HTP EL-399NVWH - Manual (Page 70)

70
LP- 346 REV. 3.20.14
B. COMBUSTION CHAMBER COIL CLEANING INSTRUCTIONS FOR HEATER
*Before beginning this procedure, you must have on hand the following items:

a nylon, stainless steel, or brass brush (not steel)

gloves and eye protection
1. Shut down the Heater by using the following steps:
a. Close the gas valve. Shut down the unit, and wait for the unit to be cool to the
touch.
b. Disconnect the condensate piping from the outside connection, (not from the Heater
side), so flow from condensate reservoir can be observed.
c. Disconnect electrical connections from the gas valve, spark electrode and flame
rectification probe and combustion blower.
d. Remove the (4) screws on the
aluminum ¾” NPT connector on the right side of the
gas valve.
e. Disconnect the wiring connected to the combustion blower motor.
f. Remove the (6) 10MM nuts from the burner plate assembly.
g. Pull the entire burner plate assembly with blower still attached towards you, while removing or pushing aside any wiring to
allow the removal of the assembly.
2. Using a spray bottle filled with tap water, spray liberally on the coils. If the condensate system is blocked, use a vacuum to clear.
3. Use the nylon, stainless steel or brass brush (do not use steel) and scrub coils to remove any buildup. Then vacuum the debris from
the coils.
4. Spray the coils with clear water, making sure to confine the spray to the area being cleaned (Try to avoid getting the back ceramic
wall of the unit wet). Flush the combustion chamber with fresh water until it runs clear from the condensate. At this point, the heater
should be ready to be re-assembled.
a. Inspect gaskets.
b. Re-install the burner assembly
c. Replace and tighten the (6) 10MM nuts to the burner plate using staggered tightening sequence. (See detail)
d. Re-connect all wiring connections
e. Inspect the gas valve to assure the O-ring is in place.
f. Replace the (4) screws on the aluminum connector on the gas valve. Turn the gas back on. (IMPORTANT: CHECK FOR
GAS LEAKS!)
g. Turn the Heater power back on and create a demand on the heater. When heater is lit, observe condensate flow from the
heater. Be sure the heater is operating properly.
h. Re-connect the condensate piping to the outside condensate connection.
Do not use solvents to clean any of the burner components. The components could be damaged, resulting in unreliable or unsafe
operation. Failure to do so could result in death or serious injury.
C. CLEANING WATER SIDE OF HEAT EXCHANGER
1. Make sure power is turned off to the heater. Run water through the hot water system to assure it is below room temperature.
2. Close isolation valves on the return and supply connections to the heaters as shown in the piping diagrams within this manual.
Slowly open the ball valves and release pressure into a bucket. Once pressure is released, connect a hose to the water line to flush the
heater. Scale removing solution may be used, but must be approved for use with stainless steel and FDA approved for use in a potable
water system.
3. Thoroughly flush the heat exchanger before commissioning the unit back in service.
Figure 34 – Heat Exchanger Detail