29th Nov 2022

Diamond Hott Rod Instructions & Tips

Step 1: Remove Existing Drain Plug

There are two basic drain openings. Petcock style(pictured in figure #1 below) and anode style which has a 1-1/16" hex nut attached to an anode rod (1995 & newer tanks). For the petcock style use pliers to remove the brass tube and "wing" valve, then use a wrench or socket to remove anode rod. Atwood tanks 1978 & newer have 7/8" hex plastic or metal plugs. Unscrew with wrench or socket to remove drain plug. 

Step 2: Install Rod Into Drain Opening

Disconnect heater plug and cord after removing probe from package. Pull the molded end and the probe apart gently. Apply Teflon tape to threaded area for fitting. Please see Figure#2 below. 

Anode style drain will need the Large supplied reducer/anode bushing. 
Atwood tanks will use the small supplied reducer bushing. First thread reducer bushing into drain opening tank - no more than two turns and then install probe. 




If the reducer bushing is leaking, tighten ONLY reducer bushing.

To drain tank, first remove the reducer bushing (if used) with the probe, both as one unit, in drain opening. 

Reattach heater plug taking care to align the holes in the plugs with the pins inside the fitting. 

Install or locate this water heater only in accordance with the provided installation instructions. 

Step 3 : Route Heater Cord From Outside Heater Compartment To Thermostat Area

Use Figure #3 & #4 for reference. Drill 1/2" diameter hole after checking for clearance inside the coach. Route the heater cord into this hole. Pull the cord gently as you do not want to snag the cord on the sharp edge of the hole. From the inside of the coach pull the end of the cord to where the thermostat will be mounted. Use the supplied piece of split loom to protect the heater cord from contacting the drilled hole. 

Check the proper clearance inside RV then drill 1/2" dia wire entry hole. Two suggested positions are shown. Your tank may be different.

  • Drill hole at an angle to avoid hitting tank
  • Make certain the heater cord does not contact any hot surfaces in the outside water heater compartment
  • Carefully line the sheet metal opening with 3/8" split loom and cover split loom hole and cord with silicone to ensure hole is air tight from outside vapors.
  • If you have Hott Rod Power Switch Wiring Kit and you chose to have the outside switch, this is where you can route the power switch cord through the same opening before sealing the split loom with silicone.

Step 4: Choose And Prepare Locations For Thermostat Control

The thermostat mounts directly to the back of the tank which can be located from inside the coach. This area is generally accessed under a cabinet, drawer or bed. If the tank is below floor level, look for access hatch at the back of the tank. There may also be an access through an outside storage compartment to the left or right of the water heater. 

Thermostat must be mounted to tank which will be covered by cardboard, styrofoam, or sheet metal. Staying toward the center the thermostat maybe placed on top, back, left or right of thee tank covering. Use sharp knife to cut a 3" by 4" thermostat opening (see Figure #5) Push back the fiberglass insulation to expose the tank surface. 

IMPORTANT  : DO NOT mount control thermostat on the pressure relief valve!! This will result in excessive water temperature, premature product failure, damage to your RV and/or personal injury, and it voids Hott Rod warranty. 

  • On sheet metal covered tanks the opening must be cut using metal shears or small grinder with cutting weal, gloves are recommended.

    Prior to mounting prepare the tanks by sanding, then wiping surface with alcohol. 

Step 5: Connect Wires and Mount Thermostat Onto Tank Surface

Refer to Figure #6 - Connect wires as shorn and snap the plastic thermostat ciover. Peel off the paper backing from thermostat tape and press thermostat onto the tank. 

  • The thermostat will bond more readily to a warm tank. Full bonding typically happens within 48 hours. Using duck tape to hold thermostat firmly.
  • The E.C.O. is a backup thermostat and will trip if the thermostat faiols and the water temperature exceeds 170 degrees Fahrenheit. This is a manual reset, you must depress the red E.C.O. button on the thermostat and if the circuit trips again after resetting, immediately disconnect power and discontinue use of unit. 
  • Add a small bead of silicone sealant along both sides of thermostate AFTER application on the tank to insure thermostate will be affixed permanently to the tank. Do Not Get Silicon On Center Of Heat Sensor Hole. Thermostate must be mounted to the tank. 
  • Check thermostate area periodically to ensure thermostat is securely attached to the tank

Diamond Group has pre-set your thermostate to 120 degrees F. Higher setting increased scald hazard.

Step 6: Choose Location for Power Source 

The 8' power cord is designed to plug into an existing outlet inside the coach. 

  • Do not use extension cord set with this water heater. If no receptacle is available adjacent to water heater, contact a qualified electrician to have one properly installed. 
  • Do not plug into power until all installation has been complete and tank is full
  • All wiring must be secured so that it does not interfere with the drawers or items in storage areas. Keep away from devices that can generate heat. The use of wire tires from cords may be used to hold down and secure the wires in position. 
  • The water heater must be grounded. Connect only to properly grounded outlet. 
  • This may be permanently wired to a power source in the coach with an on-off switch. 
  • You can install a Hott Rod Power Switch Wiring Kid designed with the color coded ends to use with Hott Rod Unit


Initial heat up should take about 45-90 minutes depending on water temperature. Once full tank temperature is achieved the Hott Rod is designed to be a total substitute for the propane system. It is designed for constant operation, however if the coach is to be left un-attended for a long period, disconnect power to the Hott Rod as you would any other non-essential items. 


The Hott Rod is designed to be immersed in water. Always make sure there is enough water in your water tank before you turn the Hott Rod on. Running the Hott Rod in a dry empty tank will IMMEDIATELY blacken and damage probe. This is not a manufacture defect and is not covered under warranty.

Refere= to Figure #2. The area around the heater plug end must be kept dry! The molded end is designed to be effect against occasional spray such as washing your motorhome. Longer exposure to water particularly from a leaking pressure relief valve will cause premature failure of the Hott Rod. Not covered under warranty. It is recommended to spray the area of the heater plug end twice a year with WD-40 or similar water displacing agent to ensure a good electrical connection. 

Warranty Information: Contact Diamond Group or Visit www.DG-USA.com for more information. 

Yearly Maintenance Required

When winterizing or draining the tank, Refer to "Step 2" to remove probe/rod from tank. Use this opportunity to examine the rod for mineral deposits. Mineral deposits can be removed using a putty knife, wire brush, steel wool or vinegar & water. Water tanks should always be flushed once or twice a year. Water tanks should be flushed once or twice a year. 

Remove Hott Rod, turn on water supply and run for at least 5 minutes or until water runs clear. The sue of pressure reducer device at the supply faucet is a must to protect your hose and water lines inside your RV.