Thomas & Betts RZ-NA 441-OMS User Manual
C E R T I F I E D
Applies to: Model Series DV
TABLE OF CONTENTS
INDOOR OR OUTDOOR, GAS,
DIRECT-FIRED, MAKEUP AIR/
HEATING SYSTEMS
(Specifications subject to change without notice.)
Operation/Maintenance/Service
Form RZ-NA 441-OMS
Page
MAINTENANCE
SECTION ...................... 2-4
Configuration ................................. 2
Maintenance Schedule ................... 2
1A. Blower Bearings .............................. 3
1B. Blower Belts ................................... 3
2. Filters ................................................. 3
3. Manifold Gas Pressure ...................... 3
4. Air Pressure ....................................... 4
5. Circuit Indicator Board (check lights) 4
6. Main Burner and Pilot Assembly ...... 4
OPERATION/SERVICE
SECTION ................... 5-15
Controls - Location ....................... 5
7. Electronic Circuit Board with
Diagnostic Lights.............................. 5
References: Installation Manual, Form RZ 441
Page
8. Temperature Limit Safety Controls... 5
•Manual Reset Limit Control ........... 5
•Emergency Cut Off Limit Control .. 6
9. Air Pressure Switches ........................ 6
•Low Air Flow Switch ...................... 6
•High Air Flow Switch ...................... 6
•Bypass Damper (Optional) Air
Flow Switches ................................ 6
10. Ignition System ................................ 6
11. Gas Train Including Direct-Fired
Burner, Gas Control Systems,
Manifold Arrangements and Gas
Pressure Switches ............................. 7
•Direct-Fired Burner ........................ 7
•Makeup Air Gas Control Systems .. 7
•Electronic Modulation Gas Control
Options AG30, AG31, AG32,
AG33, AG35, AG36 ...................... 7
•Electronic Modulation Gas Control
Option AG37 ................................. 7
12. Outside Air Ambient Cutoff ............ 8
13. Door Switch ..................................... 9
14. Inlet Air Controls ............................ 9
15. Dirty Filter Switch ......................... 10
16. Photoelectric Smoke Detector ....... 10
17. Firestat ........................................... 10
18. Freezestat ....................................... 10
19. Troubleshooting ............................. 11
Index ................................................... 12
Replacement Parts Manual, Form RZ 741
Page
•Manifold Arrangements ................. 8
•Gas Pressure Switches .................... 8
•Air Flow Dampers ........................... 9
•Damper Motor ................................. 9
•Potentiometer .................................. 9
•Pressure Null Switch ....................... 9
•Photohelic Pressure Switch ........... 10
Chart 1 - General Troubleshooting
Guide (Check the diagnostic lights on
the circuit board)
FOR YOUR SAFETY
WARNING: The use and storage of gasoline or
other flammable vapors and liquids in the vicinity
of this appliance is hazardous.
If you smell gas:
1. Open windows.
2. Don't touch electrical switches.
3. Extinguish any open flame.
4. Immediately call your gas supplier.
WARNING: Improper installation, adjustment,
alteration, service, or maintenance can cause
property damage, injury or death. Read the
installation, operation, and maintenance
instructions thoroughly before installing or
servicing this equipment.
KEEP THIS BOOKLET
FOR MAINTENANCE AND
SERVICE REFERENCE.
Operating/Maintenance/Service
Instructions
The information in this manual applies to Model Series DV, direct-fired heating/makeup air systems. As with any gas burning
equipment, regular maintenance procedures are required to ensure continued safety, reliability and efficiency of the installation.
If service is required, this system should be serviced only by a
qualified service person. Service information in this booklet is
intended as a guideline for a qualified gas-fired equipment service person.
Mfg No. 161442
Page 1
DANGER: The gas burner in this direct gas-fired system is designed and equipped to provide safe and
economically controlled complete combustion. However, if the installation does not permit the burner to
receive the proper supply of combustion air, complete combustion may not occur. The result is incomplete
combustion which produces carbon monoxide, a poisonous gas that can cause death.
Always comply with the combustion air requirements in the installation codes and operating instructions.
The amount of air over the burner must be within the specified range. The burner profile plates are set at
the factory to match CFM requirements. Do not adjust the burner profile plates without contacting the
factory. FAILURE TO PROVIDE PROPER COMBUSTION AIR CAN RESULT IN A HEALTH
HAZARD WHICH CAN CAUSE PROPERTY DAMAGE, SERIOUS INJURY, AND/OR DEATH. Directfired installations should provide for air changes as required by the applicable installation codes.
Maintenance Section
This direct-fired makeup air system is designed to require only a minimum
amount of maintenance. Some maintenance procedures outlined in this Section
require inspection only and some require action. Frequency requirements of
each maintenance procedure are listed in the Maintenance Schedule. Depending
on the environment and the number of operating hours, more frequent inspection and/or cleaning may be required to certain components.
Although maintenance requirements are minimal, the routine maintenance procedures in this Section are necessary to ensure safe, reliable, and/or efficient
operation. The paragraphs which follow discuss the components and systems
that require routine inspection/maintenance. At the beginning of each paragraph,
there is a code indicating why that maintenance procedure is necessary. The
legend for that code is shown below.
Maintenance Codes
Reason for Maintenance
S = Safety (to avoid personal injury and/or property damage)
R = Continued Reliability
E = Efficient Operation
WARNING: Disconnect all power to the
system before doing any maintenance.
Failure to do so may cause electrical shock,
personal injury, or death.
Maintenance Schedule
See Chart
Quarterly
Semi-Annually
Annually
Lubricate bearings, Paragraph 1
Check the filters, Paragraph 2
Check air pressure sensing tubes,
Paragraph 4
Check blower belts, Paragraph 1
Verify gas pressures, Paragraph 3
Clean air pressure sensing tubes,
Paragraph 4
Check indicator lights, Paragraph
5
Check main burner and pilot
assembly, Paragraph 6
Page 2
Discharge Air
Optional Return Air
Outside Air
Figure 1 - System
Configuration
Blower
Section
Burner/Control Section
Location of Optional Filter
Cabinet (not shown)
Screened Inlet Base
R
1. Drive Components
The blower, motor and drive components are located in the blower
cabinet at the top of the system. Systems with horizontal discharge
have a cabinet with eight removable door panels. Systems with vertical
discharge have a cabinet with six removable door panels. Remove the
panels required to access the components being serviced.
1A. Blower Bearings
All blowers are Class I with pillow block bearings. Clean the fitting and
add type NLG-2 or -2 standard grade grease. Add grease with a handgun
until a slight bead of grease forms at the seal. Be careful not to unseat
the seal by over lubricating.
NOTE: If unusual environmental conditions exist (temperatures below
o
F or above 200oF; moisture; or contaminants) more frequent lubri-
32
cation is required.
excessive motor and blower bearing wear. If adjustment is required,
adjust belt tension by means of the adjusting screw on the motor base
until the belt can be depressed 1/2" to 3/4" (Figure 2). Tighten the lock
nut on the adjusting screw. Be sure the belt is aligned in the pulleys.
Figure 2 Belt
Tension
3/4 (19mm)
CAUTION: If the blower is unused for more than
three months, the bearings should be purged with
new grease prior to startup.
Recommended Bearing Lubrication Schedule in Months
Bearing Bore Diameter (Inches)
RPM
1/2 >1 to >1-1/2 to
to 1 1-1/2 1-15/16
to 500 6 6 6
501 - 1000 6 6 6
1001 - 1500 5 5 5
1501 - 2000 5 4 5
1B. Blower Belts
Check belts for proper tension and wear. Adjust belt tension as needed.
Replace worn belts.
Proper belt tension is important to the long life of the belt and motor. A
loose belt will cause wear and slippage. Too much tension will cause
3. Manifold Gas Pressure
S
Semiannually, check the gas pressure to the burner and to the pilot. Measure both manifold pressure and pilot supply pressure with the blower in
operation. Refer to Figure 3 for pressure tap locations. Verify against pressures listed on the rating plate.
R E
If the system includes filters, check the filters quarterly. Filters could
be either in the optional inlet base or in an optional filter cabinet.
If the filters are in the perimeter of the inlet base; they are two-inch
permanent filters. Remove and clean the filters as needed.
If the filters are in a filter cabinet (the filter cabinet is always between
the inlet base and the burner/control section), remove the filter cabinet
door panels to access the V-bank filter rack. Filters may be either 2"
disposable, 1" or 2" permanent, or 1" or 2" disposable pleated. Clean or
replace as needed.
Size 109 112 115 118 122 125
16" x 16" 4 4 - - 16 16
16" x 20" 4466- -
16" x 25" - - 6688
2. Filters
Sizes and Quantity of Filters in the Filter Cabinet
( same for all types of filters)
Figure 3 - Location of
pressure taps for
measuring burner and
pilot gas pressure.
Measure with blower
operating.
Supply
Gas
Pilot Manifold
Valve
Inlet Pressure Tap
Pilot
Regulator
Valve
Pilot Solenoid Valve
Pilot Pressure Tap
Regulator
Manifold Pressure Tap
Page 3
S
4. Air Pressure
Profile plate sensing tubes should be checked quarterly and cleaned no
less than semiannually. If the sensing tubes become even partially
blocked, false pressure readings may be relayed. To clean, remove the
screened end caps. Clean the screens and the tubes, if necessary. Replace the cleaned end caps. Check the pressure differential across the
profile plate using a slope gauge. Air pressure differential should be
between -.5" and -.7" w.c.
To attach the slope gauge, open the control compartment door panel.
Just below the junction box, locate the tubing connections. Remove the
cap at each connection and attach the slope gauge using two fieldsupplied 1/4" x 1/8" female NPT barbed tubing connections. For instructions on measuring air pressure, see Service Section, Paragraph 9.
5. Circuit Indicator Board (check
R
lights)
The circuit indicator board is located in the control compartment electrical box (See Figure 7). Check operation of all indicator lights by
switching lights that are not lit with one that is currently lit. Replace all
burned out indicator bulbs (P/N 125189).
Figure 4 - Circuit
Indicator Board,
P/N 151263
Check bulbs not
lit with other
bulbs; replace
any burned out
bulbs
Row of Bulbs
Figure 5 - Burner
End Plate showing
Hot Surface Ignitor
Burner End Plate
Flame Sensor
Ignitor
If air pressure does not unplug burner orifices or pilot tube, drill
burner orifices with a Size #50 drill and/or pilot tube with a Size #55
drill.
WARNING: Do not enlarge burner ports or
performance may be drastically affected.
Inspect the upstream and downstream sides of the mixing plates.
Remove any accumulation of scale or foreign material with a wire
brush. If any mixing plate fasteners are loose or missing, tighten or
replace. Always use zinc plated or stainless fasteners.
If any cracks are present, replace that mixing plate. Because of the
effect of flame temperature on the metal, fasteners may be difficult
to remove. Be careful not to damage the gaskets that go between the
mixing plates and the burner body. The gaskets are designed to
overlap approximately 1/16" for tight air seal.
5) Follow Steps in reverse order to re-install the pilot assembly. Close
all panels and check for proper operation.
6. Main Burner and Pilot Assembly
S
For the most part, the burner and pilot are self cleaning. However, if the
application is extremely dirty or dusty, cleaning of the burner and pilot
may be necessary. Inspect the burner annually. Follow these instructions. If it is necessary to replace any parts, use only factory-authorized replacements.
1) Turn off the gas and power supply to the system.
2) Remove the door panels in the burner/control cabinet (four or six
depending on whether or not the system has return air). Locate the
pilot.
3) Disconnect the two ignition wires (male and female quick connections) and disconnect the flame sensor lead at the burner. Remove
the set screw located in the ignitor tube (set screw holds the brass
bushing in place). Carefully remove the brass bushing and the ignitor.
Check the hot surface ignitor for cracks or unusual deterioration.
Check the flame rod for integrity. Replace the flame rod (P/N 131188)
and/or the hot surface ignitor (P/N 121865) if not in good condition.
4) Clean the burner and pilot by back-flushing, using high pressure air
(40-80 lbs). Continue until dust particles are completely expelled
from both the upstream and downstream sides of the burner.
CAUTION: Wear eye protection while pressure
cleaning and drilling.
Figure 6 - Illustration of the first Burner Section
Mixing
Plate
Full length of the
burner is made up of a
series of 6" or 12"
burner sections in a
linear or oval
configuration
Burner
WARNING: Burner profile plates are factory set
to match CFM requirements.
Do not adjust profile plates without contacting your
Sales Representative for technical assistance.
Page 4
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