T-H3 Installation Manual

51 Page
Normal Operaon
Owner's Guide
UNIT DRAINING AND FILTER CLEANING
Inlet water
valve
Gas
valve
Drain plug
(Small)
Drain plug
with Filter (Large)
Pressure
port
-Measuring inlet gas pressure-
The water heater cannot perform properly without sufficient inlet gas pressure. Below are instructions
on how to check the inlet gas pressure. THIS IS ONLY TO BE DONE BY A LICENSED PROFESSIONAL.
1. Shut off the manual gas valve on the gas supply line.
2. Remove the screw from the pressure port which is located on the gas inlet of the water
heater shown in the diagram on the right.
3. Connect the manometer to the pressure port and zero the manometer.
4. Re-open the manual gas valve. Verify that there are no gas leaks.
5. With all gas burning equipment off, take a reading of the static gas pressure and make a note
of it.
6. Measure gas supply pressure at maximum heater operation: Open hot water faucets to cre-
ate maximum flow. Press the MAX button on the computer board. (Refer to the diagrams
below.) Take a reading of the supply dynamic gas pressure with all gas burning equipment
running at maximum rate.
7. The static and dynamic pressures should be within the ranges specified on the heater's rating
plate and the table on p. 29.
8. The difference of static to dynamic pressure should not exceed 1.5" W.C. Pressure drops
that exceed 1.5" W.C. can indicate restricted gas flow, undersized gas lines, and/or undersized supply regulators.
(NOTICE: In Canada, the pressure drops cannot exceed those specified in CSA B149.1.)
9. Measure gas supply pressure at minimum heater operation: Reduce water flow so the heater is running at mini-
mal operation. Press the MIN button on the computer board. (Refer to the diagrams below.) Take a supply gas
pressure reading and verify that it is within the specified inlet gas pressure range.
1. Turn off all electric power to the water heater if service is to be performed.
2. Turn the manual gas valve located on the outside of the unit to the off position.
3. Failure to follow these steps could lead to fire or explosion, resulting in personal injury
or death.
WARNING
240 and 340 Computer board
MAX button
MIN button
540 Computer board
MAX button
MIN button
1. Close the manual gas shutoff valve.
2. Turn off power to the unit and wait a couple of seconds. Turn on
again.
3. Wait 30 seconds, and then turn off power to the unit.
4. Close the inlet water valve.
If the heater is part of an Easy-Link or Multi-Unit System, close
the inlet and outlet water valves to isolate the heater. Then pro-
ceed to step 6.
5. Open all hot water taps in the house. When the residual water
flow has ceased, close all hot water taps.
6. Have a bucket or pan to catch the water from the unit’s drain
plugs. If Isolation valves are installed, open the drains to drain the
water. If isolation valves are not installed, unscrew the two drain
plugs (large and small) to drain all the water out of the unit. Do
not lose the o-rings that will be on the two drain plugs.
7. Wait a few minutes to ensure all water has completely drained
from the unit.
8. Clean the filter: Check the water filter located within the cold
inlet. With a tiny brush, clean the water filter of any debris which
may have accumulated and reinsert the filter back into the cold
water inlet.
9. Securely screw the drain plugs back into place.
Hand- tighten only.