Raypak 408 Owner's manual

Gas-Fired Pool
and Spa Heater
Catalog No. 6000.64B Eective: 07-15-18 Replaces: 11-15-17 P/N 241452 Rev. 3
TM
INSTALLATION AND
OPERATION MANUAL
Atmospheric Models 268 and 408
This manual should be maintained in legible condition and kept adjacent to the heater or in a safe place for future
reference.
AAWARNING: If these instructions are not followed exactly, a re or explosion may result causing property
damage, personal injury or death.
FOR YOUR SAFETY: Do not store or use gasoline or other flammable vapors and liquids or other com-
bustible materials in the vicinity of this or any other appliance. To do so may result in an explosion or
fire.
WHAT TO DO IF YOU SMELL GAS:
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone in your building.
• Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire department.
Installation and service must be performed by a qualified installer, service agency or the gas supplier.

2
Revision 3 reects the following changes:
Manual updated to the new format style. Removed California Proposition 65 warning.

3
CONTENTS
1. WARNINGS ................................................................... 4
1.1. Pay Attention to These Terms..............................4
2. WATER CHEMISTRY ................................................... 5
2.1. Automatic Chlorinators and Chemical
Feeders .......................................................................5
3. OPERATING INSTRUCTIONS .................................... 6
3.1. Start-Up Procedures...............................................6
3.2. Before Start-Up.........................................................6
3.3. Visual inspection......................................................6
3.4. Caution........................................................................6
3.5. Maintenance .............................................................8
3.6. Cold Weather Operation........................................8
4. BEFORE INSTALLATION ............................................ 9
4.1. Receiving equipment..............................................9
4.2. Rating and certications .......................................9
4.3. Ambient Temperature Rating of Heater
Components..............................................................9
4.4. Atmospheric heaters ..............................................9
5. INSTALLATION ............................................................. 9
5.1. Installation Codes....................................................9
5.2. Clearances.............................................................. 10
5.3. Outdoor Heater Installation............................... 11
5.4. Combustion and Ventilation Air ....................... 12
5.5. Vent Piping.............................................................. 15
5.6. Gas Supply Connections.................................... 16
5.7. Water Connection Installation.......................... 18
5.8. Unitherm Governor Operation.......................... 18
5.9. Internal Automatic Bypass Valve ..................... 18
5.10. External Auxiliary Bypass Valve........................ 19
5.11. Auxiliary Bypass Valve Adjustment................. 19
5.12. Pressure Relief Valve Installation .................... 19
5.13. Plumbing.................................................................. 19
6. ELECTRICAL WIRING ...............................................20
6.1. Electrical Power Draw......................................... 20
6.2. Transformer Wiring .............................................. 21
7. WIRING DIAGRAM ....................................................23
8. CONTROLS..................................................................24
8.1. Control Panel Removal........................................ 24
8.2. Control Adjustments............................................ 24
8.3. Operation................................................................. 24
8.4. Status and Diagnostics....................................... 26
8.5. Remote Control Wiring........................................ 28
9. REPLACEMENT PARTS ............................................32
10. TROUBLESHOOTING ...............................................33
10.1. Mechanical ............................................................. 33
10.2. Control Logic - Flow Chart................................. 34
11. ILLUSTRATED PARTS LIST......................................35

4
AADANGER: Failure to install the drafthood on indoor
installation and properly vent the heater to the outdoors
as outlined in the venting section of this manual can
result in unsafe operation of the heater. To avoid the risk
of re, explosion, or asphyxiation from carbon monoxide,
never operate this heater unless it is properly vented
and has an adequate air supply for proper operation. Be
sure to inspect the vent system for proper installation at
initial start-up, and at least annually thereafter. Refer to
the venting section of this manual for more information
regarding vent system inspections.
AAWARNING: Gasoline, as well as other ammable
materials and liquids (adhesives, solvents, etc.), and
the vapors they produce, are extremely dangerous. Do
not handle, use, or store gasoline or other ammable or
combustible materials in the vicinity of a heater.
AAWARNING: Improper installation, adjustment,
alteration, service, or maintenance can cause property
damage, personal injury or loss of life. Installation and
service must be performed by a qualied installer, service
agency, or the gas supplier.
AAWARNING: Do not install within 3 feet (0.9 m) of a heat
pump or an outdoor condensing unit. Strong air intake
from this type of equipment can disturb the combustion
process and cause damage or personal injury.
AAWARNING: UL-recognized fuel gas detectors are
recommended in all enclosed propane and natural gas
applications wherein there is a potential for an explosive
mixture of fuel gas to accumulate and their installation
should be in accordance with the detector manufacturer’s
recommendations and/or local laws, rules, regulations,
or customs.
AAWARNING: The heater shall not be located in an area
where water sprinklers, or other devices, may cause water
to spray through the cabinet louvers and into the heater.
This could cause internal rusting or damage electrical
components, and void the warranty.
1. WARNINGS
1.1. Pay Attention to These Terms
AADANGER Indicates the presence of immediate hazards which will cause severe personal injury, death or
substantial property damage if ignored.
AAWARNING Indicates the presence of hazards or unsafe practices which could cause severe personal injury,
death or substantial property damage if ignored.
AACAUTION Indicates the presence of hazards or unsafe practices which could cause minor personal injury
or product or property damage if ignored.
CAUTION CAUTION used without the warning alert symbol indicates a potentially hazardous condition
which could cause minor personal injury or product or property damage if ignored.
NOTE Indicates special instructions on installation, operation, or maintenance which are important but
not related to personal injury hazards.
AAWARNING: Both natural gas and propane have an
odorant added to aid in detecting a gas leak. Some people
may not physically be able to smell or recognize this
odorant. If you are unsure or unfamiliar with the smell
of natural gas or propane, ask your local gas supplier.
Other conditions, such as “odorant fade,” which causes
the odorant to diminish in intensity, can also hide,
camouage, or otherwise make detecting a gas leak by
smell more dicult.
AAWARNING: To minimize the possibility of improper
operation, serious personal injury, re, or damage to the
heater:
• Always keep the area around the heater free of
combustible materials, gasoline, and other ammable
liquids and vapors.
• Heater should never be covered or have any blockage
to the ow of fresh air to the heater.
AAWARNING: This unit contains refractory ceramic
ber (RCF) insulation in the combustion chamber. RCF,
as manufactured, does not contain respirable crystalline
silica. However, following sustained exposure to very
high temperatures [>2192°F (1200°C)], the RCF can
transform into crystalline silica (cristabolite). The
International Agency for Research on Cancer (IARC) has
classied the inhalation of crystalline silica (cristabolite)
as carcinogenic to humans.
When removing the burners or heat exchangers, take
precautions to avoid creating airborne dust and avoid
inhaling airborne bers. When cleaning spills, use wet
sweeping or High Eciency Particulate Air (HEPA)
ltered vacuum to minimize airborne dust. Use feasible
engineering controls such as local exhaust ventilation or
dust collecting systems to minimize airborne dust. Wear
appropriate personal protective equipment including
gloves, safety glasses with side shields, and appropriate
NIOSH certied respiratory protection, to avoid inhalation
of airborne dust and airborne ber particles.

5
2. WATER CHEMISTRY
NOTE: Corrosive water voids all warranties.
Chemical imbalance can cause severe damage to your
heater and associated equipment. Maintain your water
chemistry according to Table A. If the mineral content
and dissolved solids in the water become too high, scale
forms inside the heat exchanger tubes, reducing heater
eciency and damaging the heater. If the pH drops below
7.2, this will cause corrosion of the heat exchanger and
severely damage the heater. Heat exchanger damage
resulting from chemical imbalance is not covered by
the warranty.
For your health and the protection of your pool equipment,
it is essential that your water be chemically balanced. The
following levels must be used as a guide for balanced
water.
AACAUTION: Free chlorine must not exceed 5 ppm which
can damage the heater and is not covered under warranty.
• Occasional chemical shock dosing of the pool or
spa water should not damage the heater providing
the water is balanced.
• Automatic chemical dosing devices and salt
chlorinators are usually more efficient in heated
water, unless controlled, they can lead to excessive
chlorine level which can damage your heater.
• Further advice should be obtained from your pool
or spa builder, accredited pool shop, or chemical
supplier for the correct levels for your water.
2.1. Automatic Chlorinators
and Chemical Feeders
All chemicals must be introduced and completely diluted
into the pool or spa water before being circulated through
the heater. Do not place sanitizing chemicals in the
skimmer. High chemical concentrations will result when
the pump is not running (e.g. overnight).
Chlorinators must feed downstream of the heater and
have an anti-siphoning device to prevent chemical backup
into the heater when the pump is shut o.
See plumbing diagrams on Figure 29 and Figure 30.
NOTE: High chemical concentrates from feeders and
chlorinators that are out of adjustment will cause rapid
corrosion to the heat exchanger. Such damage is not
covered under the warranty.
Table A. Pool Water Chemistry
Recommended Level(s) Fiberglass Pools Fiberglass Spas Other Pool and Spa Types
Water Temperature 68-88°F (20-31°C) 89-104°F (31-40°C) 68-104°F (20-40°C)
pH 7.3-7.4 7.3-7.4 7.6-7.8
Total Alkalinity (ppm) 120-150 120-150 80-120
Calcium Hardness (ppm) 200-300 150-200 200-400
Salt (ppm) 4500 Maximum 4500 Maximum 4500 Maximum
Free Chlorine (ppm)* 2-3 2-3 2-3
Total Dissolved Solids (ppm) 3000 Maximum** 3000 Maximum** 3000 Maximum**
*Free Chlorine MUST NOT EXCEED 5 ppm!
**In saltwater chlorinated pools, the total TDS can be as high as 6000 ppm.

6
3. OPERATING INSTRUCTIONS
3.1. Start-Up Procedures
Your pool/spa heater has been designed for years of safe
and reliable pool/spa water heating. It is available with
electronic ignition. This manual provides installation,
operation, maintenance, and service information for these
heaters.
TEMP
MODE
ON OFF
LCD Display
Temp Adjust Buttons
Mode Button
Figure 1. Heater Control Toggle Switch
If your heater has been installed correctly, operating the
heater is an easy task. The upper front panel of the heater
contains the control center that allows you to turn the
heater On or O and adjust the temperature settings for
the pool or spa. The temperature range is factory set from
65°F (18°C) to 104°F (40°C). See Figure 1 for location of
toggle switch to turn the heater On and O.
See Section 8 for additional details about the use of the
controls in the Control Adjustments subsection.
3.2. Before Start-Up
3.2.1. Burners
Clean main burners and air louvers of dust, lint and debris.
Keep heater area clear and free from combustibles,
ammable liquids and chemicals. Do not obstruct the
ow of combustion and ventilation air.
3.2.2. Water
Water must be owing through the heater during
operation. Ensure that the system is lled with water and
that the pump is operating.
3.2.3. After Start-Up
Feel the inlet and outlet pipes. Outlet pipe should be only
slightly warmer than the inlet. It should not be hot.
AAWARNING: Should overheating occur or the gas
supply fail to shut o, turn o the manual gas control to
the appliance.
3.3. Visual inspection
3.3.1. Atmospheric Heaters
With the heater on, remove the door and make a visual
check of the pilot and burner. The ame should be blue
with a well-dened pattern.
A yellow or “oating” ame indicates restricted air
openings or incorrect orice size. Should this occur, shut
the heater o and contact your installer or gas supplier.
AAWARNING: Operation of the heater without water
circulation will cause rapid and severe damage to the
heater, and will void the warranty.
3.4. Caution
Elevated water temperature can be hazardous. The
U.S. Consumer Product Safety Commission has these
guidelines:
1. Spa water temperatures should never exceed 104°F
(40°C). A temperature of 100°F (38°C) is considered
safe for a healthy adult. Special caution is suggested
for young children.
2. Drinking of alcoholic beverages before or during spa
or hot tub use can cause drowsiness which could
lead to unconsciousness and subsequently result in
drowning.
3. Pregnant Women Beware! Soaking in water over
102°F (39°C) can cause fetal damage during the first
three months of pregnancy resulting in the birth of a
brain-damaged or deformed child. Pregnant women
should stick to the 100°F (38°C) maximum rule.
4. Before entering the spa or hot tub, users should
check the water temperature with an accurate
thermometer; spa or hot tub thermostats may err
in regulating water temperatures by as much as 4°F
(2.2°C).
5. Persons with a medical history of heart disease,
circulatory problems, diabetes, or blood pressure
problems should obtain a physician’s advice before
using pools or hot tubs.
6. Persons taking medications which induce
drowsiness, such as tranquilizers, antihistamines, or
anticoagulants, should not use spas or hot tubs.

7
AACAUTION: Propane gas is heavier than air and will settle on the ground. Since propane can accumulate in conned
areas, extra care should be exercised when lighting propane heaters.
OPERATING INSTRUCTIONS AND SHUT-OFF PROCEDURES
ELECTRONIC IGNITION SYSTEM
(AUTOMATICALLY LIGHTED PILOT)
A. This appliance is equipped with an ignition
device which automatically lights the pilot. Do
not try to light the pilot by hand.
B. BEFORE OPERATING, smell all around the
appliance area for gas. Be sure to smell near
the oor because some gas is heavier than
air and will settle on the oor.
WHAT TO DO IF YOU SMELL GAS:
*Do not try to light any appliance.
*Do not touch any electric switch; do not use
any phone in your building.
*Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.
*If you cannot reach your gas supplier, call the
re department.
C. Use only your hand to push in or turn the gas
control knob. Never use tools. If the knob
will not push in or turn by hand, do not try to
repair it. Call a qualied service technician.
Force or attempted repair may result in a re
or explosion.
D. Do not use this appliance if any part has been
under water. Immediately call a qualied
service technician to inspect the appliance
and to replace any part of the control system
and any gas control which has been under
water.
1. STOP! Read the safety information above.
2. Set the thermostat to the lowest setting.
3. Turn off all electrical power to the appliance.
4. This appliance is equipped with an ignition
device which automatically lights the pilot. Do
not try to light the pilot by hand.
5. Remove heater door panel.
6. Turn gas control knob clockwise to
“Off”. (Honeywell VR 8300 and Robertshaw
7000)
7. Wait 5 minutes to clear out any gas. If you
then smell gas, STOP! Follow “B in the safety
information above. If you don’t smell gas, go
to the next step.
8. Turn gas control knob counter-clockwise
to “On”. (Honeywell VR 8300 and Robertshaw
7000)
9. Replace heater door panel.
10. Turn on all electrical power to the appliance.
11. Set thermostat to desired setting.
12. If the appliance will not operate, follow the
instructions “To Turn Off Gas To Appliance”
and call your service technician or gas
supplier.
OPERATING INSTRUCTIONS
1. Set the thermostat at the lowest setting.
2. Turn off all the electrical power to the appli-
ance if service is to be performed.
3. Remove heater door panel.
4. For Honeywell VR 8300 and Robertshaw
7000 gas valve.
Turn gas control knob clockwise
to “Off”. Make sure knob rest against stop.
5. Replace heater door panel.
SHUT-OFF PROCEDURES
ROBERTSHAW 7000
GAS VALVE IID
HONEYWELL
VR 8300 GAS
VALVE IID
GAS
INLET

8
3.5. Maintenance
AAWARNING: Check the heater for possible rodent nests
after long periods of non-use.
To be followed one month after start-up and then semi-
annually.
1. Inspect top of heater and drafthood for soot, a
sticky black substance around finned tubes and “V”
baffles, and open flue gas passageways. Any visible
soot should be cleaned for proper operation.
AACAUTION: Soot may be combustible. Wet sooted
surfaces completely prior to cleaning. Do not use steel
wire brush.
2. Clean main burners and pilot burner of dust and lint.
3. Inspect and operate all controls, gas valve and
pressure relief valve (if equipped).
4. Make visual check of the burner and pilot flames.
Yellow flame means restriction of the air openings.
Lifting or blowing flame indicates high gas pressure.
Low flame means low gas pressure. Should the
latter occur, shut the heater off and contact your gas
supplier or qualified service agency.
5. On indoor heaters, clean room intake openings to
ensure adequate flow of combustion and ventilation
air.
AACAUTION: Combustion air must not be contaminated
by corrosive chemical fumes which can damage the
heater and void the warranty.
6. Keep area around heater clear and free from
combustible materials, gasoline and other flammable
and corrosive vapors and liquids.
If Heater Will Not Fire:
If you have no electrical power, it may be that your “circuit
breaker” has tripped. Try re-setting it.
If you have electrical power but the heater will not re
check the following or see Troubleshooting section:
1. The time clock must be in the “ON” position.
2. Your pump strainer basket may be full. If so remove
debris.
3. Your filter may be dirty. If so, backwash or clean
filter. (To tell if your filter is dirty, look to see if the
filter pressure will be higher than usual).
4. The pump may have lost its prime and be running
dry. Check the pressure on the filter. If there is no
pressure; then you are not moving water (or your
gauge is broken). Try to get the pump to run at its
normal flow rate.
5. Check flow switch operation and paddles (“F” paddle
on 268 or “A” paddle on 408).
3.6. Cold Weather Operation
3.6.1. Important Freeze Information
MODERATE CLIMATE: Heater operation can continue
during short-term cold spells. When temperatures are
between 0° (-17°C) and 32°F (0°C), ow (continuous pump
operation) must be maintained.
AACAUTION: Do not use the heater to maintain water
temperatures just above freezing or for freeze protection.
When heater is used during freezing weather, care must
be taken to avoid freeze-ups. Continuous pump operation
is a must. Additional protection may be required. The
heater is not warranted against freeze-ups.
COLD CLIMATE: Prolonged operation with water
temperatures below 50°F (10°C) is not recommended.
When starting the heater with water temperatures below
50°F (10°C), operate the heater continuously until higher
temperatures are reached. Operating the heater for
prolonged periods with pool water below 50°F (10°C)
can seriously damage the heater, and is not covered by
the warranty. For cold climate areas, please follow the
winterizing procedures listed.
3.6.2. Winterizing the Pool and Spa
Heater
Heaters installed outdoors in freezing climate areas
may be shut down for the winter. Observe the following
procedure for winterizing the heater:
1. Turn off gas valve, manual gas valve, and electrical
supply to the heater.
2. Open drain valve located on the inlet/outlet header,
(under water pipes). Remove the heat exchanger
inspection panel on the side opposite water piping
to gain access to the drain plug on the return header.
Open drain plug on return header.
DRAIN
Figure 2. Return Header Drain Valve

9
4. BEFORE INSTALLATION
4.1. Receiving equipment
The manufacturer recommends that this manual be
reviewed thoroughly before installing the pool/spa heater.
If there are any questions that this manual does not answer,
please contact the factory or your local representative.
On receipt of your equipment it is suggested that you
visually check for external damage to the carton. If the
carton is damaged, a note should be made on the Bill
of Lading when signing for the equipment. Remove the
heater from the carton. If it is damaged, report the damage
to the carrier immediately. Save the carton.
These items are shipped inside a box in the carton with
the heater:
1. “Pagoda” top
2. In/Out flanges (2)
3. 2" CPVC female tailpiece, ring nut and O-ring
4. 2" flange gaskets (2)
5. Flange bolts (4)
6. Pressure relief valve
7. 2" CPVC adapter
8. Plastic pipe finish flange for gas line
9. Bonding lug with mounting screw
10. 2" CPVC manifold adapter
11. Prewired 1" flow switch with outdoor cover
12. Temperature and pressure gauge
The Model and Serial No.
can also be found inside
the bezel above the display
Model and Serial No.
located on Rating Plate
Alternate
Rating Plate
location
Figure 3. Rating Plate Location
Be sure that you receive the number of packages indicated
on the Bill of Lading.
When ordering parts, you must specify the model and
serial numbers of the heater. See below for location of
serial number. When ordering under warranty conditions,
you must also specify date of installation.
4.2. Rating and certications
These heaters are design-certied and tested under the
latest requirements of the ANSI Z21.56 / CSA 4.7 Standard
for Gas-Fired Pool Heaters. All heaters can be used either
indoor or outdoors. The appropriate top designated for
each type of use is required. If necessary, the top can be
changed at a later date to change from outdoor to indoor
or vice versa.
All units have heat exchangers which are ASME-certied
(BPV Section IV part HLW) and are registered with
National Board.
4.3. Ambient Temperature Rating
of Heater Components
Electronic Ignition Heater* -32°F to + 175°F (-36°C to 79°C)
*Requires 120 or 240VAC Power Supply
4.4. Atmospheric heaters
Rated inputs are suitable for up to 2,000 ft (610 m)
elevation. For elevations above 2,000 ft (610 m), reduce
input 4% for each 1,000 ft (305 m) above sea level, as high
elevation reduces combustion performance.
5. INSTALLATION
5.1. Installation Codes
Installation must be in accordance with local codes, or,
in the absence of local codes, with the latest edition of
the National Fuel Gas Code, ANSI Z223.1/NFPA54 and
National Electrical Code, ANSI/NFPA 70, and for Canada,
the latest edition of CAN/CSA-B149 Installation Codes,
and Canadian Electrical Code, CSA C22.1 Part 1 and
Part2.

10
5.2. Clearances
5.2.1. All Heaters
For indoor and outdoors clearances from combustible
surfaces, see the chart below.
Location Indoor Installation
Top * 30" (762 mm) Drafthood
Front Alcove (Open)
Vent 6" (152 mm)
Floor ** 0"
Back 6" (152 mm)
Right Side 12" (305 mm) Water Side
Left Side 6" (152 mm) Opposite Water Side
Location Outdoor Installation
Top * Unobstructed (Outdoor Stack)
Top *** 36" (76 mm) (Stackless Top)
Right Side 12" (305 mm) Water Side
Left Side 6" (152 mm)
Floor 0"
Back 6" (152 mm)
* Clearance from top of vent terminal
** Do not install on carpeting
*** Clearance from top of heater
Table B. Minimum Clearances from Combustible Installations
Forced Air Inlet
4' (1.2 m)
Minimum
3' (0.9 m)
Minimum
10' (3 m)
Minimum
1' (0.3 m)
Minimum
4' (1.2 m)
Minimum
4' (1.2 m)
Minimum
Figure 4. Minimum Distances to Building Openings from
Where Flue Products Exit the Boiler
Description Location Distance
in. (mm)
a. 3-1/2" (89 mm) thick
masonry walls without
ventilated air space
Back 9 (229)
Right 9 (229)
Left 9 (229)
Vent 5 (127)
Indoor Top 39 (991)
Outdoor Top Unobstructed
b. 1/2" (13 mm)insulation
board over 1" (25 mm)
glass ber or mineral
wool batts
Back 6 (152)
Right 6 (152)
Left 6 (152)
Vent 3 (76)
Indoor Top 30 (762)
Outdoor Top Unobstructed
c. 0.024 sheet metal over
1" (25 mm) glass ber
or mineral wool batts
reinforced with wire on
rear face with ventilated
air space
Back 4 (102)
Right 4 (102)
Left 4 (102)
Vent 3 (76)
Indoor Top 24 (610)
Outdoor Top Unobstructed
d. 3-1/2" (89 mm) thick
masonry wall with
ventilated air space
Back 6 (152)
Right 6 (152)
Left 6 (152)
Vent 6 (152)
Indoor Top 39 (991)
Outdoor Top Unobstructed
e. 0.024 sheet metal with
ventilated air space
Back 4 (102)
Right 4 (102)
Left 4 (102)
Vent 2 (51)
Indoor Top 24 (610)
Outdoor Top Unobstructed
f. 1/2" (13 mm) thick
insulation board with
ventilated air space
Back 4 (102)
Right 4 (102)
Left 4 (102)
Vent 3 (76)
Indoor Top 24 (610)
Outdoor Top Unobstructed
g. 0.024 sheet metal with
ventilated air space over
0.024 sheet metal with
ventilated air space.
Back 4 (102)
Right 4 (102)
Left 4 (102)
Vent 3 (76)
Indoor Top 24 (610)
Outdoor Top Unobstructed
h. 1" (25 mm) glass ber
or mineral wool batts
sandwiched between
two sheets 0.024 sheet
metal with ventilated air
space
Back 4 (102)
Right 4 (102)
Left 4 (102)
Vent 3 (76)
Indoor Top 24 (610)
Outdoor Top Unobstructed
Derived from National Fuel Gas Code, Table 10.2.3
Table C. Reduction of Clearances to Protected Surfaces
When installed according to the listed minimum clearances
from combustible construction, the pool heater can still
be serviced without removing permanent construction
around the heater.
However for ease of servicing, we recommend a clearance
of at least 24" (610 mm) in the front, and at least 18" (457
mm) on the water connection side.

11
This will enable the heater to be serviced in its installed
location, that is, without movement or removal of the heater.
Clearances less than these (6" [152 mm] minimum), may
require removal of the heater to service either the heat
exchanger or the burner tray. In either case, the heater
must be installed in a manner that will enable the heater
to be serviced without removing any structure around the
heater.
5.2.2. Flooring
This heater can be installed on combustible ooring.
The combustible clearances listed can be reduced by
protecting the exposed combustible surfaces as shown in
Table C.
5.3. Outdoor Heater Installation
These heaters are design-certied for outdoor installation,
when equipped with the approved tops designated for
outdoor use.
AAWARNING: The heater shall not be located in an area
where water sprinklers, or other devices, may cause water
to spray through the cabinet louvers and into the heater.
This could cause internal rusting or damage electrical
components, and void the warranty.
AAWARNING: Do not install within 3' (914 mm) of a heat
pump or an outdoor condensing unit. Strong air intake
from this type of equipment can disturb the combustion
process and cause damage or personal injury.
PAGODA TOP
Figure 5. Heater with Outdoor Stackless Top
Heaters must not be installed under an overhang of less
than three 3' (0.9 m) from the top of the heater. Three sides
must be open in the area under the overhang. Roof water
drainage must be diverted away from the heaters installed
under overhangs with the use of gutters.
For U.S. installations, the point from where the ue
products exit the heater must be a minimum of 4' (1.2m)
below, 4' (1.2 m) horizontally from, or 1' (0.3 m) above any
door, window or gravity inlet into any building. The top
surface of the heater shall be at least 3' (0.9 m) above any
forced air inlet, or intake ducts located within 10' (3 m)
horizontally.
For installations in Canada, pool heaters shall not be
installed with the top of the vent assembly within 10' (3 m)
below, or to either side, of any opening into the building.
Refer to the latest revisions of CAN/CSA-B149.
5.3.1. Pagoda Top Installation
1. Insert tabs into keyhole (4 places). See Figure 6,
detail A.
2. Snap tabs into keyholes so as not to pull out. See
Figure 6, detail B.
OUTDOOR TOP
(SHIPPED LOOSE WITH HEATER)
DETAIL A DETAIL B
Figure 6. Outdoor Top Installation
For installations in Florida and Texas, that must
comply with the Florida or Texas Building Code, follow
the directions shown in Figure 9 for the installation of
hurricane tie-down brackets for all models.
5.3.2. Indoor Heater Installation
The heater is also design-certied for indoor installation
when equipped with the approved drafthood.
For Canada, indoor installation is restricted to an enclosure
that is not occupied and does not directly communicate
with an occupied area. Refer to the latest edition of CAN/
CSA-B149 for specic requirements. Locate heater as
close as is practical to a chimney or gas vent. Heater must
always be vented to the outside. See section "Vent Piping"
on page 15 for details. Minimum allowable space is
shown on the nameplate.
AAWARNING: Indoor heaters require a drafthood that
must be connected to a vent pipe and properly vented to
the outside. Failure to follow this procedure can cause
re or fatal carbon monoxide poisoning.

12
5.3.3. Outdoor and Indoor Stack
The outdoor and indoor stacks are optional equipment
and do not come standard with the heater. Refer to
installation instructions inside box for instructions on how
to install outdoor/indoor stack.
Model Outdoor Stack Indoor Stack
268 009835 009839
408 009837 009841
Table D. Outdoor and Indoor Stack Kit Number
OUTDOOR STACK KIT
(1) Drafthood, painted
(1) Adapter plate
(3) Mounting brackets (clips)
(1) Top panel cover
(2) 1-foot sections of metal tape
(3) Screws
(1) Instructions Clips
Figure 7. Outdoor Stack Kit Components
NOTE: The outdoor drafthood kit does not require any
additional vent pipe for proper operation. This drafthood
functions as the vent termination.
INDOOR STACK KIT
(1) Drafthood, unpainted
(1) Adapter plate
(3) Mounting brackets (clips)
(3) Screws
(1) Instructions
Clips
Figure 8. Indoor Stack Kit Components
5.4. Combustion and Ventilation Air
5.4.1. Indoor Units Only
The heater must have both combustion and ventilation air.
Minimum requirements for net free air supply openings
are one opening that is 12" (305 mm) from the ceiling for
ventilation, and one opening that is 12" (305 mm) from the
oor for combustion air as outlined in the latest edition of
the National Fuel Gas Code, ANSI Z223.1(Canada-CAN/
CSA-B149) and any local codes that may have jurisdiction.
All Air from Inside the Building:
Each opening shall have a minimum net free area as noted:
Model Square Inches Model Square Inches
268 266 408 399
Table E. Opening Minimum Net Free Requirements
All Air from Outdoors:
When air is supplied directly from outside the building,
each opening shall have a minimum net free area as noted:
Model
Unrestricted
Opening
(sq. in.)
Typical Screened
or Louvered
Opening (sq. in.)
Typical Screened
and Louvered
Opening (sq. in.)
268 67 101 134
408 100 150 200
Table F. Opening Minimum Net Free Requirements
AACAUTION: Combustion air must not be contaminated
by corrosive chemical fumes which can damage the
heater and void the warranty.

13
TOH
Model B
268 23" (583 mm)
408 29" (735 mm)
FLORIDA AND TEXAS BUILDING CODES
WIND SPEED = 150 MPH, 3 SECOND GUST
EXPOSURE = C
268/408 ATMOSPHERIC
B
28"
(709 mm)
40"
(1 m)
3" (76 mm)
Min. Conc.
Pad by others
3" (76 mm)
Min. Conc.
Pad by others
(1)–1/4" x 1-3/4" S.S. T
apcon Bolt & Washer (Field Supplied)
Ea. Pallet Anchor Bracket
Use hole closest to unit (4 total)
(1)–1/4" x 1-3/4" S.S.
Tapcon Bolt & Washer (Field Supplied)
Ea. Pallet Anchor Bracket
Use hole closest to unit (4 total)
2" x 6" x 1/8" Pallet
Anchor Bracket (4 Total) (Kit# 011636)
1/4" x 1-3/4" S.S.
Tapcon Bolt and Washer (Field Supplied)
NOTE: Use hole closest to unit with
washer overlapping edge of unit. Min. Edge
Distance
6"
(152 mm)
Min. Edge
Distance
6"
(152 mm)
Figure 9. Florida And Texas Building Codes

14
Heater
Model
BTUH
Input
(000)
(A)
Cabinet
Width
in. (mm)
(B)
Flue
Dia.
in.
(mm)
(C)
Indoor
Drafthood
in. (mm)
(D)
in. (mm)
(J)
Min.
in. (mm)
Gas
Conn.
Water
Conn.
Shipping Weights - lbs (kg)
Standard
Heater
w/Stackless
Top
ASME
Heater
w/Stackless
Top
Indoor
Draft-
hood
R268 266.0 23
(584)
7
(178) 62 (1574) 11.5 (292)
11
(279) 3/4" 2" 210 (95)
229
(104)
16
(7)
R408 399.0 29
(737)
9
(229)
64-9/16
(1640)
14.5
(368)
12-1/8
(307) 3/4" 2" 249 (113)
268
(121)
21
(9)
Designation for a heater using propane gas is “EP”; a heater using natural gas is “EN”.
Prex “B” is for brass (ASME) headers.
Sux “X” is for cupro-nickel tubing.
EXAMPLE: B-R408-EN-X = Brass headers, 408 model size, AFT, natural gas, cupro-nickel.
Reduce input 4% for each 1000 ft (305 m) above sea level when installed above 2000 ft (610 m) elevation.
For Canada, no de-rating is required for elevations up to 4500 ft (1,372 m)
*Note: For outdoor stack, use J dimension in the table above for appropriate size plus 6" (152 mm).
B
C
INDOOR
DRAFTHOOD
38"
(963 mm)
13-1/4"
(336 mm)
GAS
CONNECTION
J*
A
28-5/8"
(725 mm)
28"
(709 mm)
3-3/8"
(85 mm)
D
FLUE


Amp Draw
120 Volt 240 Volt
4 2
32-11/16"
(830 mm)
ELECTRICAL
CONNECTION
40"
(1,016 mm)
ELECTRICAL
CONNECTION
6-5/8"
(167 mm)
10"
(253 mm)
Figure 10. Heater Specication and Dimensions

15
5.5. Vent Piping
AAWARNING: Indoor heaters require a drafthood that
must be connected to a vent pipe and properly vented to
the outside. Failure to follow this procedure can cause
re or fatal carbon monoxide poisoning.
Vent piping the same size as the drafthood outlet is
recommended, however, when the total vent height is at
least 10 ft (drafthood relief opening to vent terminal), the
vent pipe size may be reduced by no more than one (1)
size as specied in Chapter 13 of the National Fuel Gas
Code, ANSI Z223.1 (Canada - CAN/CSA-B149). As much
as possible, avoid long horizontal runs of vent pipe and too
many elbows. If installation requires horizontal runs, the
vent pipe must have a minimum of 1/4 in. per ft rise and
should be supported at not more than ve foot intervals.
Plumbers tape, criss-crossed, will serve to space both
horizontal and vertical piping. Gas vents supported only
by the ashing and extending above the roof more than
ve feet should be securely guyed or braced to withstand
snow and wind loads. We recommend use of insulated
vent pipe spacers through the roofs and walls. Another
option for installation that requires horizontal runs is
using the D-2 power vent kit option.
Model 120 VAC P/N 240 VAC P/N
268 010744 009832
408 010745 009833
Table G. Power Vent Kit Part Number
NOTE: The D-2 Power Vent operates with a positve
vent static pressure and with a vent gas temperature
that prevents excessive condensate production in the
vent, and as such, is a CATEGORY III appliance. For
more information consult the D-2 Power Vent manual
6000.57.1.
Figure 11. Optional Raypak D-2 Power Vent
The unit, when installed as directed, is capable of
operating in applications such as through-the-wall venting
and reduced horizontal and vertical vent pipe sizes in new
and current installations. The unit is factory-wired for 240
VAC, with capability of rewiring for 120 VAC.
For protection against rain or blockage by snow, the vent
pipe must terminate with a vent cap which complies with
the local codes or, in the absence of such codes, to the
latest edition of the National Fuel Gas Code, ANSI Z223.1
(Canada - CAN/CSA-B149).
The discharge opening must be a minimum of 2' (0.6
M) vertically from the roof surface and at least 2' (0.6 m)
higher than any part of the building within 8' (2.4 m). Vent
stack shall be at least 5' (1.5 m) in vertical height above
the drafthood outlet. The vent cap location shall have a
minimum clearance of 4' (1.2 m) horizontally from, and in
no case below, unless a 4' (1.2 m) horizontal distance is
maintained, from electric meters, gas meters, regulators
and relief equipment.
The weight of the vent stack or chimney must not rest on
heater drafthood. Support must be provided in compliance
with applicable codes. The heater top and drafthood must
be readily removable for maintenance and inspection.
Vent pipe should be adequately supported to maintain
proper clearances from combustible construction. This
unit operates under venting Category I conditions, with
natural draft.
Type “B” double-wall or equivalent vent pipe is
recommended. However single-wall metal vent pipe may
be used as specied in the latest edition of the National
Flue Gas Code ANSI Z223.1 (Canada - CAN/CSA-B149).
VENT CAP
2' MIN
(610 mm)
VENT PIPE
DRAFT HOOD
5' MIN
(1.5 m)
HEATER
2' MIN
(610 mm)
8' (2.4 m)
OR LESS
Figure 12. Venting Clearances
NOTE: With venting application of two or more heaters,
contact the factory.

16
5.5.1. Appliance Categories
Heaters are divided into four categories based on the
pressure produced in the exhaust and the likelihood of
condensate production in the vent.
Category I – A heater which operates with a non-positive
vent static pressure and with a vent gas temperature that
avoids excessive condensate production in the vent.
Category II – A heater which operates with a non-positive
vent static pressure and with a vent gas temperature that
may cause excessive condensate production in the vent.
Category III – A heater which operates with a positive
vent pressure and with a vent gas temperature that avoids
excessive condensate production in the vent.
Category IV – A heater which operates with a positive
vent pressure and with a vent gas temperature that may
cause excessive condensate production in the vent.
5.6. Gas Supply Connections
GAS INLET
HEATER JACKET
MANUAL SHUT-OFF VALVE
(Field supplied)
GAS VALVE
FINISH FLANGE
UNION
(Field supplied)
SEDIMENT TRAP
(Field supplied)
Figure 13. Gas Supply Plumbing
Gas piping must have a sediment trap ahead of the heater
gas controls, and a manual shut-o valve located outside
the heater jacket. All gas piping should be tested after
installation in accordance with local codes.
AACAUTION: The heater and its manual shut-o valve
must be disconnected from the gas supply during any
pressure testing of that system at test pressures in excess
of 1/2 psi (3.45 kPa). Dissipate test pressure in the gas
supply line before reconnecting the heater and its manual
shut o valve to gas supply line. FAILURE TO FOLLOW
THIS PROCEDURE MAY DAMAGE THE GAS VALVE.
OVER PRESSURIZED GAS VALVES ARE NOT COVERED
BY WARRANTY. The heater and its gas connections shall
be leak tested before placing the appliance in operation.
Use soapy water for leak test. DO NOT use open ame.
5.6.1. Supply Pressure
AACAUTION: Only sealant tape or a pipe compound rated
for use with natural and propane gases is recommended.
Apply sparingly only on male pipe ends, leaving the two
end threads bare.
A minimum of 6 in. WC and a maximum of 14 in. WC
upstream pressure under load and no-load conditions
must be provided for natural gas. A minimum of 12 in. WC
and a maximum of 14 in. WC are required for propane gas
under load and no-load conditions.
5.6.2. Gas Pressure Regulator
The gas pressure regulator is preset at 4.0 in. WC
throughout for natural gas, and 10.5 in. WC. for propane
gas. The pressure at the gas valve, taken with a manometer,
should be about 4.0 in. WC natural gas and 10.5 in. WC
propane gas. If an adjustment is needed, remove seal and
turn adjustment screw clockwise to increase pressure or
counter-clockwise to decrease pressure.
MANOMETER
MANUAL
SHUT-OFF
VALVE
UNION
Figure 14. Manual Shut-O Valve Installation
5.6.3. Gas Pressure Adjustment Locations
Gas Pressure Adjustment
Figure 15. Robertshaw 7000 BDER (Heater Model 268)

17
Gas Pressure Adjustment
Figure 16. Robertshaw 7000 DERHC (Heater Model 408)
Gas Pressure Adjustment
Figure 17. Honeywell VR8304 (Heater Models 268 and 408)
5.6.4. Pipe Sizing for Gas Connection
These capacities shown below based on using SCH 40
black iron pipe. For capacities using other materials,
consult local code.
Model
Input 3/4" 1" 1-1/4" 1-1/2"
(KBTU) N P N P N P N P
268 266.0 15
(5)
35
(11)
50
(15)
125
(38)
210
(64)
480
(146)
445
(136)
408 399.0 * 15
(5)
20
(6)
55
(17)
95
(29)
225
(69)
215
(66)
480
(146)
Natural Gas 1000 BTU/FT3 0.60 specic Gravity @ 0.5 in. WC Pressure Drop
Propane Gas 2500 BTU/FT3 1.53 specic Gravity @ 0.5 in. WC Pressure Drop
* A 3/4" gas line can be used for up to 5' (1.5 m) maximum length from the gas valve
in addition to the sediment trap.
Table H. Maximum Equivalent Pipe Length (ft/m)Flow
Rates
Model Pipe Size Min. GPM
(lpm)
Max. GPM*
(lpm)
268 1-1/4"–1-1/2" - 2" 25 (95) 125 (473)
408 1-1/4"–1-1/2" - 2" 40 (151) 125 (473)
* When ow rates exceed maximum GPM (lpm) an external auxiliary bypass valve
is required. See external bypass valve section for details.
Table I. Flow Rates
Figure 18. External Bypass Valve
Flow
GPM (lpm)
Pressure Drop (Ft of Head)
268 408
30 (114) 8.0
40 (151) 9.0 9.0
50 (189) 9.8 9.8
60 (227) 10.5 10.5
70 (265) 11.0 11.0
80 (302) 11.5 11.5
90 (341) 14.0 14.0
100 (378) 17.0 17.0
Table J. Heat Exchanger Pressure Drop

18
5.7. Water Connection Installation
Gather the loose items that were shipped with the heater.
Figure 19. Water Connection Components
The components should be assembled onto the inlet and
outlet header of the unit as shown below.
Figure 20. Water Connection Assembly
Once all components are in place and installed properly,
the water connections will appear as shown below:
Figure 21. Water Connection Installation
The heater must be located so that any water leaks will not
damage the structure of adjacent area. High temperature
2" plastic pipe (CPVC) may be threaded directly into the
header anges. This is not the same as the Schedule 80
PVC pipe which is also gray. PVC may be used immediately
after the supplied CPVC adapters.
DO NOT use petroleum-based assembly uids (such
as petroleum jelly or lubricating oil). If assembly lube is
required, use a silicon base such as AquaLube etc.
5.8. Unitherm Governor Operation
AACAUTION: The patented Unitherm Governor is a
thermostatic mixing valve specically designed to
maintain constant heater internal temperature between
105° (41°C) and 115°F (46°C) despite continually changing
ow rates from the lter and changing pool temperatures.
This narrow range is needed to prevent damaging
condensation on the burners which will occur if the
heater runs for any length of time below 100°F (38°C). It
is also needed to inhibit scale formation in the tubes by
maintaining temperatures well below accelerated scaling
temperatures.
UNITHERM
GOVERNOR
UG SPRING
UG PLUG
GASKET
(BEHIND UG)
Figure 22. Unitherm Governor Valve
5.9. Internal Automatic Bypass Valve
In addition to the Unitherm Governor, a built-in automatic
bypass valve is provided in the in/out header. While the
Unitherm Governor responds to the changes in water
temperature in the heater, the internal bypass valve
automatically responds to changes in water pressure in the
piping system. Proper amount of water ow is maintained
through the heater under varying pressures dictated by
the conditions of the pump and lter.

19
BYPASS
PLUG & SHAF
T
BYPASS SPRING
BYPASS VALVE
Figure 23. Internal Automatic Bypass Valve
5.10. External Auxiliary Bypass Valve
Where Required - An auxiliary bypass valve should
be used when ow rates exceed 125 GPM (473 lpm).
Usually a high-performance pump size larger than
two horsepower will exceed this ow rate. This valve is
required to complement the function of the automatic
bypass valve, particularly when starting the heater in
winter or early spring when the spa or pool temperature
is below 50°F (10°C). It also serves to eliminate needless
pressure drop through the heater and accompanying
reduction in the ow rate to the spa jets, etc.
FROM HEATER
TO HEATER
TO POOL/SPA FROM POOL/SPA
FULL PORT
BALL VALVE
OR GLOBE
VALVE
BYPASS VALVE
Figure 24. Auxiliary Bypass Valve
5.11. Auxiliary Bypass Valve
Adjustment
To set bypass - With clean lter, adjustment is made by
feeling the inlet and outlet pipes at the heater. Outlet pipes
should be slightly warmer than inlet and comfortable to
the touch. If pipe is hot, close bypass; if cold, open bypass.
5.12. Pressure Relief Valve
Installation
To conform to local building codes, it may be necessary
to install a pressure relief valve. A 3/4" pressure relief
valve, having a capacity equal to the BTUH output of the
model to be installed, is recommended for this heater.
The maximum acceptable pressure relief valve setting is
125 psi.
PRV
Figure 25. Pressure Relief Valve
NOTE: To avoid water damage or scalding due to valve
operation, drain pipe must be connected to valve outlet
and run to a safe place of discharge. Drain pipe must be the
same size as the valve discharge connection throughout
its entire length and must pitch downward from the valve.
No shut-o valve shall be installed between the relief
valve and the drain line. Valve lever should be tripped at
least once a year to ensure that waterways are clear.
5.13. Plumbing
5.13.1. Water Connection
The heater requires water ow and positive pressure to
re and operate properly. It must therefore be installed
downstream of the discharge side of the lter pump.
SeeFigure 29 and Figure 30.
A typical installation is plumbed as follows:
1. The inlet side of the filter is plumbed directly to the
discharge side of the filter pump;
2. The outlet side of the filter is then plumbed to the
inlet of the heater; and
3. The outlet of the heater is plumbed to the return
line to the pool or spa. The pump, filter and heater
are thus plumbed in series (Salt generators and
chemical feeders must be down stream of the pool
heater).

20
Plumbing from the heater back to the pool or spa must
not have any valves or restriction that could prevent ow
when the pump is operating.
AACAUTION: An additional source of heated water, e.g. a
solar system, must be connected to the main line ahead
of the heater inlet pipe in order for it to act as the primary
heat source. If the primary system provides adequate heat
to maintain set-point, the heater will not re. Be advised
that the control panel will then display sensed water
temperatures downstream of the primary heating system,
rather than the temperature of the water exiting the pool.
Heater must be located so that any water leaks will not
damage the structure of adjacent area.
6. ELECTRICAL WIRING
NOTE: If it is necessary to replace any of the original
wiring, use 105°C wire or its equivalent, and/or 150°C
wire or its equivalent, like the original wiring.
AAWARNING: Heaters are factory-wired for 240 VAC
power supply. DO NOT attempt to operate at 208 VAC.
The standard eld-wiring connection is on the right side
of the heater.
To wire the heater from the left side, follow these steps:
1. Remove the two (2) screws that hold the front door
to the heater. Remove and set aside door for better
access to wiring.
2. Remove the four (4) screws that hold down the
junction box to the sway brace.
3. Remove the transformer cover located on the far
right by removing one (1) screw.
4. Remove the two (2) screws that hold down the
transformer.
5. Remove the one (1) screw that holds down the
ground wires.
6. Disconnect P6 connector from PC board.
7. Remove transformer from its current location and
relocate it on the far left side of the heater.
8. Re-route all high-voltage wires and ground wires
through the left jacket side of heater.
9. Re-install P6 connector, ground wires (SPG),
transformer, junction box, front door, and plug right
side with the left side’s grommet plug.
NOTE: 7/8" diameter holes not utilized on jacket and
control box can be used for reman switch, auxiliary
control interface or power vent (D-2) wiring.
6.1. Electrical Power Draw
AACAUTION: Heater must be electrically grounded and
bonded. Bonding lug is provided loose with the heater.
Install bonding lug on lower right or left side of jacket
as necessary for bonding the heater. Mounting hole is
provided on the jacket.
NOTE: Failure to ground the heater electrically could
aect the heater’s electronics.
NOTE: See "Time Clock/Fireman’s Switch" on page 29
for further instructions if using a time clock/reman’s
switch.
The Electronic Intermittent Ignition Device automatically
lights the pilot and main burners upon a call for heat. The
heater is supplied with a dual-voltage transformer for 120
VAC or 240 VAC input power hookup.
4 amps at 120VAC
2 amps at 240VAC
CONTROL BOX
(FACTORY MOUNTED
LOCATION)
OPTION LOCATION
LEFT SIDE FIELD WIRING
SWAY BRACE
Figure 26. Heater Wiring Locations