Watts AERCO 58015-04 Owner's manual

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 1 of 20
Maintenance Kit 58015-04 Contents
Latest Release: 10/12/2017 (Replaces TSB-2009-15)
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 these
materials.
TECHNICAL INSTRUCTIONS
Benchmark®3.0LN 24-Month Maintenance Kit# 58015-04
This kit applies to units with an Ignitor and a separate gas injector.
For units with an Ignitor-Injector (P/N 58023), see Kit 58025-04 and TID-0065.
ITEM 7
Condensate
Trap O-Ring
P/N 84017
ITEM 1
Igniter
P/N GP-122435-S
ITEM 2
Flame
Detector
P/N 66034
ITEM 3
Flame Detector
Gasket
P/N 81048
ITEM 8
Condensate Trap
Orifice Gasket
P/N 81092
ITEM 4
Gas Injector
Gasket
P/N 81047
ITEM 5
Exhaust
Manifold Seal
P/N 49102
ITEM 6
Burner Gasket
P/N 81030
ITEM 9
Exhaust
Manifold Orifice
Gasket
P/N 81098
ITEM 10
Burner Housing
Gasket
P/N 81019
ITEM 11
LWCO Kit
P/N 69126

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 2 of 20
Table of Contents
1. INTRODUCTION............................................................................................................ 3
2. CONTENTS OF KIT 58015-04....................................................................................... 3
3. TOOLS, TEST EQUIPMENT & MATERIALS REQUIRED............................................. 3
3.1 Tools ........................................................................................................................ 3
3.2 Test Equipment ........................................................................................................ 3
3.3 Materials................................................................................................................... 4
4. PRELIMINARY INSPECTION PROCEDURES .............................................................. 4
5. WATERSIDE INSPECTION OF BENCHMARK 3.0 HEAT EXCHANGER ..................... 5
6. FIRESIDE INSPECTIONS & COMPONENT REPLACEMENTS .................................... 7
6.1 Fireside Inspection of Benchmark 3.0 Heat Exchangers........................................... 7
6.1.1 Burner Inspection................................................................................................................7
6.1.2 Burner Reassembly.............................................................................................................9
6.1.3 Igniter Replacement..........................................................................................................10
6.1.4 Flame Detector Replacement ...........................................................................................11
6.1.5 Exhaust Manifold Inspection.............................................................................................11
6.1.6 External Condensate Trap Maintenance ..........................................................................14
6.2 Replacing the LWCO Probe/Capacitor Assembly....................................................16
6.3 Low Water Cutoff (LWCO) Capacitor Integrity Test .................................................16
6.3.1 Low Water Cutoff (LWCO) - Capacitor Electrical Short Test............................................17
7. FINAL REASSEMBLY AND TESTING .........................................................................19
7.1 Reassembly and Set-Up Following Completion of Inspections ................................19
7.2 Final Testing Following Inspections.........................................................................19
AERCO Technical Support:
(Mon–Fri, 8am-5pm EST)
1 [phone]
www.aerco.com

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 3 of 20
1. INTRODUCTION
This Technical Instruction Document provides the procedures to perform waterside and fireside
inspections of the heat exchangers contained in Benchmark 3.0LN and 3.0LN Dual-Fuel Boilers.
The replacement parts required to perform the waterside and fireside inspections on the
Benchmark 3.0LN and 3.0LN Dual-Fuel Boilers are provided in the 24 - Month Inspection Kit,
part number 58015-04, listed and described in section 2.
2. CONTENTS OF KIT 58015-04
The items included in the 24 Month Inspection Kit required for Benchmark 3.0LN and 3.0LN
Dual-Fuel Boilers are listed in Table 1.
Table 1. Benchmark 3.0LN: 24 Month Inspection Kit, Part Number 58015-04
ITEM QTY PART NO. DESCRIPTION
1 1 GP-122435-S IGNITER
2 1 66034 FLAME DETECTOR
3 1 81048 FLAME DETECTOR GASKET
4 1 81047 GAS INJECTOR GASKET
5 1 49102 EXHAUST MANIFOLD SEAL
6 2 81030 BURNER GASKETS
7 1 84017 CONDENSATE TRAP O-RING
8 1 81092 CONDENSATE TRAP ORIFICE GASKET (.25" I.D.)
9 1 81098 EXHAUST MANIFOLD ORIFICE GASKET
10 1 81019 BURNER HOUSING GASKET
11 1 69126 LWCO / CAPACITOR ASSEMBLY KIT
3. TOOLS, TEST EQUIPMENT & MATERIALS REQUIRED
The items required to perform the inspections, replacements and tests specified in this
document are listed in section 3.1, 3.2 and 3.3 which follow.
3.1 Tools
Common hand tools, plus the items listed below are required:
•Small Wire Brush
•Spark Gap Feeler Gauge
3.2 Test Equipment
No test equipment is required to perform the 24 - month inspections include in this document.
However, following completion of these inspections, the Benchmark Boiler should be tested
using the combustion calibration procedures provided in O & M Manual GF-116, or GF-117. See
section 7.2 for instructions.

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 4 of 20
3.3 Materials
Expendable materials required to perform the procedures described in this document are not
included in the 24 -Month Inspection Kits. These materials may include such items as:
•Pipe joint compound
•Teflon tape
•Cleaning solvents and materials
•High-temperature anti-seize compound
4. PRELIMINARY INSPECTION PROCEDURES
Perform the preliminary set-up and disassembly procedures in this section before performing
the waterside and fireside inspections included in this document.
WARNING!
High voltages are used to power these boilers and so it is required
that all power applied to these boilers is removed first before
performing any of the procedures described in this document.
Serious personal injury or death may occur if this warning is not
observed.
1. At the front panel of the unit, set the ON/OFF switch on the C-More Control Panel to the
OFF position.
2. Disconnect electrical power to the unit by turning off the external circuit breaker.
3. Turn off the external gas supply shutoff valve.
4. Close the water supply and return valves to the unit.
5. Refer to Figure 1 and remove the top and side panels of the unit.
6. With the top and side panels removed, the burner, heat exchangers and exhaust
manifold can be accessed to prepare the boiler for the required waterside and fireside
inspections described in sections 5 and 6.

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 5 of 20
Figure 1. Benchmark 3.0 Low NOx (LN) Boiler
5. WATERSIDE INSPECTION OF BENCHMARK 3.0 HEAT EXCHANGER
Benchmark 3.0LN units contain both a primary heat exchanger and a secondary heat
exchanger, as shown in Figure 2. Perform the waterside inspection as follows:
1. Ensure that the preliminary set-up and disassembly procedures in section 4 have been
performed to provide access to the unit‘s heat exchangers.
2. Allow the unit to cool prior before proceeding.
3. At the rear of the unit (Figure 3), slowly open the drain valve and drain the boiler water
from both heat exchangers.
4. Open the P&T relief valve, or loosen/remove the shell sensor to allow air to enter the
heat exchangers during draining.
5. After the heat exchangers have been drained, remove the 2-1/2 inch access port plugs
on the right side of the primary and secondary heat exchangers, as shown in Figure 2.
6. If waterside inspection is required by your local inspector, follow the inspector's
instructions. Upon satisfactory completion of the inspection, proceed to step 7.
7. Apply pipe compound to the threads of the access port plugs and replace them using a
pipe wrench.
8. Close the drain valve at the rear of the boiler.
9. Close the P&T relief valve or reinstall/tighten the shell sensor removed in step 4.
10. Open the water supply and return valves to the unit and refill the heat exchangers. This
completes the waterside inspection for the unit.

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 6 of 20
PRIMARY HEAT
EXCHANGER SECONDARY
HEAT EXCHANGER
ACCESS
PORT
ACCESS
PORT
DRAIN
VALVE
EXHAUST
MANIFOLD
Figure 2. Benchmark 3.0LN - (Right Side View)
DRAIN
VALVE
EXHAUST
MANIFOLD
WATER INLET
CONNECTION
HOT WATER OUTLET
CONNECTION
GAS
INLET
CONNECTING
MANIFOLD
Figure 3. Benchmark 3.0LN - (Rear View)

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 7 of 20
6. FIRESIDE INSPECTIONS & COMPONENT REPLACEMENTS
Benchmark 3.0LN heat exchanger fireside inspections include removal of the burner and
exhaust manifold assembly from the boiler. In addition, the 24 Month Inspection Kit includes the
recommended replacement parts for annual maintenance, which should also be performed at
this time. Therefore, the procedures in this section are organized as follows:
Fireside Inspections:
•Burner Inspection
•Exhaust Manifold Inspection
Annual Maintenance Replacements:
•Burner Component Replacement
•Condensate Trap Component Replacements
The procedures for the above inspections and replacements are provided in the following
sections.
6.1 Fireside Inspection of Benchmark 3.0 Heat Exchangers
Perform the fireside inspections of the low NOx burner (section 6.1.1) and exhaust manifold
(section 6.1.5).
6.1.1 Burner Inspection
The burner assembly is located at the top of the primary heat exchanger as shown in Figure 4.
1. Ensure that all preliminary set-up and disassembly procedures in section 4 have been
completed.
WARNING!
THE BURNER ASSEMBLY MAY BE EXTREMELY HOT. TO
AVOID BURNS, ALLOW IT TO COOL SUFFICIENTLY BEFORE
ATTEMPTING TO REMOVE IT FOR INSPECTION.
2. Disconnect the lead wire from the flame detector, shown in Figure 5, below.
3. Remove the two (2) screws securing the flame detector to the burner housing flange and
then remove the flame detector and gasket.
4. Disconnect the igniter cable from the igniter (Figure 5), then unscrew and remove the
igniter.
5. Remove the two (2) 10-32 screws securing the staged ignition assembly to the burner
housing and then separate the staged ignition assembly from the burner. Remove the gas
injector gasket (P/N 81070) from the burner, as it will be replaced during reassembly.
6. Disconnect the burner housing from the blower by removing the six (6) 1/4-20 screws
using a 3/8” wrench.
7. Remove the eight (8) 3/8-16 nuts and washers from the burner flange (Figure 5) using a
9/16” wrench.
8. Remove the burner housing from the burner flange by pulling straight up.
NOTE
The burner housing weighs approximately 20 pounds.
9. Remove the grounding screw.

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 8 of 20
10. If there is an extension ring around the burner, remove it.
11. Remove the burner and two (2) burner gaskets by pulling straight up. Figure 6 shows an
exploded view of the Benchmark 3.0LN burner assembly.
AIR/FUEL
VALVE
BURNER
HOUSING
BURNER
HEAT
EXCHANGER
EXHAUST
MANIFOLD
AIR
INLET
Figure 4. Benchmark 3.0LN - Top View
3/8-16
NUTS (8)
BURNER
HOUSING
BURNER
STAGED
IGNITION
ASSEMBLY
GROUNDING
SCREW
1/4-20
SCREWS
(6)
10-32
SCREWS (2)
SPARK
IGNITER
FLAME
DETECTOR
Figure 5. Benchmark 3.0LN Burner Disassembly – Top View
(GP-122435-S)
(66034)
FLAME DETECTOR GASKET
(81048)

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 9 of 20
6.1.2 Burner Reassembly
Referring to Figure 6, below, reassemble the burner assembly as described below. The
following parts from the kit will be used during this procedure:
•Burner Gasket P/N 81030 (2)
•Burner Housing Gasket P/N 81019
•Gas Injector Gasket P/N 81047
Figure 6. Benchmark 3.0LN Burner Assembly Exploded View
1. Replace both burner gaskets with two new burner gaskets (P/N 81030), one above and
one below the burner flange. IMPORTANT!
When installing new burner gaskets, it is imperative that the
gaskets be properly aligned to assure that the cutouts for the
observation port, igniter-injector, and flame detector line up with
those in the heat exchanger top plate, burner flange and burner
housing. Failure to properly align these items may result in
damage to the gaskets or interference with the components.
2. Place the burner back into the heat exchanger.
GAS INJECTOR
GASKET
(81047)
FLAME DETECTOR
(66034)
IGNITOR
(GP-122435-S)
BURNER GASKET
(81030)
BURNER FLANGE
BURNER HOUSING
GASKET
(81019)
BURNER GASKET
(81030)
BURNER HOUSING
10-32 SCREWS (2)
STAGED IGNITION
ASSEMBLY

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 10 of 20
3. Place the new burner housing gasket (P/N 81019) on top of the blower,ensuring is
positioned correctly in relation to the burner housing’s mounting holes.
4. Position the burner housing on the blower and the burner flange, aligning it with both
burner and blower.
5. Reinstall the the six (6) 1/4-20 screws that connect the burner housing to the blower, but
only hand-tighten them at this point, to ensure proper positioning.
6. If there was an extension ring around the burner at disassembly, replace it.
7. Add one 3/8” flat washers to each of the eight (8) mounting studs coming up through the
burner flange, removed in section 6.1.1, step 7.
IMPORTANT!
It is imperative that the burner housing is fully tighten to the top of the heat
exchanger BEFORE its other end is bolted to the blower.
8. Apply Loctite 246 to the mounting studs and then loosely tighten the eight (8) 3/8-16 nuts
attaching the burner housing to the burner, and then torque the eight nuts in a star (or
alternating) pattern to 35 ± 5 ft./lbs.to to ensure a uniform seal.
9. Fully tighten the the six (6) 1/4-20 screws hand-tighten in step 5 to fully connect the burner
housing to the blower. DO NOT ATTEMPT to pull the burner housing down to meet the
blower. If there is a gap, adjust the blower mounting plate till the blower contacts the
housing.
10. Check to ensure that the grounding screw is reinstalled. Also, ensure that conductive,
high-temperature, anti-seize compound is applied to the threads of the ground screw.
11. Reinstall the staged ignition assembly with the new gas injector gasket (P/N 81070) on the
burner housing using the two (2) 10-32 screws removed in section 6.1.1, step 5.
12. After servicing is complete, perform a water bubble test during purge to ensure the burner
gaskets are providing a good seal, as specified in section 7.2.
6.1.3 Igniter Replacement
Complete the instructions below on Benchmark 3.0 LN units to reinstall the igniter (P/N GP-
122435-S).
1. Using a spark gap feeler gauge, check to ensure that the igniter is gapped at 1/8".
2. Prior to installation, a high-temperature anti-seize compound must be applied to the
igniter threads.
3. Reinstall the igniter in the location shown in Figure 9. Do not over-tighten. A slight
snugging up is sufficient.
4. Reconnect the igniter cable.

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 11 of 20
6.1.4 Flame Detector Replacement
Flame detector (P/N 66034) and gasket (P/N 81048) are used on Benchmark 3.0 Low NOx
units. Complete the instructions below to replace these parts.
1. Refer to Figure 7 to locate the flame detector installation location.
2. Install the replacement flame detector and gasket in the location shown. Secure the
flame detector to the burner housing flange using the two screws removed in section
6.1.1, step 3.
3. Reconnect the flame detector lead wire.
FLAME
DETECTOR IGNITER
BURNER
BURNER
HOUSING
Figure 7. Burner Assembly Igniter & Flame Detector Locations
6.1.5 Exhaust Manifold Inspection
The exhaust manifold of the Benchmark 3.0LN is installed on the top of the secondary heat
exchanger, at the rear of the unit, as shown below in Figure 8. Perform the following steps to
remove and inspect the manifold:
1. Remove the four (4) bolts securing the flue starter section collar to the top of the exhaust
manifold.
2. Disconnect the flue starter section from the exhaust manifold.
3. Disconnect the condensate trap drain hose from the 1-1/2" O.D. pipe on the bottom of
the exhaust manifold.
4. Using a 3/4" socket wrench, remove the five (5) bolts securing the exhaust manifold to
the heat exchanger (Figure 9). Also, remove the three (3) hex nuts from the manifold
PEM studs. Remove the complete exhaust manifold from the unit.
5. Remove the silicone rubber seal from the recess in the flange of the exhaust manifold.
Ensure that all seal residue is removed from the flanges of the exhaust manifold and
secondary heat exchanger.
6. From the opening at the top of the manifold, remove the condensate trap float (with
guide attached). Also, remove the orifice gasket located beneath the float.
FLAME DETECTOR GASKET
(81048)
FLAME DETECTOR
(66034)
IGNITOR
(GP-122435-S)

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 12 of 20
7. Inspect and clean the exhaust manifold as necessary.
8. Replace the exhaust manifold seal (P/N 49102) with the new seal provided in the kit.
Install the adhesive-backed seal in the recess of the exhaust manifold flange (Figure 9)
so that the adhesive side is in contact with the exhaust manifold.
9. Align the exhaust manifold with the upper flange of the secondary heat exchanger.
Secure the manifold in place using the five (5) bolts removed in step 4. Also, replace the
hex nuts on the three (3) PEM studs. Alternately tighten the bolts and nuts to obtain a
uniform seal.
10. From the opening at the top of the manifold, install the new orifice gasket (0.75" I.D., P/N
81098) provided in the kit. Ensure that the gasket is lying flat in the bottom of the
condensate trap.
11. Next, insert the condensate float (with guide attached) into the trap.
12. Reconnect the 1-1/2" I.D. drain hose to the condensate trap drain opening.
13. Reconnect the flue starter section and collar to the top of the exhaust manifold using the
bolts removed in step 1.
14. Benchmark 3.0LN units also contain a second, external condensate trap. This trap is
attached to the exhaust manifold at the rear of the unit using an adapter. Disconnect this
trap from the manifold and perform the procedure described in section 6.2.2.
15. Upon completion of the procedure described in section 6.2.2, reconnect the condensate
trap to the 1-1/2" pipe on the connecting manifold.

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 13 of 20
B
B
A
A
SECONDARY
HEAT
EXCHANGER
EXHAUST
MANIFOLD
PRIMARY
HEAT
EXCHANGER MANIFOLD
MOUNTING
BOLTS (3)
VIEW A - A VIEW B - B
STARTER
SECTION
BOLTS (4)
ORIFICE
GASKET
FLOAT
Figure 8. Benchmark 3.0LN Exhaust Manifold Location
TOP VIEW BOTTOM VIEW
PEM STUDS
(3)
INSERT SEAL IN
RECESS OF FLANGE
Figure 9. Benchmark 3.0LN Exhaust Manifold
EXHAUST MANIFOLD
ORIFICE GASKET
(81098)

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 14 of 20
6.1.6 External Condensate Trap Maintenance
NOTE
Benchmark 3.0LN boilers actually contain two condensate traps. One is
an integral part of the unit’s exhaust manifold. This trap is inspected and
serviced during the exhaust manifold inspection procedures described in
section 6.1.2. The second, external condensate trap (P/N 24060), is
used on all Benchmark models. The inspection and servicing procedure
for the external condensate trap is described below.
NOTE
There are two slightly different types of external condensate traps (P/N
24060) that may be used at your site; an older style without an inlet
adapter, or a newer style with a built-in inlet adapter (see Figure 10).
Maintenance is the same, except that the newer style does not need an
orifice gasket (Step 6).
For Benchmark 3.0 boilers, the external condensate trap (P/N 24060) is attached to the
connecting manifold drain pipe using a special adapter (Figure 10). This trap should be
disconnected from the connecting manifold and serviced as follows:
1. If the trap is still attached to the connecting manifold, loosen the adapter thumb screw
and disconnect the trap from the manifold.
2. Remove the connections on the inlet and outlet sides of the condensate trap, as shown
in Figure 10.
3. Refer to Figure 10 and loosen the four (4) thumb screws securing the cover on the
condensate trap and then remove the cover.
4. Remove and discard the cover O-ring gasket currently installed in trap. It will be replaced
with the new O-ring included in the kit during reassembly.
5. Remove the float (with float guide attached) from the condensate trap.
6. On older-style traps, remove and discard the currently installed orifice gasket from the
trap. A new orifice gasket will be installed in step 9. The newer traps, with a built-in inlet
adaptor, do not use an orifice gasket, so this step may be bypassed for those traps.
7. Thoroughly clean the trap and float. Also inspect the drain piping for blockage. If the trap
cannot be thoroughly cleaned, replace the entire condensate trap (P/N 24060).
8. Check the condensate drain pipe on the connecting manifold (Figure 11) to ensure it is
clear of blockage.
9. On older-style traps, replace the orifice gasket with a new gasket included with the kit
(P/N 81092). Ensure that the replacement gasket is lying flat in the trap.
10. Replace the cover O-ring (P/N 84017) with the new one provided in the kit.
11. Reinstall the float with float guide attached.
12. Replace the condensate trap cover and tighten the four (4) thumb screws.
13. Reassemble all piping and hose connections to the condensate trap inlet and outlet.
14. Reconnect the trap to the connecting manifold drain pipe using the trap adapter (Figure
11). Tighten the adapter thumb screw.
15. Ensure that the trap is horizontal and level to ensure proper drainage.

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 15 of 20
Figure 10. Condensate Trap P/N 24060
CONDENSATE
TRAP
CONNECTING
MANIFOLD
DRAIN
PIPE
3/4" NPT
NIPPLES
TO
FLOOR
DRAIN
CLAMP
1" I.D.
HOSE
ADAPTER
Figure 11. Connecting Manifold Condensate Drain Location

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 16 of 20
6.2 Replacing the LWCO Probe/Capacitor Assembly
The replacement LWCO probe sensor comes with a capacitor assembly attached. This
procedure replaces an old probe assembly with a new probe assembly (P/N 69126).
1. Cut the shell harness wire just below the female spade connector (Figure 12). The new
LWCO assembly includes a new female connector to crimp onto the shell harness wire.
Figure 12: Removing Old LWCO Probe/Capacitor Assembly
2. Remove the LWCO probe from the recess well on the hot water outlet piping by
unscrewing the brass coupling to which it is attached.
3. Retrieve the new LWCO probe from the kit and sparingly apply an NSF approved pipe
dope to the threads of the brass coupling (Do NOT use Teflon tape) and install into the
probe well vacated by the old LWCO probe.
4. The new LWCO assembly comes with a spare female connector already inserted into the
male connector, and this should be crimped onto the stripped end of the shell harness
wire.
6.3 Low Water Cutoff (LWCO) Capacitor Integrity Test
The LWCO capacitor should be tested for electrical shorts after it has been replaced. The
LWCO capacitor integrity test consists of two parts as described in the next two sections.
The first procedure explains how to test for electrical shorting of the LWCO probe capacitor,
while the second procedure instructs how to perform the standard Low Water Cutoff test
using the C-More controls.
Refer to Figure 13 for an illustration of the LWCO probe assembly and its typical installation.
MALE SPADE
CONNECTOR
FEMALE SPADE
CONN.ON THE
SHELL HARNESS WIRE
OLD LWCO PROBE
CUT OFF WIRE
TO OLD LWCO
ASSEMBLY
HERE
OLD CAPACITOR
(COVERED BY LARGE
SHRINK TUBING)
PROBE WELL OF
HOT WATER
OUTLET PIPING
LWCO PROBE
& CAPACITOR
ASSEMBLY

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 17 of 20
Figure 13: LWCO Probe Location (BMK3000 Shown)
6.3.1 Low Water Cutoff (LWCO) - Capacitor Electrical Short Test
This test determines if there is an electrical short between the LWCO capacitor and the heat
exchanger. Perform the capacitor electrical short test as described below.
1. Turn OFF AC power to the unit. WARNING!
High voltages are used to power these units and so it is required
that power applied to these units is removed first before
performing the procedure described in this instruction. Serious
personal injury or death may occur if this warning is not observed.
2. Remove the Shell Harness Cable (male) connector from the P-5 (female) connector on
the rear panel of the C-More controller (see Figure 14).
Figure 14: Removing Cable from P5 Connnector
LWCO Probe
Capacitor Assembly
(Covered By Large
Shrink Tubing)
Connector
(to Shell Harness)
Plastic Acorn Nut
LWCO Probe
Terminal
Hot Water
Outlet Pipe
Rear
Panel
Unplug Shell
Harness Cable
from
P5 Connector

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 18 of 20
3. Using an ohmmeter, connect one ohmmeter probe to the LWCO capacitor terminal on the
unit shell as shown on left in Figure 15.
4. Connect the second ohmmeter probe to Pin #6 of Shell Harness Connector (removed
from the C-More controller) as shown on right in Figure 15.
Figure 15: Connecting Ohmmeter between LWCO Probe & Shell Harness Cable
5. Confirm that the ohmmeter does NOT read a short.
NOTE
If the ohmmeter reads a short, the capacitor assembly needs to be
replaced. See section 4.9 for replacement instructions or contact
AERCO technical support for more information.
6. Remove both ohmmeter probes and reconnect the Shell Harness connector to the P5
connector on the rear of the C-More controller.
Connect 2nd Lead to PIN #6
19-Pin Shell Harness Cable
Connector
LWCO Probe Assembly Connector
Ohmmeter
Connect 1st Lead to LWCO Terminal

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 19 of 20
7. FINAL REASSEMBLY AND TESTING
Upon completion of all waterside and fireside inspections, reassemble the unit and perform the
tests specified in sections 7.1 and 7.2.
7.1 Reassembly and Set-Up Following Completion of Inspections
Following completion of the all required inspections and replacements, perform the following
reassembly and setup procedures:
1. Ensure that the heat exchanger has been filled and the water supply and return valves
have been opened.
2. Turn ON the external circuit breaker to the unit.
3. At the front panel of the unit, set the ON/OFF switch on the C-More Control Panel to the
ON position.
4. Press the LOW WATER LEVEL RESET button to reset the low water cutoff.
5. Press the CLEAR switch to reset the fault relay. This will turn off the FAULT LED and
clear any displayed error message.
6. Replace the unit side panels and top panels.
7.2 Final Testing Following Inspections
Upon completion of the inspections and replacements specified in this document, perform the
Combustion Calibration Tests specified in Chapter 4 of the O & M Manual GF-116, or GF-117
(Dual-Fuel).
Perform a water bubble test during purge to ensure the burner gaskets, replaced in section
6.1.2, are providing a good seal.
Following successful completion of the Combustion Calibration Tests, return the Benchmark
3.0LN Boiler to service use.

Benchmark 3.0LN 24-Month Maintenance Kit 58015-04
Technical Instruction Document TID-0135_0C
10/12/2017 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone] Page 20 of 20
© AERCO International, Inc., 2017
Change Log:
Date Description Changed By
06/03/2016 Rev B:
DIR 335: Clarified reassembly order in section 6.1.2, added
water bubble test to section 7.2 Chris Blair
10/12/2017 Rev C:
DIR 335: Changed “Blower Plenum” to “Burner Housing” and
“Burner Housing Gasket” P/N 81019, modified section 6.1.2.
Chris Blair
AERCO Technical Support:
(Mon–Fri, 8am-5pm EST)
1 [phone]
(www.aerco.com)