Installation

Diagrams: Show images of the TD5 and HS-21 pumps.

Thread the TD5 into the street elbow near the red dot and the HS-21 into the elbow to the left, using a generous amount of Teflon Tape. The HS-21 should pump AWAY from the heat exchanger, and the TD5 pump INTO the heat exchanger. The arrow on the pump body points towards the output side and should align with the direction of the red arrow in the illustration. For the HS-21, use a wrench on the thread being installed, NOT the one on the opposite side of the pump, as the pump cannot withstand tightening torque.

Diagram: Shows the heat exchanger with the TD5 and HS-21 pumps attached. Arrows indicate "Pumping Direction for HS-21" (away from exchanger) and "Pumping Direction for TD5" (into exchanger).

Thread the 3/8" OD Compression to 1/2” Female Pipe Adapter onto the remaining ports of both pumps. Thread the 3/8" OD Compression to 1/2" Male Pipe Adapters into the street elbow and the normal elbow.

Glycol and Water Connections

Connecting the solar water heater to the existing plumbing involves using two included 1/2" tees inserted into the cold supply to the water heater and the hot output from the water heater, respectively. Most standard RV water heaters have 1/2" female threaded ports. The fittings kit includes two 1/2" nipples that thread into the water heater ports, followed by the two tees. This leaves two openings on each tee. The diagram on page 1 shows how connections are made to and from system parts. It is critical that connections to the heat exchanger are made exactly as shown in the following image:

Diagram: Shows connections to the heat exchanger: "To Glycol Fill Valve", "To Tee in Hot Output of Water Heater", "To Expansion Tank", "To Tee in Cold Input of Water Heater".

Electrical Connections

Both pumps must be connected to the 20W PV panel on the roof using the included wire. Connect both red wires from the pumps to the red wire from the PV panel, and both black wires from the pumps to the black wire from the PV panel, securing connections with included wire nuts.

The TD5 pump has a small hole in the back for power setting selection, enabled by a small plastic key included with the pump. It is very important to set this pump so the arrow points between the two number 1's; if this setting is incorrect, the entire system will not function properly. The HS-21 does not need to be set up.

Installing the Glycol Fill Valve

The installation of the Glycol Fill Valve is described in the instructions included with the item. While it can be installed anywhere on the hot return line, choose the location carefully. Using this valve involves pouring glycol into a bucket or container and extending two two-foot hoses (included) into the glycol. Therefore, locate the fill valve where this process is easy. Usually, this is on the hot return line close to its connection back to the heat exchanger, allowing the bucket to be placed on the ground near the water heater.

Diagram: Shows the Glycol Fill Valve with input "Return Pipe from Panels" and output "Pipe to Heat Exchanger".

For proper operation and to eliminate the risk of toxic contamination of your RV plumbing, Heliatos recommends Propylene Glycol RV Antifreeze fluid. DO NOT use ethanol-based RV Antifreeze or Ethylene Glycol (Automotive Antifreeze).

Installing the Expansion Tank

Install the expansion tank inline with the cool feed line going TO the panels. The fittings kit includes a 1/2" brass tee and two 3/8" compression to 1/2" male pipe adapters. First, thread the two adapters into the tee, then thread this assembly onto the expansion tank using sealant.

Diagrams: Show the assembly of a 1/2" Brass Tee with two 3/8" Compression to 1/2" Male Pipe Adapters, and then the tank installed inline.

Once the expansion tank fitting is installed, you can install the tank inline on the pipe carrying the cooler glycol from the heat exchanger to the panels. The location along this line is not important.

General Installation Hints

• No matter the climate, insulating all exposed fittings/pipes is extremely important. Small exposed areas cause significant solar heat loss. The system WILL NOT FUNCTION PROPERLY until ALL insulation is installed.
• Observe the polarity of the pumps: connect the positive supply to the red wire and the negative to the black wire. Reversing polarity will immediately destroy the electronics in the pumps.
• It is important to set the power setting on the TD5 pump correctly.
• If fittings on the panels get very hot but fittings on the heat exchanger do not, it is highly likely the glycol loop was not filled completely. Try flushing the glycol loop one more time to remove any remaining air pockets.