AERCO BMK 2.0 LN Nat. Gas User Manual

0 (0)

InstructionNo. GF-110LN

AERCO INTERNATIONAL, Inc., Northvale, New Jersey, 07647 USA

Installation, Operation

& Maintenance Instructions

Benchmark™

Series

Gas Fired

Low NOx

Boiler System

Condensing, Modulating

Forced Draft, Hot Water Boiler

2,000,000 BTU/H Input

Applicable To Serial Numbers G-05-1393 and above

Patent # : 2.155.12

Printed in U.S.A.

REVISED JANUARY, 2009

Telephone Support

Direct to AERCO Technical Support

(8 to 5 pm EST, Monday through Friday)

(800) 526-0288

AERCO International, Inc.

159 Paris Avenue

Northvale, NJ 07647-0128

www.aerco.com

The information contained in this installation, operation and maintenance 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.

CONTENTS

GF-110LN - AERCO BENCHMARK 2.0 GAS FIRED LOW NOx BOILER

Operating & Maintenance Instructions

FOREWARD					A
Chapter 1 – SAFETY PRECAUTIONS					1-1
Para.	Subject	Page	Para.	Subject	Page
1-1	Safety Warnings	1-1	1-3	Prolonged Shutdown	1-1
1-2	Emergency Shutdown	1-1
Chapter 2 – INSTALLATION PROCEDURES					2-1
Para.	Subject	Page	Para.	Subject	Page
2.1	Receiving the Unit	2-1	2.7	I/O Box Connections	2-7
2.2	Unpacking	2-1	2.8	Auxiliary Relay Contacts	2-8
2.3	Installation	2-2	2.9	Flue Gas Vent Installation	2-9
2.4	Gas Supply Piping	2-3	2.10	Combustion Air	2-9
2.5	Electrical Supply	2-4
2.6	Mode of Operation and Field	2-5
	Control Wiring
Chapter 3 – CONTROL PANEL COMPONENTS AND
	OPERATING PROCEDURES				3-1
Para.	Subject	Page	Para.	Subject	Page
3.1	Introduction	3-1	3.6	Configuration Menu	3-6
3.2	Control Panel Description	3-1	3.7	Tuning Menu	3-7
3.3	Control Panel Menus	3-3	3.8	Start Sequence	3-7
3.4	Operating Menu	3-5	3.9	Start/Stop Levels	3-9
3.5	Setup Menu	3-5
Chapter 4 – INITIAL START-UP					4-1
Para.	Subject	Page	Para.	Subject	Page
4.1	Initial Startup Requirements	4-1	4.4	Unit Reassembly	4-5
4.2	Tools and Instruments for	4-1	4.5	Over-Temperature Limit Switch	4-5
	Combustion Calibration
4.3	Natural Gas Combustion	4-2
	Calibration

CONTENTS
Chapter 5 – MODE OF OPERATION					5-1
Para.	Subject	Page	Para.	Subject	Page
5.1	Introduction	5-1	5.6	Boiler Management System	5-4
5.2	Indoor/Outdoor Reset Mode	5-1		(BMS)
5.3	Constant Setpoint Mode	5-2	5.7	Combination Control System	5-5
5.4	Remote Setpoint Mode	5-2		(CCS)
5.5	Direct Drive Modes	5-3

Chapter 6 – SAFETY DEVICE TESTING PROCEDURES					6-1
Para.	Subject	Page	Para.	Subject	Page
6.1	Testing of Safety Devices	6-1	6.8	Air Flow Fault Test	6-4
6.2	Low Gas Pressure Fault Test	6-1	6.9	SSOV Proof of Closure Switch	6-4
6.3	High Gas Pressure Test	6-1	6.10	Purge Switch Open During	6-5
6.4	Low Water Level Fault Test	6-2		Purge
6.5	Water Temperature Fault Test	6-2	6.11	Ignition Switch Open During	6-5
6.6	Interlock Tests	6-2		Ignition
6.7	Flame Fault Test	6-3	6.12	Safety Pressure Relief Valve	6-5
				Test

Chapter 7 – MAINTENANCE REQUIREMENTS					7-1
Para.	Subject	Page	Para.	Subject	Page
7.1	Maintenance Schedule	7-1	7.7	Condensate Drain Trap	7-4
7.2	Spark Igniter	7-1	7.8	Shutting the Boiler Down For An	7-4
7.3	Flame Detector	7-2		Extended Period of Time
7.4	Combustion Calibration	7-2	7.9	Placing The Boiler Back In	7-4
7.5	Safety Device Testing	7-3		Service After A Prolonged
7.6	Burner	7-3		Shutdown

Chapter 8 – TROUBLESHOOTING GUIDE					8-1
Para.	Subject	Page	Para.	Subject	Page
8.1	Introduction	8-1

CONTENTS

APPENDICES

App	Subject	Page	App	Subject	Page
A	Boiler Menu Item Descriptions	A-1	E	Boiler Default Settings	E-1
B	Startup, Status and Fault	B-1	F	Dimensional and Part Drawings	F-1
	Messages		G	Piping Drawings	G-1
C	Temperature Sensor Resistance	C-1	H	Wiring Schematics	H-1
	Chart		I	Recommended Periodic Testing	I-1
D	Indoor/Outdoor Reset Ratio	D-1		Checklist
	Charts		J	Benchmark Control Panel Views	J-1

WARRANTIES

W-1

iii

FOREWORD

Foreword

The AERCO Benchmark 2.0 LN Boiler is a true industry advance that meets the needs of today's energy and environmental concerns. Designed for application in any closed loop hydronic system, the Benchmark's modulating capability relates energy input directly to fluctuating system loads. The Benchmark’s 20:1 turn down ratio and condensing capability, provides extremely high efficiencies and makes it ideally suited for modern low temperature, as well as, conventional heating systems.

When installed and operated in accordance with this Instruction Manual, the Benchmark 2.0 LN Boiler 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, Chaptr 117, Rule117.465

Whether used in singular or modular arrangements the Benchmark 2.0 LN offers the maximum flexibility in venting with minimum installation space requirements. The Benchmark's advanced electronics are available in several selectable modes of operation offering the most efficient operating methods and energy management system integration.

For service or parts, contact your local sales representative or AERCO INTERNATIONAL.

NAME:

ORGANIZATION:

ADDRESS:

TELEPHONE:

INSTALLATION DATE: _____________________________________________

SAFETY PRECAUTIONS

CHAPTER 1 SAFETY PRECAUTIONS

1.1 WARNINGS & CAUTIONS

Installers and operating personnel MUST, at all times, observe all safety regulations. The following general warnings and cautions must be given the same attention as specific precautions included in these instructions. In addition to all the requirements included in this Instruction Manual, the installation of units MUST conform with local building codes, or, in the absence of local codes, ANSI Z223.1 (National Fuel Gas Code Publication No. NFPA-54). Where ASME CSD-1 is required by local jurisdiction, the installation must conform to CSD-1.

Where applicable, the equipment shall be installed in accordance with the current Installation Code for Gas Burning Appliances and Equipment, CGA B149, and applicable Provincial regulations for the class; which should be carefully followed in all cases. Authorities having jurisdiction should be consulted before installations are made.

IMPORTANT

This Instruction Manual is an integral part of the product and must be maintained in legible condition. It must be given to the user by the installer and kept in a safe place for future reference.

WARNINGS!

MUST BE OBSERVED TO PREVENT SERIOUS INJURY.

WARNING!

BEFORE ATTEMPTING TO PERFORM ANY MAINTENANCE ON THE UNIT, SHUT OFF ALL GAS AND ELECTRICAL INPUTS TO THE UNIT.

WARNING!

THE EXHAUST VENT PIPE OF THE UNIT OPERATES UNDER A POSITIVE PRESSURE AND THEREFORE MUST BE COMPLETELY SEALED TO PREVENT LEAKAGE OF COMBUSTION PRODUCTS INTO LIVING SPACES.

WARNING

DO NOT USE MATCHES, CANDLES, FLAMES, OR OTHER SOURCES OF IGNITION TO CHECK FOR GAS LEAKS.

WARNING!

FLUIDS UNDER PRESSURE MAY CAUSE INJURY TO PERSONNEL OR DAMAGE TO EQUIPMENT WHEN RELEASED. BE SURE TO SHUT OFF ALL INCOMING AND OUTGOING WATER SHUTOFF VALVES. CAREFULLY DECREASE ALL TRAPPED PRESSURES TO ZERO BEFORE PERFORMING ANY BOILER MAINTENANCE.

WARNING!

ELECTRICAL VOLTAGES UP TO 460 VAC MAY BE USED IN THIS EQUIPMENT. THEREFORE THE COVER ON THE UNIT’S POWER BOX (LOCATED BEHIND THE FRONT PANEL DOOR) MUST BE INSTALLED AT ALL TIMES, EXCEPT DURING MAINTENANCE AND SERVICING.

CAUTIONS!

Must be observed to prevent equipment damage or the loss of operating effectiveness.

CAUTION!

Many soaps used for gas pipe leak testing are corrosive to metals. The piping must be rinsed thoroughly with clean water after leak checks have been completed.

CAUTION!

DO NOT use this boiler if any part has been under water. Call a qualified service technician to inspect and replace any part that has been under water.

1-1

SAFETY PRECAUTIONS

1.2 EMERGENCY SHUTDOWN

If overheating occurs or the gas supply fails to shut off, close the manual gas shutoff valve (Figure 1-1) located external to the unit.

IMPORTANT

The Installer must identify and indicate the location of the emergency shutdown manual gas valve to operating personnel.

1.3 PROLONGED SHUTDOWN

After prolonged shutdown, it is recommended that the startup procedures in Chapter 4 and the safety device test procedures in Chapter 6 of this manual be performed, to verify all systemoperating parameters. If there is an emergency, turn off the electrical power supply to the AERCO boiler and close the manual gas valve located upstream the unit. The installer must identify the emergency shut-off device.

Figure 1-1

Manual Gas Shutoff Valve

1-2

INSTALLATION

Chapter 2 - INSTALLATION

2.1 RECEIVING THE UNIT

Each Benchmark is shipped as a single crated unit. The shipping weight is approximately 1850 pounds, and must be moved with the proper rigging equipment for safety and to avoid damages. The unit should be completely inspected for shipping damage and completeness at the time of receipt from the carrier and before the bill of lading is signed.

NOTE:

AERCO is not responsible for lost or damaged freight.

Each unit has a Tip-N-Tell indicator on the outside of the crate. This indicates if the unit has been turned on its side. If the Tip-N-Tell indicator is tripped, do not sign for the shipment. Note the information on the carrier’s paperwork and request a freight claim and inspection by a claims adjuster before proceeding. Any other visual damage to the packaging materials should also be made clear to the delivering carrier.

2.2 UNPACKING

Carefully unpack the unit taking care not to damage the unit jacket when cutting away packaging materials. A close inspection of the unit should be made to determine if there has been any damage not indicated by the Tip-N- Tell. The freight carrier should be notified immediately if any damage is detected. The following accessories come standard with each unit and are packed separately within the unit’s’ packing container or are factory installed on the boiler.

•Pressure/Temperature Gauge

•Spare Spark Ignitor

•Spare Flame Detector

•ASME Pressure Relief Valve

•Regulator Adjustment Tool (One per Site)

•Condensate Drain Trap

•2” Gas Supply Shutoff Ball Valve

When ordered, optional accessories may be packed separately or within the boiler shipping container, or may be installed on the boiler. Any standard or optional accessories shipped loose should be identified and put in a safe place until ready for installation or use.

Figure 2.1

Boiler Clearances

2-1

INSTALLATION

2.3 INSTALLATION

The unit must be installed by qualified personnel (i.e. licensed plumber, gas fitter, etc.) in compliance with local and state regulations. The prescribed clearances for service are shown in Figure 2.1. The minimum clearance dimensions, required by AERCO, are listed below. Local building codes may require more clearance and take precedence

Minimum clearances required:

Sides	24"
Front	24"
Rear	36"
Top	18"

All gas piping, water piping and electrical conduit or cable must be arranged so that they do not interfere with the removal of any cover, or inhibit service or maintenance of the unit.

WARNING!

KEEP UNIT AREA CLEAR AND FREE FROM COMBUSTIBLE MATERIALS AND FLAMMABLE VAPORS AND LIQUIDS.

CAUTION!

While packaged on the shipping skid, the boiler must be moved by pallet jack or forklift from the rear only.

2.3.1. SETTING THE UNIT

The unit must be installed on a 4 to 6 inch housekeeping pad for proper condensate drainage. If anchoring the unit, see the dimensional drawings in Appendix F for anchor location. Lifting lugs are provided for moving the unit when it has been removed from the shipping skid (See Fig. 2.2). USE ONLY THE LIFTING LUGS TO MOVE THE UNIT. Remove the rear top panel from the unit to provide access to the lifting lugs. Remove the four (4) lag screws securing the boiler to the shipping skid. Lift the unit off the shipping skid and position it on to the 4 to 6 inch housekeeping concrete pad (required) in the desired location.

In multiple unit installations, it is important to plan the position of each unit. Sufficient space for piping connections and future maintenance requirements must be given. All piping must include ample provision for expansion.

If installing a Combination Control (CCP) system, it is important to identify and place the

Combination Mode units in the proper physical location. If these boilers are not properly located, it will be necessary to reprogram them.

Figure 2.2

Lifting Lug Location

2.3.2 SUPPLY AND RETURN PIPING

The Benchmark 2.0 utilizes 4" 150# flanges for the water system supply and return piping connections. See Appendix F for dimensional data. The physical location of the supply and return piping connections is on the rear of the unit (See Fig 2.3 For Details).

BOILER SUPPLY (4"-150# FLG'D CONN.)

BOILER RETURN (4"-150# FLG'D CONN.)

Figure 2.3

Supply and Return Location

2-2

2.3.3 CONDENSATE DRAIN & PIPING

The Benchmark Boiler is designed to condense water vapor from the flue products. Therefore, the installation must have provisions for suitable drainage or collection. A 1/2” NPT drain connection is provided on the exhaust manifold (see Fig 2.4). A separate condensate drain trap (part no. 24060) is shipped loose and must be installed on the floor behind the unit. Connect the trap to the exhaust manifold as follows:

1.First, install a 1/2” NPT nipple in the condensate drain port (Fig. 2.4). Next, connect a 3/4-to 1/2” reducer to the 1/2” nipple.

2.On the condensate drain trap, install 3/4” NPT nipples in the tapped inlet and outlet of the trap.

3.Attach a length of 1” I.D. polypropylene hose between the exhaust manifold drain and the inlet side of the condensate trap (Fig 2.5). Secure both ends of the hose with clamps. Drainage from the condensate drain trap outlet must be by gravity to a nearby floor drain via a polypropylene hose or suitable piping.

If a floor drain is not available, a condensate pump can be used to remove the condensate to drain. The maximum condensate flow rate is 11 GPH. The condensate drain trap, associated fittings and drain line must be removable for routine maintenance. Do Not hard pipe.

Figure 2.4

Condensate Drain Connection Location

INSTALLATION

Figure 2.5

Condensate Trap Installation

2.4. GAS SUPPLY PIPING

The AERCO Gas Fired Equipment Gas Components and Supply Design Guide (GF-2030LN) must be consulted before any gas piping is designed or started.

WARNING!

DO NOT USE MATCHES, CANDLES, FLAMES OR OTHER SOURCES OF IGNITION TO CHECK FOR GAS LEAKS.

CAUTION!

Many soaps used for gas pipe leak testing are corrosive to metals. Therefore, AERCO recommends the use of non-corrosive soaps for leak tests. The piping must be rinsed thoroughly with clean water after leak checks have been completed.

NOTE:

All gas piping must be arranged so that it does not interfere with removal of any cover, inhibit service or maintenance, or prevent access between the Unit and walls, or another unit.

The location of the 2" inlet gas connection is on the rear of the unit as shown in Figure 2.5.

All pipes should be de-burred and internally cleared of any scale or iron chips before installation. No flexible connectors or nonapproved gas fittings should be installed. Piping

2-3

INSTALLATION

should be supported from floor, ceiling or walls only and must not be secured to the unit.

A suitable piping compound, approved for use with natural gas or propane, should be used. Any excess must be wiped off to prevent clogging of components.

To avoid damage to the unit, when pressure testing gas piping, isolate the unit from the gas supply piping. At no time should there be more than 2 psi to the unit. Leak test all external piping thoroughly for leaks using a soap and water solution or suitable equivalent. The gas piping must meet all applicable codes.

2.4.1 GAS SUPPLY SPECIFICATONS

−Natural Gas:

The maximum static pressure to the unit must be no more than 2 psi. Minimum natural gas operating pressure is 5.3“ W.C. for FM gas trains & 5.5“ W.C. for IRI gas trains when the unit is firing at maximum input (2000 cfh). For Benchmark 2.0 Low NOx boilers configured for De-Rated capacity, the required minimum natural gas operating pressure is 4.0” W.C. for FM gas trains (4.2” W.C. for IRI gas trains) at maximum input of 1,750,000 BTU/hr (1750 cfh).

2.4.2 MANUAL GAS SHUTOFF VALVE

A 2” manual gas shut-off valve is furnished with each unit. The valve should be positioned on the inlet to the unit, as shown in Figure 2.5.

Figure 2.5

Manual Shut-Off Valve Location

2.4.3 IRI GAS TRAIN KIT

The IRI gas train is an optional gas train required in some areas by code or for insurance purposes. The IRI gas train is factory pre-piped and wired.

2.5 ELECTRICAL SUPPLY

The AERCO Gas Fired Equipment Electrical Power Wiring Guide, (GF-2060), must be consulted in addition to the following material before wiring to the unit is started. External AC power connections are made to the unit inside the power box on the front panel of the unit, behind the removable front door (Figure 2.6).

NOTE:

All electrical conduit and hardware should be installed so that it does not interfere with the removal of any cover, inhibit service or maintenance, or prevent access between the unit and walls or another unit.

Figure 2.6

AC Input Terminal Location

2.5.1 ELECTRICAL REQUIREMENTS

The Benchmark Boiler is available in one three different AC power configurations:

220 Vac/1 Phase/60 Hz @ 20 amps

208 Vac/3-Phase/60 @15 amps

460 Vac/3-Phase/60 Hz @ 15 amps

2-4

Each of the above power configurations contain a Power Box with a terminal block which matches the configuration ordered. The three different terminal block configurations are shown in Figure 2.7. A wiring diagram showing the required AC power connections is provided on the front panel of each Power Box.

Each Benchmark Boiler must be connected to a dedicated electrical circuit. No other devices should be on the same electrical circuit as the Benchmark Boiler. A means for disconnecting AC power from the unit (such as a service switch) must be installed near the unit for normal operation and maintenance. All electrical connections should be made in accordance with the National Electrical Code and/or with any applicable local codes.

For electrical power wiring diagrams, see the Benchmark Electrical, Power Wiring Guide, GF2060

INSTALLATION

2.6 MODE OF OPERATION and FIELD CONTROL WIRING

The Benchmark Boiler is available in several different modes of operation. While each unit is factory configured and wired for a particular mode, some field wiring may be required to complete the installation. This wiring is typically run to the Input/Output (I/O) Box located on the front of the unit behind the removable front door (see Fig. 2.8). A brief description of each mode of operation, and their requirements, is described in the following paragraphs. Additional information concerning field wiring is provided in paragraphs 2.7.1 through 2.7.9. For additional information on modes of operation, refer to Chapter 5.

Figure 2.8

I/O Box Terminal Location

2.6.1 CONSTANT SETPOINT MODE

The Constant Setpoint Mode is used when it is desired to have a fixed setpoint that does not deviate. No wiring connections other than electrical supply connections are required for this mode. However, if desired, fault monitoring or enable/disable interlock wiring can be utilized (see paragraphs 2.7.9.1 and 2.7.10).

Figure 2.7

AC Terminal Block Configurations

2-5

INSTALLATION

2.6.2 INDOOR/OUTDOOR RESET MODE

This mode of operation increases supply water temperature as outdoor temperatures decrease. An outside air temperature sensor (AERCO PN 122790) is required. The sensor MUST BE wired

to the I/O Box wiring terminals (see Fig. 2.9). For more information concerning the outside air sensor installation, refer to paragraph 2.7.1

Figure 2.9 I/O Box Terminal Strip

2.6.3BOILER MANAGEMENT SYSTEM (BMS) MODE

NOTE

BMS Model 168 can utilize either pulse width modulation (PWM) or RS485 Modbus signaling to the Boiler. BMS II Model 5R5-384 can utilize only RS485 signaling to the Boiler.

only at the AERCO BMS. The boiler end of the shield must be left floating. For additional instructions, refer to Chapter 5, paragraph 5.6 in this manual. Also, refer to GF-108M (BMS Model 168) and GF-124 (BMS II Model 5R5384), BMS -Operations Guides.

2.6.4 REMOTE SETPOINT and DIRECT

DRIVE MODES

When using an AERCO Boiler Management System (BMS), the field wiring is connected between the BMS Panel and each Boiler’s I/O Box terminal strip (Figure 2-9). Twisted shielded pair wire from 18 to 22 AWG must be utilized for the connections. The BMS Mode can utilize either pulse width modulation (PWM) signaling, or RS485 Modbus signaling. For PWM signaling, connections are made from the AERCO Boiler Management System to the B.M.S. (PWM) IN terminals on the I/O Box terminal strip. For RS485 Modbus signaling, connections are made from the BMS to the RS485 COMM terminals on the I/O Box terminal strip. Polarity must be maintained and the shield must be connected

The Benchmark Boiler can accept several types of signal formats from an Energy Management System or other source to control either the setpoint (Remote Setpoint Mode) or firing rate (Direct Drive Mode) of the Boiler. These formats are:

4 to 20 mA/1 to 5 Vdc

0 to 20 mA/0 to 5 Vdc

PWM – (Pulse Width Modulated signal. See paragraph 2.7.4)

Network – (RS485 Modbus. See para. 2.7.7)

2-6

While it is possible to control a boiler or boilers using one of the previously described modes of operation, it may not be the method best suited for the application. Prior to selecting one of these modes of operation, it is recommended that you consult with your local AERCO representative or the factory for the mode of operation that will work best with your application. For more information on wiring the 4 to 20 mA / 1to 5VDC or the 0 to 20 mA / 0 to 5 VDC, see paragraph 2.7.3.

2.6.4COMBINATION MODE

NOTE

Only BMS Model 168 can be utilized for the Combination Mode, not the BMS II (Model 5R5-384).

With a Combination Mode unit, field wiring is connected between the unit’s I/O Box wiring terminals, the CCP (Combination Control Panel), and the BMS Model 168 (Boiler Management System). The wiring must be done using a shielded twisted pair of 1822 AWG wire and polarity must be maintained. For further instructions and wiring diagrams, refer to the GF-108 Boiler Management System Operations Guide and the CCP-1 data sheet.

2.7 I/O BOX CONNECTIONS

The types of input and output signals and devices to be connected to the I/O Box terminals shown in Figure 2.9 are described in the following paragraphs.

CAUTION!

DO NOT make any connections to the I/O Box terminals labeled “NOT USED”. Attempting to do so may cause equipment damage.

2.7.1 OUTDOOR SENSOR IN

An outdoor air temperature sensor (AERCO Part No. 122790) will be required mainly for the Indoor/Outdoor reset mode of operation. It can also be used with another mode if it is desired to use the outdoor sensor enable/disable feature. This feature allows the boiler to be enabled or disabled based on the outdoor air temperature.

The factory default for the outdoor sensor is DISABLED. To enable the sensor and/or choose an enable/disable outdoor temperature, see the Configuration menu in Chapter 3.

INSTALLATION

The outdoor sensor may be wired up to 200 feet from the boiler It is connected to the OUTDOOR SENSOR IN and SENSOR COMMON terminals in the I/O box (see Figs. 2.8 and 2.9). Wire the sensor using a twisted shielded pair cable of 1822 AWG wire. There is no polarity when terminating the wires. The shield is to be connected only to the terminals labeled SHEILD in the I/O box. The sensor end of the shield must be left free and ungrounded.

When mounting the sensor, it must be located on the North side of the building where an average outside air temperature is expected. The sensor must be shielded from direct sunlight as well as impingement by the elements. If a shield is used, it must allow for free air circulation.

2.7.2 AUX SENSOR IN

The AUX SENSOR IN terminals can be used to add an additional temperature sensor for monitoring purposes. This input is always enabled and is a view only input that can be seen in the operating menu. The sensor must be wired to the AUX SENSOR IN and SENSOR COMMON and must be similar to AERCO BALCO wire sensor P/N 12449. A resistance chart for this sensor can be found in APPENDIX C.

2.7.3 ANALOG IN

The ANALOG IN + and – terminals are used when an external signal is used to drive the firing rate (Direct Drive Mode) or change the setpoint (Remote Setpoint Mode) of the Boiler.

Either a 4 to 20 mA / 1 to 5 VDC or a 0 to 20 mA / 0 to 5 VDC signal may be used to vary the setpoint or firing rate. The factory default setting is for 4 to 20 mA / 1 to 5 VDC, however this may be changed to 0 to 20 mA / 0 to 5 VDC using the Configuration Menu described in Chapter 3. If voltage rather than current is selected as the drive signal, a DIP switch must be set on the PMC Board located inside the Control Box. Contact the AERCO factory for information on setting DIP switches.

All supplied signals must be floating (ungrounded) signals. Connections between the source and the Boiler’s I/O Box must be made using twisted shielded pair of 18 –22 AWG wire such as Belden 9841(see Fig. 2.9). Polarity must be maintained and the shield must be connected only at the source end and must be left floating (not connected) at the Boiler’s I/O Box.

2-7

INSTALLATION

Whether using voltage or current for the drive signal, they are linearly mapped to a 40o to 240oF setpoint or a 0% to 100% firing rate. No scaling for these signals is provided

2.7.4 B.M.S. (PWM) IN

NOTE

Only BMS Model 168 can utilize Pulse Width Modulation (PWM), not the BMS II (Model 5R5-384).

These terminals are used to connect the AERCO Boiler Management System (BMS) Model 168 to the unit. The BMS Model 168 utilizes a 12 millisecond, ON/ OFF duty cycle. This duty cycle is Pulse Width Modulated (PWM) to control firing rate. A 0% firing rate = a 5% ON pulse and a 100% firing rate = a 95% ON pulse.

2.7.5 SHIELD

The SHIELD terminals are used to terminate any shields used on sensor wires connected to the unit. Shields must only be connected to these terminals.

2.7.6 mA OUT

These terminals provide a 4 to 20 mA output that can be used to monitor setpoint ( 40o to 240oF), outlet temperature (30o to 240oF), or fire rate (0% to 100%). This function is enabled in the Configuration Menu (Chapter 3, Table 3.4).

2.7.7 RS-485 COMM

These terminals are used for RS-485 MODBUS serial communication between the unit and an external “Master” such as a Boiler Management System or other suitable device.

2.7.8 EXHAUST SWITCH IN

These terminals permit an external exhaust switch to be connected to the exhaust manifold of the boiler. The exhaust sensor should be a normally open type switch (such as AERCO Part No. 123463) that closes (trips) at 500oF.

2.7.9 INTERLOCKS

The unit offers two interlock circuits for interfacing with Energy Management Systems and auxiliary equipment such as pumps or louvers. These interlocks are called the Remote Interlock and Delayed Interlock (Fig. 2.9). The wiring terminals for these interlocks are located inside the I/O Box on the unit front panel. The I/O Box cover contains a wiring diagram which shows the terminal strip locations for these interlocks labeled REMOTE INTL’K IN and

DELAYED INTL’K IN. Both interlocks, described below, are factory wired in the closed position.

NOTE:

Both the Delayed Interlock and Remote Interlock must be in the closed position to allow the unit to fire.

2.7.9.1 REMOTE INTERLOCK IN

The remote interlock circuit (REMOTE INTL’K IN) is provided to remotely start (enable) and stop (disable) the Boiler if desired. The circuit is 24 VAC and comes factory pre-wired closed (jumped).

2.7.9.2 DELAYED INTERLOCK IN

The delayed interlock circuit (DELAYED INTL’K IN) is typically used in conjunction with the auxiliary relay described in paragraph 2.8. This interlock circuit is located in the purge section of the start string. It can be connected to the proving device (end switch, flow switch etc.) of an auxiliary piece of equipment started by the Boiler’s auxiliary relay. The delayed interlock must be closed for the boiler to fire. If the delayed interlock is connected to a proving device that requires time to close (make), a time delay (Aux Start On Dly) that holds the start sequence of the boiler long enough for a proving switch to make can be programmed. Should the proving switch not prove within the programmed time frame, the boiler will shut down. The Aux Start On Dly can be programmed from 0 to 120 seconds. This option is locate in the Configuration Menu (Chapter 3).

2.7.10 FAULT RELAY

The fault relay is a single pole double throw (SPDT) relay having a normally open and normally closed set of relay contacts that are rated for 5 amps at 120 VAC and 5 amps at 30 VDC. The relay energizes when any fault condition occurs and remains energized until the fault is cleared and the CLEAR button is depressed. The fault relay connections are shown in Figure 2.9

2.8 AUXILIARY RELAY CONTACTS

Each Boiler is equipped with a single pole double throw (SPDT) relay that is energized when there is a demand for heat and deenergized after the demand for heat is satisfied. The relay is provided for the control of auxiliary equipment, such as pumps and louvers, or can be used as a Boiler status indictor (firing or not

2-8

firing). Its contacts are rated for 120 VAC @ 5 amps. Refer to Figure 2.9 to locate the AUX RELAY terminals for wiring connections.

2.9 FLUE GAS VENT INSTALLATION

The AERCO Venting and Combustion Air Guide, GF-2050, must be consulted before any flue gas vent or inlet air venting is designed or installed. U/L listed, positive pressure, watertight vent materials as specified in AERCO’s GF-2050, must be used for safety and code compliance. Because the unit is capable of discharging low temperature exhaust gases, the flue must be pitched back to the unit a minimum of 1/4" per foot to avoid any condensate pooling and to allow for proper drainage.

The combined pressure drop of vent and combustion air systems must not exceed 140 equivalent feet of 8 inch ducting. Fittings as well as pipe lengths must be calculated as part of the equivalent length.

For a natural draft installation the draft must not exceed -0.25”/+0.25" W.C. These factors must be planned into the vent installation. If the maximum allowable equivalent lengths of piping are exceeded, the unit will not operate properly or reliably.

2.10 COMBUSTION AIR

The AERCO Venting and Combustion Air Guide, GF-2050, MUST be consulted before any flue or combustion supply air venting is designed or started. Combustion air supply is a direct requirement of ANSI 223.1, NFPA-54, and local codes. These codes should be consulted before a permanent design is determined.

The combustion air must be free of chlorine, halogenated hydrocarbons, or other chemicals that can become hazardous when used in gasfired equipment. Common sources of these compounds are swimming pools, degreasing compounds, plastic processing and refrigerants. Whenever the environment contains these types of chemicals, combustion air must be supplied from a clean area outdoors for the protection and longevity of the equipment.

The Benchmark is UL listed for 100% sealed combustion and can be ordered with a sealed combustion option, or can be installed using room air as long as there is an adequate supply.

INSTALLATION

(See paragraph 2.10.3 for more information concerning sealed combustion air.)

If the sealed combustion air option is not being used, an inlet screen will be attached at the blower suction and the knockout at the top of the unit will be and should remain in place.

The more common methods of supplying combustion air are outlined below. For more information concerning combustion air, consult the AERCO GF-2050, Venting and Combustion Air Guide.

2.10.1 COMBUSTION AIR FROM OUTSIDE THE BUILDING

Air supplied from outside the building must be provided through two permanent openings. Each opening must have a free area of not less than one square inch for each 4000 BTU boiler input. The free area must take into account restrictions such as louvers and bird screens.

2.10.2 COMBUSTION AIR FROM INSIDE THE BUILDING

When combustion air is provided from within the building, it must be supplied through two permanent openings in an interior wall. Each opening must have a free area of not less than one square inch per 1000 BTUH of total boiler input. The free area must take into account any restrictions such as louvers.

2.10.3 SEALED COMBUSTION

The BENCHMARK boiler is UL listed for 100%- sealed combustion and can be ordered with a sealed combustion option or without. Units ordered in the sealed combustion configuration will come with an air inlet assembly installed on the blower. The knockout at the top of the boiler must be removed and the combustion air ductwork must be attached to the 6" x 8" adapter that is provided just below the knockout. Remove and discard the screen attached to the adapter.

In a sealed combustion air application, the combustion air ducting pressure losses must be taken into account when calculating the total maximum allowable venting run. See the AERCO Venting and Combustion Air Guide, GF2050. When using the boiler in a sealed combustion air configuration, each unit must have a minimum 8" diameter connection at the unit.

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CONTROL PANEL OPERATING PROCEDURES

Chapter 3 - CONTROL PANEL OPERATING PROCEDURES

3.1. INTRODUCTION

The information in this Chapter provides a guide to the operation of the Benchmark Boiler using the Control Panel mounted on the front of the unit. It is imperative that the initial startup of this unit be performed by factory trained personnel. Operation prior to initial startup by factory trained personnel will void the equipment warranty. In addition, the following WARNINGS and CAUTIONS must be observed at all times.

CAUTION:

All initial installation procedures must be satisfied before attempting to start the unit.

WARNING:

THE ELECTRICAL VOLTAGES IN THIS SYSTEM MAY INCLUDE 460, 220, 120 AND 24 VOLTS AC. IT MUST NOT BE SERVICED OR ACCESSED BY OTHER THAN FACTORY CERTIFIED SERVICE TECHNICIANS.

WARNING:

DO NOT ATTEMPT TO DRY FIRE THE BOILER. STARTING THE UNIT WITHOUT A FULL WATER LEVEL CAN SERIOUSLY DAMAGE THE UNIT AND MAY RESULT IN PERSONNEL INJURY OR PROPERTY DAMAGE. THIS SITUATION WILL VOID ANY WARRANTY.

3.2. CONTROL PANEL DESCRIPTION

The Benchmark Control Panel shown in Figure 3-1 contains all of the controls, indicators and displays necessary to operate, adjust and troubleshoot the Benchmark Boiler. These operating controls, indicators and displays are listed and described in Table 3-1. Additional information on these items are provided in the individual operating procedures provided in this Chapter.

2
1	3
	3
	4
12	5
	5
11	6
10	7
	8
9
	Figure 3-1.

Control Panel Front View

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CONTROL PANEL OPERATING PROCEDURES

Table 3-1 Operating Controls, Indicators and Displays

ITEM	CONTROL, INDICATOR
NO.	OR DISPLAY	FUNCTION
1	LED Status Indicators	Four Status LEDs indicate the current operating status as
		follows:
	COMM	Lights when RS-232 communication is occurring
	MANUAL	Lights when the unit is being controlled using the front panel
		keypad.
	REMOTE	Lights when the unit is being controlled by an external signal
		from an Energy Management System
	DEMAND	Lights when there is a demand for heat.
2	OUTLET	3–Digit, 7–Segment LED display continuously displays the
	TEMPERATURE	outlet water temperature. The °F or °C LED next to the
	Display	display lights to indicate whether the displayed temperature is
		in degrees Fahrenheit or degrees Celsius.
3	VFD Display	Vacuum Fluorescent Display (VFD) consists of 2 lines, each
		capable of displaying up to 16 alphanumeric characters. The
		information displayed includes:
		Startup Messages
		Fault Messages
		Operating Status Messages
		Menu Selection
4	RS-232 Port	Port permits a Laptop Computer or External Modem to be
		connected to the boiler Control Panel.
5	FAULT Indicator	Red FAULT LED indicator lights when a boiler alarm
		condition occurs. An alarm message will appear in the VFD.
6	CLEAR Key	Turns off the FAULT indicator and clears the alarm message
		if the alarm is no longer valid. Lockout type alarms will be
		latched and cannot be cleared by simply pressing this key.
		Troubleshooting may be required to clear these types of
		alarms.
7	READY Indicator	Lights when all Pre-Purge conditions have been satisfied.
8	ON/OFF Switch	Enables and disables boiler operation.
9	LOW WATER LEVEL	Allows operator to test operation of the water level monitor.
	TEST/RESET Switches	Pressing TEST opens the water level probe circuit and
		simulates a Low Water Level alarm.
		Pressing RESET resets the water level monitor circuit.
		Pressing CLEAR resets the display.

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CONTROL PANEL OPERATING PROCEDURES

Table 3-1 Operating Controls, Indicators and Displays - Continued

ITEM	CONTROL, INDICATOR
NO.	OR DISPLAY	FUNCTION
10	Menu Keypad	Consists of 6 keys which provide the following functions for
		the Control Panel Menus:
	MENU	Steps through the main menu categories shown in Figure
		3-2. The Menu categories wrap around in the order shown.
	BACK	Allows you to go back to the previous menu level without
		changing any information. Continuously pressing this key
		will bring you back to the default status display in the VFD.
		Also, this key allows you to go back to the top of a main
		menu category.
	▲ (UP) Arrow	When in one of the main menu categories (Figure 3-2),
		pressing the ▲ arrow key will select the displayed menu
		category. If the CHANGE key was pressed and the menu
		item is flashing, pressing the ▲ arrow key will increment the
		selected setting.
	▼ (DOWN) Arrow	When in one of the main menu categories (Figure 3-2),
		pressing this key will select the displayed menu category. If
		the CHANGE key was pressed and the menu item is
		flashing, pressing the ▼ arrow key will decrement the
		selected setting.
	CHANGE	Permits a setting to be changed (edited). When the
		CHANGE key is pressed, the displayed menu item will begin
		to flash. Pressing the ▲ or ▼ arrow key when the item is
		flashing will increment or decrement the displayed setting.
	ENTER	Saves the modified menu settings in memory. The display
		will stop flashing.
11	AUTO/MAN Switch	This switch toggles the boiler between the Automatic and
		Manual modes of operation. When in the Manual (MAN)
		mode, the front panel controls are enabled and the
		MANUAL status LED lights.
		When in the Automatic (AUTO) mode, the MANUAL status
		LED will be off and the front panel controls disabled.
12	FIRE RATE Bargraph	20 segment red LED bargraph continuously shows the Fire
		Rate in 5% increments from 0 to 100%

3-3

CONTROL PANEL OPERATING PROCEDURES

3.3. CONTROL PANEL MENUS

The Control Panel incorporates an extensive menu structure which permits the operator to set up, and configure the unit. The menu structure consists of four major menu categories as shown in Figure 3-2. Each of the menus shown, contain options which permit operating parameters to be viewed or changed. The menus are protected by a password to prevent unauthorized use.

Prior to entering the correct password, the options contained in the Operating, Setup, Configuration and Tuning Menu categories can be viewed. However, with the exception of Internal Setpoint Temperature (Configuration Menu), none of the viewable menu options can be changed.

Once the valid password (159) is entered, the options listed in the Setup, Configuration and Tuning Menus can be viewed and changed, if desired.

3.3.1. Menu Processing Procedure

Accessing each menu and option is accomplished using the Menu Keys shown in Figure 3-1. Therefore, it is imperative that you be thoroughly familiar with the following basic steps before attempting to perform specific menu procedures.

1.The Control Panel will normally be in the Operating Menu and the VFD will display the current unit status. Pressing the ▲ or ▼ arrow key will display the other available data items in the Operating Menu.

2.Press the MENU key. The display will show the Setup Menu which is the next menu category shown in Figure 3-2. This menu contains the Password option which must be entered if other menu options will be changed.

3.Continue pressing the MENU key until the desired menu is displayed.

4.With the desired menu displayed, press the ▲ or ▼arrow key. The first option in the selected menu will be displayed.

5.Continue to press the ▲ or ▼ arrow key until the desired menu option is displayed. Pressing the ▲ arrow key will display the available menu options in the Top-Down sequence. Pressing the ▼ arrow key will

display the options in the Bottom-Up sequence. The menu options will wraparound after the first or last available option is reached.

6.To change the value or setting of a displayed menu option, press the CHANGE key. The displayed option will begin to flash. Press the ▲ or ▼ arrow key to scroll through the available menu option choices for the option to be changed. The menu option choices do not wrap around.

7.To select and store a changed menu item, press the ENTER key.

Figure 3-2. Menu Structure

NOTE:

The following paragraphs provide brief descriptions of the options contained in each menu. Refer to Appendix A for detailed descriptions of each menu option. Factory Default settings for all menu options are listed in Appendix E. Refer to Appendix B for listings and descriptions of displayed startup, status and error messages.

3-4

CONTROL PANEL OPERATING PROCEDURES

3.4. OPERATING MENU

The Operating Menu displays a number of key operating parameters for the unit as listed in Table 3-2. This menu is “Read-Only” and does not allow personnel to change or adjust any other displayed items. Since this menu is “ReadOnly”, it can be viewed at any time without entering a password. Press the ▲ arrow key to display the menu items in the order listed (TopDown). Pressing the ▼ arrow key will display the menu items in reverse order (Bottom-Up).

3.5. SETUP MENU

The Setup Menu (Table 3-3) permits the operator to enter the unit password (159) which is required to change the menu options. To prevent unauthorized use, the password will time-out after 1 hour. Therefore, the correct password must be reentered when required. In addition to permitting password entries, the

Setup Menu is also used to enter date and time, language to be used for display messages, units of temperature measurements and entries required for external communication and control of the unit via the RS-232 port. A view-only software version display is also provided to indicate the current Control Box software version.

NOTE:

The Outdoor Temp display item shown with an asterisk in Table 3-2 will not be displayed unless the Outdoor Sensor function has been enabled in the Configuration Menu (Table 3-4).

Table 3-2. Operating Menu

	Available Choices or Limits
Menu Item Display	Minimum	Maximum	Default
Status Message
Active Setpoint	40°F	240°F
Aux Temp	30°F	245°F
Outdoor Temp*	-70°F	130°F
Fire Rate In	0%	Max Fire Rate
Flame Strength	0%	100%
Run Cycles	0	999,999
Run Hours	0	999,999
Fault Log	0	9	0

Table 3-3. Setup Menu

	Available Choices or Limits
Menu Item Display	Minimum		Maximum	Default
Passsword	0		9999	0
Language	English			English
Time	12:00 am		11:59 pm
Date	01/01/00		12/31/99
Unit of Temp	Fahrenheit			Fahrenheit
	Celsius
Comm Address	0		127	0
Baud Rate	2400,	4800		9600
	9600, 19.2K

Software	Ver 0.00		Ver 9.99

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CONTROL PANEL OPERATING PROCEDURES

3.6. CONFIGURATION MENU

The Configuration Menu shown in Table 3-4 permits adjustment of the Internal Setpoint (Setpt) temperature regardless of whether the valid password has been entered. Setpt is required for operation in the Constant Setpoint mode. The remaining options in this menu require the valid password to be entered, prior to changing existing entries. This menu contains a number of other configuration settings which may or may not be displayed, depending on the current operating mode setting.

NOTE:

The Configuration Menu settings shown in Table 3-4 are Factory-Set in accordance with the requirements specified for each individual order. Therefore, under normal operating conditions, no changes will be required

Table 3-4. Configuration Menu

	Available Choices or Limits
Menu Item Display	Minimum	Maximum	Default
Internal Setpt	Lo Temp Limit	Hi Temp Limit	130°F
Unit Type	Boiler		Boiler
	Water Heater
Unit Size	0.5 MBTU, 1.0 MBTU		1.0 MBTU
	1.5 MBTU, 2.0 MBTU
	2.5 MBTU, 3.0 MBTU
Boiler Mode	Constant Setpoint		Constant
	Remote Setpoint		Setpoint
	Direct Drive
	Combination
	Outdoor Reset
Remote Signal	4 – 20 mA/1 – 5V		4 – 20 mA,
(If Mode = Remote	0 -20 mA/0 – 5V		1-5V
Setpoint, Direct Drive	BMS (PWM Input
or Combination)	Network
Bldg Ref Temp	40°F	240°F	70°F
(If Boiler Mode =
Outdoor Reset)
Reset Ratio	0.1	9.9	1.2
(If Boiler Mode =
Outdoor Reset)
Outdoor Sensor	Enabled or Disabled		Disabled
System Start Tmp	30°F	100°F	60°F
(If Outdoor Sensor =
Enabled)
Setpt Lo Limit	40°F	Setpt Hi Limit	60°F
Setpt Hi Limit	Setpt Lo Limit	240°F	200°F
Temp Hi Limit	40°F	240°F	215°F
Max Fire Rate	40%	100%	100%
Pump Delay Timer	0 min	30 min	0 min
Aux Start On Dly	0 sec	120 sec	0 sec
Failsafe Mode	Shutdown or	Constant Setpt	Shutdown
mA Output	Setpoint, Outlet Temp,		Off
	Fire Rate Out, Off
Lo Fire Timer	2 sec	120 sec	2 sec
Setpt Limiting	Enabled or Disabled		Disabled
Setpt Limit Band	0°F	10°F	5°F

3-6

CONTROL PANEL OPERATING PROCEDURES

3.7. TUNING MENU

The Tuning Menu items in Table 3-5 are Factory set for each individual unit. Do not change these

menu entries unless specifically requested to do so by Factory-Trained personnel.

Table 3-5. Tuning Menu

	Available Choices or Limits
Menu Item Display	Minimum		Maximum	Default
Prop Band	1°F		120°F	70°F
Integral Gain	0.00		2.00	1.00
Derivative Time	0.0 min		2.0 min	0.0 min
Reset Defaults?		Yes		No
		No
	Are You Sure?

3.8. START SEQUENCE

When the Control Box ON/OFF switch is set to the ON position, it checks all pre-purge safety switches to ensure they are closed. These switches include:

•Safety Shut-Off Valve Proof of Closure (POC) switch

•Low Water Level switch

•High Water Temperature switch

•High Gas Pressure switch

•Low Gas Pressure switch

If all of the above switches are closed, the READY light above the ON/OFF switch will light and the unit will be in the Standby mode.

When there is a demand for heat, the following events will occur:

NOTE:

If any of the Pre-Purge safety device switches are open, the appropriate fault message will be displayed. Also, the appropriate fault messages will be displayed throughout the start sequence, if the required conditions are not observed.

1.The DEMAND LED status indicator will light.

2.The unit checks to ensure that the proof of closure switch in the Safety Shut-Off Valve (SSOV) is closed (Figure 3-3).

Figure 3-3.

Safety Shut-Off Valve

3.With all required safety switches closed, a purge cycle will be initiated and the following events will occur:

3-7

CONTROL PANEL OPERATING PROCEDURES

(a)Blower relay energizes and turns on blower.

(b)Air/Fuel Valve rotates to full-open purge position and closes purge position switch. The dial on the Air/Fuel Valve (Figure 3-4) will read 100 to indicate that it is full-open (100%).

(c)The FIRE RATE bargraph will show 100%.

Figure 3-4.

Air/Fuel Valve In Purge Position

4.Next, the blower proof switch (Figure 3-5) closes. The display will show Purging and indicate the elapsed time of the purge cycle in seconds. The normal (default) time for the purge cycle is 7 seconds.

Figure 3-5.

Blower Proof Switch

5.Upon completion of the purge cycle, the Control Box initiates an ignition cycle and the following events occur:

(a)The Air/Fuel Valve rotates to the low-fire ignition position and closes the ignition switch. The dial on the Air/Fuel Valve (Figure 3-6) will read between 25 and 35 to indicate that the valve is in the lowfire position.

(b)Simultaneously, the ignition transformer and the staged ignition solenoid valve will be activated. The ignition transformer provides ignition spark. The activated (open) solenoid valve allows a small volume of gas to flow directly to the burner assembly (Appendix F).

(c)The gas Safety Shut-Off Valve (SSOV) is energized (opened) allowing gas to flow into the Air/Fuel Valve.

6.Up to 7 seconds will be allowed for ignition to be detected. The igniter relay will be turned off one second after flame is detected.

7.After 2 seconds of continuous flame, Flame Proven will be displayed and the flame strength will be indicated. After 5 seconds, the current date and time will be displayed in place of the flame strength.

3-8

CONTROL PANEL OPERATING PROCEDURES

8.With the unit firing properly, it will be controlled by the temperature controller circuitry. The FIRE RATE will be continuously displayed on the front panel bargraph.

BLOWER

BURNER

DIAL (DETAIL "A")

DETAIL "A"

Figure 3-6.

Air/Fuel Valve In Ignition Position

Once the demand for heat has been satisfied, the Control Box will turn off the gas valve. The blower relay will be deactivated and the Air/Fuel Valve will be closed. Standby will be displayed.

3.9. START/STOP LEVELS

The start and stop levels are the fire rate percentages that start and stop the unit, based on load. These levels are Factory preset as follows:

• Start Level:

20%

•Stop Level: 16%

Normally, these settings should not require adjustment

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