User Guide

42 Page
DESCALING THE UNIT
Hard water is a severe problem for the copper coils inside heat exchangers. Heat exchanger failure due
to scale buildup from hard water conditions is NOT covered by warranty. It is highly suggested that a
scale inhibitor be installed before the cold water inlet after this procedure is done.
1) TOOLS - Gather the following materials:
a. Pump: The pump should provide a minimum of 1
gpm through the heater.
b. Descaling Solution
c. Water hoses
d. Bucket
2) SETUP -
a. Set the unit to its highest temperature setting.
b. Open multiple hot water fixtures to run
a large volume of water through the water
heater. Allow the unit to run at its full
firing rate for at least 2 minutes.
c. While the water heater is still firing, disconnect
power to the water heater.
d. Shut off all the open hot water fixtures.
3) WATERLINES – Assuming isolation valves with drain
ports are installed.
a. Isolate the water heater by closing the incoming/
outgoing water isolation valves C and D.
b. Relieve pressure within the water heater by
temporarily opening up the pressure relief valve.
c. Drain the water heater and connect hoses/pump to the
drain ports of the isolation valves: Outlet of the
pump to valve B (cold side), and another hose from valve A (hot side) to the bucket.
4) PUMP and DESCALE –
a. Fill the bucket with 5 gallons of diluted solution. Dilution ratio depends on the
cleaning/descaling solution used.
b. Place the pump into the bucket if it is submersible, or use an inlet hose into the bucket if it is
not submersible.
c. Open valves A and B.
d. Circulate descaling solution through the water heater for 45 minutes or until return water is
cleared.
5) CLEANSE THE SYSTEM – Flush the chemicals out of the heat exchanger with fresh water.
a. Close valve B.
b. Open valve D and run fresh water through the water heater and drain out of Hose 2 for 15 minutes.
c. Close all valves, relieve pressure from the water heater with the pressure relief valve, and
clean the inlet water filter with fresh water.
d. Once the water heater is flushed and cleansed, replace the water filter, open C and D, and
reconnect power to the water heater.
e. Change the temperature setting back to the desired temperature.
Normal Operaon
Owner's Guide
Isolation Valve
Water
Heater
H
C
Gas Supply
Isolation
Valve
Pressure Relief
Valve
Hose 1
Pump
Inlet Hose
(may or may not be needed,
depending on type of pump.)
Hose 2
Descaling Solution
A
B
C D