Cambridge Air Solutions Blow-Thru SA Series User manual

SA-SERIES
Direct Gas-Fired
Industrial Blow-Thru®Space Heater
Technical Manual
SA-TM3-0120
WARNING:
Improper installation, adjustment, alteration, service or maintenance can cause property
damage, injury or death. Read the installation, operating, and maintenance instructions
thoroughly before installing or servicing this equipment.
FOR YOUR SAFETY
The use and storage of gasoline or other flammable vapors and liquids in open containers in
the vicinity of this appliance is hazardous.
FOR YOUR SAFETY
If you smell gas:
1. Open windows.
2. Don’t touch electrical switches.
3. Extinguish any open flame.
4. Immediately call your gas supplier.
Made in the USA
90.1
ASHRAE
ASHRAE
COMPLIANT
COMPLIANT

LIMITED WARRANTY
Cambridge Air Solutions (“Manufacturer”) warrants that its products (“the Products”) to be free from
defects in material and workmanship. Manufacturer’s SA-Series Products shall be warranted for a period
of 24 months from the date of shipment, except that burner assemblies are warranted for five years from
date of shipment.
Buyer’s sole and exclusive remedy for any nonconformity with this warranty shall be, at Manufacturer’s
option, repair or replacement of nonconforming parts, provided that Buyer shall return to Manufacturer,
shipping prepaid, said non-conforming part(s) bearing a durable tag indicating the Serial Number of
the Product from which the part was taken. In addition, Manufacturer may opt not to repair or replace
nonconforming Product or part(s), but instead may refund to Buyer the price thereof, in lieu of repair
or replacement. In no event shall Manufacturer be liable for more than a refund of the purchase price or
replacement value of the Product or part(s), whichever is less. This Warranty does not apply to field labor
charges.
This Warranty does not apply and shall be void as to any Products that are misused or misapplied, that are
installed, operated or maintained not in conformity with Manufacturer’s design, specifications, instructions,
or Technical Manual, or are installed, operated or maintained in violation of any applicable national or
local codes or industry standards.
Manufacturer does not warrant Products, if they are abused, improperly operated or maintained, subjected
to abnormal wear and tear, damaged due to improper gas or electric service, damaged in transit, or that
have been repaired or modified by others without Manufacturer’s written authorization.
Buyer shall have no right to enforce this Warranty unless it has complied with all of its obligations under
the contract for purchase/lease of the Products, including without limitation, being current on all payment
terms.
THIS LIMITED WARRANTY IS MANUFACTURER’S ONLY WARRANTY WITH RESPECT
TO THE PRODUCTS, AND IT IS IN LIEU OF AND SUPERSEDES ANY AND ALL OTHER
WARRANTIES OF ANY KIND WHATSOEVER, WHETHER WRITTEN, ORAL OR IMPLIED,
INCLUDING WITHOUT LIMITATION ANY IMPLIED WARRANTIES OF MERCHANTABILITY
OR FITNESS FOR A PARTICULAR PURPOSE. THE REMEDIES AFFORDED BUYER BY THIS
WARRANTY ARE THE ONLY REMEDIES AFFORDED BUYER FOR ANY NONCONFORMITY
WITH THIS
WARRANTY OR FOR ANY DEFECT IN PRODUCTS, SERVICES, OR REPRESENTATIONS
PROVIDED BY MANUFACTURER IN CONNECTION WITH SUCH PRODUCTS. IN NO EVENT
SHALL MANUFACTURER BEAR ANY LIABILITY FOR INCIDENTAL OR CONSEQUENTIAL
DAMAGES OF ANY KIND WHATSOEVER, INCLUDING WITHOUT LIMITATION PERSONAL
INJURY (INCLUDING DEATH), PROPERTY DAMAGE, LOST PROFITS OR OTHER ECONOMIC
LOSS.
Buyer acknowledges that the foregoing warranty, limitations, and exclusions are a reasonable allocation
of commercial risks by and among sophisticated business entities and are not subject to dispute as to their
commercial reasonableness, fairness or ability to satisfy the essential purposes of the parties’ transaction.

Cambridge Air Solutions
760 Long Road Crossing Dr.
Chesterfield, MO. 63005
Phone: [phone]
Fax: [phone]
www.cambridgeair.com
SA-SERIES
BLOW-THRU®SPACE HEATER
TECHNICAL MANUAL
Copyright © 2020
Cambridge Air Solutions
All Rights Reserved
Contents
Hazard Summary .............................................................................................................. 2
General Installation Instructions....................................................................................... 3
Uncrating Instructions....................................................................................................... 3
Mounting Location............................................................................................................ 3
Typical System Overview ................................................................................................. 4
Accessory Identification..................................................................................................4
Heater Operation.............................................................................................................5
Heater Configuration ......................................................................................................5
Roof Top Mounting.........................................................................................................6
Thru Wall Mounting........................................................................................................8
Under Roof Mounting...................................................................................................10
Gas Piping.....................................................................................................................12
Electrical Wiring ..........................................................................................................13
Start-up Instructions........................................................................................................14
Shutdown Instructions .................................................................................................... 17
Calibration Procedure .................................................................................................... 17
Operating Instructions..................................................................................................... 19
Operating Sequence ......................................................................................................19
TSS Controller .............................................................................................................20
Troubleshooting Instructions .......................................................................................... 29
Troubleshooting Guide..................................................................................................29
Reference ........................................................................................................................ 35
Electrical Control Enclosure .........................................................................................35
Electrical Wiring Diagrams...........................................................................................36
Electrical Connection Diagram ....................................................................................38
Individual Component Descriptions .............................................................................39
ANSI/ASHRAE/IESNA Standard 90.1 ........................................................................42

Cambridge Air Solutions 2 SA-Series Technical Manual
HAZARD SUMMARY
Hazard Identification
Warnings and Cautions appear at appropriate sections throughout this manual. Read these carefully.
WARNING: Indicates a potentially hazardous situation which could result in
death or serious injury.
CAUTION: Indicates a potentially hazardous situation which may result in minor or
moderate injury. It may also be used to alert against
unsafe practices.
CAUTION: Indicates a situation that may result in accidents with equipment or
property damage only.
The following safety precautions apply to the
installation, operation, and maintenance of the
equipment described by this technical manual.
WARNING:
Any unauthorized modification of this equipment
shall void the warranty.
WARNING:
Only qualified personnel should attempt
installation, service, and repair of this equipment.
Use extreme caution and observe safety
regulations at all times.
WARNING:
Recirculation of room air is not permitted.
Adequate building relief must be provided so as to not
over pressurize the building when the heating system
is operating at its rated capacity. It should be noted
that this can be accomplished by taking into account,
through standard engineering methods, the structure’s
designed infiltration rate, by providing properly sized
relief openings, or by interlocking a powered exhaust
system, or by a combination of these methods.
If the failure or malfunction of this heater creates
a hazard to other fuel burning equipment in the
building, (e.g. when the heater is providing the make-
up air to a boiler room), the unit is to be interlocked
to open inlet air dampers or other such devices.
If the heater is installed such that an inlet duct is
utilized, the duct system must be purged with at least
four air changes prior to an ignition attempt.
Installation in Aircraft Hangars
Refer to the Standard for Aircraft Hangars,
ANSI/NFPA 409, for specific information on
the installation requirements for these heaters in
aircraft hangars.
Installation in Parking Garages
Refer to the Standard for Parking Structures, ANSI/
NFPA 88A, or the Standard for Repair Garages,
ANSI/NFPA 88B, for specific information on the
installation requirements for these heaters in public
garages.
IMPORTANT
If in doubt regarding installation application, contact
Cambridge Customer Service Group at 1-800-473-
4569 during the hours of 8:00 a.m. to 5:00 p.m.
Central Time, Monday through Friday.

SA-Series Technical Manual 3 Cambridge Air Solutions
GENERAL INSTALLATION INSTRUCTIONS
UNCRATING INSTRUCTIONS
1. Verify that the number of items on the Bill of Lading
matches the number of items received.
2. Check for shipping damage.
IMPORTANT
If damage is found, immediately file a claim with the
carrier before proceeding further.
3. Check the items received to ensure they agree with
the ordering information including verification of
data on the unit nameplate.
IMPORTANT
Do not discard any components or accessories.
MOUNTING LOCATION
Verify feasibility of the installation location selected
with respect to accessibility to the heater for service and
maintenance functions. Ensure the positioning of the
heater does not inhibit fork truck operation, storage rack
locations, or other operations within the facility. Ensure
the heater inlet and outlet are not blocked or severely
restricted in any way that would affect the rated airflow
through the heater or affect the desired air distribution
pattern of the heater.
WARNING:
It is recommended the heater mounting structure
be reviewed and approved by a qualified structural
engineer and the roof manufacturer before installing
this equipment.
WARNING:
To prevent contaminated air from being drawn
into the heater, install the heater’s inlet at least 10
feet from any building exhaust, process exhaust,
sewer stacks, or other sources that would allow
contaminants to be drawn into the heater. Consult
local codes for additional references.
IMPORTANT
Where the mounting height of the heater is required to
be above 15 feet, work platforms or service lifts should
be provided for accessibility to the equipment for
service and maintenance activities.
IMPORTANT
Field constructed intake accessories should be designed
to minimize the entry of snow and rain.
IMPORTANT
The minimum clearance from the face of the electrical
control enclosure to surrounding grounded surfaces for
service activities is 42". Adequate clearance of 42" for
burner removal is also required. Access for installation
is also recommended on the side of the unit opposite
the control enclosure for a distance of 24".

Cambridge Air Solutions 4 SA-Series Technical Manual
TYPICAL SYSTEM OVERVIEW
ACCESSORY IDENTIFICATION
Roof Top Mounting
RH
UNIT
AMS
MC
DE
DD
Thru Wall - Spiral Mounting
Thru Wall Mounting
RH
IC
UNIT
DE
AMS Adjustable Mounting Stand
DD Discharge Duct
DE Directional Elbows
IC Inlet Collar
IT Inlet Transition
MC Mounting Curb
RH Rain Hood
Component Identification
Under Roof Mounting
IT UNIT
DE

SA-Series Technical Manual 5 Cambridge Air Solutions
HEATER CONFIGURATION
Cambridge SA-Series Blow-Thru®heaters are utilized
to meet the space heating requirements of commercial
or industrial buildings. The control system is typically
designed to cycle the heaters on and off in response to
the rise and fall of the space temperature. The heater
will discharge air at the temperature selected (up to
160ºF). The operating thermostat is typically located
near the perimeter of the building in a location which
is out of the direct path of the heated discharge air,
insulated from cold surfaces, and shielded from cold
drafts created by air infiltrating the building.
TYPICAL SYSTEM OVERVIEW
HEATER OPERATION
SA250
SA350

Cambridge Air Solutions 6 SA-Series Technical Manual
INSTALLATION INSTRUCTIONS
ROOF TOP MOUNTING
WARNING:
It is recommended the heater mounting structure
be reviewed and approved by a qualified structural
engineer and the roof manufacturer before
installing this equipment.
IMPORTANT
Before proceeding with the installation, verify the
feasibility of the location selected with respect
to accessibility to the equipment for service and
maintenance functions.
IMPORTANT
To minimize snow and rain ingestion, position the
heater inlet opposite the prevailing winds.
IMPORTANT
To prevent contaminated air from being drawn
into the heater, install the heater’s inlet at least 10
feet from any building exhaust, process exhaust,
sewer stacks, or other sources that would allow
contaminants to be drawn into the heater. Consult
local codes for additional references.
1. Prepare roof penetration to the dimensions below.
Prepare gas and electric penetrations.
IMPORTANT
Accurate measurements are critical and will affect
the installation process.
2. Secure the mounting curb and mounting
stands per the structural engineer and roof
manufacturer’s recommendations.
IMPORTANT
The roof curb and mounting stands should be
installed so that the heater will mount level.
Cambridge recommends mounting the heater 24"
off the roof surface in areas where snow
accumulation could impact heater operations.
3. Lower the discharge duct through the mounting
curb and the roof opening and secure the
counterflashing to the mounting curb.
4. Use a crane or comparable lifting device to raise
and position the equipment. Block the heater
where necessary. Use a spreader bar to prevent
damage and connect slings to the lifting brackets.
WARNING:
Do not attach lifting means to heater accessories.
Make connections to heater only.
IMPORTANT
Inlet accessories may be attached on the ground or
on the roof depending on the method chosen by the
installer.
5. Using the adjustable mounting stand, lower the
heater inlet slightly (1/8" below level) so that any
ingested moisture will drain out of the heater and
onto the roof surface.
6. Caulk all the joints between the heater and the
accessories with silicone caulk to prevent water
leaks.
7. Seal all roof penetrations to prevent roof leaks.
8. Install the directional elbows. Consult the job
layout for the orientation of the elbows.
Weight A B
Roof Opening
Model L W
SA250 265 lbs. 48.25” 21.17” 8.5" 16"
SA350 550 lbs. 65.5” 25.5” 13" 25"

SA-Series Technical Manual 7 Cambridge Air Solutions
CURB SECTION
(PROVIDED)
2 x 2 WOOD NAILER
INSULATION
2.5" 1.6"
FLASHING
STAND DETAIL
2 x 6 TREATED LUMBER
(BY OTHERS)
522.5"
4
RAINHOOD
UNIT
MOUNTING CURB
DIRECTIONAL ELBOWS
DISCHARGE DUCT
SECURING BRACKET
ELECTRICAL CONTROL ENCLOSURE
ADJUSTABLE MOUNTING STAND
BLOWER ACCESS PANEL
CONTROL WIRING CONDUIT
REMOTE CONTROL STATION/
THERMOSTAT CONTROLS
INCOMING POWER
(BY OTHERS)
(SA250)
(SA350)
BLOWER ACCESS PANEL
(SA250)
TYPICAL INSTALLATION
ROOF TOP MOUNTING
NOTES
TREATED TIMBER REQUIRED UNDER MOUNTING CURB
AND STAND TO SECURE AND LEVEL UNIT.
SECURE MOUNTING STAND TO TIMBER WITH WOOD LAG
SCREWS AS SHOWN.
MOUNTING STAND CONSTRUCTION:
12 GA. GALVANIZED STEEL
ATTACH MOUNTING STAND TO UNIT
ADJUSTABLE ±3.75"
1
2
3
4
5

Cambridge Air Solutions 8 SA-Series Technical Manual
INSTALLATION INSTRUCTIONS
THRU WALL MOUNTING
WARNING:
It is recommended the heater mounting structure
be reviewed and approved by a qualified structural
engineer and the roof manufacturer before
installing this equipment.
IMPORTANT
Before proceeding with the installation, verify the
feasibility of the location selected with respect
to accessibility to the equipment for service and
maintenance functions.
IMPORTANT
To prevent contaminated air from being drawn
into the heater, install the heater’s inlet at least 10
feet from any building exhaust, process exhaust,
sewer stacks, or other sources that would allow
contaminants to be drawn into the heater. Consult
local codes for additional references.
1. For square duct - prepare wall penetration for
inlet collar to the dimensions below.
For round duct - prepare wall penetration to
accommodate the inlet duct (by others).
2. For square duct - Connect the inlet collar and the
rain hood to the unit prior to lifting the heater in
place.
For round duct - Attach the inlet duct to the rain
hood. Lift the rain hood and inlet duct into place
and attach to the wall.
3. Install hanging rods to adequate ceiling supports
and align with the hanging brackets on the unit.
Locate the hanging rods so that the weep holes
provided in the rain hood are located a minimum
of 3" beyond the outside wall surface.
4. Install the hanging brackets on the heater.
5. Use a forklift or comparable lifting device to
raise and position the heater. Take precautions
to prevent equipment damage (dents and/or
scratches) when the heater is being lifted into
position.
6. Use washers and double lock nuts to secure the
unit on the hanging rods.
7. For round duct - Attach the inlet duct to the
inlet transition.
IMPORTANT
The discharge end of the heater should be raised
slightly (1/8" above level) to slope the rain hood so
any ingested moisture will run outside the building.
8. Install fiberglass insulation in the gaps around
the wall opening. Apply enough material to
accommodate the full thickness of the wall.
9. Install finish trim pieces (by others) to the top,
sides and bottom of the wall opening on both the
inside and outside wall surfaces.
10. Apply silicone caulk at the joint between the top
of the rain hood and the outside wall surface.
Make certain this is a continuous bead and that it
runs the entire width of the rain hood. Caulk all
other exposed joints.
11. Install the directional elbows. Consult the job
layout for the orientation of the elbows.
Weight
Hanging Rods Wall Opening
Model Qty. Size A B H W
SA250 220 lbs. 4 3/8" dia. 53" 23.16" 23" 23"
SA350 550 lbs. 4 3/8" dia. 58" 33.25" 25" 27.5"

SA-Series Technical Manual 9 Cambridge Air Solutions
TYPICAL INSTALLATION
THRU WALL MOUNTING
HANGING ROD DETAILHANGING BRACKET DETAIL
HANGING ROD
WASHER
WASHER
NUT
SHIPPING POSITION
DOUBLE NUT
SA250 SA350
HANGING RODS, NUTS AND WASHERS BY OTHERS

Cambridge Air Solutions 10 SA-Series Technical Manual
INSTALLATION INSTRUCTIONS
UNDER ROOF MOUNTING
WARNING:
It is recommended the heater mounting structure
be reviewed and approved by a qualified structural
engineer and the roof manufacturer before
installing this equipment.
IMPORTANT
Before proceeding with the installation, verify the
feasibility of the location selected with respect
to accessibility to the equipment for service and
maintenance functions.
IMPORTANT
To prevent contaminated air from being drawn
into the heater, install the heater’s inlet at least 10
feet from any building exhaust, process exhaust,
sewer stacks, or other sources that would allow
contaminants to be drawn into the heater. Consult
local codes for additional references.
1. Install the accessories for roof intake (by others).
2. Install the hanging brackets on the heater.
3. Install hanging rods to adequate ceiling supports
and align with the hanging brackets on the heater.
4. Use a forklift or comparable lifting device to
raise and position the heater. Take precautions
to prevent equipment damage (dents and/or
scratches) when the heater is being lifted into
position.
5. Use washers and double lock nuts to secure
equipment on the hanging rods.
6. Install the directional elbows. Consult the job
layout for the orientation of the elbows.
Weight
Hanging Rods
Model Qty. Size A B
SA250 220 lbs. 4 3/8" dia. 53" 23.16"
SA350 550 lbs. 4 3/8" dia. 58" 33.25"

SA-Series Technical Manual 11 Cambridge Air Solutions
INLET PLENUM
(BY OTHERS)
INSULATED INLET DUCT
(BY OTHERS)
INLET TRANSITION
DIRECTIONAL ELBOWS
ELECTRICAL CONTROL ENCLOSURE
BLOWER ACCESS PANEL
(BY OTHERS)
INCOMING POWER
(BY OTHERS)
HANGING ROD
THERMOSTAT CONTROLS
REMOTE CONTROL STATION/
CONTROL WIRING CONDUIT
(BY OTHERS)
INSULATED INLET DUCT
(BY OTHERS)
INSULATED INLET ELBOW BLOWER ACCESS PANEL
(SA350)
(SA250)
TYPICAL INSTALLATION
UNDER ROOF MOUNTING
HANGING ROD DETAILHANGING BRACKET DETAIL
SA250 SA350
HANGING RODS, NUTS AND WASHERS BY OTHERS
HANGING ROD
WASHER
WASHER
NUT
SHIPPING POSITION
DOUBLE NUT

Cambridge Air Solutions 12 SA-Series Technical Manual
INSTALLATION INSTRUCTIONS
GAS PIPING
IMPORTANT
Refer to the heater nameplate for determining the
minimum gas supply pressure for obtaining the
maximum gas capacity for which this heater is specified.
1. Check with the local utility or gas supplier to
determine the gas supply pressure.
CAUTION:
If the gas supply pressure is in excess of the maximum
pressure indicated (14" WC) on the heater nameplate,
a separate positive shutoff high pressure regulator must
be added upstream of the heater’s individual manual
shutoff valve. This regulator must be vented to outside
of building at least 10 feet from any intake opening.
The vent pipe should be designed to prevent the entry
of water, snow, insects or other foreign material that
could cause blockage. There must be no reduction in
size of the vent piping. Depending on the length and
the configuration of the vent piping the pipe size may
need to be increased. Refer to the applicable codes
for proper sizing.
2. Properly size the gas supply piping for the rated
input capacity, per local codes, and/or the National
Fuel Gas Code, ANSI Standard Z223.1 or the
CAN/CSA B149 Installation Codes.
3. Make sure the supply piping is free of foreign
matter and purged.
4. Verify that the gas piping, when installed, will not
restrict or block the unit access door from fully
opening.
5. Install the gas piping to the unit in accordance
with local codes or, in their absence, in accordance
with the National Fuel Gas Code, ANSI Standard
Z223.1 or the CAN/CSA B149 Installation Codes.
IMPORTANT
A 1/8" NPT tap is supplied with the heater for measuring
the gas supply pressure. If the gas supply pressure
exceeds that indicated on the nameplate, the installer
must install a 1/8" NPT tap and high pressure manual
shutoff valve upstream of the high gas pressure regulator.
CAUTION:
An adequate sediment trap must be installed
upstream of all gas controls for the heater and as
close to the gas inlet connection of the heater as
practical.
IMPORTANT
Many gas train components are equipped with Listed
Vent Limiters as atmospheric bleeds, however, local
codes may require that these vents and bleeds be
vented to the outdoors. If so, the vent piping should be
designed to prevent the entry of water, snow, insects or
other foreign materials that could cause blockage.
6. Apply test pressure to the supply piping system
and check for leaks. Use liquid gas detector. Do
not use flame.
CAUTION:
If the test pressure is in excess of 1/2 PSIG
(3.45 KPA), the heater and its manual shutoff valve
must be disconnected from the gas supply system
during pressure testing. Failure to comply will void
warranty.
If the test pressure is less than or equal to 1/2 PSIG
(3.5 KPA), the heater must be isolated from the gas
supply piping by closing its manual shutoff valve
during pressure testing.
WARNING:
Do not attempt to start unit at this time. Premature
start-up can result in damage to equipment and
components.

SA-Series Technical Manual 13 Cambridge Air Solutions
INSTALLATION INSTRUCTIONS
ELECTRICAL WIRING
IMPORTANT
Before attempting electrical installation, review the
following instructions and the wiring and connection
diagrams to make sure you have a thorough
understanding of the requirements.
WARNING:
High voltage electrical input to this equipment is
required. Extreme caution should be exercised.
This equipment must be electrically grounded in
accordance with local codes or in accordance with
National Electrical Code ANSI/NFPA No. 70 or the
Canadian Electrical Code C22.1.
1. Check the heater nameplate to determine the
voltage and amperage requirements.
IMPORTANT
Do not proceed with installation unless the supply
voltage agrees with the nameplate voltage. If supply
voltage does not agree with nameplate voltage, check
with your local agent or Cambridge Air Solutions
Customer Service Group at 1-800-473-4569 to
determine what changes are required.
2. Install the supply wiring and adequate Branch
Circuit Protection in accordance with National
Electric Code ANSI/NFPA 70 or Canadian
Electrical Code C22.1.
3. Mount the remote control station. This panel
should be located inside of the building and
convenient to the operator without being
susceptible to damage.
4. Any temperature sensors should be located along
a perimeter wall and out of the direct path of
the discharge air or air infiltration. Consult the
design drawing and/or Cambridge’s Customer
Service Group for placement assistance. Do
not locate remote mounted temperature sensors
immediately adjacent to overhead doors because
infiltration air can affect the sensor when the door
is closed and the sensor may not adequately sense
the temperature when the door is open. In this
application, the sensor should be located on the first
column in from the outside wall.
CAUTION:
Observe special notes and instructions on Wiring
and Connection Diagrams regarding sensor
installation.
The wiring for any temperature sensors mounted
remote from the remote control station must be
shielded, twisted-pair wiring and must run separate
from other AC wiring.
If the thermistor is not mounted remote from the
remote control station, trim the excess wire length
from the thermistor, as required.
Shielded wire which is routed to the heater’s electrical
control enclosure should extend beyond the high
voltage section of the enclosure before the shielding is
terminated and the wiring is distributed to its ultimate
destination.
Shielding must be grounded at the remote control
station end only.
5. Wire the remote control station and other
temperature control options using Class II wiring
per the Cambridge wiring diagram and National
Electrical Code Article 725 or Canadian Electrical
Code C22.1 section 16 or local codes.
6. Connect the supply wiring to an electric
disconnect switch (by others) having adequate
ampacity per National Electrical Code, Article
430, ANSI/NFPA 70 or Canadian Electrical
Code C22.1 Sections 12 and 28. See the heater
nameplate for voltage and ampacity requirements.
IMPORTANT
Power and control wiring inlets on all outdoor units
must be sealed with silicone caulk to prevent moisture
accumulation.
7. Return the wiring diagram to the manual holder.
Replace and fasten all access covers.
WARNING:
Do not attempt to start unit at this time.
Premature start-up can result in damage to
equipment and components.

Cambridge Air Solutions 14 SA-Series Technical Manual
START-UP INSTRUCTIONS
1. Visual Inspection of Equipment (page 14)
2. Electrical Supply Voltage Verification (page 14)
3. Gas Supply Pressure Verification (page 14)
4. Motor Amp Draw Check (page 15)
5. Burner Manifold Pressure Adjustment (page 15)
6. Minimum Fire Adjustment (page 15)
7. Calibration Check (page 16)
8. Gas Valve Leak Check (page 16)
9. Gas Train Leak Check (page 17)
10. Remote Control Station Check (page 17)
11. Final Heater Preparation (page 17)
After start-up, please complete and fax the SA-Series
Start Up Checklist to the Cambridge Customer Service
Group. Receipt of completed checklist will start your
warranty period from the date of start-up.
IMPORTANT
Read the following instructions carefully. Any
unauthorized modifications to, or deviations from these
instructions will void warranty.
VISUAL INSPECTION OF EQUIPMENT
1. Check for any physical damage from shipping or
installation that could render the heater inoperable.
2. Verify all heater accessories have been properly
installed.
3. Check for loose components.
4. Verify the field wiring, both primary and control,
has been installed according to the Cambridge
wiring diagram, National Electrical Code, and local
electrical codes.
5. Verify that the sediment trap has been installed prior
to all gas controls.
6. Verify the high pressure regulator, if applicable, has
been vented to the outside.
7. Verify that the unions in the gas piping located at
the burner and just external to the heater housing,
are tight.
8. If inlet ducting is utilized, determine the time
required to purge it with four (4) air changes and
select a pre-purge time that will accommodate
this time. Utilize jumper settings on the Multi-
functional PC Board to set the Purge Timer to 2, 4,
8, 16, or 32 seconds, as applicable.
ADJUSTMENT
TIMER
PREPURGE
ELECTRICAL SUPPLY VOLTAGE VERIFICATION
1. Check electrical supply voltage at the supply wiring.
2. Nameplate Volts 115V/1PH (SA250)
208-230V/1PH (SA350)
Actual Volts __________________
IMPORTANT
Do not proceed with start-up unless supply voltage
agrees with nameplate voltage. If supply voltage does
not agree with nameplate voltage, check with your
local agent or Cambridge Air Solutions Customer
Service Group to determine what changes are required.
3. Set transformer jumper for correct voltage (page 37)
GAS SUPPLY PRESSURE VERIFICATION
1. Verify the gas supply pressure complies with heater
nameplate.
2. Nameplate Max Gas Supply Pressure 14" WC
Actual Gas Supply Pressure ________" WC
IMPORTANT
Do not proceed with start-up unless the gas supply
pressure agrees with nameplate pressure requirements.
If the gas supply pressure is in excess of the maximum
pressure indicated, a separate positive shut-off high
pressure regulator must be added upstream of the
heater’s individual low pressure manual shut-off valve.
If a high pressure regulator is needed and has not been
installed, check with your local agent or Cambridge
Air Solutions Customer Service Group to determine the
size and capacity requirements.

SA-Series Technical Manual 15 Cambridge Air Solutions
MOTOR AMP DRAW CHECK
IMPORTANT
The blower access door must be closed for this test.
1. Turn the blower service switch to the “LOCAL”
position and let the motor warm up.
2. Check motor current at the motor starter.
3. Turn the blower service switch to “OFF” position.
IMPORTANT
The motor current must not exceed 103% of the Motor
Nameplate FLA. High amperage may indicate excessive
blower RPM
BURNER MANIFOLD PRESSURE ADJUSTMENT
1. Turn off the disconnect switch (by others).
2. Remove the wire from terminal #3 on the amplifier.
This will drive the modulating valve to full open.
3. Remove the 1/8" plug from the manual shut-off
valve located just prior to the burner, and connect
a manometer for the purpose of measuring the
manifold pressure.
4. Refer to the heater nameplate for the Manifold
Differential Pressure (MDP) and record in step 7.
5. Turn on the disconnect switch (by others).
6. Turn the blower service switch to the “LOCAL”
position. The blower motor will start. Observe the
pressure reading on the manometer and record in
step 7. (Note whether the reading is positive or
negative.)
7. Using the formula below, determine the required
manifold pressure reading for the manometer.
Nameplate MDP _______ " WC
Manifold Static Pressure
(Blower Only) + _______ " WC
Manifold Pressure Reading = _______ " WC
IMPORTANT
A negative manifold static (blower only) will cause
the manifold pressure reading to be lower than the
nameplate manifold differential pressure.
8. Turn the burner service switch to the “LOCAL”
position. After a delay for prepurge and igniter
warm-up, the burner will light. Allow 15 seconds for
the low fire start to time out.
9. Observe the manometer reading and compare to
the manifold pressure determined (Step 7). If the
manifold pressure reading does not equal this value,
adjust the control regulator until the proper manifold
pressure is obtained.
10. Turn the blower and burner service switches to the
“OFF” position.
11. Reconnect the wire to terminal #3 on the amplifier.
MINIMUM FIRE ADJUSTMENT
The minimum fire setting is preset at the factory at
approximately 20°F rise.
IMPORTANT
A DC microammeter is required to monitor flame
signal during the adjustment procedure. Ensure the
flame signal remains steady and of sufficient strength to
maintain burner operation for both consistent ignition
at minimum fire and locking in the flame safeguard
relay. Do not allow the flame signal to drop below 2.0
microamps DC.
1. Remove the cover of the Discharge Air Temperature
Sampling Box. Refer to the Heater Configuration
(page 5) for the Discharge Air Temperature Box
location, and the Individual Component Description
Section (page 39) for additional information. Install
a thermocouple in the grommet inside the Discharge
Air Temperature Sampling Box, and then reinstall
the cover. Route the thermocouple wire to a meter
located outside of the unit.
2. Turn the blower service switch to the “LOCAL”
position and monitor the discharge temperature.
3. Remove the wire from terminal #8 on the amplifier.
This will cause the burner to light on low fire and
then fall to minimum fire.
4. Turn the burner service switch to the “LOCAL”
position. After a delay for prepurge and igniter

Cambridge Air Solutions 16 SA-Series Technical Manual
warm-up, the burner will light. Allow 15 seconds for
the low fire start to time out.
5. Monitor the discharge temperature and flame signal.
Subtract temperature from step 1 above from this
reading to determine temperature rise. If minimum
fire temperature rise is above 20ºF and flame signal is
above 2.0 microamps DC, proceed to step 7.
6. Remove the cap (A) exposing the minimum fire
adjusting screw. Turn the adjusting screw (B) to obtain
the desired minimum fire setting.
7. Replace the cap (A).
8. Turn blower and burner service switches to the “OFF”
position.
9. Reconnect the wire to terminal #8 on the amplifier.
10. When performing start-up proceed to next step,
otherwise perform Final Heater Preparation (page 17).
CALIBRATION CHECK
The discharge temperature control system has been
calibrated at the factory to the specified airflow, static
pressure, and temperature rise. The actual operating
conditions may require minor adjustments to the control
settings to ensure the heater functions within the operating
parameters of its listing.
1. Remove the cover of the Discharge Air Temperature
Sampling Box. Refer to the Heater Configuration
(page 5) for the Discharge Air Temperature Box
location, and the Individual Component Description
Section (page 39) for additional information. Install
a thermocouple in the grommet inside the Discharge
Air Temperature Sampling Box, and then reinstall the
cover. Route the thermocouple wire to a meter located
outside of the unit.
2. The discharge temperature should match the
temperature shown on the MAX dial located on the
amplifier with a resistor of 7,500 ±250 Ω connected
between terminals 21 and 22. The dial should be set
to 160°F.
IMPORTANT
The heater access doors must be closed for the remaining
portion of this test.
3. Turn the blower and burner service switches to the
“LOCAL” position. After a delay for prepurge and
igniter warm-up, the burner will light. Allow 15
seconds for the low fire start to time out.
4. Monitor the discharge temperature until it stabilizes.
Do not rush through this step.
5. The discharge temperature should be 160 +0/-
5°F. If the discharge temperature complies with
this requirement, no calibration is required. If the
discharge temperature does not equal the expected
value, proceed to Calibration Procedure (page 17).
6. For CE-SmartTM Controls remove the resistor
on terminals 21 and 22 and connect the Space
Temperature Selector (STS).
7. When performing a start-up proceed to the next step,
otherwise perform Final Heater Preparation (page 17).
GAS VALVE LEAK CHECK
All heaters should be evaluated for the gas tightness of the
gas valve seat. This evaluation must be performed at least
once per year.
1. Connect a 0 to 10 inches water column (" WC)
manometer to the 1/8" NPT tapped fitting directly
before the manual shut-off valve located just prior to
the burner for the purpose of monitoring an increase
in pressure, and verify the manometer is properly
zeroed.
2. Close the manual burner shut-off valve and, with
supply gas connected, wait 30 seconds to read the
manometer. If reading is greater than 0" WC, replace
the gas valve and retest. If reading is 0" WC, remove
manometer and install pipe plug.
3. When performing start-up proceed to next step,
otherwise perform Final Heater Preparation (page 17).
GAS TRAIN LEAK CHECK
1. Remove the wire from terminal #3 on the amplifier.
This will drive the modulating valve to full open.
2. Turn the blower service switch to the “LOCAL”
position. Blower motor will start after the motorized
damper (optional) opens.

SA-Series Technical Manual 17 Cambridge Air Solutions
3. Turn the burner service switch to the “LOCAL”
position. After a delay for prepurge and igniter warm-
up, the burner will light. Allow 15 seconds for the
low fire start to time out.
CAUTION:
Do not allow leak detector solution to come in
contact with electrical components.
4. With the burner operating, spray the complete gas
train with leak detector solution, checking all pipe
connections and plugs.
WARNING:
Any gas leak detected must be repaired before unit
is placed into service.
5. Turn the blower and burner service switches to the
“OFF” position.
6. Reconnect the wire to terminal #3 on the amplifier
7. When performing start-up proceed to next step,
otherwise perform Final Heater Preparation (page
17).
REMOTE CONTROL CHECK
1. If the ambient temperature is at or above the
Entering Air Thermostat (EAT) setpoint, note the
setpoint position. Pull the jumper off the temperature
setpoint (Normal Mode) and reinstall it sideways on
the terminal block (Bypass Mode) as shown below.
Refer to the Individual Component Description
section for additional information.
2. Turn the blower and burner service switches to the
“REMOTE” position.
3. On the thermostat, activate a call for heat by raising
the heat temperature set point to the highest possible
value.
4. After a short delay for damper (optional) operation,
the blower should operate, followed by burner
ignition after a delay for pre-purge and igniter warm-
up.
5. Reset the thermostat to the desired space temperature.
6. Reinstall jumper to (Normal Mode).
7. Service switches should be in "REMOTE".
FINAL HEATER PREPARATION
1. Perform visual inspection of all wiring and gas valve
plugs to ensure they have been properly replaced.
2. Remove all test instrumentation.
3. Replace and fasten all covers and panels. Close the
control enclosure and latch the door.
4. Turn on the disconnect switch (by others).
IMPORTANT
If technical assistance is needed, call the Cambridge
Customer Service Group at 1-800-473-4569 during the
hours of 8:00 a.m. to 5:00 p.m. Central Time, Monday
through Friday.
SHUTDOWN INSTRUCTIONS
1. Turn mode selector switch to “OFF” position.
CALIBRATION PROCEDURE
1. Remove the two mounting screws from the Maxitrol
A1044 Amplifier located in the Electrical Control
Enclosure. Refer to the Electrical Control Enclosure
Isometric Drawing (page 35) for additional
information.
2. Turn the amplifier over and adjust the amplifier
calibration potentiometer shown in the drawing.
To raise the discharge temperature, use a Phillips
screwdriver to adjust the potentiometer counter
clockwise. To lower the discharge temperature, adjust
the potentiometer clockwise.
3. Wait for the discharge temperature and manifold
pressure to stabilize after making adjustments. Do not
rush this step.
4. In rare cases, the amplifier calibration potentiometer
will reach its adjustment limit before the proper
discharge temperature is achieved. If this occurs, the
Discharge Temperature Sensor (DTS) will need to be
adjusted:

Cambridge Air Solutions 18 SA-Series Technical Manual
a. Turn the burner service switch to the “OFF”
position and allow the Discharge Air
Temperature Sampling Box time to cool.
b. Turn blower service switch to “OFF” position.
c. Open the control enclosure door.
d. Remove the access cover from the Discharge
Air Temperature Sampling Box and remove the
two mounting screws from the DTS. Refer to the
Individual Component Description Section (page
38-40) for additional information.
e. Carefully remove the DTS from the sampling
box, turn it over and adjust the DTS calibration
potentiometer shown in the drawing. To raise the
discharge temperature, adjust the potentiometer
90˚ counterclockwise.
f. Carefully reinstall the DTS. Replace the
Discharge Air Temperature Sampling Box cover,
and close the unit access doors.
g. Turn the blower and burner service switches to
the “LOCAL” position. After a delay for the
prepurge and igniter warm-up, the burner will
light.
h. Wait for the discharge temperature and manifold
pressure to stabilize. Do not rush this step.
i. Repeat steps 2 through 4 until manifold pressure
and discharge temperature comply with guidelines
of Calibration Check procedure step 5 (page 16).
j. Reinstall the amplifier that was removed in step 1.
MAINTENANCE INSTRUCTIONS
BELT TENSIONING (SA350 ONLY)
Using a Browning Belt Tension Checker and a straight
edge, verify proper belt tension to a center span
deflection of 1/4" for 2-3 lbs. for new belts or 1-2 lbs.
for used belts.
Periodic belt adjustments may be required. Indications
of loose belts include barking or squealing when blower
starts.
BLOWER CLEANING
The blower wheel should be examined for accumulation
of dust on the blades. These surfaces must be kept clean.
Dirt accumulation will result in significant air flow
reduction and/or possible imbalance of the blower wheel.
CAUTION:
Prolonged imbalance can result in catastrophic
failure of the blower wheel and other related
components.
BURNER CLEANING
The Cambridge Air Solutions burner is for the most part
self-cleaning. However, if the application is extremely
dirty or dusty, it may become necessary to periodically
clean the burner. Remove and clean the burner in
accordance with the following recommended procedures:
1. Turn off the disconnect switch (by others). Close the
manual gas supply shut-off valve.
2. Loosen the union in the gas train.
3. Disconnect the ignition cable from the burner and
remove the flame rod and the igniter.
4. Examine the flame rod ceramic for cracks and replace
if necessary. Clean the flame rod element with emery
cloth to remove oxidation.
5. Remove fasteners that secure burner to housing. The
burner will then be free to slide out.
6. Clean burner by back-flushing using high pressure
air (40-80 PSI). Continue back flushing until dust
particles are completely expelled from burner.
7. Reinstall burner using above steps in reverse order.
GAS TRAIN LEAK CHECK
Periodically check the gas control assembly, internal and
external piping for leaks. Refer to the Gas Train Leak
Check procedure (page 16). All relief vents on the gas
controls should be checked for blockage (gas pressure
regulators and pressure switches).