The L5, L10, and FVI12 tankless water heaters have a control system operated by water pressure. This control system senses where there is a demand for hot water and activates the gas and ignition sequence. If there is insufficient pressure to safely operate, the system will not allow the water heater to run.
The minimum water pressure needed to operate the CE-L5 is 20psi. The operating pressure range is preset at approximately 40psi. This is the average water pressure found on municipal systems, wells, and most 12 volt supply pumps. Water pressures below 40psi may require adjustment to the pressure diaphragm as outlined instruction and photo below.
Some systems may still fall below the necessary pressure and supplemental pressure may be needed. The addition of a pump rated at 2+GPM and 40+psi will eliminate the issue.
**ShurFlo, FloJet, and other manufacturers produce pumps of these specifications.
GRAVITY FED WATER SYSTEMS SELDOM HAVE SUFFICIENT PRESSURE TO OPERATE WITHOUT A SUPPLEMENTAL PUMP.
ADJUSTING WATER PRESSURE SENSITIVITY:
1. There are two screws inside of the water heater that allow you to adjust its sensitivity to water pressure. Sometimes it is easier to make this adjustment after removing the cover, which is done by removing the screws on the top and bottom of the cover.
2. The knobs will also need to be removed and can be pulled off by hand. Once the cover is removed you will find the adjustment screws located in the body of the gas-water valve assembly, pictured below.
3. To adjust the screws to be more sensitive to water pressure, tighten them both down in a clockwise direction. ONLY TIGHTEN UNTIL YOU FEEL RESISTANCE. DO NOT APPLY ANY KIND OF FORCE, i.e., DO NOT OVER-TIGHTEN.
4. Loosen the smaller screw, on the left, one full turn. Then, loosen the screw on the right.
5. Loosen the smaller screw, on the left, one full turn. Then, loosen the screw on the right approximately 1/3 of a turn.
**If after following these steps your water heater still does not ignite and continue to run, see the instructions below in the captions on the picture.