Rheem RHP-2805 Series Technical Document

Owner’s Guide
and
Installation Instructions
Air Sourced Heat Pump Water Heater
RHP-2805 Series
This water heater must be installed and serviced by a qualified person.
Please leave this guide with the householder.

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Contents
Packing List.....................................................................................................................................................2
General Precautions ......................................................................................................................................3
Technical Specifications ................................................................................................................................5
Installation Instruction....................................................................................................................................6
Pipe Connection ............................................................................................................................................. 9
Wiring Diagram.............................................................................................................................................13
Operation and Usage................................................................................................................................... 14
Maintenance .................................................................................................................................................20
Common Faults and Solutions ...................................................................................................................22
Replacement Parts.......................................................................................................................................24
Warranty Policy.............................................................................................................................................25
Packing List
No. Name Qty.
1 Heat pump water heater 1
2 T&P relief valve 1
3 Non-return valve 1
4 Drain valve 1
5 Water outlet connection 1
6 Condensation drainpipe 1
7 Instruction manual 1

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General Precautions
Please read this instruction manual carefully before taking any installation or operation action
and keep this manual in a safe place for future reference.
•Rheem Manufacturing Company group of companies (hereinafter referred to as “Rheem”).
•The water heater is intended to be installed by a qualified technician. Rheem shall not be liable
for any loss or consequences caused by improper operation and performance faults, like pipe
leakage, machine malfunction or any other damages due to the installation of personnel not
approved by Rheem or using unauthorized installation materials.
•The water heater is suitable for domestic usage. Commercial purpose will shorten its life cycle.
•A suitable floor drain that enables water to be drained away to a safe location must be installed
near the water heater to prevent damage to other facilities.
•The working voltage of water heater is 220-240V~, violation of the range will cause operation
failure.
•The water heater must be installed as per national wiring standards.
•Neither unqualified and damaged cables nor unqualified, aging socket can be used, otherwise,
electric shock, short circuit, fire and other accidents may easily occur.
•A special circuit and circuit breaker protection must be provided for the electrical connections.
The compliance of meter, circuit breaker, wire diameter and socket shall be inspected by those
skilled in this art.
•The power supply to the water heater must not be switched on until the water heater is filled with
water.
•In case of abnormal conditions of grounding system of other equipment, user should
immediately stop using the water heater, unplug the power supply or cut off all connections with
power supply circuit, and contact the maintenance people of the manufacturer to solve the
problem.
•If the power cable is damaged, it can only be replaced by qualified personnel approved by the
company.
•A non-return valve must be installed for the cold water inlet pipe of the water heater.
•Water temperature exceeding 50°C may cause scald to human body. Please use before mixed
with cold water.
•When you don’t use water heater for a long-time in winter, please switch off and discharge your

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water heater to prevent freezing damage.
•Pressure relief device must be installed. For safety reason, DO NOT change installation position
of the relief device or block its exit. A drain tube must be connected to the relief valve and kept
going down. Water flowing out from the tube shall be discharged to suitable floor drain.
•Do not attempt to install, repair or remove the water heater, all work must be carried out by a
qualified technician.
•Do not insert any foreign objects into air inlet or outlet to avoid injury.
•If the water heater begins to operate abnormally (i.e., excessive noise, emit smoke, peculiar
smell, etc.,), stop operation of the equipment, isolate power supply promptly and contact the
Service Department. Do not attempt to repair the unit by yourself.
•Max. water supply pressure is 0.68MPa.
If the requirements in this instruction are not strictly followed, a fire accident may occur,
causing property damage, personal injury, or death!
Warning: The power socket must be grounded reliably. It is strictly forbidden to use the
water heater without a reliable grounding measure!

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Technical Specifications
Model RHP180-2805 RHP280-2805
Power supply 220-240V~ 50Hz
Circuit fuse - model number T3.15AL250V
Circuit fuse - parameters 3.15A 250V
IP rating IP24
Heat pump heating capacity* 2800W
Heat pump power input/current* 666W/3A
Coefficient of Performance (COP)* 4.2
Heat pump heating water capacity* 60L/h
Refrigerant (charging amount) R134a (0.9 kg)
Element rating/current 2500-3000W/11.4-12.5A (@220-240V)
Max. power input/current 4000W/16.7A
Operation ambient temperature range -7～43°C
Water temperature adjustment range 35～75°C
Rated water temperature 65°C
Max. water temperature of heat pump 70°C
Water side
Heat exchanger type Microchannel
Tank capacity 180L 280L
Maximum Pressure 850 kPa
Inlet/outlet connection RP3/4" / DN20
Relief/drain valve connection RP3/4" / DN20
Air side Heat exchanger type Internal thread tube with hydrophilic
aluminum foil
Air outlet Back exhaust
Dimension Diameter 525 mm 648 mm
Height 1810 mm 1815 mm
Heater weight - Empty 96 kg 120 kg
Heater weight - Full 276 kg 400 kg
*Testing conditions: power supply 220V~ 50Hz, ambient temperature 20˚C/15°C (dry
bulb/wet bulb), and water temperature from 15˚C to 55˚C for water heater operation.

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Dimensions
Condensate
Drain
Hot Water
Outlet
T&P Relief
Valve
Display Board
ECO Elec Quick
Mode
Model A(mm) B(mm)
RHP180-2805 1130 1810
C(mm) D(mm)
525 576
Cold Water
Inlet
Drain Valve
Power
Cable
1095 1815 648 702RHP280-2805
Installation Instruction
Installation Location
•Do not install this water heater in a place where freezing may occur.
•The water heater should be installed as close as possible to the hot water point with the highest
frequency of use.
•There should be enough clearance around the water heater so that the entire unit can be

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removed for repair or replacement if necessary. The electrical junction box and T&P relief valve
should be oriented for easy maintenance, and the nameplate should be easy to read.
•The water heater should be installed on the floor to ensure that it is placed vertically and avoid
tilting. The building must be able to withstand the total weight of the water heater after being
filled with water without severe vibration.
•The water heater should be placed on a refractory base with a height of not less than 50mm,
and there should be a high temperature resistant floor drain with unobstructed drainage near
the base to prevent damage to other facilities in case the water heater or pipeline leaks.
•The installation location should be well ventilated, no obstacles that hinder the wind in and out,
and should not be exposed to rain and direct sunlight.
•The water heater should be installed at location where its running noise and exhaust will not
affect the neighbors.
•Make sure there is no leakage of flammable and corrosive gas at the installation location; no
oily smoke and dust; no or only small fluctuations of power supply voltage.
Installation Clearance
150mm
≥500mm
≥500mm
≥500mm
≥500mm
≥500mm
ECO Elec Quick
Mode
Floor Drain
Air Inlet Air Inlet

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Installation Precautions
Wiring work must be done by a qualified electrician and must meet electrical safety requirements.
When the user needs to install and move, please contact the company's after-sales service center
for professional help. DO NOT install and move by yourself. Otherwise, the company will not be
responsible for any damage and failure caused and warranty of water heater will be invalid.
Warning: If the water heater is installed on the roof of a building that is vulnerable to
lightning strikes, the water heater must be protected by lightning protection facilities!
Note: After the machine is in place, be sure to let the water heater stand for more than
30 minutes before turning on the power!
Note: Please transport the water heater according
to the state when it leaves the factory. Do not
move the water heater at an angle of more than
30°, let alone place the machine vertically, and do
not disassemble or assemble it yourself!
（C ≤

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Pipe Connection
Pipe Connection Diagram
Floor Drain
Condensate
Drain
Outlet TPR Valve
Inlet
Drain
Valve
Cold Water
Hot Water
Refractory
Base
TPR Valve drain
Non-return
Valve
Shutoff Valve
Shutoff Valve
K
itchen WashBatheLaundry
Connection Instruction
Material Requirements
Because the water heater and its piping system will bear pressure from tap water, all water-side pipes
must be made of temperature-resistant, pressure-resistant, and corrosion-resistant metal or new-type
plastic material. Pressure resistance performance of the pipes must not be lower than the relief
pressure of the T&P valve, while the temperature resistance must not be lower than 99°C.

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Cold/Hot Water Pipe Connection
1. Connection size
Rp 3/4"
2. Pipeline Size
To ensure the best performance, the pipe size should be selected according to the specific
installation needs. The following are the recommended pipe sizes.
Hot water pipe: Main pipe - 20mm（3/4"）; Branch pipe ≥ 15mm（1/2"）.
Cold water pipe: The size of the cold-water pipe should be the same or larger than the size of
the hot water pipe used.
3. Cold Water Connection
The cold-water inlet is at lower part of the water heater and should be directly connected with
tap water. As shown in the figure, first connect a shut-off valve, then connect a non-return
valve on the side close to the heater, and finally connect a union.
If supply water pressure exceeds the rated max. pressure (680 kPa), a pressure limiting valve
shall be connected behind the non-return valve. If supply water quality does not meet the
specific water quality requirements, an expansion control valve shall be used.
4. Hot water connection
The hot water supplied by the water heater has a relatively high temperature and cannot be
used directly for washing. It must be mixed with cold water. Therefore, the cold and hot water
mixing valve should be installed at the hot water use point, as shown in the figure.
Note: The water heater has a hot water pipe for the outlet connector and a joint bushing
on the inlet connector. These devices are installed when the water heater leaves the factory
and must not be removed or damaged during installation. When the threaded joint is
screwed in, these devices will naturally be installed to the correct depth.

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If the hot water outlet of the water heater is too far away from the hot water use point (more
than 12 meters), it is recommended that the hot water pipe be insulated with heat insulating
materials to reduce the waste of hot water and electricity.
5. Water Supplied by Domestic Tank
If cold water to the heat pump water heater is supplied by the domestic tank on the top floor,
be noted that cold water connection should meet the following requirements:
The domestic tank shall be at least 1m higher than the highest hot water outlet. If the distance
between the bottom of the domestic tank and the highest hot water outlet is less than 5 meters,
care must be taken to avoid air locks in the hot water pipe, the shut-off valve in cold water
pipeline shall be changed to gate valve, which shall be fully open to ensure the full flow of cold
water inlet.
Condensation Drain Pipe Connection
The water heater is equipped with a condensation drain hose, one end of which is connected to the
condensation drain and another to the floor drain. To keep the water pipe drainage unobstructed,
there should be no bends or distortion.
Installation of T&P Relief Valve
The temperature and pressure relief (TPR) valve is a safety device, which can keep system pressure
at a safe level by discharging hot water to reduce pressure and cool down system temperature when
detecting system pressure exceeds rated value (850 kPa). If water temperature is heated up to 93°C,
the temperature sensing device will open the TPR valve for hot water discharging and cold water
entering to cool the system down and reduce pressure. The discharge pipe connected to the relief
valve should be installed in a frost-free environment in a continuous downward manner, making sure
Warning: Regardless of the water supply method, the non-return valve on the cold-water
inlet pipe must be installed correctly, otherwise the water heater or its parts might be
damaged.

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water can flow out freely; and the discharge pipe should be kept open to the atmosphere.
Specification of the TPR valve is 3/4″× 125PSI (850 kPa).
•Take out the T&P relief valve, make sure that the probe is not bent. Inspect the operation
lever and the flexibility of the handle.
•Wrap the thread with PTFE, do not let the PTFE to go beyond the end of the thread; screw
the T&P valve into the installation hole, and make sure the valve drain outlet is facing down.
•Connect a DN20 drainpipe from the drain outlet of the TPR valve to suitable floor drain. It
is strictly forbidden to install a valve on the drainpipe, and the total length of the pipe shall
not exceed 9 meters while the right-angle bend shall not exceed 3.
•If the drainpipe is too long, to facilitate disassembly, a live connection can be connected
near the outlet of the TPR valve.
Warning: Drainpipe of the T&P relief valve shall be installed in forest-free
environment and kept inclined downwards. The outlet of the drainpipe should not
be blocked at any time, and it should be kept in contact with the atmosphere, and
make sure the discharged hot water will not endanger people’s safety or cause
property damage.
Warning: drainpipe of the T&P relief valve shall be protected with insulation
material from freezing in winter that may cause safety accidents; and the handle
should be operated regularly to remove calcium carbonate deposits and verify if
the device is blocked.

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Wiring Diagram
•Rated power supply of this water heater is 220-240V~ 50Hz. Wiring diagram is as below:
•A specific power cable equipped with all-pole disconnecting device with at least 3mm contact
interval shall be provided for water heater. The ground and zero lines of the power supply
must be strictly separated, and do not connect the zero lines with the ground line.
•The water heater is equipped with a power cable when it leaves factory. The cable at the user
end shall be directly connected to the distribution box to connect the 30A air switch with
leakage protection function. The operation shall be carried out by those designated by factory
rather than users themselves.

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Operation and Usage
Filling the Water Heater
1. Cut off power supply of the water heater.
2. Turn on the nearest hot water tap to empty air in the system
3. Turn on cold water valve completely to fill the tank and pipes
4. When there is water flowing out from the hot water faucet, it indicates the tank is full, turn off the
hot water faucet and check if there is any water leakage
Warning: please fill the water heater before power it on! Otherwise, any damage caused by
dry heating will not be covered by the Rheem warranty.
Note: If the power cord is damaged, for your safety, it must be replaced by professionals
from the manufacturer, its maintenance department, or similar departments!
Warning: The power supply must be grounded properly! DO NOT use the water heater if
without proper grounding.

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Controller Display (built-in on water heater)
Button Description
•“ON/OFF” button: power “ON” and “OFF” the water heater.
•“UP” and “DOWN” button: adjust the set temperature point.
•“Mode” button: switch between “ECO” – Energy Conservation (heat pump only), “Elec” -
Electric Heating (heating element only)” and “Quick” - Heating (heat pump + heating element)
modes.
Function Description
•ON/OFF
Switch on and off the water heater by pressing “ON/OFF” button.
When the water heater is powered on, the controller switches on and starts self-check, following
by a “beep” sound and the display screen illuminating for 2 secs.

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•Setting the Water Temperature
In switch-on status, press “UP” or “DOWN” arrow button to adjust water temperature within the
range of 35-75°C. The default set point is 65°C.
•Mode Selection
ECO mode (default mode)
Press “Mode” button and select “ECO” mode, the ECO icon will light up.
Under this mode, only heat pump to be started for heating purpose when operation conditions
are satisfied; if operation conditions are not satisfied, the electric heating will only operate.
When water temperature reaches setting point, the water heater enters heat preservation
status. Under heating status, the “heating indicator” icon will light up.
Electric Heating Mode
Press “Mode” button to enter electric heating mode. In this mode, only heating element will be
operate for heating.
When water temperature reaches setting point, the water heater enters heat preservation
status. Under heating status, the “heating indicator” icon will light up.
Quick Heating Mode
Press “Mode” button to enter quick heating mode. In this mode, compressor and heating
element will operate simultaneously. Heat pump will only heat up to heat pump maximum
temperature, heating element continue to operate to setting temperature if higher setting
temperature is set. When water temperature reaches setting point, the water heater enters
heat preservation status.
Note: In the "ECO" (energy saving) and "Quick" heating modes, when the heat pump fails, it
automatically switches to electric heating operation, and the displayed mode remains
unchanged. When the system detects that the heat pump or heating element is working, the
"heating indicator light" icon will be on, otherwise it will be off.

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•Wi-Fi Function
See “APP Manual”.
•Anti-Freeze Function (“On” by default)
Under the premise that the water heater is powered on, no matter it is in switch-on or off
status, the anti-freeze function will activate heating element and heating icon will be lightened
up when lower tank sensor detecting that the temperature is below 5°C (the heating icon will
be lightened up even if the water heater is in switch off status). Heating is to be suspended
until the water temperature of lower tank reaches 10°C and will be restarted repeatedly when
temperature descends below 5°C.Priority will be given to normal heating operation in case of
anti-freeze function and heating function co-exists.
•Memory for Power-Failure
In the case of power-failure (power-outage or disconnection), the unit has a smart auto-
memory recall function. After power is back on, all the settings, including temperature, mode
and status will be restored to prior settings before power-failure.
•Sterilization
To activate the one-time high-temperature sterilization function, ensure the water heater is
powered on. Press both “UP” and “Mode” button simultaneously for 5 seconds to enable the
sterilization function. The heating icon will be lightened constantly after flashing for 5 seconds
indicating sterilization function is turned on. Once the water temperature is reaches ≥80°C, the
water heater will exit sterilization mode and automatically return to the set mode. To manually
Note: DO NOT disconnect power supply of the water heater when it is to be operated in
environment where ambient temperature will be below 2
℃
. If the power must be
disconnected, please discharge all the water in the tank in advance and make sure it is
empty. Otherwise, Rheem will not be responsible for any water heater failure and
property loss caused.

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exit the sterilization process at any time, simultaneously press both “UP” and “Mode” button for
5 seconds. The sterilization function will be disabled, and the display will return back to normal
status.
•Hot Water Volume Display
When the heat pump is operating (heating water in progress), the 25 bars will fluctuate back
and forth left to right. The amount of hot water volume available is represented by the static
length of the 25 bars on the display (the more the bars displayed, the more hot water available
in the tank).
Hot Water Usage
•Under normal circumstances, the cold-water inlet shut-off valve should always be open, and
cold water will be automatically replenished when hot water is discharged.
•During the heating process of the water heater, it is normal for the T&P relief valve to
discharge a small amount of hot water.
•In the event of a power failure, the stored hot water can still be used.
•When the water supply is cut off, it is recommended to close the cold water shut-off valve of
the water heater to prevent water flowing back and emptying the tank due to failure of the non-
return valve, which can be reopened when the water supply is restored.
Turning Off the Water Heater
If the water heater needs to be turned off for maintenance or long-time shutoff, please follow the
instructions below:
•Cut off power supply of the water heater.
•Turn off cold water and hot water shut-off valve.
Warning: To prevent scald and burns, never let children use the hot water faucet or take a
bath by themselves; never leave children or disabled people alone in the bathtub or under
the shower head without care.

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Emptying the Water Heater
If the water heater needs to be turned off for maintenance or long-time shutoff in winter or cold area,
please empty it by following the instructions below:
1. Cut off power supply of the water heater;
2. Close cold water inlet valve;
3. Open drain valve;
4. Lift up the handle on the T&P relief valve, water will flow out from the drain valve.
About Water Quality
Poor water quality will have a detrimental effect on the water heater and its operation and /or life
expectancy. If you are unsure of your water quality, information can be obtained from your local water
supply authority.
•This water heater can be used in areas where the total dissolved solid content (TDS) in water
is less than 1000mg/L, but when TDS is more than 600 mg/L, it will accelerate the
consumption of power anode rod and shorten service life of the water heater.
•Saturation index of water that is prone to scaling:
The calcium carbonate in the water can deposit on the surfaces of hot metal, which can cause
scaling. When the saturation index of water is greater than 0.4, the scaling will be obvious. The
higher the water temperature and water consumption, the more serious the scaling will be. In
this case, it is required to install an expansion control valve after the non-return valve on the
cold-water pipeline of the water heater.
When the saturation index of water is less than -1.0, its corrosiveness will be very strong and it
can dissolve copper pipes, but it will not have any effect on the water heater itself.
Note: If you do not need to use the water heater in winter in cold areas, please empty the
water in the tank in case freezing damage.
Warning: When reusing, the water heater must be filled with water before powered on.

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Reducing the temperature setting of the water heater can alleviate the scale deposition to the inner
surface of the tank cylinder, and so increase the life expectancy of water heater.
Water which is easy to scale may be treated with a water softening device to reduce the saturation
index of the water.
Maintenance
Safety Inspection
Check the performance of the safety valve every two weeks. Inspection method: Lift up the handle
of the safety valve and observe whether there is water flowing out of the drain pipe. If no water is
flowing out, please contact service provider for repairing.
Jacket Cleaning
To maintain the good appearance of the water heater, the surface of the jacket can be cleaned
regularly. Proceed as follows:
•Cut off power supply of the water heater.
•Use a damp cloth to take a small amount of soap or detergent and lightly wipe the jacket.
•Do not use gasoline or other corrosive chemicals.
•Restart the water heater.
Note: This water heater should be repaired and maintained only by qualified service
personnel. Incorrect maintenance methods may cause serious injury to human body or
property losses.
Warning: Before disassembling the unit or taking any repairing/maintenance action, be
sure to disconnect the power supply of the water heater.
Note: When checking the TPR valve, please be careful that water flowing out from the
valve may cause scalding.