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Tank Heater Installation

Outside temperature and mounting surface must be at least 50°F (10°C) when applying tank, pipe and elbow heaters.


Caution: You should only perform UltraHeat RV Tank Heater installation on plastic tanks or electrically non-conductive surfaces. (unless specifically custom ordered for metallic tanks)


Please read the entire holding tank heater installation instructions before attempting to install the UltraHeat Tank Heaters.



1. Prepare the Tank Surface.


  • Select a location on the bottom of the holding tank. It is recommended that the tank heater be placed as close to the drain or discharge portal on the holding tank as is practical. Select a location where the tank heater can lay as flat as possible against the bottom surface of the tank, with the wires running towards the discharge portal (this places the built-in sensor at the tank’s low point, were it will operate with minimal fluids present).

  • If your holding tank has grooves in the bottom of the tank surface or ribs that stick out of the tank surface, select a location that will minimize the contact with the grooves or ribs and still be relatively close to the holding tank drain.

  • Pre-clean the dust, dirt and other foreign matter from the holding tank surface using soap and water. In some situations lightly scuffing the surface with course sandpaper (80 Grit) can help give a better adhesion. Rinse with clean water and let the surface dry completely.

  • Next clean the holding tank surface using isopropyl alcohol (90% alcohol at a minimum) with a clean cloth or rag. Allow the tank surface to dry or flash-off completely. The tank surface must be clean and dry before proceeding to the next step.


      Caution: Do not use any other type of solvent than isopropyl alcohol for final cleaning of the holding tank surface.


2. Placing the Tank Heater onto the Tank Surface.


  • Peel ALL layers of the brown release paper off the back side of the tank heater exposing the adhesive side across the entire back of the heat panel.

  • Place the tank heater onto the bottom tank surface with the adhesive side against the tank, and the power leads towards the discharge portal.  It is usually best to start at one end of the tank heater and slowly but firmly press and roll the tank heater in place until the entire tank heater makes contact with the tank surface. Be careful not to stretch the tank heater beyond its original size.

  • If your holding tank has grooves in the tank surface or ribs that stick out of the tank surface you will need to make sure that you do not create air gaps or loose edges. Slowly placing the tank heater on the tank surface, work from one end being careful to lay the tank heater into the grooves or over the ribs in such a way as to make sure the tank heater is in full and complete contact with the tank surface. Be careful not to stretch the tank heater beyond its original size.

  • Press down firmly on all parts of the tank heater backing once in place. This will activate the pressure sensitive adhesive on the UltraHeat Tank Heater.


       Caution: When properly installed the UltraHeat RV Tank Heater will be very difficult to remove without destroying it.


3. Electrical Tank Heater Installation




Select the Appropriate Power Source based on your heat panel selections.



120 Volt AC (VAC) Powered Tank Heaters (Model 3600, Model 4200 & Model 4800)


  • All of the 120 VAC powered tank heaters are furnished with a 15-foot (13.5m) power cord and a standard two prong plug. Simply connect an extension cord into a convenient 120 VAC outlet and connect the other end to the tank heater's power cord. (we recommend that this power cord is protected by a GFCI circuit, and protected from moisture or pooling water )

  • All of the 120 VAC tank heaters may also be "hard wired" to the RV's high voltage system thru a 120 VAC power switch (sold separately).  Use only Stranded 14 gauge (or 12 gauge) in your System,  Romax wire does not meet the codes and standards of used within an RV.

  • If you are not comfortable hard wiring 120 volt circuits, consult an electrician or someone who is acquainted with basic 120 voltage wiring.  We strongly recommend that higher voltage wiring be encased within some type of tubing or conduit, to protect against rubbing due to vibration and breaking the protective jacket and shorting to metal and frame. For this reason, we also recommend that these circuits be protected by a GFCI breaker.    


        Caution: Make sure the power cord/extension cord connection is off the ground & protected from water exposure.


13.5 Volt DC (VDC) Powered Tank Heaters (Model 900, Model 1200, Model 2400 & Model 3600)


  • UltraHeat's 13.5 VDC RV Heaters must be powered from the output fuse panel of an RV's 13.5 VDC power converter. UltraHeat 13.5 VDC Heaters should not be powered directly from the battery (this could drain down the battery to the point of permanently damage it).

  • All 13.5 VDC power circuits for UltraHeat Heaters should be dedicated to powering UltraHeat RV tank, pipe and elbow heaters only. Do not combine UltraHeat Tank Heaters on 13.5 VDC power circuits with devices that use electric motors (water pumps, furnace blower motors, etc.).


We suggest that in place of wiring the ground to chassis, running a ground return lead back to the converter panel. This return power lead must be of a gauge wire rated to handle the combined ampere draw of all panels connected to it.  


  • UltraHeat's 13.5 VDC RV Holding Tank Heaters can be combined on the same power circuit with UltraHeat Pipe and Elbow Heaters as long as the following conditions are met:

    All UltraHeat heaters must be connected in parallel only. All heater "hot-wire" leads (colored red) must be connected together with the positive wire. All the heater negative wire leads (colored white) must be connected together with the ground wire.

    The total current draw of all tank, pipe and elbow heaters to be combined on one 13.5 Volt DC circuit must be less than what the wiring and switch are rated for.


  • Each 13.5 VDC power circuit for UltraHeat heaters must use a 20 Ampere rated fuse or circuit breaker, with the wiring gauge of at a minimum of 12ga stranded for the circuit.


  • Install a 20 Ampere fuse in an open fuse slot of the 13.5 VDC fuse panel. If you do not have enough open circuits in your 13.5 VDC fuse panel for the number of UltraHeat Heaters you want to install please refer to the "Frequently Asked Questions" or the "Video Tips" page about adding a 12 volt sub-panel concerning this subject. If appropriate, you can install a 20 Ampere in-line fuse or circuit breaker off the direct output of the 13.5 VDC power converter if a 13.5 VDC fuse slot in the panel is not available to use.


Run Circuit Wire from the Fuse or Circuit Breaker to the 13.5 VDC Power Switch.


  • Each 13.5 VDC power circuit must use a minimum of Stranded, 12 AWG (American Wire Gauge) sized circuit wires in order to comply with National Electrical Code for 20 Ampere rated circuits. It is acceptable to use a larger gauge circuit wire (10 AWG, 8 AWG, etc.) for a 20 Ampere rated circuit but not a smaller gauge wire (16 AWG, etc.).

  • Use a female slide connector (sold separately, packaged in UltraHeat switch kits) to connect the circuit wire from the fuse/circuit breaker to the input side of the 13.5 VDC power switch (also packaged separate in an UltraHeat switch kit).


Run Circuit Wire from 13.5 VDC Power Switch to the UltraHeat® Tank Heater Positive Lead.


  • Use a female slide connector (packaged separate in an UltraHeat switch kit) to connect the circuit wire to the output side of the 13.5 VDC power switch.

  • Use the crimp cap connectors that were packaged with your UltraHeat 13.5 VDC Tank Heater to connect the heater's lead wires to the 13.5 VDC circuit wires. Connect the positive circuit wire coming from the 13.5 VDC power switch to the red positive lead wire on the UltraHeat Tank Heater.

  • If larger connectors are necessary to properly connect multiple heater lead wires to the circuit wires, large crimp cap connectors are recommended (not included).


Run Circuit Wire from the UltraHeat RV Holding Tank Heater Negative Lead to Ground.


  • Connect the circuit wire to be used for the ground side or negative return of the circuit using a crimp cap connector to the UltraHeat RV Tank Heater's white negative lead wire. Run the circuit wire back to the RV's 13.5 VDC grounding bar which is normally located near or within the RV's 13.5 VDC power converter.

  • It is also acceptable practice to connect the 13.5 VDC negative circuit wire directly to the RV's frame to use as a ground for the UltraHeat Tank Heater. It is recommended that a crimp-on eyelet, a star washer, a bolt and nut or other appropriate hardware be used to attach the negative circuit wire to the RV's frame. Removing a small amount of the paint on the RV's frame where the ground connection will be located will help insure a good ground connection.  Once completed and system is tested, fully cover this frame connection with a silicone sealant to protect against rust.


Caution: Do not cross wire higher AC voltage on the 13.5 VDC UltraHeat Heat Panel power circuits, this will cause permanent damage to the heater.


4.  Testing the Holding Tank Heat Panel(s).


Test the heat panel to complete your tank heater installation. Your Heat panels are designed to work continuously in freezing temperatures only, and fluids must be present. 


You can test the Holding Tank Heat Panel in the following manner: 


  • Locate the built-in temperature sensor, placed close to where the power leads enter the heat panel.  A hard lump approx. 1in x 3/8 in (2.54cm X .95cm)

  • Power 'on' the heat panel.

  • Place a small  bag containing crushed ice, or a bag containing Dry Ice, over and against the back of the heat panel were the sensor is located. You have to fool the sensor into thinking it's colder than 44° F (7° C).  Depending on the ambient temperature, this may take a while. 

  • While holding the ice in place with one hand (or other temporary method), place your other hand on another point on the backing, in the center of the panel.   At some point you will feel the panel start to heat up a little, when this happens you know everything is wired and functioning in the correct manor.

  • Power 'off' the heat panel. 





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