Freeze Protection And Winterization; Maximum Vent Length - Rinnai RL75i Installation And Operation Manual

Maximum vent length

(indoor models only)
1. Determine the number of 90 degree elbows in
the vent system. (Two 45 degree elbows count as
one 90 degree elbow.)
2. Refer to the table to find the maximum vent
length based on the number of elbows.
Number of
90° Elbows
0
1
2
3
4
5
6
3. Adjust switch No. 1 in the SW1 DIP switch (tan
switches) if required by the applicable note.
 If the length is greater than 21 ft (6.4 m) then
move switch No. 1 (SW1) to OFF.
 If the length is greater than 15 ft (4.6 m) then
move switch No. 1 (SW1) to OFF.
 If the length is greater than 9 ft (2.7 m) then move
switch No. 1 (SW1) to OFF.
 Move switch No. 1 (SW1) to OFF.
Example: If you have one elbow then your maximum
vent length is 35 feet (10.7 m). If your
actual length is greater than 15 ft (4.6 m)
then move switch no. 1 (SW1) to OFF.
NOTICE
If you have a longer vent length (see number 3
regarding max. vent length), switch No. 1 is required
to be in the OFF position. This ensures the water
heater will run properly. Blocked flue diagnostic
codes and shutdowns may result if switch No. 1 is not
in the correct position.
Maximum vent length
41 ft (12.5 m) 
35 ft (10.7 m) 
29 ft (8.8 m) 
23 ft (7.0 m) 
17 ft (5.2 m) 
11 ft (3.4 m) 
5 ft (1.5 m) 
Freeze Protection
Make sure that in case of freezing weather that the
water heater and its water lines are protected to
prevent freezing. Damage due to freezing is not
covered by the warranty.
With electrical power and gas supplied, the water
heater will not freeze when the outside air
temperature is as cold as –22°F (-30°C) for indoor
models or is as cold as –4°F (-20°C) for outdoor
models, when protected from direct wind exposure.
Because of the "wind-chill" effect, any wind or
circulation of the air on the unit will reduce its ability
to protect itself from freezing.
In the event of a power failure and/or gas
interruption at temperatures below freezing the
water heater should be drained of all water to
prevent freezing damage. In addition, drain the
condensate trap and drain line.
Loss of freeze protection may result in water damage
from a burst heat exchanger or water lines.
The unit may be drained manually. However, it is
highly recommended to:

drain down solenoid valves be purchased and
installed that will automatically drain the unit if
power is lost. These are available in a kit,
104000059. (The condensate trap is not affected
by the auto drain down solenoid valves and will
have to be manually drained.)

a surge protector with terminals be purchased
and installed which allows the solenoid valves to
operate if the unit is disabled due to a diagnostic
code. This is available as 104000057.
In addition, the solenoid valves should be connected
electrically to a surge protector with terminals. This
allows the solenoid valves to operate if the water
heater is disabled due to a diagnostic code.
The freeze protection features will not prevent the
external piping from freezing. It is recommended that
hot and cold water pipes be insulated. Pipe cover
enclosures may be packed with insulation for added
freeze protection.
VC Series Manual 11