AERCO KC Standard to Low NOx SERVICE BULLETIN

INTERNATIONAL, INC.

159 PARIS AVENUE • NORTHVALE, NJ 07647 • PHONE [phone]

TECHNICAL SERVICE BULLETIN

Date: 08/19/05 Number: 2005-03
Subject: KC1000 LOW NOx CONVERSION KIT INSTRUCTIONS

Page 1 of 42

1. INTRODUCTION

The KC1000 Low NOx Conversion Kit, Part No. 124918 contains all of the assemblies, cables and
attaching parts necessary to upgrade a KC1000 Boiler or Water Heater for Low NOx compliance.
When so equipped, the Boiler or Water Heater complies with the NOx emission standards outlined in:

• South Coast Air Quality Management District (SCAQMD), Rule 1146.2.

• Texas Commission on Environmental Quality (TCEQ), Title 30, Chapter 117, Rule

117.465.

NOTE

These Conversion Kit instructions are applicable to all KC1000 units,
regardless of the Control System and/or Safety Shutoff Valve (SSOV) installed
on your unit. Unless otherwise specified, the descriptions and procedures
contained in this Service Bulletin apply to all Natural Gas KC1000 Water
Heater and Boiler configurations. If you are not certain of your current unit
configuration, contact your nearest AERCO Representative.

1.1 General Description

In order to comply with the above-mentioned low NOx emission standards, the existing KC Burner
Assembly must be replaced with a new Low NOx Burner Assembly and a Staged Ignition Assembly.
In addition, several other assemblies must be modified to ensure low NOx emissions.

The Low NOx Conversion procedures provided in this Service Bulletin are divided into the following
main categories:

• Equipment Removal

• Equipment Modification/Rework

• Equipment Replacement/Reinstallation

• Post-Installation Setup and Calibration

The procedures in each of these categories are presented in Sections 2 through 5 respectively.

The following paragraphs in this Section describe the contents of the Low NOx Conversion Kit and the
tools and test equipment required to perform all procedures in this Service Bulletin.

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1.2 Conversion Kit Contents

KC1000 Low NOx Conversion Kit, Part No. 124918-( ) is available in four configurations, designated ­1, -2, -3 and -4. The -1 and -2 Kits apply to newer KC1000 Water Heaters and Boilers respectively,
equipped with Siemens Safety Shutoff Valves (SSOVs) and C-More Control Systems. The -3 and -4
Kits apply to older KC1000 Water Heaters and Boilers respectively, equipped with Honeywell SSOVs.
Older KC1000 units may also be equipped with Modular or Digital Control Systems, instead of the C­More Control Systems used on current KC1000 units. The “Kit Dash Number” column in the following
Table indicates which parts are included in each Kit. As this Table shows, only minor differences exist
between the contents of the four Kit configurations.

Conversion Kit, Part No. 124918-( ) Contents

Item No. Part No.

Kit Dash

Number

Description

1 201258 All Low NOx Burner Assembly

2 124715 All 5/16-18 x 1-3/4” Long Studs (Qty=6)

3 124867 -1, -2 Only Staged Ignition Assembly

4 124983 -3, -4 Only Staged Ignition Assembly

5 124991 All Low NOx Air/Fuel Valve Gas Plate

Assembly

6 161625 All Low NOx Air/Fuel Valve Butterfly

7 124803 All Low NOx Gas Regulator Plated Spring

8 124870 All Solenoid Valve Harness

9 124839 All Low NOx Combustion Chamber Liner

10 124570 All Low NOx Igniter Assembly

11 124837 All Low NOx Flame Rod Assembly

12 124919 All Low NOx Conversion Labels Sheet

13 124797 -1, -3 Only Low NOx Heater Specs. Label

14 124798 -2, -4 Only Low NOx Boiler Specs. Label

15 GF-111LN

or

GF-109LN

-1 Only
or

-2 Only

Low NOx Heater O & M Manual
or
Low NOx Boiler O & M Manual

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1.3 Tools and Test Equipment Required

The required tools and test equipment are listed in paragraphs 1.3.1 and 1.3.2 respectively.

1.3.1 Tools

The following tools are required to perform the conversion procedures specified in this Service
Bulletin:

• Wrenches: 3/16”, 7/16”, 1/2”, two 9/16”, 5/8”, 11/16”, 15/16”

• Vise-Grip Pliers

• Flat Tip Screwdriver, 1/2” - Inch Blade

• Phillips Head Screwdriver, No. 3

• AERCO Differential Gas Pressure Regulator Adjustment Tool, Part No. GM-122643

1.3.2 Test Equipment

Following installation of all Conversion Kit items, the following test equipment will be required to
perform combustion calibration of the modified KC1000 Boiler or Water Heater using the applicable
Operation & Maintenance Manual:

• Digital Combustion Analyzer – Oxygen accuracy to ±0.5 %, carbon monoxide and NOx
resolution to 1 ppm.

• One 16” W.C. Manometer and plastic tubing

• One 1/4 inch and two 1/8 inch NPT-to-barbed fittings for use with manometers

WARNING

HIGH VOLTAGE OF 120 VAC IS USED IN KC1000 SYSTEMS. USE
EXTREME CARE WHEN ACCESSING CIRCUITS AND ELECTRICAL
CONNECTIONS WITHIN THE EQUIPMENT. SERIOUS PERSONAL INJURY
OR DEATH MAY OCCUR IF THIS WARNING IS NOT OBSERVED.

2. EQUIPMENT REMOVAL

The locations of the major items to be removed from the KC1000 are shown in Figure 1. These items
include the existing Burner Assembly, Combustion Chamber Liner, Gas Inlet Pipe and the Air/Fuel
Valve. The existing Burner and Combustion Chamber Liner will be replaced with new assemblies
provided in the Conversion Kit. The Air Fuel Valve will be modified using the applicable procedures in
Section 3.

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NOTE

ILLUSTRATION SHOWS KC BOILER WITH
COVERS REMOVED. THE LOCATIONS OF
THE AFFECTED ITEMS ARE IDENTICAL FOR
BOTH KC BOILERS AND WATER HEATERS

COMBUSTION

CHAMBER

LINER

CONDENSATE

DRAIN TUBE

BURNER

ASSEMBLY

CONTROL

AIR/FUEL

VALVE

I/O

BOX

GAS INLET

PIPE

DIFFERENTIAL

GAS PRESSURE

REGULATOR

Figure 1. KC1000 Component Locations

BOX

SSOV

LOW GAS

PRESSURE

SWITCH

Removal of the required items is accomplished as follows:

CAUTION

DO NOT DISCARD ANY OF THE REMOVED PARTS OR ASSEMBLIES
UNLESS IT IS SPECIFICALLY INDICATED THAT THEY WILL NO LONGER
BE USED. IT IS RECOMMENDED THAT ALL REQUIRED ITEMS BE
REMOVED AS INDICATED IN THE FOLLOWING STEPS PRIOR TO
PERFORMING ANY REPLACEMENT PROCEDURES IN SECTION 4.

1. Turn off the gas supply and disconnect AC power from the unit.

2. Remove the top and side sheet metal covers from the unit.

3. At the rear of the unit, disconnect the plastic tubing from the condensate cup to the drain.

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4. Remove the rear covers from the unit.

5. Remove the condensate cup from under the unit and disconnect the condensate drainage

tube from the exhaust manifold.

6. Disconnect the flame detector and igniter cable leads from the flame detector and igniter

contactor.

7. Remove the ground terminal connection from the Burner by loosening the top screw shown in

Figure 2. Slide the connector off the grounding rod.

Figure 2. Ground Terminal Location

8. Using a 7/16 inch socket or open end wrench, remove the four 1/4 – 20 hex nuts on the gas

inlet pipe flange at the Burner. See Figure 3.

9. Using two 9/16 inch wrenches, remove the two 3/8” – 16 hex nuts and bolts on the gas inlet

pipe flange at the Air/Fuel Valve (Figure 3). Remove the gas inlet pipe and gaskets from the
unit.

10. Loosen the hose clamp on the Air/Fuel Valve side of the valve-to-burner air hose as shown in

Figure 3.

11. Using a 1/2 inch socket wrench, remove the six 5/16 – 18 hex nuts supporting the existing

Burner Assembly (Figure 3).

12. Lower the Burner Assembly while sliding the valve-to-burner air hose off the Air/Fuel Valve.

Completely remove the Burner from the rear of the unit.

13. Loosen the hose clamp on the removed Burner Assembly inlet and slide the valve-to-burner

air hose off the Burner. Retain the hose and clamp. These items will be reinstalled in Section

4. The removed Burner Assembly will be replaced with the new Low NOx Burner provided in

the Conversion Kit.

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Figure 3. Burner & Air/Fuel Valve Removal

14. Remove the 8-inch Combustion Chamber Liner from the Heat Exchanger (Figure 4). Since

this liner will be replaced, It may be cut or broken to simplify removal.

NOTE

If difficulty is encountered during removal of the 5/16-18 studs, it may be
necessary to “Double-Nut” the studs to simplify the removal process.

15. Using vise-grip pliers, remove the six 5/16–18 x 1-1/2” long studs used to secure the removed

Burner Assembly to the Exhaust Manifold. These studs will be replaced with 1-3/4” studs
provided in the Conversion Kit.

16. Disconnect the Air/Fuel Valve wiring harness from the Control Box.

17. Disconnect the two wire leads from the Blower Proof Switch shown in Figure 5.

18. Loosen the hose clamp on the Air/Fuel Valve inlet side of the blower-to-valve air hose shown

in Figure 3.

19. Using an 11/16 inch wrench, loosen the two compression fittings securing the feedback tube to

the Air/Fuel Valve and Differential Pressure Regulator shown in Figure 3.

20. Using two 9/16 inch wrenches, remove the two 3/8–16 bolts and hex nuts securing the Air Fuel

Valve to the Differential Pressure Regulator (Figure 3).

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EXHAUST

MANIFOLD

INSULATION

1/4-20 SCREW &

FENDER WASHER

(3 PLACES)

COMBUSTION
CHAMBER LINER

Figure 4. KC1000 With Burner & Air/Fuel Valve Removed

Figure 5. Blower Proof Switch

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CAUTION

USE CARE WHEN REMOVING THE AIR/FUEL VALVE TO AVOID
DAMAGING OR LOSING THE FLANGE O-RING.

21. Completely remove the Air/Fuel Valve from the unit. This assembly will be modified in

Section 3.

22. Remove the Exhaust Manifold insulation (Figure 4) by removing the three 1/4-20 screws and

fender washers securing it in place.

NOTE

Current KC1000 units are equipped with Siemens Safety Shutoff Valves
(SSOVs). However, some earlier units may be equipped with Honeywell
SSOVs. The mounting location of the Low Pressure Gas Switch will differ
slightly, depending on the SSOV installed. Refer to Figure 6 (Siemens) or
Figure 7 (Honeywell) for the appropriate SSOV installed.

23. Next, refer to Figure 6 (Siemens SSOV) or Figure 7 (Honeywell SSOV) to locate the Low

Pressure Gas Switch on the right side of the unit. Disconnect the two wire leads from the
switch.

24. For Siemens SSOVs, the Low Pressure gas Switch is installed in the upstream SSOV port

using an NPT reducer. For Honeywell SSOVs, the Switch is installed directly in the gas supply
inlet pipe. Temporarily remove the Low Pressure Gas Switch as follows:

(a) For Siemens SSOVs, remove the switch (with NPT reducer attached) from the upstream

SSOV port using a 5/8” wrench.

(b) For Honeywell SSOVs, remove the switch from the tapped hole in the gas supply inlet

pipe using a 1/2” wrench.

The Low Pressure Gas Switch will be reinstalled in Section 4.

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Figure 6. Low Pressure Gas Switch Location With Siemens SSOV Installed

Figure 7. Low Pressure Gas Switch Location With Honeywell SSOV Installed

25. This completes the equipment removal procedures for the KC Boiler or Water Heater. Proceed

to the Modification/Rework procedures in Section 3.

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3. EQUIPMENT MODIFICATION/REWORK

The equipment items to be modified are the Air/Fuel Valve and Differential Gas Pressure Regulator.
The Air/Fuel Valve was removed from the unit in Section 2 of this Service Bulletin. The Differential
Gas Pressure Regulator can be modified in place without removal. The modification procedures for
these items are presented in paragraphs 3.1 and 3.2 which follow.

3.1 Air/Fuel Valve Modification

The modifications to be made to the Air/Fuel Valve consist of replacing the lower gas plate and the air
valve butterfly with the replacement items contained in the Conversion Kit. Place the Air/Fuel Valve
on a workbench and proceed as follows:

1. Rotate the Air/Fuel Valve butterfly so that the valve is in the fully closed position.

2. Using a 7/16 inch socket or wrench, remove the four 1/4-20 hex head machine screws

securing the lower portion of the Air/Fuel Valve body to upper valve body as shown in
Figure 8.

CAUTION

DO NOT ROTATE THE VALVE BUTTERFLY FROM THE FULLY CLOSED
POSITION AFTER SEPARATING THE UPPER AND LOWER VALVE BODY.

3. Separate the upper and lower portions of the valve body to access the gas plate as shown in

Figure 9.

4. Remove the existing gas plate with upper/lower O-rings from the Air/Fuel Valve.

5. Obtain the replacement low NOx gas plate and O-rings from the Conversion Kit. Apply O-ring

lube (Dow-Corning Compound #111, or equiv.) to the replacement O-rings and install them in
the grooves on the gas plate.(Figure 10).

6. Refer to the cut-away view in Figure 9. Ensure that the valve components are positioned as

shown in the upper valve body.

7. Position the low NOx gas plate so that the plate slot engages the locating pin in the upper

valve body (Figure 9). Also, ensure that the shutter stop pin (Figures 9 and 10) is facing the
upper portion of the valve body.

8. Apply LocTite No. 242 (Blue), or equivalent, to the threads of the four 1/4-20 hex head

machine screws removed in step 2. Reassemble and secure the lower and upper portions of
the valve body by alternately tightening the four 1/4-20 machine screws.

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STEPPER
MOTOR
COVER

AIR INLET

VALVE BODY

(UPPER)

VALVE BODY

(LOWER)

A

(SEE FIGURE 9)

A

1/4-20 HEX HEAD

SCREWS (4)

GAS INLET

Figure 8. Air/Fuel Valve Modification

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VALVE SHAFT

SPRING RING-

SHAFT SEAL

SHAFT SEAL-

BACKUP WASHER

RETAINING RING

PRE-LOAD SPRING

SHAFT DRIVE PIN

SHUTTER STOP PIN

GAS VALVE

SHUTTER

GAS PLATE

O-RINGS (2)

FUEL OUTLET

PLATE LOCATING
PIN

FUEL INLET

GAS PLATE

VIEW A - A

Figure 9. Air/Fuel Valve – Partial Cross-Sectional View

Figure 10. Low NOx Gas Plate

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9. Next, remove the #8-32 screw securing the existing air butterfly to the Air/Fuel Valve shaft

(Figure 11) and remove the butterfly.

10. Apply a small amount of LocTite No. 222 (purple) to the #8-32 screw threads and install the

new air butterfly and flat washer provided in the Conversion Kit onto the shaft. Center the
butterfly so that there is equal clearance between the valve bore and the edges of the butterfly.

11. Manually open and close the butterfly several times to ensure that it is properly positioned on

the shaft with equal clearances around the valve bore

12. This completes the Air/Fuel Valve modifications. The modified Air/Fuel Valve is now ready to

be reinstalled using the procedures in Section 4.

Figure 11. Air Butterfly Replacement

3.2 Differential Gas Pressure Regulator Modification

The modification to be made to the Differential Gas Pressure Regulator consist of removing the exist
spring and replacing it with the new plated spring provided in the Conversion Kit. Proceed as follows:

1. Remove the cap on the Differential Gas Pressure Regulator (Figure 12).

2. Remove the adjustment screw and the installed regulator spring from the Differential Gas

Pressure Regulator.

3. Install the replacement plated spring provided in the Conversion Kit.

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