Aqua-Hot 400 series User manual

Installation Manual
400Series
AHE-400-P02
with

Introduction
©Aqua-Hot® 400P Installation Manual p. 1
Caution Notes
As you read this information, take particular note of the NOTICE,
CAUTION, WARNING and DANGER symbols when they appear.
This information is important for safe and effi cient use of the
Aqua-Hot system.
NOTICE signals a situation where potential damage to the
Aqua-Hot could occur.
CAUTION signals a situation where potential harm or risk
of minor or moderate injury could occur if you do not follow
instructions.
WARNING signals a hazardous situation where potential harm,
risk of serious injury, or death could result if instructions are
not followed.
DANGER signals a situation where immediate risk of serious
injury or death will result if instructions are not followed.
NOTE: This manual will also use notes sections similar to
this one to draw attention to features and practices which
should be observed.
Contents
Caution Notes ...............................................................................1
Introduction ..................................................................................2
System Features ..........................................................................4
Component Cut-Aways .................................................................5
Installing the Aqua-Hot ................................................................7
Support & Clearances ..................................................................8
Installation of the Expansion Tank ..............................................9
Exhaust System ..........................................................................10
Installing the Heat Exchangers ................................................ 13
Mounting the Heat Exchangers .................................................15
Wiring the Heat Exchangers ......................................................16
Plumbing the Heating Loop .......................................................17
Heat Exchangers Layout ............................................................19
Propane Fuel System ................................................................ 20
Domestic Water System Requirements ....................................21
Plumbing the Domestic Water System .................................... 22
Thermostats .............................................................................. 23
Interior Switch Panel ..................................................................24
Wiring the Aqua-Hot .................................................................. 26
Aqua-Hot Reporter..................................................................... 29
Reporter Manual Mode ............................................................. 33
Connecting the 400P to 12V DC Power ................................... 34
Connecting the 400P to AC Power ........................................... 35
Filling the Aqua-Hot ................................................................... 36
Purging the Interior Heating Loop/Water System....................37
Purging the Propane System .................................................... 38
First Operation ........................................................................... 39
Winterizing ................................................................................. 40
Flow Diagram ..............................................................................41
Wire Sizing ................................................................................. 42
Appendix A: System Schematics .............................................. 43
Appendix B: Antifreeze .............................................................. 49
Appendix C: Parts & Accessories ............................................. 52
Warranty .................................................................................... 58

Introduction
©Aqua-Hot® 400P Installation Manual p. 2
Safety Features
Low-Voltage Shutdown
The Aqua-Hot Reporter is designed to operate between 11V
DC and 16V DC. If the Reporter detects that it is receiving
voltage below 11.8V DC, a System Voltage fault will trigger
a display on the screen. If the Reporter system drops below
11.2V DC for 30 seconds, it will discontinue operation of
the Aqua-Hot heating system.
Over-Current
An Over-Current fault condition occurs when too much
current is drawn by a component, usually a fan or pump.
When this fault is triggered, the output channel is shut off
until the system has been reset or power-cycled.
Over-Temperature
An over-temperature fault will occur if your Aqua-Hot heating
system has reached 218°F. The Reporter will deactivate
the heater and display an over-temperature fault on the
display screen.
Low-Level Cutoff
If the system senses low fl uid levels, the heating system will
shut down all fans, heat sources, and pumps until the unit
is adequately refi lled.
Reporter “Heartbeat Function”
The Reporter unit with fi rmware 1v5 and later and all
Reporter 2.0 units are equipped with a “heartbeat”
function that establishes a signal between the RV-C system
and the Reporter. The Reporter constantly awaits for a
signal from the RV-C network indicating to the Reporter that
it is to continue normal operation. Loss of 6 consecutive
signals from the RV-C network will trigger the Reporter to
deactivate the Aqua-Hot. Once power is restored to the
coach and the Reporter, “BATTERY DISCONNECT SWITCH
OFF” will be displayed in the fault log, indicating that the
Reporter lost connectivity with the RV-C network.
Manual Mode
The 2.0 Reporters with CFG 1.9 and greater come with a
manual mode in case the general coach RV-C network fails.
It will allow for limited operation while the larger network/
module problem is addressed.
Interlock Switch
The Aqua-Hot 400P is equipped with an interlock switch
that prevents the heater from operating when the cover is
not installed in the correct position or if it is not properly
secured in place. This is a safety device to ensure the
burner will not ignite if the service panel is not properly
secured.
Read all instructions before installing the Aqua-Hot unit. Aqua-
Hot Heating Systems is not liable for damage resulting from
failing to follow instructions contained in this, and any other
Aqua-Hot documentation relevant to this unit.
• Read this manual before installing or using the Aqua-Hot
System to reduce the risk of injury to persons or damage to
the equipment.
• The product identity label contains specifi cations of the
unit, to what standards it has been tested, and important
safety notices.
• Disconnect electric wiring to the Aqua-Hot System before
welding or plasma cutting the coach to avoid damage to
equipment.
• The Aqua-Hot tank and heating loop operate at 0.0 PSI
(zero pressure system). Air pressure to the tank must not
exceed 20 PSI. Exceeding this rating will cause internal
damage to the Aqua-Hot.
• Use caution when working on or near any propane/diesel
fuel system.
• DO NOT connect the 12-volt DC power to the Aqua-Hot if the
vehicle requires welding.
• At maximum operating temperature, the coolant will be
very hot and scalding. Hot vapor or coolant may cause in
serious burns or injury. Be aware of hot surfaces.
• Installation and repairs may only be carried out by an
authorized, factory-trained Aqua-Hot technician. The
heating system must be installed in accordance with local
codes, or in accordance with the Standard for Recreational
Vehicles, (RVIA) ANSI A 119.2/NFPA 501C, NFPA 1192.
• Aqua-Hot will not be liable for problems or damage caused
by the system being installed by untrained personnel.
WHAT TO DO IF YOU SMELL GAS
• Evacuate all persons from the vehicle.
• Shut off the gas supply at the gas container or source.
• Do not touch any electrical switch or use any phone or radio
in the vehicle.
• Do not start the vehicle’s engine or electric generator.
• Do not turn on the gas supply until leak has been repaired.
If the information in this manual is not followed exactly,
a fi re or explosion may result, causing property damage,
personal injury or death.
As with any appliance, allow the Aqua-Hot to completely shut
down BEFORE disengaging the coach 12V power disconnect.

Introduction
©Aqua-Hot® 400P Installation Manual p. 3
System Overview
The Aqua-Hot 400P is a Hydronic (water-based) Heating
System and a tank-less hot water system.
The heating system provides moist, quiet, comfortable,
interior heat with up to 5 separate, thermostatically-controlled
temperature zones, and prevents tank and line freezing in the
bays.
The tank-less hot water system produces 75 gallons per
hour of continuous, on-demand hot water.
This TribridHot™ designated system uses one or a
combination of heat sources to heat FDA-Approved Generally
Recognized As Safe (“GRAS”) Propylene Glycol-based antifreeze
solution in the Aqua-Hot’s boiler tank.
The 400P has multiple heating sources: one 120V AC -
1650W Electric Element (when plugged into shore power) and
a 12V DC powered propane burner (when dry camping). These
heat sources can be used separately or simultaneously.
New Low Emissions Technology virtually
eliminates smoke and odor from the exhaust
by reducing total hydrocarbon emission by
82%, making Aqua-Hot the cleanest burning propane-powered
hydronic heating system available.
Should additional assistance be needed, please contact the
Technical Support at 574-AIR-XCEL (574-247-9235), Monday
through Friday, between 7:00am and 4:00pm MST.
Important Notes:
• A qualifi ed installer or service technician must perform
equipment installation or service. Contact Aqua-Hot for
Factory Authorized Service Centers or Certifi ed Technicians
located near you at www.aquahot.com/service-help, or call
us at 574-AIR-XCEL (574-247-9235).
• Warranty work must be performed by an Aqua-Hot
Authorized Service Center.
• Your on-product identity label contains the specifi cations of
your unit. Factory settings may be adjusted by the vehicle
manufacturer, confi rm fi nal setting with your dealer.
• This heating system has been certifi ed for installation only
in recreational vehicles, not certifi ed for use in boats.
• The Aqua-Hot heating system operates independently of
the vehicle engine and is connected directly to the electrical
system and fuel system of the vehicle.
• Please read this manual and follow instructions to avoid
injuries during installation and/or operation.
Hot Water Priority System
The Aqua-Hot 400P is a Hot Water Priority heating system.
Meaning that the 400P cannot heat the interior of the coach
and produce hot water simultaneously. When hot water is being
used, the interior heating system will shut off temporarily, until
hot water is no longer being used.
When hot water is requested, domestic water from the
coach’s fresh water tank is transported through a copper coil
in the Aqua-Hot’s boiler tank where heat is transferred from
the heated antifreeze and distilled water solution. The heated
domestic water then fl ows through the tempering valve to be
mixed with cool water from the fresh water tank to achieve an
appropriate temperature before it fl ows to the faucet.
NOTE: For networked control of the Reporter, Aqua-
Hot requires system integrators ensure that individual
commands are received and processed. Aqua-Hot requires
that commands be repeated or confi rmed so that if a
single message were dropped, or if there is a brief network
disturbance, the Reporter would get into the correct state as
soon as the disruption was removed.
The Aqua-Hot Reporter monitors the heating system and
handles all logic relating to safeties and heating control.
As such, the system integrator is required to display all
pertinent status information but not use that information to
lock out operation or add additional safety layers that could
impact the end of operation if a message from the Reporter
was missed.

System Features
©Aqua-Hot® 400P Installation Manual p. 4
System Specifi cations
Propane Burner
Heat Input (Firing Rate) ........................................55,331 BTU/hr
Fuel Consumption .......................................................0.72 gal/hr
Electric Element
Power Consumption ......................................1650 W (maximum)
Voltage ..............................................................................120V AC
DC Power
Consumption ....................................................174 W (maximum)
Zone Heat Circulation
Pumps ...........................................................................................2
Power Consumption (max) .........................................21 W (each)
Voltage ............................................................................... 12V DC
Heating Zones
Maximum ......................................................................................5
Domestic Water Heating
Maximum .....................................................1.5 GPM On-demand
Physical Specifi cations
Dimensions (US)..................................12” H x 18.5” W x 29.5” L
Dry Weight ......................................................................... 127lbs.
Wet Weight ......................................................................... 185lbs.
All vehicle installations must comply with the requirements listed in
the Recreational Vehicle Industry Association’s (RVIA) ANSI/NFPA
1192 Handbook for Recreational Vehicle Standards. To receive a
copy of this handbook and other Pertinent RVIA Standards, write to:
Recreation Vehicle Industry Association, 1896 Preston White Drive,
PO Box 2999, Reston, VA 22090-0999. Call them at (703) 620-
6003 or visit online at www.rvia.org.
Figure 2
NOTE: This product label is attached to the top of the Aqua-
Hot, and provides a ready reference to specifi cations, test
standards, and important safety notices.
Figure 1

Component Cut-Aways
©Aqua-Hot® 400P Installation Manual p. 5
15 6
14
Figure 5
Figure 3
Figure 6
2 3
8
17
15
NOTE: The top panel has been made transparent in the
view above to aid in the explanation of the heater. DO NOT
remove the top panel. Doing so risks irreparable damage to
the Aqua-Hot. Only remove the service panels.
201918
Figure 4
1. Drain Valve
2. Zone 1 Circulation Pump
3. Zone 2 Circulation Pump
4. Dual Gas Valve
5. Propane Burner
6. Interlock Switch
7. Propane Inlet Ball Valve
8. Propane Burner Controls
9. AC Terminal Port
10. Heating Zone 2 Outlet
11. Heating Zone 1 Outlet
12. AC Terminal Block
13. AC Terminal Port
14. Aqua-Hot Reporter
15. Electric Element
16. Aqua-Hot Boiler Tank
17. Domestic Water Coil
18. Tempering Valve
19. Domestic Hot Water
Outlet
20. Domestic Cold Water
Inlet
13
12
11 10 9
16
7
4

Component Cut-Aways
©Aqua-Hot® 400P Installation Manual p. 6
Propane Fuel Inlet
& Outlet Ports
Zone 1 & 2 Inlet Ports
Zone 1 & 2 Outlet Ports
Wiring Harness Port
AC Wiring Port
Expansion Tank
Connection
Product ID Label
The Aqua-Hot tank and heating loop operate at 0.0
PSI (zero pressure system). Air pressure applied to
the tank MUST NOT exceed 20 PSI. Excess pressure
will result in internal damage.
Figure 7
Air Release Valve

Support and Clearance
©Aqua-Hot® 400P Installation Manual p. 7
Installing the Mounting Tray & Aqua-Hot
Install the Aqua-Hot in a compartment that is completely
closed off from living quarters and is accessible only from the
exterior of the coach.
1. Reference the following illustrations below for mounting
information.
2. Cut out the required mounting tray as shown in Figure 8.
3. Install the mounting tray fl ange into the cut out opening.
Reference Figure 9.
4. Insert a #10 machine screw into each of the embossed
holes in the mounting tray (6 total), and tighten to secure
the mounting tray to the coach.
NOTE: Inspect the area near the mounting location to
ensure that no structural members will interfere with
the cut-out for the mounting tray.
Figure 8
NOTE: The Aqua-Hot must be
supported by structural cross-
members that can support at least
185lbs.
5. Secure the mounting tray into place prior to installing the
Aqua-Hot.
6. Place the Aqua-Hot securely into the mounting tray to
ensure that the unit does not move or shift under normal
operating conditions. Reference Figure 10.
Figure 10
Figure 11
NOTE: Remove the bolt securing the front of
the access cover to the mounting tray. This
bolt will need to be reinstalled once the total
installation procedure is complete.
Figure 9
Mounting Tray
Flange Slots
Rear of
Mounting Tray

Support and Clearance
©Aqua-Hot® 400P Installation Manual p. 8
All measurements
are in inches
TOP VIEW
FRONT VIEW
SIDE VIEW
BOTTOM VIEW
REAR VIEW

Fluid Expansion Bottle
©Aqua-Hot® 400P Installation Manual p. 9
Installation of the Expansion Tank
Introduction:
The fl uid expansion tank is integral to the operation of the
Aqua-Hot. It provides an area for hot, expanded fl uid to empty
into, and also protects the Aqua-Hot from low-fl uid, which could
lead to catastrophic damage of the Aqua-Hot.
Follow the directions in this section to correctly install the
fl uid expansion tank.
Installation Procedure:
1. Mount the expansion tank as illustrated in Figure 13. The
overfl ow tube should have an incline.
2. Connect and clamp the overfl ow tube from the expansion
tank to the Aqua-Hot’s expansion tank connection as
shown in Figure 13.
3. Drill a hole in the bay fl oor and connect a long enough piece
of overfl ow tubing so that it can be connected to the top
of the expansion tank and extend through the bay fl oor.
Secure tubing with clamps.
NOTE: Avoid any bends or dips in the overfl ow tubing from
the Aqua-Hot. Air can become trapped in these bends and
will prevent excess antifreeze and water heating solution
from depositing properly in the expansion bottle.
Hot Fluid Line
Cold Fluid Line
Fill Cap
Lower Fitting
Upper Fitting
Figure 12
Figure 13
Overfl ow Tube
Expansion Tank
Pressure Relief Valve
Expansion hose. Must
vent to the exterior of
the vehicle
Fluid Expansion Tank
NOTE: The top of the expansion tank must be mounted
higher than the highest point on the Aqua-Hot.
The Aqua-Hot tank and heating loop operate at 0 PSI (Zero
pressure system). Air pressure applied to the tank MUST
NOT exceed 20 PSI. Excess pressure will result in internal
damage.
Hole in the coach bay
fl oor for overfl ow hose
Tension Clamp
Tension Clamp

Fluid Expansion Bottle
©Aqua-Hot® 400P Installation Manual p. 10
Exhaust System
Exhaustion System Requirements
• The exhaust must be able to freely exit away from the
vehicle without any obstructions.
• Angle the exhaust pipe towards the rear of the vehicle,
so that exhaust fumes will naturally move away while the
vehicle is in motion. See Figure 17.
• Use standard 2” automotive-type exhaust piping and avoid
bends, if possible. A minimum 1.75” ID automotive-type
exhaust pipe may be used. See Figure 17 & Figure 19.
• A maximum of three 90° exhaust bends are allowed.
Reference Figure 14.
• Do not use galvanized pipe fi ttings (only black-iron pipe and
fi ttings should be used). Reference Figure 19.
• The total length of exhaust pipe should not exceed 27.5
feet.
• The Aqua-Hot is supplied with a 3 inch and 4 inch black pipe
nipple (1.5 inch diameter) along with a 1.5 inch exhaust
elbow. Reference Figure 16. These three exhaust system
components MUST BE utilized with all product installations.
Be sure to reference Figure 18 and 19 to determine which
exhaust nipple should be connected directly to the Aqua-
Hot’s exhaust port (the 3 inch of the 4 inch black pipe
nipple).
Exhaust System
The Aqua-Hot’s exhaust is HOT and must be kept away
from any heat sensitive material(s). Do NOT direct
exhaust downward as a fi re may result when parked in
dry, grassy areas.
All Aqua-Hot exhaust system installations MUST utilize the
two black pipe nipples and black pipe elbow, which are
provided with the heating system in the confi guration to be
suited for the particular RV application. Failure to conform
could create a hazardous situation and WILL void the Aqua-
Hot’s ETL Product Listing.
NOTE: Refer to “Internal Combustion Engine Exhausts and
Vehicle Wall Openings” in RVIA’s ANSI/NFPA 1192 Handbook
for the Recreational Vehicle Standards, as well as the
National Fire Protection Associations’ (NFPA) 1192 Standard
on Recreational Vehicles for additional information.
Installation Procedure:
1. Run the exhaust pipe to the driver’s side or to the back
of the vehicle and ensure that the exhaust fumes cannot
enter into the passenger compartment.
2. Be sure to secure the end of the exhaust pipe to the vehicle
with the proper exhaust hanger/support hardware.
3. Slide the exhaust tip over the end of the exhaust pipe,
being sure to leave a required clearance of one inch
between the band on the tip and the end of the exhaust
pipe. Mark where the holes should be drilled to allow for a
#8 sheet metal screw ⅜ inch in length to securely mount
the exhaust tip to the exhaust pipe. Drill the holes in the
pipe and mount the exhaust tip. This will prevent excessive
air movement up the exhaust pipe, preventing the propane
burner from extinguishing. See Figure 17.
NOTE: Should this particular application require more than
27.5 feet of exhaust pipe, please contact Aqua-Hot at +1
[phone] for assistance.
Figure 14

Fluid Expansion Bottle
©Aqua-Hot® 400P Installation Manual p. 11
Exhaust System
Figure 17
NOTE: The exhaust elbow can be rotated 270°,
as shown in the illustration; however, the exhaust
must not terminate beneath the vehicle or beneath
an open-able window or vent.
NOTE: A maximum of three 90° bends are allowed
in the exhaust pipe. Also, the exhaust pipe cannot
be longer than 27.5 feet.
1.5 inch ID Black Pipe Exhaust Fitting
The two black pipe exhaust fi ttings MUST be utilized
with all installations! Failure to conform could create
a hazardous situation and will void the Aqua-Hot ETL
Product Listing.
1.5 inch Exhaust Port
View from Underneath Aqua-Hot
Exhaust Elbow and
Nipples Assembly
2.0 inch ID Automotive Type Exhaust Pipe Figure 15
#8, ⅜”
Exhaust Tip
#8, ⅜”
Vehicle’s Exhaust
Pipe
Figure 16

Fluid Expansion Bottle
©Aqua-Hot® 400P Installation Manual p. 12
Exhaust System
Figure 18
Figure 19
3” Black Pipe
Nipple Installed
Black Pipe Elbow
4” Black Pipe
Nipple Installed
2” Automotive Type
Exhaust Pipe

Installing Heat Exchangers
©Aqua-Hot® 400P Installation Manual p. 13
Installation Requirements
Cozy heat exchangers can be mounted in one of two
confi gurations: either fl at on the ground, or vertically. Reference
Figure 20.
• Supply ventilation cross-sectional area of at least 29in2
(74cm2) must be supplied to each heat exchanger.
• Do not supply heat exchangers air which is drawn from the
bay areas; air supply should only be from the living areas.
• Return air should be drawn from the same room the heat
exchanger is heating.
• The antifreeze and water heating solution must fl ow in
through the bottom of the heat exchanger, and out the top
(reference Figure 23).
• In order to provide suffi cient ventilation, the return air
registers must be the same size, or larger, than the outlet
air registers.
Vertical Orientation
Horizontal Orientation
Figure 20
Figure 21
Heat Exchanger Locations and
Clearances
• Position the heat exchangers so that even heat is distributed
throughout the coach interior.
• The fi rst heat exchanger on the loop will output the most
interior heat.
• It is best practice to place the heat exchanger in an area
where it can be easily accessed for maintenance and
cleaning.
• Place the heat exchangers as close to the fl oor as possible
for best performance.
• If a heat exchanger is kept in the fresh water storage bay,
then the last heat exchanger in the coolant loop should be
used. See Figure 21.
• The heating air supply may be fresh or recirculated air that
is drawn from a clean area not likely to be contaminated.
Aqua-Hot advises against placing a heat exchanger on the
slide-out section of any vehicle due to the high probability
of damage occurring to the heating loop from moving parts.
NOTE: Do NOT install more than four heat exchangers per
heating loop. If additional heat exchangers are required,
use a booster pump (not included) to provide additional
antifreeze fl ow capability.
Figure 22

Locations and Clearances
©Aqua-Hot® 400P Installation Manual p. 14
Mounting
Tabs (both
sides)
Inlet
Outlet
Figure 23
Installing Heat Exchangers
13.69 in
10.50 in 6.50 in 2.81 in 0.38 in
3.50 in
5.50 in
1.06 in
14.44 in
13.06 in
6.44 in
Figure 24

Locations and Clearances
©Aqua-Hot® 400P Installation Manual p. 15
Mounting the Heat Exchangers
1. Cut out a 2.5” H x 10” W (7cm x 26cm) opening for each
heat exchanger outlet and cold-air return grate as shown
in Figure 25.
2. Mount each heat exchanger permanently into place. There
are 4 tabs on both sides - see Figure 23.
3. Install the hot-air outlet and cold-air return grate.
A minimum of supply ventilation cross-sectional area of at
least 29in2 (74cm2) must be supplied to each heat exchanger.
If the toe-kick area is inadequate to house a heat exchanger
for regular installation, a plenum assembly may be purchased
to redirect air via ducting. Refer to Figure 26.
1 2 3 4 5
1. Hot Air Outlet Vent
2. Air Ducting Hose
3. Plenum
4. Cozy Heat Exchanger
5. Toe Kick Board
Mounting the Heat Exchangers
Figure 25
Figure 27
Figure 26
NOTE: When wiring the heat exchangers in parallel, the
main 18-gauge wire is split to allow the heat exchanger
wires to combine with the main wire to be powered or
grounded, respectively.
Figure 28
- (Ground) Black Wires
+ (Positive) Red Wires

Wiring Heat Exchangers
©Aqua-Hot® 400P Installation Manual p. 16
Wiring the Heat Exchangers
This section will explain in detail how to wire the heat
exchangers for optimal functionality. Do not deviate from these
guidelines. If a deviation is required, contact Aqua-Hot Heating
Systems prior to installing these exchangers for express
permission to proceed with modifi cations.
1. Wire each heat exchanger (in a heating zone) in parallel to
one another as shown in Figure 31.
2. Wire each heat exchanger independently to the J7 plug of
the Reporter.
3. Pin-out information is shown below.
NOTE: Night-mode functionality of the new controller requires
that the heat exchangers be wired directly into the controller.
Zone Fan Number Supply (+) Pin
Number
Ground (-) Pin
Number
1 J7-12 J7-9
2 J7-2 J7-5
3 J7-11 J7-8
4 J7-1 J7-4
5 J7-10 J7-7
Connector Part Numbers
Part Number Manufacturer Description
1-480706-0 TE Connectivity J7 Plug Housing
350550-1 TE Connectivity J7 Socket Terminal
J7 Mating Plug
Figure 29
Figure 30
Figure 31
1211
987
654
J7 Wire insertion view shown
321
10
J7 Socket Terminal

Plumbing the Heating Loop
©Aqua-Hot® 400P Installation Manual p. 17
Plumbing the Heating Loop
Once all heat exchangers have been mounted, plan the
routing of the plumbing lines from each heating zone to the
Aqua-Hot. The following guidelines should be used when
planning the coolant loop(s) for the heating zone. The order
of the heat exchangers should consider priority on the loop(s).
Failure to adhere to these installation principles can hinder the
operation of the heat exchangers.
• All plumbing should be installed as fl atly as possible.
• Extreme rises in height should be avoided to avoid any
potential air traps.
• Use ⅝” ID (Inside Diameter) plumbing lines, ¾” SAE J20
type coolant hose, heater hose, or PEX tubing for the
heating loop(s).
• Use wide-sweeping elbows or “bend supports” whenever
the plumbing lines may be susceptible to kinking.
• Plumbing lines should be run in areas where there is no
reasonable possibility that they can be pinched off or
damaged under normal operating conditions.
• Secure all lines where necessary and apply
protective shielding in areas where chafi ng may
occur.
• Rubber coated/closed-type clamps are
recommended when securing the plumbing lines.
• Inlet and outlet plumbing lines can be installed with
a straight fi tting or an elbow.
• See Figure 33 for reference.
Instructions:
1. Layout the plumbing lines for all heat exchangers.
2. Label each line with the heating loop number and
designate as an outlet or an inlet line.
3. Connect and clamp the outlet line from the heater
to the lowest port (inlet port) with the longest run for
both heating loops.
4. Connect and clamp a line from the fi rst heat
exchanger’s highest port, and connect the other
end to the next heat exchanger’s lowest point.
5. Connect each additional heat exchanger in the
same arrangement.
6. Connect and clamp the inlet line from the heater
to the highest port on the last heat exchanger to
complete the heating loop.
Figure 33
Inlet
Outlet
PEX Insert Hose
Clamps ¾” Coupler
Figure 32
NOTE: Plumbing heat exchangers in this manner will allow
air to escape naturally. If air is trapped in any heat exchanger,
it will signifi cantly reduce the exchanger’s overall heating
performance.
Heating Loop #1
Heating Loop #2
Heating Zone #1
Heating Zone #3 Heating Zone #2 Heating Zone #4
Incoming Plumbing Lines
Outgoing Plumbing Lines
NOTE: The kitchen and living room heat exchangers
must be plumbed together in-series on “Heating Loop
1”. The fresh water tank, bedroom, and bathroom
heat exchangers must be plumbed together in-series
on “Heating Loop 2”. See the diagram in Figure 33.

Plumbing the Heating Loop
©Aqua-Hot® 400P Installation Manual p. 18
Figure 34
Figure 36
Figure 35
Figure 37
Barbed Fittings Components Compression Fittings Components
Barbed Fittings Components Installed Compression Fittings Components Installed

Plumbing the Heating Loop
©Aqua-Hot® 400P Installation Manual p. 19
NOTE: For the best performance, the fi rst heat
exchanger should be placed where heat loss is the
greatest. The fi rst heat exchanger will always output
the largest volume of heat as compared to subsequent
exchangers.
NOTE: This is just a sample for mounting locations of the
Cozy heat exchangers. Actual placement and quantity may
vary on the individual design of the RV. For questions or
assistance, contact Aqua-Hot at 574-AIR-XCEL (574-247-
9235).
Figure 38
Heat Exchangers Layout
Figure 39