I have been contremplating an onboard shower for some time. With our upcoming trip to the Rubicon, seemed like a good time to get it done. Two main components to the On-board shower, the Heat Exchanger and the pump. reffug was kind enough to sell me his Heat Exchanger after he IMPALED his truck. Course, now he has a another nice truck or I wouldn't have made that comment. Email: email@example.comWebsite: www.twine4wdshowers.com.au The Instructions to install the Twine Heat Exchanger are as follows: Overview The Heat Exchange Unit (HEU) should be installed between the vehicle engine and the cabin heater control valve Mounting the HEU with Outlet B on top will ensure maximum hot water flow through the HEU. Mounting the motor section of the pump (silver part) uppermost will prevent any leaking water shorting out the motor. CAUTION Allow vehicle to cool before beginning installation You will require the following items: Suitable lengths of ½" hose Clamps to secure ½" hose Heat Exchange Unit (HEU) mounting bracket – if standard bracket not sufficient (specific brackets available for some vehicles Install HEU 1. Identify cabin heating system supply line from engine. 2. Secure Heat Exchange Unit (HEU) close to heater supply line using mounting bracket. 3. Remove cabin heating system supply hose. 4. Using suitable length of 5/8" Gates® heater hose and supplied Unicoils™ connect HEU Inlet A to engine port. 5. Using another suitable length of 5/8" Gates® heater hose and supplied Unicoils™ connect HEU Outlet B to cabin heater on the firewall. 6. Check that heater hoses are not crimped and do not rub on any part of engine. 7. Bleed vehicle cooling system: • Disconnect hose from HEU Outlet B • Set engine speed to 1,000rpm • Stop engine when water runs from HEU • Re-Connect hose to HEU Outlet B 8. Top up vehicle’s engine coolant supply. Install Shower Pump 1. Secure shower pump in an appopriate position in engine bay using pump plate supplied. 2. Connect Inlet Assembly Male Snap Connector to inlet of shower pump using suitable length of ½" hose (not supplied). 3. Connect output of shower pump to HEU Cold Water Inlet. 4. Connect the HEU Hot Water Outlet to Outlet Assembly Male Snap Connector. 5. Screw Outlet Assembly Female Snap Connector to one end of shower hose. 6. Wire up shower pump to battery using Electrical Kit – mount switch in an accessable but protected place. 7. CUSTOMER to connect filter to Inlet Assembly Female Snap Connector using ordinary garden hose cut to length required. System Check 1. Start engine and allow it to reach normal operating temperature. 2. Set cabin heater control to maximum – for vehicles without constant flow heating systems. 3. Set engine speed between 1,200 – 1,800rpm and hold (depending on engine). 4. Ensure cold water supply hose is placed in a suitable water source. 5. Check shower rose shut-off valve is fully open. 6. Switch on shower pump. CAUTION – SCALDING RISK Extremely hot water will flow from the shower rose after the initial water flow (allow 20 seconds of flow to clear). 7. If shower water is too hot, temperature can be adjusted by: • increasing shower rose flow • reducing cabin heater control • reducing engine speed • reducing flow through the HEU – adding a tap (eg Repco HT58) between engine and HEU (A) Now for the Pump, I selected a Shurflo 2.8gpm. I know there are faster out there, but 2.8 gpm is a pretty good flow rate and some times I may be feeding this out of a bucket or 5 gallon can. I ordered a Shurflo model 2088-422-444. Lots of differnt models with a similar part number. This one has a higher psi, 45 vs 40. The specs are as follows: 12VDC - 13.7VDC Max. 7 Amps. 2.8 Gallons per minute. 45 PSI cut off switch (3.1 BAR). 1/2" intake/outflow pipe thread connections. 2-Year Warranty (see paperwork for details). Quiet performance. Self-priming. Easy installation. Runs dry without damage. Built-in check valve. Standard 1/2" Intake and Outflow pipe thread connections. My plan was to run 1/2" heater hose to the bumper and install Brass fittings. Not disconnects, just 1/2" fittings with caps.