Rinnai RH180 User manual

Rinnai RH180 Hybrid Tank –
Tankless Water Heater
Installation Fundamentals, Level II
1

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3
RH180 Hybrid Tank-Tankless Water Heater
Level II Training Program
Installation Fundamentals

RH180 Technology
4
+=
Combining Technologies:
With the combination of a tank and a Rinnai tankless water heater into
one appliance, the RH180 hybrid provides increased hot water capacity
with the ease of a tank installation.

• Circulation pump for
tank/engine
• Hot water supply from
engine to tank
• Cold water supply
from tank to engine
• Tankless water heater
engine
• 40 gallon storage tank
• ¾” cold water supply
into tank
• ¾ hot water feed
into building
• Pressure relief valve
• 4” B-vent exhaust
connection
• Combustion air inlet
and filter
• Tank drain valve
• Temperature controller
• 120 Volt power cord
(not shown)
Product Component Identification
5
• Gas connection

RH180
Sequence of Operation
6

Sequence of operation:
7
1. When the water temperature at the bottom of the tank (at the tank
therm stor) drops to a pre-determ ned temperature, the startup
sequence w ll beg n.
2. The tankless eng ne’s combust on fan w ll beg n turn ng, draw ng
fresh a r from the space. Th s w ll allow the flammable vapor sensor
to ensure the ntake a r s free of combust ble vapors.
3. The pump w ll beg n c rculat ng water through the tank-tankless
loop.
4. The eng ne w ll f re when t detects the water flow from the pump.
5. The heated water from the eng ne w ll be depos ted back nto the
tank. The water w ll be d rected toward the top of the tank close to
where hot water s be ng drawn nto the plumb ng system.
6. In t ally as water s drawn from the tank nto the eng ne, the Delta T
w ll be fa rly large and the eng ne w ll operate n a h gh f re mode.
7. As the water at the bottom of the tank beg ns to heat, warmer
water w ll then beg n to enter the eng ne — th s w ll reduce the
Delta T allow ng a h gher flow rate through the eng ne.
8. As the water n the tank cont nues to warm and gets closer to the
set temperature, the tankless eng ne w ll automat cally reduce ts
gas nput.
9. When the temperature at the bottom of the tank reaches the set
po nt, the pump turns off — the tankless eng ne w ll go nto a
standby mode unt l the next start sequence.
9.
6.
3.
5.
2.
8.
4.
7.
1.

RH180
Water Heater
Sizing
8

RH180 Sizing
Water Heat ng
Opt ons
Max nput (Btuh
/ Kwh)
Tank Capac ty
(gal.)
T me of ava lable
hot water (m n.)
T me of ava lable
hot water (m n.)
Recovery t me
(m n.)
Showers In use
at one t me 70⁰ temp r se 70⁰ temp r se 70⁰ temp r se
Electr c Tank 4.5 Kw 40 21 10 88
Gas Tank
34,000 Btu 40 18 8 36
40,000 Btu 50 26 11 40
75,000 Btu 75 50 19 32
R nna RH180
Hybr d
Tank -Tankless
91,300 Btu 40 Cont nuous 11 16
R nna Tankless Up to 199,000
Btu N/A Cont nuous Cont nuous N/A
•Data is based on a 50⁰F inlet water temperature and a 120⁰F hot water set point (70⁰F rise).
•Shower heads assumed to be 2.5 gpm mixed low rate with 105⁰F at the ixture.
•Available hot water time and recovery time based on industry standard calculation methods
and Rinnai lab testing. Actual results may vary based on the application.

RH180
Product Features &
Safety devices
10

Product Features
• 180 gallon First Hour Rating.
• Quick recovery: Approximately 16 minutes starting from a cold tank.
• Thermal Efficiency: 80%.
• Temperature controller: 5 temperature settings.
• Maintenance/diagnostic codes: Error codes displayed if a fault is detected.
• 40 gallon storage tank: Two inches of insulation, no heating element, burner, or
vent stack which helps to minimize standby heat loss.
• Direct electronic ignition: No standing pilot.
• Blue-zircon-glass coated tank.
• Uses standard 4” B-Vent.
• Can be common vented with a furnace.
• Piping configuration and connections same as standard tanks.
• 1/2” gas line connection.
• Water is heated in the engine not the tank: Less thermal stress on the tank.
• Circulation system compatible.
11

Safety Devices
• Flame rod: Detects when flame is present or is extinguished.
• Overheat bi-metal sensor: Detects overheated water conditions.
• Boiling protection sensor: Monitors heat exchanger water temperature.
• Heat exchanger thermal fuse: Detects heat exchanger overheat condition.
• Burner/combustion fan sensor: Indicates if there is a blocked flue.
• Flammable vapor sensor: Monitors for flammable vapors in intake air supply.
• CO sensor: Monitors exhaust gasses for poor combustion, (NOTE: not a room CO
sensor).
• Built in surge protector.
• Power supply is protected by 5-amp glass fuse.
• Main circuit board monitors component operation and will post error codes or
maintenance codes on the temperature controller if abnormal operation is detected.
12

Specifications
Model RH180
Min / Max Gas Input Rates
Min. 59,500 Btu-Natural Gas / 47,600 Btu-Propane
Max. 91,300 Btu-Natural Gas / 87,300 Btu-Propane
(two stage burner, does not modulate between max-min inputs)
First Hour Rating 180 Gallons / hour
Storage Tank Volume 40 gallons
Temperature Selections 110⁰F, 120⁰F, 130⁰F, 135⁰F, 140⁰F (43⁰C, 49⁰C, 54⁰C, 57⁰C, 60⁰C )
Weight 150 lbs. (68kg)
Thermal Efficiency 80%
Noise Level 50 dB
Electrical 120 VAC, 60 Hz. , Normal Operation - 150 watts / Standby – 3 watts (5 amp
fuse)
Minimum Gas Supply Pressure 4.0” w.c. Natural Gas / 8.0” w.c. Propane
Maximum Gas Supply Pressure 10.5” w.c. Natural Gas / 13.5” w.c. Propane
Connections Gas Supply: ½” MNPT – Water Connections: ¾” MNPT
Water Supply Pressure 20 - 150 psi (Recommend 30 – 50 psi for maximum performance)
Sensor and Switches Flammable Vapor, Combustion Air CO Sensor, Bi-Metal Overheat Switch
13 See Operation / Installation manual for more complete information. Specifications subject to change without prior notice.

RH180
Installation
Requirements
14
A licensed professional must install the appliance, inspect it and leak test it before use. The
warranty may be voided due to improper installation.
The installer should have skills such as:
• Gas sizing
• Connecting gas lines, water lines, valves and electricity.
• Knowledge of applicable national, state and local codes.
• Installing venting through a wall or roof.
• Venting Category I, Fan Assist Appliances per NFPA 54 and local codes.
If you lack these skills contact a licensed professional.

Installation Location
• Not approved for mobile homes or outdoor installations (can be used in light commercial
applications where the temperature requirement do not exceed 140⁰ F).
• Installation must be accomplished in such a manner that if the tank or any connection
should leak, the flow of water will not cause damage to the structure. For this reason it is
not advisable to install the water heater in an attic or upper floor. When such location
cannot be avoided, an approved drain pan should be used and piped to a drain line or
outside the home.
• Use an approved tank water heater drain pan. (Rinnai recommends 26” diameter pan. See
next page for example). See International plumbing code for details.
• Gasoline or other flammable substances MUST NOT be stored in the vicinity of the water
heater.
• A stand is not required as this water heater complies with the FVIR requirements and the
burner and igniter are positioned greater than 18 inches from the base of the unit (verify
with local codes).
• If installed in a crawl space with a dirt floor, position the unit on a solid level surface (such
as concrete) away from the ground’s moisture.
• If installed in a closet or alcove, ensure all intake (combustion) air requirements are
followed, see owner’s/installation manual.
• The RH180 meets or exceeds the National Appliance Energy Conservation Act Standards
with respect to insulation and standby losses. If an insulation blanket is still desired, follow
the installation procedures outlined in the Operation and Installation manual.
15

Drain Pan Installation.
Rinnai recommends using a 26” diameter drain
pain minimum to provide protection from leaks
and still allow removal of the front pipe/pump
shroud for service.
Use only an approved drain pan and install in
accordance with all applicable plumbing and
building codes.

Installation Location
17
Minimum Clearances:
The minimum clearances from
both combustibles and non-
combustibles construction is:
• 0 inches from the sides.
• 0 inches from the back.
• 12 inches from the top.
• 4 inches from the front.
NOTE: These clearances are
minimums. Be sure to allow
sufficient clearance for future
servicing and maintenance.

Dimensions
18

Code Adherence
- Installation MUST comply with National, State, and Local codes.
Electrical Requirements
- Standard three-prong 120 VAC, 60 Hz. grounded circuit.
- Ensure plumbing lines are grounded in accordance to Local, State, and National codes.
Water Installation Requirements
- Supply pressure 20 – 150 psi.
- A temperature/pressure relief valve is supplied with the product. The discharge must be
piped per local code requirements.
- Water quality should meet Part 143 of the National Secondary Drinking Water Regulations.
(see installation manual for guidelines).
- Ensure inlet water filter on appliance is clean before filling tank.
- Do not operate water heater unless tank is completely full of water.
Electrical and Water Installation
19

Water Requirements (continued)
- Make sure the water heater and its water lines are protected from freezing. Damage due
to freezing is not covered by the warranty.
- Do not use this appliance in an application such as a pool or spa heater that uses
chemically treated water. (the RH180 is suitable for filling large or whirlpool spa tubs using
potable water).
- If a water heater is installed in a closed water supply system, such as one having a
backflow preventer, a means shall be provided to control thermal expansion (expansion
tank).
- If required, install a vacuum relief valve per local codes. (Massachusetts 248 CMR section
10.14 (I) “All potable water pressure tanks shall be provided with a vacuum relief valve at
the top of the tank that will operate up t a maximum water pressure of 200 P.S.I.G. and to
a maximum water temperature of 200°F.”)
Electrical and Water Installation