AER Modulex MLX Series Owner's manual

AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page | 47
TID-0027_0A
TECHNICAL INSTRUCTIONS
MLX-303 Fireside Maintenance Kit
Kit 58019-07
MLX-454 Fireside Maintenance Kit
Kit 58019-08
MLX-606 Fireside Maintenance Kit
Kit 58019-09
MLX-757 Fireside Maintenance Kit
Kit 58019-10
MLX-909 Fireside Maintenance Kit
Kit 58019-11
MLX-1060 Fireside Maintenance Kit
Kit 58019-12
NOTE
For Modulex 12-Month maintenance
instructions (Annual Inspection), see
Document TID-0026.
Procedure:
Modulex
Fireside (24-Month)
Maintenance
Applies to Modulex Boiler Models:
•MLX-303
•MLX-454
•MLX-606
•MLX-757
•MLX-909
•MLX-1060
\
Description of Document:
A Fireside Inspection (24-month
maintenance) consists of an inspection
and maintenance to the burner modules,
flue collector, spark igniter, and flame
detector.
Modulex MLX Series Boiler
Modulex Fireside (24-Month) Maintenance Kit
Revised: 05/19/2011
Modulex Models and Associated Fireside Maintenance Kit P/Ns

PR1: 04/01/11 Page| 2
Modulex Fireside (24-month) Maintenance
AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone]
Technical Instruction Document
TID-0027_0A
Disclaimer
The information contained in this manual is subject to change without notice from AERCO International,
Inc. AERCO makes no warranty of any kind with respect to this material, including but not limited to
implied warranties of merchantability and fitness for a particular application. AERCO International is not
liable for errors appearing in this manual. Nor for incidental or consequential damages occurring in
connection with the furnishing, performance, or use of this material.
Technical Support:
(Mon–Fri, 8am-5pm EST)
1-800-526-0288
www.aerco.com

PR1: 04/01/11 Page| 3
Modulex Fireside (24-month) Maintenance
AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone]
Technical Instruction Document
TID-0027_0A
1. Fireside (24-Month) Maintenance Instructions
Following are the procedures necessary to perform the Fireside Inspection (24 month) maintenance on
all Modulex MLX boiler models and sizes. Each Fireside Maintenance Kit contains a flame detector,
spark igniter, and associated gaskets for burner modules, flue collector, and condensate tray.
A correctly adjusted Modulex boiler needs very little care other than yearly maintenance. The frequency
of cleaning needed depends on the cleanliness of the air used for combustion. Note that dust present in
the air at the combustion intake will result in reduced burn efficiency and, consequently, reduced heat
output.
This document provides instructions for a Fireside (24-Month) maintenance, including maintenance to
the burner modules, flue collector, spark igniter, and flame detector. These instructions contain all
procedures described in the Annual (12-Month) maintenance instructions (P/N TID-0026) as well as
additional procedures concerning the burner modules. For each of the different Modulex boiler models,
there is an associated maintenance kit P/N, as shown in the table on the cover and at the end of these
instructions.
REQUIRED Tasks:
•Inspect igniter and flame sensor (replace, Igniter: P/N 95251245, Detector: P/N 95251246)
•Check flame detection circuitry (See paragraph 1.3)
•Inspect and clean burner modules (clean if needed) (see Section 1.4)
•Inspect flue collector (clean if needed) (see Section 1.5)
•Wash heat exchanger (clean if needed)
•Inspect air filters (replace if needed, AERCO P/N 95261879)
•Inspect condensate drain lines (clean if needed)
•Check for gas leaks using a soapy solution
•Inspect igniter and flame sensor (replace, Igniter: P/N 95251245, Detector: P/N 95251246)
•Check pH of boiler system water (refer to Appendix C, Boiler Water Chemistry and Maintenance
in MLX boiler manual GF-115-H).
RECOMMENDED Tasks:
•Inspect condensate tray (clean if needed)
•Inspect vent pipe (clean if needed)
•Check and adjust air/fuel ratio (see MLX boiler manual GF-115-H, paragraph 7.5.5)
•Inspect heat transfer surfaces (clean if needed)
•Clean strainer mesh (Monthly)
•Check inlet gas pressure. Changes in gas pressure require combustion recalibration (see MLX
boiler manual GF-115-H, paragraph 7.5.5)
•Check vent and inlet air terminations
•Check electrical supply voltages
Tools Required
Common hand tools, plus a spark gap feeler gauge are required to perform the annual maintenance tasks
described in this bulletin.
Prior to performing the following disassembly and inspection procedures, ensure that all electrical
power to the boiler has been turned off and the external gas shut-off valve is fully closed.
WARNING
!
!

PR1: 04/01/11 Page| 4
Modulex Fireside (24-month) Maintenance
AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone]
Technical Instruction Document
TID-0027_0A
1.1 - Disassembly for Fireside Maintenance
Disassemble the unit per Instruction 1.1, below, and locate the electrical components to be replaced.
Unit Disassembly for Annual
Maintenance
1. Disconnect electrical power to the unit
by turning off the external circuit
breaker.
2. Turn off the external gas supply shutoff
valve.
3. Remove the top cover from the boiler. A
screwdriver may be needed to pry the
cover from the two pins on either end.
4. Carefully detach the ground wire clips
from the underside of the cover (see
note above).
5. Remove the front panel from the boiler
to provide access to the spark igniter
and flame detector for each heat
module of the boiler (see Figure 1).
6. Refer to Figure 2and Figure 3and
locate the installed locations of the
igniters and flame detectors. These
Figures show a Modulex MLX-757
containing five (5) igniters and five (5)
flame detectors.
NOTE
The cover is secured with spring clips
and pins to front, back and side panels
of the unit. In addition, two (2) groups of
ground wires from the frame of the
boiler are attached with clips to the
underside of the top cover. Use care
when disconnecting these ground wire
clips. Note that all lugs have capture
spring clips that are released by
pressing a small nub under lug itself.
INSTRUCTION 1.1
Figure 1: Cover Removed (Rear)
Figure 2: Electrical Connections
Figure 3: Electrical Components
See Figure 3
See Figure 2
Flame
Detector
Lead
Igniter
Cable
Ground Lead
View
Port
Mounting
Screws (2)
NOTE
The number of burner sections, and thus the
electrical components, varies by model.
END

PR1: 04/01/11 Page| 5
Modulex Fireside (24-month) Maintenance
AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone]
Technical Instruction Document
TID-0027_0A
1.2 Replacing the Spark Igniters and Flame Detectors
The Spark Igniter and Flame Detector are replaced per Instructions 1.2 A and 1.2Bbelow.
1.3 Testing the Flame Detection Circuitry
The Modulex boiler is designed to automatically shut down in the absence of a flame to prevent the
buildup of unburned fuel in the combustion chamber. Test the circuit by removing a flame detector lead
from any of the burner sections (Figure 3) while the unit is running. If the unit shuts down after a few
seconds, the flame detection circuitry is functional. If boiler does not automatically shut down, there is a
problem with the circuit. In this case, manually shut down the boiler and contact appropriate technical
help to resolve the problem.
1.4 Burner Module Inspection and Cleaning
This section provides instructions for disassembly of the unit, as well as inspection and cleaning of the
burner modules. Before performing this procedure, it is advised to check the CO2percentage at the
boiler input. If the CO2percentage is within 5% of the value shown in Table 1, then the burner modules
do not need to be inspected and cleaned. The operation then can be limited to the inspection and
cleaning of the flue collector.
Table 1: Acceptable Combustion Gas Ratios at Boiler Input
GAS SUPPLY OXYGEN (O2)
CARBON
DIOXIDE (CO2)
CARBON
MONOXIDE (CO)
NATURAL GAS 4.7% to 5.3% 9.1% to 8.8% <100 ppm
PROPANE 4.4% to 5.0% 10.7% to 10.4% <100 ppm
Note that a reduction of airflow at the input may indicate the burners need cleaning, but first check the
flue outlet and the air intake for any physical obstruction. If there is no obstruction, then proceed with
the maintenance procedures starting with unit disassembly per Instruction 1.4.1 on the next page.
Replacing the Spark Igniter
The spark igniter for each heat module is installed to
the left of the view port as shown in Figure 3.
Remove and replace as follows:
1. Disconnect the spark igniter ground wire and
unplug the igniter cable.
2. Using a Phillips head screwdriver, remove the two
(2) screws securing the igniter and remove it from
the boiler.
3.
Obtain a replacement igniter from the
maintenance kit. Using a spark gap feeler gauge,
ensure that the igniter spark gap is 4mm to 5 mm.
4. Install the replacement igniter and secure it in
place with the two (2) screws removed in step (b).
5. Reconnect the igniter cable and ground wire
6. Repeat steps (1) through (5) for each igniter in the
Modulex boiler.
Replacing the Flame Detector
The flame detector for each heat module is
installed beneath the view port as shown in
Figure 3. Remove and replace as follows:
1. Disconnect the flame detector wire lead.
2. Using a Phillips head screwdriver,
remove the two (2) screws securing the
flame detector and remove it from the
boiler.
3. Obtain a replacement flame detector
from the maintenance kit.
4. Install the replacement flame detector
and secure it in place with the two (2)
screws removed in step (b).
5. Reconnect the flame detector wire lead.
6. Repeat steps (1) through (5) for each
flame detector in the boiler.
INSTRUCTION 1.2 A
INSTRUCTION 1.2 B
END
END

PR1: 04/01/11 Page| 6
Modulex Fireside (24-month) Maintenance
AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone]
Technical Instruction Document
TID-0027_0A
1.4.1 – Unit Disassembly for Burner Maintenance
Tools required: Phillips head screwdriver, 13mm socket wrench (with extender), and an Exacto blade (or
small sharp knife). Access to a steel brush and water jet are also recommended. See Instruction 1.4.1.
Unit Disassembly for Fireside
Inspection
1. Disconnect electrical power to the unit by
turning off the external circuit breaker.
2. Turn off the external gas supply shutoff valve.
3. Remove the top cover from the boiler. A
screwdriver may be needed to pry the cover
from the two pins on either end. The cover is
secured with spring clips and pins to the front,
back and side panels of the unit. In addition,
two (2) groups of ground wires from the frame
of the boiler are attached with clips to the
underside of the top cover. Use care when
disconnecting these ground wire clips. Note
that all lugs have capture spring clips that are
released by pressing a small nub under the
lug body.
4. Remove the front panel from the boiler to
provide access to the fan assembly cover
(Figure 4).
5. Remove the screws from the various
locations on the fan assembly cover. A
sampling of screw locations is shown in
Figure 4.
6. Remove the plastic cap bolt covers (C) from
the bottom of the fan chamber to access the
bolts holding the fan assembly in place
(Figure 5).
7. Using a 13 mm socket wrench, remove the
bolts D1, D2, D3, and D4 that secure the fan
chamber cover onto the burner assembly
(Figure 6).
(Continued on Next Page)
INSTRUCTION 1.4.1
Cover Screw Locations
Fan Assembly
Cover
Figure 4: Remove Fan Assy Cover
Figure 5: Remove Plastic Bolt Covers (C)
D3
D4
Figure 6:
Remove Plastic Bolt Covers (C)
Prior to performing the following disassembly and
inspection procedures, ensure that all electrical
power to the boiler has been turned OFF and the
external gas shut-off valve is fully CLOSED.
WARNING
!
!

PR1: 04/01/11 Page| 7
Modulex Fireside (24-month) Maintenance
AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone]
Technical Instruction Document
TID-0027_0A
Unit Disassembly for Fireside Inspection
(Continued From Previous Page)
8. Unscrew the two air filters from each end of the
burner manifold (Figure 7).
9. Remove the two screws and the sheet metal
cover from each of two ends of the burner
manifold (Figure 8).
10. Position burner manifolds, at each end, 3/8”
(10mm) higher than the standard position
(Figure 8, left). Line up the “E” hole of the gas
pipe flange with the “G” hole of the side support
panel and affix with one of the two screws
previously removed.
11. Lift up the fan group (L)by rotating it on the gas
manifold axis and keep it up by inserting the
support rods (I), attached to the frame, in the
holes (M) (Figure 10).
12. Access the condensate tray (N, Figure 11) and
remove the cleaning plate (O)from the side
opposite from the flue collector (depends on
which side it was originally installed). Remove
the screw securing the baffle (P) and lower the
baffle onto the tray bottom.
Two Filters Located on Both
Ends of Burner Manifold
Figure 7: Removing Intake Filters
Figure 8: Removing End Plates
Figure 9: Reposition Endplates to Offset
NOTE
There are six boiler models with two, three, four,
five, six, or seven burner modules. Figure 12
shows a Modulex MLX-606 with four modules.
INSTRUCTION 1.4.1
END

PR1: 04/01/11 Page| 8
Modulex Fireside (24-month) Maintenance
AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone]
Technical Instruction Document
TID-0027_0A
Figure 12: Fan Assembly Lifted to Access Burner Modules
Figure 11: Accessing Condensate Tray
Figure 10: Fan Assy (L), Support Rod (I) and Holes (M)
Burner Modules

PR1: 04/01/11 Page| 9
Modulex Fireside (24-month) Maintenance
AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone]
Technical Instruction Document
TID-0027_0A
1.4.2 - Removing The Burner Modules
To remove the burner modules and gaskets, refer to Instruction 1.4.2, below.
Removing Burner Module(s)
1. If present, remove all the grounding tabs (Figure 13)
at the rear of the burner modules (one per burner
and screwed onto the boiler body) and discard.
These are no longer needed as the new
replacement gaskets are self-grounding. Use only
the newer style gaskets as replacements.
2. Remove each burner module from its seat by
inserting a cutter between the gasket and the
aluminum body on which it rests, and then carefully
running the cutter down three sides of the burner.
The photos in Figure 14 show the (1) cutter being
run along the shorter front edge, (2) along right long
edge, and (3) along left long edge.
3. Next, remove the burner by carefully rotating it
upward ONLY along the left or right long edge axis
(#4 in Figure 14). Take care to avoid deforming the
burner module as it is removed.
INSTRUCTION 1.4.2
NOTE
Before removing the burners and gaskets, verify if
the gaskets have been glued to the aluminum
surface. If they have, apply an appropriate solvent
and let set for the recommended time before
attempting to remove the gaskets.
Figure 13: Remove Ground Tabs
Figure 14: Cutting the Gasket (1-3) and Removing a Burner Module (4)
1
2
3
4
Ensure that the small plaited copper grounding
used on OLD gaskets is completely removed along
with old gaskets from the burner mounting surfaces.
CAUTION
!
!
END
NOTE
Old style gaskets are orange.
Newer style gaskets are grey.

AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page | 47
TID-0027_0A
1.4.3 - Maintenance of Burner Modules and Combustion Chamber
After disassembly of the boiler, do the procedures as described in Instruction 1.4.3.
1.4.4 - Reassembly After Burner Mainentance
After maintenance reassemble the unit per Instruction 1.4.4.
1.4.5 - Testing the Flame Detection Circuitry
The Modulex boiler is designed to automatically shut down in the absence of a flame to prevent the
buildup of unburned fuel in the combustion chamber. Test the circuit by removing a flame detector lead
from any of the burner sections (Figure 3) while the unit is running. If the unit shuts down after a few
seconds, the flame detection circuitry is functional.
Maintenance of Burner Modules and Combustion Chamber
1. After removing the burner modules and sealing gaskets from the recesses, use compressed air
and blow the modules from the convex side to the dished side to blow away debris. Inspect for
deformations and damage to the mesh and the module body.
2. Inspect the combustion chamber below the burners for scale and ash. Using compressed air,
blow out the combustion chamber between the sections to remove all dirt and foreign particles
from the aluminum protrusions. Use a water jet to wash the chamber out. Use care to avoid
wetting the electrical wiring.
3. Inspect the flue duct and flue collector. During this operation, ensure that the condensate drain
pipe is free of blockage so water does not accumulate in the tray. Clean out the condensate tray
of any scale or ash collected from cleaning the combustion chamber.
INSTRUCTION 1.4.3
Unit Reassembly After Maintenance
1. The burner sealing gaskets must be replaced after each burner cleaning. When positioning
the replacement gaskets (P/N 95261173), place them on top of the burner modules and not
between the burner modules and aluminum boiler body.
2. Reassemble all other components previously removed by reversing order of disassembly steps.
3. Before starting the boiler, verify that the condensate siphon and boiler are filled with water
and pump is running.
4. Before opening the gas cock on the burner manifold, make sure that the coupling is securely
tightened. To do this, open the gas cock and check the union for leaks using a soap solution.
5. As soon as a burner is put into operation, check immediately for leakage between the gas valve
and the relevant premixing chamber.
6. Perform the combustion analysis and check combustion parameters per paragraph 7.5.5. in
Modulex boiler Manual, GF-115-H.
INSTRUCTION 1.4.4
The burner sealing gaskets
MUST BE REPLACED
after each and every burner cleaning.
WARNING
!
!
NOTE
Make sure that all gas pressure test nipples previously open, are closed and tight.
END
END

PR2: 04/01/11 Page 11 of 12
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, New York 10913
•
Phone: [phone]
Modulex Annual (12 Month) Maintenance
Technical instruction Document
TID-0026_99
1.5 Inspection and Maintenance of the Flue Collector
Depending on the installation configuration, the flue collector may be installed on the left side, right side
or rear of the Modulex boiler. Inspect the flue collector per Instruction 1.5 below.
Disassembly, Inspection,
and Maintenance of the
Flue Collector
1. Disconnect flue starter section
from the flue collector by
loosening the hose clamp
(Figure 15).
2. Remove the flue collector and
flue collector gasket from the
condensate tray (Figure 15).
The collector is secured to the
tray with three (3) M4 bolts
(bottom flange) and three M4
hex nuts (top flange). You will
need to use a 7mm socket
wrench with universal joint and
extender to reach and remove
the nuts and bolts.
3. Disconnect exhaust connector
and exhaust connector gasket
from the flue collector by
removing the four (4) M5-20
bolts and washers shown in
Figure 15.
4. Inspect and then clean the flue
collector using a water jet or wet
cloth.
5. Following inspection and
cleaning refer to Figure 15,
then reconnect the flue collector
to the condensate tray using a
new flue collector gasket (P/N
95250612).
6. Install the exhaust connector
using a new exhaust connector
gasket (P/N 95250632).
7. Connect the flue starter section
to the flue connector and secure
it using the clamp removed in
Step 1.
INSTRUCTION 1.5
Flue Starter
Section
M5-20 Bolt (4) &
5x15mm OD washers
Exhaust
Connector Gasket
Hose Clamp
Exhaust
Connector
Flue
Collector
M4 Hex Nuts
(3)
M4 Bolts (3)
Condensate
Tray
Figure 15: Flue Collector Parts and Assembly
END
Hose Clamp
Exhaust
Connector
Flue Collector
Flue Collector
Gasket

PR2: 04/01/11 Page 12 of 12
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, New York 10913
•
Phone: [phone]
Modulex Annual (12 Month) Maintenance
Technical instruction Document
TID-0026_99
MLX-303 Fireside Maintenance Kit
Kit 58019-07
MLX-454
Fireside Maintenance Kit Kit 58019-08
MLX-606 Fireside Maintenance Kit
Kit 58019-09
MLX-757 Fireside Maintenance Kit
Kit 58019-10
MLX-909 Fireside Maintenance Kit
Kit 58019-11
MLX-1060
Fireside Maintenance Kit Kit 58019-12
© AERCO International, Inc., 2011
Modulex Models and Associated Fireside Maintenance Kit P/Ns