Pressure relief Valve 
             HOT        COLD       GAS 
 
WARNING: Be careful not to reverse the hot 
outlet and cold supply line connections to the 
MOBIUS Water Heater. This will cause your 
heater to operate dangerously and void 
warranty. Make sure the hot and cold lines are 
connected properly. Refer to the FOR YOUR 
SAFETY section at the front of this manual. 
 
 
PRESSURE RELIEF VALVE 
 
The Mobius has a built Hi-Limit (high-
temperature) shut off switch and no store hot 
water therefore only a “pressure only” relief 
valve is required. 
This unit does not come with an approved 
pressure relief valve. An approved pressure 
relief valve must be installed on the hot water 
outlet. A “Tee” fitting should be used to attach 
the pressure relief valve. Then place the 
pressure relief valve 6” inches from water flow 
as shown in picture to prevent premature wear 
of relief valve. The pressure relief valve must 
meet and followed local code. 
 
The discharge capacity must be at least 
235,000 Btu/hr. The discharge piping for the 
pressure relief valve must be directed so that 
the hot water cannot splash on anyone or 
nearby equipment. Attach the run-off tube to 
the pressure relief valve, and run the end of 
the tube to within 6" from the floor. Do not 
install any reducing couplings, valves or any 
other type of restriction in this line. This run-off 
tube must be installed to allow free and 
complete drainage of both the valve and the 
run-off tube.  
If the pressure relief valve on the appliance 
discharges periodically, this may be due to the 
thermal expansion in a closed water supply 
system or defective pressure relief valve, 
replace a new pressure relief valve. Contact 
the water supplier or local plumbing inspector 
on how to correct this situation.  
The pressure relief valve must be manually 
operated once a year to check for correct 
operation. 
Should overheating occur or gas supply fail to 
shut off, turn off the manual gas control valve 
to the appliance. 
 
 
        Pressure Valve 
 
CAUTION: Only the pipes within the heater are 
protected on the MOBIUS Water Heater. Any 
hot or cold water pipes located outside of the 
unit will not be protected. Properly protect and 
insulate these pipes from freezing. 
 
Electrical Connections 
 
WARNING: The heater must be electrically 
grounded. Follow the requirements of the local 
authority having jurisdiction. In the absence of 
such requirements, follow the latest edition of 
the National Electrical Code ANSI/NFPA 70 in 
the U.S., or the latest edition of CSA C22.1 
Canadian Electrical Code, Part 1, in Canada. 
Do not rely on the gas or water piping to 
ground the metal parts of the water heater. 
Plastic pipe or dielectric unions may isolate the 
water heater electrically. Service and 
maintenance personnel who work on or around 
the water heater may be standing on wet floors, 
and could be electrocuted by an un-grounded 
water heater. 
 
CAUTION: Label all wires prior to 
disconnection when servicing controls. Wiring 
error can cause improper and dangerous 
operation.  Verify proper operation after 
servicing. 
The MOBIUS water heater requires an 
electrical power supply from 120 VAC 60 Hz 
circuit and be properly grounded.