Rheem Raypak Delta Limited 399B User manual

1
FOR YOUR SAFETY: Do not store or use gasoline or other ammable vapors and liquids or other
combustible materials in the vicinity of this or any other appliance. To do so may result in an explosion
or re.
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 re department.
Installation and service must be performed by a qualied installer, service agency or the gas
supplier.
This manual should be maintained in legible condition and kept adjacent to the heater or in another safe place for
future reference.
Models 399B–2339B
Types H & WH
AWARNING: If these instructions are not followed exactly, a re or explosion may result
causing property damage, personal injury or death.
INSTALLATION AND
OPERATION MANUAL
Effective: 07-28-23
Replaces: 06-30-23
P/N: 241330 Rev. 8
SCAN WITH QR EQUIPPED SMART
DEVICE FOR ONLINE MANUAL.
SEE PAGE 64 FOR QR CODE.
NOTICE

2
Revision 8 reects the following changes:
Added two warnings regarding carbon monoxide to “Warnings” section per ANSI Z21.13_22 Chapters 4.33.1 b and 4.34 i.

3
WARNINGS 4
BEFORE INSTALLATION 5
Product Receipt 5
Model Identication 5
Ratings and Certications 5
Installations at Elevation 5
Component Locations 6
General Information 7
GENERAL SAFETY 8
Time/Temperature Relationships in
Scalds 8
INSTALLATION 9
Installation Codes 9
Equipment Base 9
Stacking 9
Clearances 11
Combustion and Ventilation Air 12
Conventional Combustion
Air Supply 12
Water Piping 14
Hydronic Heating 16
Gas Supply 18
Electrical Power Connections 21
Field Wiring Connection 22
Venting 25
Changing the Flue Outlet 27
Venting Installation Tips 27
Venting Congurations 28
Outdoor Installation 32
Controls 32
Heater Sequence of Operation 33
Wiring Diagrams 39
START-UP 41
Pre Start-up 41
Start-Up 42
OPERATION 45
Lighting Instructions 45
To Turn O󰀨 Gas To Appliance 45
TROUBLESHOOTING 46
MAINTENANCE 47
Suggested Minimum
Maintenance Schedule 47
Preventive Maintenance Schedule 47
APPENDIX 49
Inside Air Contamination 49
ILLUSTRATED PARTS LIST 50
QR CODE 64
WARRANTY 65
START-UP CHECKLIST 66
TABLE OF CONTENTS
THIS INSTALLATION MANUAL MAY NOT BE THE LATEST REVISION PRINTED AT THE TIME OF PRODUCT SHIPMENT. VISIT THE
RAYPAK WEBSITE TO VERIFY THE MANUAL DELIVERED WITH YOUR RAYPAK UNIT IS THE MOST UP-TO-DATE VERSION.

4
WARNINGS
Pay Attention to These Terms
ADANGER: Indicates the presence of immediate hazards which will cause severe
personal injury, death or substantial property damage if ignored.
AWARNING: Indicates the presence of hazards or unsafe practices which could cause
severe personal injury, death or substantial property damage if ignored.
ACAUTION: Indicates the presence of hazards or unsafe practices 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.
ADANGER: Make sure the gas on which the heater will operate
is the specied on the heater rating plate.
AWARNING: Should overheating occur or the gas supply valve
fail to shut, do not turn o󰀨 or disconnect the electrical supply to
the heater. Instead, shut o󰀨 the gas supply at a location external
to the heater.
EWARNING - CALIFORNIA PROPOSITION 65: This
product contains chemicals known to the State of California to
cause cancer, birth defects or other reproductive harm.
AWARNING: 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 (>2192F), 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.
AWARNING: Do not use this heater if any part has been under
water. Immediately call a qualied service technician to inspect
the heater and to replace any part of the control system and any
gas control which has been under water.
AWARNING: 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.
AWARNING: Risk of electrical shock. More than one disconnect
switch may be required to de-energize the equipment before
servicing.
AWARNING: For appliances that allow indoor installation
within a residential living space or home, the installer must verify
that at least one carbon monoxide alarm has been installed
within a residential living space or home following the alarm
manufacturer’s instructions and applicable local codes before
putting the appliance into operation.
AWARNING: For appliances that allow indoor installation within
a residential living space or home, note that this product burns
gas to produce heat. The appliance must be properly installed,
operated, and maintained to avoid exposure to appreciable levels
of carbon monoxide and the installer is required to conrm that at
least one carbon monoxide alarm is installed in the living space
before the appliance is put into operation. It is important for the
carbon monoxide alarms to be installed, maintained, and replaced
following the alarm manufacturer’s instructions and applicable
local codes.
ACAUTION: If this heater is to be installed above radiation
level, it must be provided with a low water cut-o󰀨 device at the
time of heater installation.
ACAUTION: Operation of this heater in low temperature
systems requires special piping. Harmful internal condensation
will occur if the inlet water temperature does not exceed 105°F.
Warranty claims will be denied when condensation occurs.
WCAUTION: If this heater is to be installed in a negative or
positive pressure equipment room, there are special installation
requirements. Consult factory for details.

5
BEFORE
INSTALLATION
Raypak strongly recommends that this manual be re-
viewed thoroughly before installing your Delta Limited
heater. Please review the General Safety information
before installing the heater. Factory warranty does not
apply to heaters that have been improperly installed
or operated. (Refer to the warranty at the back of this
manual.) Installation and service must be performed
by a qualied installer, service agency or gas supplier.
If, after reviewing this manual, you still have questions
which this manual does not answer, please contact the
manufacturer or your local Raypak representative.
Thank you for purchasing a Raypak product. We hope
you will be satised with the high quality and durability
of our equipment.
Product Receipt
On receipt of your heater it is suggested that you visu-
ally check for external damage to the shipping crate. If
the crate is damaged, make a note to that e󰀨ect on the
Bill of Lading when signing for the shipment. Remove
the heater from the shipping packaging. Report any
damage to the carrier immediately.
On occasion, items are shipped loose. Be sure that
you receive the correct number of packages as indicat-
ed on the Bill of Lading.
Claims for shortages and damages must be led with
the carrier by consignee. Permission to return goods
must be received from the factory prior to shipping.
Goods returned to the factory without an authorized
Returned Goods Receipt number will not be accepted.
All returned goods are subject to a restocking charge.
When ordering parts, you must specify the model and
serial number of the heater.
When ordering under warranty conditions, you must
also specify the date of installation.
Purchased parts are subject to replacement only
under the manufacturer’s warranty. Debits for defec-
tive replacement parts will not be accepted and will be
replaced in kind only per Raypak’s standard warran-
ties.
Model Identication
The model identication number and heater serial
number are found on the heater rating plate located on
the lower right outside jacket of the heater. The model
number will have the form H8 1259B or similar
depending on the heater size and conguration. The
letter(s) in the rst group of characters identies the
application (H = Hydronic Heating, WH = Domestic
Hot Water (DHW)). The number which fol-lows iden-
ties the ring mode (1 or 4 = on-o󰀨, 3 = 2-stage, 8 =
3-stage and 9 = 4-stage). The second group of charac-
ters identies the size of the heater (four numbers
representing the approximate MBTUH input), and,
where applicable, a letter, indicating the manufacturing
series.
Ratings and Certications
Standards:
• ANSI Z21.13 · CSA 4.9 - latest edition, Gas-Fired
Hot Water Boilers
• CAN 3.1 - latest edition, Industrial and
Commercial Gas-Fired Package Boilers
• ANSI Z21.10.3 · CSA 4.3 - latest edition Gas
Water Heaters
All Raypak heaters are National Board Approved, and
design-certied and tested by the Canadian Standards
Association (CSA) for the U.S. and Canada. Each
heater is constructed in accordance with Section IV of
the American Society of Mechanical Engineers
(ASME) Heater Pressure Vessel Code and bears the
ASME stamp. The heater also complies with the latest
edition of ASHRAE 90.1 Standard.
AWARNING: Altering any Raypak pressure
vessel by installing replacement heat exchang-
ers, tube bundle headers, or any ASME parts not
manufactured and/or approved by Raypak will
instantly void the ASME and CSA ratings of the
vessel and any Raypak warranty on the vessel.
Altering the ASME or CSA ratings of the vessel
also violates national, state, and local approval
codes.
Installations at Elevation
Rated inputs are suitable for up to 5,000 ft elevation
without de-rating. Consult the factory for installations
at altitudes over 5,000 ft above sea level.

6
OPTIONAL FLUE
CONNECTION
GAS TRAIN
OPERATIONAL CENTER
CONTROL
COMBUSTION
BLOWER
IGNITER
REMOTE SENSORBURNER GROUP
HEAT EXCHANGER
PRESSURE RELIEF
VALVE
Component Locations
Fig. 1: Component Locations – Back
Fig. 2: Component Locations – Left Side
Panels removed for clarity
Fig. 3: Component Locations – Front

7
General Information
Table A: Basic Data
Table B: Manifold Data
Model
No.
Quantity of Vent Size in. (mm)
Burners Gas Valves Blowers Flue Intake
399B 8 1 1 6 (152) 6 (152)
499B 10 2 1 6 (152) 6 (152)
649B 13 2 1 8 (203) 6 (152)
749B 15 2 1 8 (203) 6 (152)
899B 18 3 1 8 (203) 6 (152)
989B 11 2 2 10 (254) 10 (254)
1259B 14 3 2 12 (305) 10 (254)
1529B 17 4 2 12 (305) 10 (254)
1799B 20 4 2 14 (356) 10 (254)
1999B 23 5 3 14 (356) 10 (254)
2069B 23 5 3 14 (356) 10 (254)
2339B 26 5 3 16 (406) 10 (254)
Model
No.
Burners per Valve Stages % Fire at Stage
1 1A 2 3 4 1 2 3 4 1 2 3 4
399B 8 1 100
499B 5 5 1 1, 2 50 100
649B 7 6 1 1, 2 54 100
749B 8 7 1 1, 2 53 100
899B 6 6 6 1, 2 1, 2, 3 66 100
989B 6 5 1 1, 2 54 100
1259B 5 3 6 1 1, 2 1, 2, 3 36 57 100
1529B 6 4 4 3 1 1, 2 1, 2, 3 1, 2, 3, 4 35 59 82 100
1799B 6 4 5 5 1 1, 2 1, 2, 3 1, 2, 3, 4 30 50 75 100
1999B 4 5 5 5 4 1, 1A 1, 1A, 2 1, 1A, 2, 3 1, 1A, 2, 3, 4 39 61 83 100
2069B 4 5 5 5 4 1, 1A 1, 1A, 2 1, 1A, 2, 3 1, 1A, 2, 3, 4 39 61 83 100
2339B 5 6 5 5 5 1, 1A 1, 1A, 2 1, 1A, 2, 3 1, 1A, 2, 3, 4 42 62 81 100

8
GENERAL SAFETY
To meet commercial hot water use needs, the high
limit safety control on this water heater is adjustable
up to 210°F. However, water temperatures over 125°F
can cause instant severe burns or death from scalds.
When supplying general purpose hot water, the rec-
ommended initial setting for the temperature control is
125°F.
Safety and energy conservation are factors to be con-
sidered when setting the water temperature on the
thermostat. The most energy-e󰀩cient operation will
result when the temperature setting is the lowest that
satises the needs of the application.
Water temperature over 125°F can cause instant se-
vere burns or death from scalds. Children, disabled
and elderly are at highest risk of being scalded.
• Feel water before bathing or showering.
• Temperature limiting valves are available.
Maximum water temperatures occur just after the heat-
er’s burner has shut o󰀨. To determine the water tem-
perature being delivered, turn on a hot water faucet
and place a thermometer in the hot water stream and
read the thermometer.
NOTE: When this water heater is supplying
general purpose hot water for use by individuals, a
thermostatically controlled mixing valve for reducing
point of use water temperature is recommended to
reduce the risk of scald injury. Contact a licensed
plumber or the local plumbing authority for further
information.
Water temperature over 125°F can
cause instant severe burns or death
from scalds.
Children, disabled, and elderly are
at highest risk of being scalded.
See instruction manual before set-
ting temperature at water heater.
Feel water before bathing or show-
ering.
Temperature limiting valves are
available, see manual.
Time/Temperature
Relationships in Scalds
The following chart details the relationship of water
temperature and time with regard to scald injury and
may be used as a guide in determining the safest wa-
ter temperature for your applications.
Water
Temp.
Time to Produce Serious
Burn
120°F More than 5 minutes
125°F 1-1/2 to 2 minutes
130°F About 30 seconds
135°F About 10 seconds
140°F Less than 5 seconds
145°F Less than 3 seconds
150°F About 1-1/2 seconds
155°F About 1 second
Table courtesy of The Shriners Burn Institute
Table C: Time to Produce Serious Burn

9
INSTALLATION
Installation Codes
Installations must follow these codes:
• Local, state, provincial, and national codes, laws,
regulations and ordinances
• National Fuel Gas Code, ANSI Z223.1/NFPA 54 –
latest edition (NFGC)
• National Electrical Code, ANSI/NFPA 70 - latest
edition (NEC)
• Standard for Controls and Safety Devices for Auto-
matically Fired Boilers, ANSI/ASME CSD-1, when
required (CSD-1)
• For Canada only: CAN/CGA B149 Installation
Code (B149) and CSA C22.1 C.E.C. Part 1 (C22.1)
The temperature of the water in the heater can be reg-
ulated by using the temperature controller. To comply
with safety regulations, the temperature controller is
set at the lowest setting when shipped from the factory.
To adjust the water temperature, insert a small straight
screwdriver into the adjustment screw on the front of
temperature controller and turn the wheel to the de-
sired setting (See Fig. 4.).
ACAUTION: Hotter water increases the risk of
scalding! There is a hot water scald potential if
the thermostat is set too high.
Fig. 4: Temperature Control
Equipment Base
The heater should be mounted on a level, structurally
sound surface. The heater is approved for installation
on a combustible surface but must NEVER be installed
on carpeting. Gas-fueled equipment installed in en-
closed parking garages must be located at least 18 in.
above the oor.
Stacking
Delta Limited units can be stacked two units high with
an optional stacking rack. A stacking kit is available
from Raypak for this type of installation.
ACAUTION: The heaters should be located in
an area where water leakage will not result in
damage to the area adjacent to the appliances or
to the structure. When such locations cannot be
avoided, it is recommended that a suitable catch
pan, adequately drained, be installed under the
appliance. The pan must not restrict air ow.
REQUIRES OPTIONAL VENT TEE.
REQUIRES OPTIONAL VENT TEE IF VENTED OUT BACK
OF HEATER.
Fig. 5: Typical Stacked Installation

10
U.S. Installations1Canadian Installations2
AClearance above grade, veranda, porch,
deck, or balcony 1 ft (30 cm) 1 ft (30 cm)
BClearance to window or door that may be
opened
4 ft (1.2m) below or to side
of opening; 1 foot (30 cm)
above opening
3 ft (91 cm)
C Clearance to permanently closed window * *
D
Vertical clearance to ventilated soffit located
above the terminal within a horizontal dis-
tance of 2 ft (61cm) from the centerline of the
terminal
5 ft (1.5m) *
E Clearance to unventilated soffit * *
F Clearance to outside corner* *
G Clearance to inside corner 6 ft (1.83m) *
HClearance to each side of center line ex-
tended above meter/regulator assembly *
3 ft (91 cm) within a height
15 ft above the me-
ter/regulator assembly
I Clearance to service regulator vent outlet *6 ft (1.83m)
J
Clearance to non-mechanical air supply inlet
to building or the combustion air inlet to any
other appliance
4 ft (1.2m) below or to side
of opening; 1 ft (30 cm)
above opening
3 ft (91 cm)
K Clearance to mechanical air supply inlet 3 ft (91 cm) above if within
10 ft (3m) horizontally 6 ft (1.83m)
LClearance above paved sidewalk or paved
driveway located on public property 7 ft (2.13m) 7 ft (2.13m) ³
MClearance under veranda, porch, deck or
balcony*12 in. (30 cm) ⁴
1In accordance with the current ANSI Z223.1/NFPA 54 National Fuel Gas Code
2In accordance with the current CAN/CSA-B149 Installation Codes
³Vent terminal shall not terminate directly above sidewalk or paved driveway located between 2 single family dwellings that serves
both dwellings
⁴Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor and top of terminal and
underside of veranda, porch, deck or balcony is greater than 1 ft (30cm)
* Clearances in accordance with local installation codes and the requirements of the gas supplier
Fig. 6: Minimum Clearances from Vent/Air Inlet Terminations – Indoor and Outdoor Installations
Table D: Vent/Air Inlet Termination Clearances

11
In addition, the heater shall be installed such that the
gas ignition system components are protected from
water (dripping, spraying, rain, etc.) during appliance
operation or service (circulator replacement, control
replacement, etc.).
Clearances
Indoor Installations
Heater
Side
Minimum Clearance
from Combustible
Surfaces in. (mm)
Recommended
Service
Clearance in. (mm)
Floor* 0 (0) 0 (0)
Rear 1(25) 6 (152)
Water Side 12 (305) 24 (610)
Other Side 1(25) 24 (610)
Top 1(25) 6 (152)
FrontOpen24 (610)
Vent 2 (51) 2 (51)
Table E: Clearances – Indoor Installations
TOP VIEW
12" (30.5 cm) 1" (2.5 cm)
1"
(2.5 cm)
1"
(2.5 cm
)
FRONT VIEW
VENTING NOT SHOWN FOR CLARITY. HEATER MUST BE
VENTED PER INSTRUCTIONS IN THIS MANUAL
Fig. 7: Minimum Clearances from Combustible Surfaces
– Indoor Installations
When installed according to the listed minimum clear-
ances from combustible construction, these heaters
can still be serviced without removing permanent
structural construction around the heater. However,
for ease of servicing, we recommend a clearance of at
least 24 in. in front, and at least 12 in. on the water con-
nection side. This will allow the heater to be serviced
in its installed location without movement or removal
of the heater.
Service clearances less than the minimums may re-
quire removal of the heater to service either the heat
exchanger or the burner tray. In either case, the heat-
er must be installed in a manner that will enable the
heater to be serviced without removing any structure
around the heater.
Outdoor Installations
These heaters are design-certied for outdoor installa-
tion. Heaters must not be installed under an overhang
that is less than 3 ft 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 heat-
ers installed under overhangs.
Heater
Side
Minimum Clearance
from Combustible
Surfaces in. (mm)
Recommended
Service
Clearance in. (mm)
Floor Open 24 (610)
Rear12 (308) 6 (152)
Water Side 36 (914) 36 (914)
Other Side 36 (914) 36 (914)
Top 36 (914)
Vent N/A N/A
Unobstructed
Table F: Clearances – Outdoor Installations
These clearances are required when the outdoor
vent cap is used. If installing the heater outdoors
with a vent stack, the indoor clearances may be
utilized.
The combustion air intake hood MUST be used for
outdoor installations. The hood is shipped loose and
installed on the side of the heater over the lter box at
the jobsite.
* DO NOT install on carpeting.

12
Conventional Combustion Air
Supply
U.S. Installations
All Air from Inside the Building
The conned space shall be provided with TWO per-
manent openings communicating directly with an ad-
ditional room(s) of su󰀩cient volume so that the com-
bined volume of all spaces meets the criteria for a
room large in comparison (NFGC). The total input of
all gas utilization equipment installed in the combined
ACAUTION: This type of installation is
recommended if damaging airborne contaminants
are or will be present in the heater area. See the
Appendix regarding air contamination.
FRONT VIEW
SIDE VIEW
12" MIN (30.5 cm)
RECOMMENDED
12" MIN (30.5 cm)
RECOMMENDED
6" MIN (15.2 cm)
RECOMMENDED
Fig. 8: Minimum Clearances from Combustible Surfaces
– Outdoor Installations
Combustion and Ventilation
Air
Indoor Units
The heater must be supplied with su󰀩cient quantities
of non-contaminated air to support proper combustion
and equipment ventilation. Combustion air can be sup-
plied via conventional means where combustion air is
drawn from the area immediately surrounding the heat-
er, or via direct vent, where combustion air is drawn
directly from outside. All installations must comply with
the requirements of the NFGC (U.S.) and B149 (Cana-
da), and all local codes.
Reversing Air Filter
Follow these instructions to change the air duct con-
nection from the left-hand side (standard) to the right-
hand side:
1. Remove the four screws and the dust cover from
the right-hand side of the heater.
2. Remove the four screws and the air lter bracket
from the left-hand side of the heater.
3. Reverse the components and reattach in the
new location, making sure that the air lter lock-
ing bracket is on the bottom. (The air lter locking
bracket is reversible.)
Direct-Ducted Combustion Air
In certain applications it may be desirable to duct the
combustion air directly to the heater. This should be
done with PVC, CPVC or single-wall galvanized duct-
ing. The duct will attach directly to the collar on the air
lter housing located on the side of the heater. The
ducting is attached to the air lter housing collar using
three or four sheet metal screws (not supplied) equally
distributed around the circumference of the duct.
ACAUTION: Combustion air must not be
contaminated by corrosive chemical fumes
which can damage the heater and void the
warranty. (See the Appendix.)
NOTE: It is recommended that the intake vent be
insulated to minimize sweating.
NOTE: Use of the heater in construction areas
where ne particulate matter, such as concrete or
dry-wall dust, is present may result in damage to
the heater that is not covered by the warranty. If
operated in a construction environment, a clean
source of combustion air must be provided directly
to the heater.

13
space shall be considered in making this determina-
tion. Each opening shall have a minimum free area of
1 in.2 per 1,000 BTUH (2,225 mm2 per kW) of the to-
tal input rating of all gas utilization equipment in the
conned space, but not less than 100 in.2 (645 cm2).
One opening shall commence within 12 in. (305 mm)
of the top, and one opening shall commence within 12
in. (305 mm) of the bottom of the enclosure. The min-
imum dimension of air openings shall be not less than
3 in. (76 mm) in any direction.
All Air from Outdoors
The conned space shall communicate with the out-
doors in accordance with one of the methods below.
The minimum dimension of air openings shall not be
less than 3 in. (76 mm) in any direction. Where ducts
are used, they shall be of the same cross-sectional
area as the net free area of the openings to which they
connect.
1. Two permanent openings, one commencing
within 12 in. (305 mm) of the top, and one com-
mencing within 12 in. (305 mm) of the bottom of
the enclosure, shall be provided. The openings
shall communicate directly, or by ducts, with the
outdoors or spaces (crawl or attic) that freely com-
municate with the outdoors.
a. Where directly communicating with the out-
doors or where communicating to the outdoors
through vertical ducts, each opening shall
have a minimum free area of 1 in.2per 4,000
BTUH (550 mm2 per kW) of total input rating of
all equipment in the enclosure.
b. Where communicating with the outdoors
through horizontal ducts, each opening shall
have a minimum free area of 1 in.2per 2,000
BTUH (1,100 mm2 per kW) of total input rating
of all equipment in the enclosure.
2. One permanent opening, commencing within 12
in. (305 mm) of the top of the enclosure, shall be
permitted where the equipment has clearances of
at least 1 in. (25 mm) from the sides and back and
6 in. (152 mm) from the front of the appliance. The
opening shall directly communicate with the out-
doors or shall communicate through a vertical or
horizontal duct to the outdoors or spaces that free-
ly communicate with the outdoors, and shall have
a minimum free area of:
a. 1 in.2 per 3,000 BTUH (740 mm2 per kW) of
the total input rating of all equipment located in
the enclosure, and
b. Not less than the sum of the areas of all vent
connectors in the conned space.
AWARNING: Do not use one permanent open-
ing method if the equipment room is under neg-
ative pressure conditions or the equipment is
common vented with other gas-red appliances.
1. Ventilation of the space occupied by the heater
shall be provided by an opening(s) for ventilation
air at the highest practical point communicating
with the outdoors. The total cross-sectional area
of such an opening(s) shall be at least 10% of the
area required in 2. and 3. (below), but in no case
shall the cross-sectional area be less than 10 in.2
(65 cm2).
2. For heaters using a barometric damper in the
vent system there shall be a permanent air sup-
ply opening(s) having a cross section area of not
less than 1 in.2 per 7,000 BTUH (320 mm2 per kW)
up to and including 1 million BTUH, plus 1 in.2per
14,000 BTUH (160 mm2 per kW) in excess of 1
million BTUH. This opening(s) shall be either locat-
ed at or ducted to a point not more than 18 in. (450
mm) nor less than 6 in. (152 mm) above the oor
level. The duct can also “goose neck” through the
roof. The duct is preferred to be straight down and
terminated 18 in. (450 mm) from the oor, but not
near piping. This air supply opening requirement
shall be in addition to the air opening for ventilation
air required in 1. (above).
3. For heaters not using a barometric damper in the
vent system, and when air supply is provided by
natural air ow from outdoors for a power burner
and there is no draft regulator, drafthood or sim-
ilar ue gas dilution device installed in the same
space, in addition to the opening for ventilation air
required in 1., there shall be a permanent air sup-
ply opening(s) having a total cross-sectional area
ACAUTION: All combustion air must be
drawn from the air outside of the building; the
mechanical equipment room must communicate
directly with the outdoors.
Canadian Installations
AWARNING: Care must be taken to ensure
that the equipment room is not under negative
pressure conditions or that the equipment is not
common-vented with other gas-red appliances.

14
5. Remove all plumbing ttings to the header. This
will include both inlet and outlet water pipe unions
and the pressure relief valve and drain piping.
6. Remove limits, control bulbs and/or thermocou-
ples.
7. Remove the six (or 8) ange nuts and the in/out
header from the left-hand side.
8. Remove the six (or 8) ange nuts and the return
header from the right-hand side.
9. Remove the header stud bolts from each tube
sheet.
10. Reverse the headers and stud bolts to the new lo-
cation.
11. Install NEW red beveled O-rings ush against both
tube sheets with the bevel facing outward.
12. Push the header rmly against the O-rings. Install
and tighten the ange nuts onto the stud bolts until
nger tight.
13. Slowly tighten the ange nuts, starting from the
center nut (number 1) in Fig. 9 and working se-
quentially around the header as indicated. Torque
all nuts to 25 ft/lb. DO NOT OVER-TIGHTEN.
14. Re-route the capillary(s), wiring etc. to the new lo-
cation, adding thermal paste and shim to the capil-
lary well.
Relief Valve Piping
WWARNING: Pressure relief valve discharge
piping must be piped near the oor and close to
a drain to eliminate the potential of severe burns.
Do not pipe to any area where freezing could oc-
cur. Refer to local codes.
of not less than 1 in.2for each 30,000 BTUH mm2
per kW) of total rated input of the burner(s), and
the location of the opening(s) shall not interfere
with the intended purpose of the opening(s) for
ventilation air referred to in (1). This opening(s)
can be ducted to a point not more than 18 in. (450
mm) nor less than 6 in. (152 mm) above the oor
level. The duct can also “goose neck” through the
roof. The duct is preferred to be straight down 18
in. (450 mm) from the oor, but not near piping.
4. Refer to B149 Installation code for additional infor-
mation.
Water Piping
General
The heater should be located so that any water leaks
will not cause damage to the adjacent area or struc-
tures.
Reversing Water Connections
Follow these instructions to change the water connec-
tions from the left-hand side (standard) to the right-
hand side.
1. Disconnect all electrical power from the heater (if
applicable).
2. Label all electrical connections and conduit lines.
This may include the ow switch, low water cut-o󰀨
probe and/or pump.
3. Disconnect or isolate the main gas pipe from the
heater (if applicable).
4. Remove both in/out and return header access
panels by removing all sheet metal screws.
ACAUTION: This heater requires forced water
circulation when the burner is operating. See
Table G and Table H for minimum and maximum
ow rates and water pump selection. The pump
must be interlocked with the heater to prevent
heater operation without water circulation.
NOTE: Minimum pipe size for in/out connections
is 2 1⁄2 in (2 in. for 399B–899B). Verify proper ow
rates and ∆T as instructed in this manual.

15
Fig. 9: Torque Sequence
ACAUTION: Damaging internal condensation
may occur if the heater inlet water temperature
does not exceed 105ºF (41ºC) within 7-minutes of
start-up.
Models 399B–899B
Models 989B–2339B

16
Cold Water Run
Cold water run di󰀨ers from cold water start in that the
system water entering the heater remains below 105ºF
(41ºC) continuously. Typically, this is the case in swim-
ming pool heating and water source heat pump appli-
cations as well as some others. If the system water is
kept in a narrow temperature range, a permanent man-
ual bypass can be employed and manually adjusted to
achieve an inlet temperature of 105ºF (41ºC) or high-
er. An injector pump arrangement may also be utilized
to keep the heater loop at or above 105ºF (41ºC). An
injector pump approach has the added value of being
able to adjust to changes in the system water coming
back to the heater take-o󰀨.
Table G: Heater Rates of Flow and Pressure Drops
Notes: 1. Basis for minimum ow: Models 399–899, 20 gpm or 40°F ∆T. Models 989–2339, 30 gpm or 40°F ∆T.
Basis for maximum ow: Models 399–899, 90 gpm. Models 989–2339, 132 gpm.
2. Flow switch will not operate if ow is less than 20 gpm.
Temperature & Pressure Gauge
The temperature and pressure gauge is factory-mount-
ed in the in/out header.
Hydronic Heating
Pump Selection
In order to ensure proper performance of your heater
system, you must install a correctly sized pump. Ray-
pak recommends using a 20°F ∆T as design ∆T. (∆T is
the temperature di󰀨erence between the inlet and outlet
water when the heater is ring at full rate). If a ∆T of
larger than 20°F is necessary, see Table G and Table
H for ow rate requirements.
Model
No.
10°F ∆T 20°F ∆T 30°F ∆T Min. Flow Max. Flow
GPM
(lpm) ∆P (ft) GPM (lpm) ∆P (ft) GPM (lpm) ∆P (ft) GPM (lpm) ∆P (ft) ∆T GPM (lpm) ∆P (ft) ∆T
399B 67
(254) 5.5 34 (129) 1.4 22 (83) 0.6 20 (76) 0.5 34 90 (341) 10.0 7
649B 55
(208) 4.1 36 (136) 1.8 27 (102) 1.1 40 90 (341) 10.8 12
749B 63
(238) 5.7 42 (159) 2.6 32 (121) 1.5 40 90 (341) 11.3 14
899B 76
(288) 8.3 50 (189) 3.8 38 (144) 2.2 40 90 (341) 11.7 17
989B 83
(341) 5.2 55 (208) 2.3 42 (159) 1.3 40 132 (500) 13.1 13
1259B 106
(401) 9.6 71 (269) 4.3 53 (201) 2.4 40 132 (500) 14.8 16
1529B 129
(488) 15.7 86 (325) 7.1 64 (242) 4.0 40 132 (500) 16.5 19
1799B 101
(382) 10.7 76 (288) 6.0 40 132 (500) 18.3 23
1999B 112
(424) 13.8 84 (318) 7.9 40 132 (500) 19.0 25
2069B 116
(439) 14.8 87 (329) 8.5 40 132 (500) 19.0 26
2339B 132
(500) 21.4 98 (371) 12.1 40 132 (500) 21.4 30

17
Pressure Drop in Feet of Head
Feedwater Regulator
Raypak recommends that a feedwater regulator be in-
stalled and set at 12 psi minimum pressure at the high-
est point of the system. Install a check valve or back
ow device upstream of the regulator, with a manual
shut-o󰀨 valve as required by local codes.
Piping
All high points should be vented. Purge valves and a
bypass valve should be installed. A heater installed
above radiation level must be provided with a low wa-
ter cut-o󰀨 device (sales order option F-10). The heater,
when used in connection with a refrigeration system,
must be installed so that the chilled medium is piped
in parallel with the heater with appropriate valves to
prevent the chilled medium from entering the heater.
The piping system of a hot water heater connected to
heating coils located in air handling units where they
may be exposed to circulating refrigerated air, must be
equipped with ow control valves or other automatic
means to prevent gravity circulation of the heater water
during the cooling cycle. It is highly recommended that
the piping be insulated.
Air-Separation/Expansion Tank
All heaters should be equipped with a properly sized
expansion tank and air separator tting as shown in
Fig. 10.
Three-Way Valves
Valves designed to blend water temperatures or re-
duce water circulation through the heater should not
be used. Raypak heaters are high-recovery, low-mass
Fig. 10: Air-Separation/Expansion Tank
heaters which are not subject to thermal shock. Ray-
pak o󰀨ers a full line of electronic sequencers that pro-
duce direct reset of heater water temperature. (Refer
to the Controls section of the Raypak Catalog.)
Domestic Hot Water
When designing the water piping system for domes-
tic hot water applications, water hardness should be
considered. Table H indicates the suggested ow rates
for soft, medium and hard water. Water hardness is
expressed in grains per gallon.
Fig. 11: Single Heater - Low-Temperature (Heat Pump)
Application with Primary/Secondary Piping
12” MAX
OR MIN FEASIBLE
SYSTEM SENSOR
(LESS THAN
4:1 TURNDOWN)
5’ MAX
5’ MAX
SYSTEM SENSOR
(4:1 TURNDOWN
OR GREATER)
Fig. 12: Dual Heaters (Reverse/Return)
with Primary/Secondary Piping

18
Potable Water and Space Heating
1. All piping materials and components connected to
the water heater for the space heating application
shall be suitable for use with potable water.
2. Toxic chemicals, such as used for boiler treatment,
shall not be introduced into the potable water used
for space heating.
3. If the heater will be used to supply potable water,
it shall not be connected to any heating system or
components previously used with a non-potable
water heating appliance.
4. When the system requires water for space heating
at temperatures higher than 140°F, a means such
as a mixing valve shall be installed to temper the
water in order to reduce scald hazard potential.
ACAUTION: When this heater is used for both
potable water and space heating, observe the
following to ensure proper operation.
Fig. 13: Single Domestic Hot Water Heater and Storage
Tank
Table H: Domestic Water Heater Flow Rate Requirements
∆T = Temperature rise, °F.
∆P = Pressure drop through heat exchanger, ft.
SHL = System head loss, ft. (System head loss based on heater and tank placed no more than 5 ft apart and equivalent length pipe/ttings as follows:
2 in. tube = 25 ft; 2 1/2 in. tube = 80 ft.
gpm = Gallons per minute, ow rate.)
MTS = Minimum tubing size.
*Must utilize optional cupronickel tubes.
**With Hard Water (16-25 grains per gallon), the operating control must be set no higher than 130F for scale free operation. For operating tempera-
tures above 130F, a water softener must be utilized.
Model
No.
Soft (0–4 grains per gallon) Medium (5–15 grains per gallon) Hard* (16–25** grains per gallon)
∆T GPM
(lpm) ∆P MTS in. (mm) SHL ∆T GPM (lpm) ∆P MTS in. (mm) SHL ∆T GPM (lpm) ∆P MTS in. (mm) SHL
399B 17 40
(151) 2.0 2 (51) 4.4 13 52 (197) 3.4 2 (51) 7.2 8 90 (341) 10.0 2 (51) 20.5
499B 21 40
(151) 2.1 2 (51) 4.5 16 52 (197) 3.5 2 (51) 7.4 9 90 (341) 10.4 2 (51) 20.9
649B 28 40
(151) 2.2 2 (51) 4.6 20 55 (208) 4.1 2 (51) 8.4 12 90 (341) 10.8 2 (51) 21.3
749B 30 42
(159) 2.6 2 (51) 5.2 20 63 (238) 5.7 2 (51) 11.1 14 90 (341) 11.3 2 (51) 21.8
899B 30 51
(193) 3.9 2 (51) 7.6 20 76 (288) 8.4 2 (51) 16.1 17 90 (341) 11.7 2 (51) 22.2
989B 28 60
(227) 2.7 2.5 (64) 4.6 20 83 (314) 5.2 2.5 (64) 8.6 13 132 (500) 13.1 2.5 (64) 21.0
1259B 30 72
(272) 4.4 2.5 (64) 7.0 20 106 (401) 9.6 2.5 (64) 14.8 16 132 (500) 14.8 2.5 (64) 22.7
1529B 30 86
(325) 7.1 2.5 (64) 10.7 20 132 (500) 16.5 2.5 (64) 24.4 20 132 (500) 16.5 2.5 (64) 24.4
1799B 30 101
(382) 10.7 2.5 (64) 15.5 23 132 (500) 18.3 2.5 (64) 26.1 23 132 (500) 18.3 2.5 (64) 26.1
1999B 30 112
(424) 13.9 2.5 (64) 19.7 26 132 (500) 19.0 2.5 (64) 26.9 26 132 (500) 19.0 2.5 (64) 26.9
2069B 30 116
(439) 14.8 2.5 (64) 21.0 27 132 (500) 19.0 2.5 (64) 26.9 27 132 (500) 19.0 2.5 (64) 26.9
2339B 30 132
(500) 21.4 2.5 (64) 29.3 30 132 (500) 21.4 2.5 (64) 29.3 30 132 (500) 21.4 2.5 (64) 29.3
Gas Supply
ADANGER: Make sure the gas on which the
heater will operate is the same type as specied
on the heater’s rating plate.

19
Gas Supply Connection
The heater must be isolated from the gas supply piping
system by closing the manual shut-o󰀨 valve during any
pressure testing of the gas supply piping system at test
pressures equal to or less than 1/2 psi (3.45 kPa). Re-
lieve test pressure in the gas supply line prior to recon-
necting the heater and its manual shut-o󰀨 valve to the
gas supply line. FAILURE TO FOLLOW THIS PRO-
CEDURE MAY DAMAGE THE GAS VALVES. Over
pressurized gas valves are not covered by warranty.
ACAUTION: The heater must be disconnected
from the gas supply during any pressure testing
of the gas supply system at test pressures in ex-
cess of 1/2 psi (3.45 kPa).
Fig. 14: Gas Supply Connection
ACAUTION: Do not use Teon tape on gas line
pipe thread. 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.
Table I: Maximum Equivalent Pipe Length
Natural gas – 1,000 BTU per ft3, .60 specic gravity at 0.5 in. WC pressure drop
Propane gas – 2,500 BTU per ft3, 1.53 specic gravity at 0.6 in. WC pressure drop
Model
No.
3/4” 1” 1-1/4” 1-1/2” 2” 2-1/2” 3” 4”
NPNPNPNPNPNPNPNP
399B 15 25 60 100 260 250
499B 65 150 130 360 500
649B 45 100 95 250 340
749B 35 80 75 180 260 600
899B 20 45 45 110 150 360 400
989B 120 300 300
1259B 75 180 170 325 560
1529B 50 120 125 250 400
1799B 40 100 100 225 340
1999B 30 80 75 175 260
2069B 30 80 75 175 260
2339B 20 55 55 135 160 400 600
Gas piping must have a sediment trap ahead of the
heater gas controls, and a manual shut-o󰀨 valve locat-
ed outside the heater jacket. It is recommended that a
union be installed in the gas supply piping adjacent to
the heater for servicing. A pounds-to-inches regulator
must be installed to reduce the gas supply pressure to
a maximum of 10.5 in. WC for natural gas and 13.0 in.
WC for propane gas. The regulator should be placed
a minimum distance of 10 times the pipe diameter up-
stream of the heater gas controls. Refer to Table I for
maximum pipe lengths.
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 an open ame.

20
Fig. 16: Gas Valves
ACAUTION: Support gas supply piping with
hangers, not by the heater or its accessories.
Make sure the gas piping is protected from
physical damage and freezing, where required.
Reversing Gas Supply Connection
Reversing the standard fuel connection from the left-
hand to the right-hand side is a simple eld operation.
1. Disconnect all electrical power from the heater
(if applicable).
2. Disconnect the main gas pipe from the heater
(if applicable).
3. Remove the left and right front panels from the
heater.
4. Locate the main gas line that traverses across the
heater above the manifold risers.
5. Remove the pipe cap from the right-hand end of
the main gas line.
6. Reinstall the pipe cap on the left-hand end of the
main gas line.
7. Remove plastic cap from the right-hand side panel
and reinstall into the standard main gas opening
located on the left-hand side of the heater.
8. Remove the rubber grommet from the left-hand-
side panel and reinstall into the standard main
gas opening, located on the right-hand side of the
heater.
9. Install a coupling, nipple, union and sediment trap
onto the right-hand end of the main gas line and
then install the gas line, making sure that a manual
shut-o󰀨 valve has been installed within 10 ft of the
heater.
10. Replace the left and right front panels on the
heater.
Gas Regulator Best Practices
From the gas pressure regulator it is recommended to
have no less than 10 pipe diameters of straight smooth
pipe downstream of the regulator discharge and to
have no less than 10 linear feet (not including ttings)
between the regulator and the inlet to the appliance for
proper operation.
Gas Supply Pressure
A minimum of 5.0 in. WC and a maximum of 10.5 in.
WC upstream gas pressure is required under load
and no-load conditions for natural gas. A minimum
of 11.0 in. WC and a maximum of 13.0 in. WC is re-
quired for propane gas. The gas pressure regulator(s)
supplied on the heater is for low-pressure service. If
upstream pressure exceeds 14.0 in. WC, an intermedi-
ate gas pressure regulator, of the lockup type, must be
installed.
When connecting additional gas utilization equipment
to the gas piping system, the existing piping must be
checked to determine if it has adequate capacity for
the combined load.
The gas valve pressure regulator(s) on the heater are
nominally preset at 3.5 in. WC for natural gas, and 10.5
in. WC for propane gas heater on models 302 thru 902.
9.0 in. WC for propane gas on heater models 992 thru
2342. The pressure at the gas valve outlet tap, mea-
sured with a manometer, while in operation should be
3.5 ± 0.1 in. WC for natural gas and 10.5 in. ± 0.1 in.
WC for propane gas on heater models 302 thru 902.
9.0 to 9.5 in. WC for propane gas on heater models
992 thru 2342. If an adjustment is needed, remove the
adjustment screw cover and turn the adjustment screw
clockwise to increase pressure or counter-clockwise to
lower pressure.
Models 399B–2339B
Models 989B–2339B
TO APPLIANCE
5X DIA
REGULATOR
10X DIA
10 FEET MIN
Fig. 15: Gas Regulator Distances