ThermoDrain Installation Support & Sizing Guides

ThermoDrain is engineered to be one of the simplest, lowest-maintenance energy recovery loops to integrate inline. Each model comes with a comprehensive, step-by-step installation guide featuring detailed technical illustrations and plumbing diagrams. Depending on the specific configuration you choose, your system features factory-integrated potable water connections and series-specific drain attachments optimized for rapid single-person installation.

📝 ThermoDrain Installation Made Easy

Installing next-generation drain water heat recovery (DWHR) technology has never been more straightforward. Whether you are a professional mechanical contractor completing a high-volume new build or a homeowner tackling a DIY basement remodel, ThermoDrain units are engineered to integrate seamlessly into standard residential and commercial plumbing systems.

📥 Download Official Installation Guides

TDX Series Installation Manual (PDF Format) — [Download Here]
TDH Series Installation Manual (PDF Format) — [Download Here]

📐 Vertical vs. Horizontal Orientation Compliance

Did you know that horizontal installation is fully possible with ThermoDrain units? Because our systems are manufactured using heavy-gauge, independently certified solid copper drain pipe, they can physically adapt to custom spatial and framing constraints.

⚠️ Important Engineering & Code Note: All certified thermal efficiency ratings, heat recovery capacity metrics (kW / BTU/h), and energy model performance credits published in our official documentation are strictly rated for vertical installations.

Installing a unit horizontally changes the fluid dynamics of the falling wastewater film (reducing wall-contact surface tension), which results in a lower thermal efficiency rating than a standard vertical setup. For maximum code credits and energy recovery, vertical orientation is always recommended.

🚰 Factory-Installed Water Fittings (Potable System Connections)

ThermoDrain units feature rugged, factory-integrated potable water manifold connections configured to fit your specific piping strategy. TDX Series models feature an integrated 360-degree swivel assembly, allowing installers to rotate connection ports in any direction for effortless alignment in tight wall studs and joist cavities.

Crimp-Style PEX Fittings (ASTM F1807)Available on: TDX & TDH Series ModelsThe Advantage: This patent-pending, factory-installed manifold option makes connecting your domestic water supply incredibly fast while eliminating open-flame torches near wood framing. Simply route standard 3/4-inch PEX lines straight to the port and secure them with a standard plumbing crimp tool.🎥 🎥 [Watch this video to learn more about Crimp PEX connections.]
Expansion-Style PEX Fittings (ASTM F1960)Available on: TDX & TDH Series ModelsThe Advantage: Engineered explicitly for cold-expansion (ProPEX / Expansion) plumbing setups. The installer utilizes an expansion tool to widen the PEX tubing and ring sleeve, slides it directly over the factory fitting, and allows the pipe to naturally shrink back down for an unconditional, industrial-grade mechanical seal.🎥 🎥 [Watch this video to learn more about Expansion PEX mechanics.]
Solid Copper 3/4″ Male Sweat ConnectionsAvailable on: TDH Series Standard UnitsThe Advantage: Designed for maximum layout flexibility. These fixed, high-purity copper ports arrive ready for traditional soldering (sweating) or can easily receive quick-connect mechanical adapters (such as press fittings, compression sleeves, or push-to-connect adapters) to tie directly into any custom copper or hybrid pipe system.

✏️ Unsure which fitting style matches your project? Review our layout guide on [Crimp vs. Expansion PEX Here].

🧼 Drain Stack Connections: TDH vs. TDX Series

The mechanical connection method to your home or building's main drain line depends on your chosen model series and pipe diameter:

🔹 TDX Series: Direct-Glue ABS & PVC Integration
The premium TDX series features factory-integrated, high-impact connection hubs at both ends. The unit solvent-welds (glues) directly inline into standard 3-inch ABS or PVC plastic drain stacks using standard plumbing solvent cement—or connects via mechanical rubber couplings—completely eliminating the need for separate adaptors or flame-soldering near wood joists.
🔹 TDH Series (3-Inch Diameter Models): Mechanical Couplings Included
Every standard residential 3-inch TDH series unit ships complete with heavy-duty mechanical rubber drain couplings (shielded/unshielded transition couplings) included inside the box, ensuring a fast, drop-in mechanical retrofit or inline installation.
🔹 TDH Series (4-Inch Commercial Models): Site-Sourced Couplings
Please note that high-capacity 4-inch diameter TDH commercial models do not ship with mechanical couplings. Due to diverse commercial plumbing setups—where local codes dictate heavy-duty shielded cast iron, PVC, or copper DWV drain stacks—commercial contractors source their own code-compliant 4-inch mechanical transition couplings (e.g., Fernco or shielded mission bands) on-site to match the building's specific pipeline material.

📝 Connecting the ThermoDrain

An average inline ThermoDrain installation takes just 20 to 45 minutes and requires roughly $30 to $50 in basic structural plumbing materials.

Every TDX and TDH model is engineered specifically for a fast, single-person installation where joist or wall cavity space is at a premium. Both series feature an ultra-low pressure drop profile, certified double-wall safety barriers (CSA B55.2), and industry-leading passive heat transfer rates.

TDX Series Connections: Outfitted with factory-integrated connection hubs, the TDX solvent-welds (glues) directly onto standard residential 3-inch ABS or PVC plastic drain stacks using standard solvent plumbing cement—or connects via mechanical rubber couplings—completely eliminating the need for separate transition adaptors.
TDH Series Connections (3″ Models): Every standard 3-inch TDH residential system comes bundled with heavy-duty mechanical rubber drain couplings custom-fitted to your unit's exact specifications. (Note: Commercial 4-inch TDH models do not include drain couplings).
Potable Water Supply Connections: Ships with your choice of factory-installed ASTM F1807 Crimp PEX ports, ASTM F1960 Expansion PEX ports, or fixed 3/4″ male copper sweat connections to fit any project layout seamlessly. TDX Series models feature a patent-pending 360-degree swivel assembly, allowing installers to rotate ports in any direction for effortless alignment in tight framing cavities.

🛠️ Simple Step-by-Step Installation

Step 1: The Main Drain Connection

Measure and Cut: Cut out a vertical section of the existing main home drain pipe directly below the primary shower location. Ensure the model line of the ThermoDrain matches your home's drain stack diameter. (For exact physical cutout measurements, please refer to the model-specific engineering installation manuals below).
Mount Inline: Secure the top and bottom of the ThermoDrain to the freshly cut open ends of your drain pipe. Use standard ABS/PVC solvent cement for the TDX series, or fasten the heavy-duty mechanical rubber couplings over the joints for the TDH series to establish a permanent, leak-proof structural seal.

Step 2: The Cold Water Supply Connection

Plumb the Inlet: Connect the fresh, incoming cold water main supply line directly to the bottom port of the ThermoDrain coil (this functions as the cold water inlet).
Plumb the Outlet: Connect the top port of the ThermoDrain coil (this functions as the preheated water exit) using one of the following three plumbing configurations:Option 1 (Equal Flow / Fixture Only): Route the preheated line straight to the cold-water inlet side of the shower valve mixing assembly.Option 2 (Equal Flow / Water Heater Only): Route the preheated line straight to the cold-water intake supply port of your water heater tank, tankless unit, or heat pump.Option 3 (Combined Equal Flow — Highly Recommended): Route the preheated line to split evenly, feeding both the shower's cold water mixing valve and the water heater's cold intake simultaneously. This balanced configuration delivers the highest possible thermal energy recovery efficiency (up to 55%–57%+).