Rinnai Circ-Logic RU80e, Service Manual

Page: 41 / 60

Condensing Water Heater Service Manual 41
100000354
KA Series Component Replacement Instructions
RC98HPi
Heat Exchanger
15. Remove the clip on the heat exchanger inlet pipe on
right side of heat exchanger. Remove the two anti
frost heaters from pipe. Remove heat exchanger
inlet pipe.
16. Disconnect condensate tube from upper heat
exchanger.
Disconnect wire harness
17. Disconnect heat exchanger thermistor (upper left).
18. Remove three anti frost heaters from clips at top of
heat exchanger.
19. Disconnect anti frost heater connectors at bottom of
cabinet. (one green connector with cables leading to
the right side, one blue connector.)
20. Disconnect burner sensor harness (lower right).
21. Disconnect thermal fuse harnesses (lower right).
Single white wire connector, single red wire
connector.
22. Disconnect fan connector.
Remove heat exchanger
23. Remove two screws at bottom of heat exchanger.
Remove two screws at top back of heat exchanger.
Remove two screws at top on reinforcement bracket
for upper heat exchanger. Upper frost sensing
switch is secured on reinforcement bracket, set
aside.
24. Remove four screws for flue connection assembly.
Remove flue connection.
25. Remove heat exchanger assembly.
26. Remove anti frost heater from connecting pipe
between upper heat exchanger and copper tee on
left side. Remove clips and connecting pipe.
27. Remove three screws on front, where upper and
lower heat exchangers meet. Discard screws. Turn
heat exchanger over; remove six screws on back
where upper and lower heat exchangers meet.
Discard screws. Separate the upper heat exchanger
from the lower heat exchanger.
28. If replacing the upper (secondary) heat
exchanger,
then remove fourteen screws to
separate it from the air inlet box assembly. Discard
screws and remove air inlet box assembly.
Remove the old gasket from the air inlet box
assembly. Install new gasket from kit. Attach air
inlet box assembly with new screws (fourteen) from
kit. Ensure reinstallation of reinforcement bracket
on top of air inlet box assembly.
Installation
29. Install new gasket from kit onto the upper heat
exchanger. (Remove the old gasket if the upper
heat exchanger is not new.) Attach upper heat
exchanger to the lower heat exchanger with new
screws from kit. (six screws on back, three screw on
front)
30. If replacing the lower (primary) heat exchanger,
transfer wiring from old heat exchanger to new heat
exchanger. Ensure proper routing of harnesses.
These include burner sensor with new gasket,
thermal fuse, bi
-
metal, ceramic heaters.
Upper (secondary)
heat exchanger
Lower (primary)
heat exchanger
Inlet pipe clip
(Step 15)
Thermistor
(Step 17)
Anti frost
heaters/clips
(Step 18)
Condensate tube clip
(Step 16)