Lochinvar FBD2001 Service Manual

FBII-SER _100208044_2000004590_Rev F

Service Manual

w/CON•X•US Interface

Models: 751 - 2001

 WARNING

Save this manual for future reference.

This manual must only be
used by a qualified heating
installer / service technician.
Read all instructions,
including this manual and
the Crest Installation and
Operation Manual, before
installing. Perform steps in
the order given. Failure to
comply could result in severe
personal injury, death, or
substantial property damage.

Contents

CONTENTS ........................................................................ 2

Hazard Definitions .............................................................. 2

PLEASE READ BEFORE PROCEEDING ........................ 3

Handling Ceramic Fiber Materials ...................................... 3

When servicing boiler ................................................... 4

Boiler operation ............................................................ 4

Boiler water ................................................................... 4

Freeze protection fluids ................................................ 4

WHAT IS IN THIS MANUAL .............................................. 5

1. SERVICE

Boiler Piping ....................................................................... 6

SMART TOUCH w/CON•X•US Interface ........................... 7

General Operation ......................................................... 8

Control Inputs ............................................................... 9

Control Outputs ........................................................... 10

Table 1A - Sequence of Operation .................................. 11

Initial Setup Screen ........................................................... 12

Viewable and Changeable Control Parameters ............... 13

Set Point Screens .................................................. 13-15

Outdoor Reset Screen ........................................... 16-17

Ramp Delay Screen .............................................. 18-19

BMS Screens .......................................................... 20-22

Advanced Setup Screen ......................................... 23-24

Night Setback Screen ................................................... 25

Pump Screen ........................................................... 26-27

Cascade Screens ....................................................28-30

Service Screen.........................................................31-32

Graph Screens .............................................................. 33

History Screens........................................................34-35

2. MAINTENANCE

Maintenance and Annual Startup ................................ 36-40

3. TROUBLESHOOTING

Before Troubleshooting .................................................... 41

Check Control Module Fuses .......................................... 41

Table 3A - Troubleshooting Chart - No Display ............... 42

Checking Temperature Sensors ...................................... 43

Table 3F - Troubleshooting Chart - Noisy System .......... 44

Table 3G - Troubleshooting Chart - Fault Messages . 46-56

Combustion Analysis Procedure ................................. 57-58

Table 3H - Flue Products ................................................. 57

Table 3I - Troubleshooting Chart - Combustion Levels . 58

Gas Valve Adjustment Procedure .................................... 59

Revision Notes .................................................. Back Cover

Hazard definitions

The following defined terms are used throughout this manual to bring attention to the presence of hazards of various risk levels or
to important information concerning the life of the product.

 DANGER

 WARNING

 CAUTION

CAUTION

NOTICE

DANGER indicates an imminently hazardous situation which, if not avoided, will result in death or serious
injury.

WARNING indicates a potentially hazardous situation which, if not avoided, could result in death or serious
injury.

CAUTION indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate
injury.

CAUTION used without the safety alert symbol indicates a potentially hazardous situation which, if not
avoided, may result in property damage.

NOTICE indicates special instructions on installation, operation, or maintenance that are important but not
related to personal injury or property damage.

2

Please read before proceeding

Service Manual

 WARNING

Installer – Read all instructions, including
this manual and the Crest Installation
and Operation Manual, before installing.
Perform steps in the order given.

User – This manual is for use only by
a qualified heating installer/service
technician. Refer to the Crest User’s
Information Manual for your reference.

Have this boiler serviced/inspected by
a qualified service technician at least
annually.

Failure to comply with the above could
result in severe personal injury, death or
substantial property damage.

NOTICE

Handling ceramic fiber materials

REMOVAL OF COMBUSTION CHAMBER LINING

 WARNING

The combustion chamber insulation in this appliance contains ceramic fiber material. Ceramic fibers can
be converted to cristobalite in very high temperature applications. The International Agency for Research
on Cancer (IARC) has concluded, “Crystalline silica in the form of quartz or cristobalite from occupational
sources is carcinogenic to humans (Group 1).” Normal operating temperatures in this appliance are below
the level to convert ceramic fibers to cristobalite. Abnormal operating conditions would have to be created
to convert the ceramic fibers in this appliance to cristobalite.

When calling or writing about the boiler
– Please have the boiler model and serial
number from the boiler rating plate.

Consider piping and installation when
determining boiler location (see the Crest
Installation and Operation Manual).

Any claims for damage or shortage in
shipment must be filed immediately
against the transportation company by the
consignee.

The ceramic fiber material used in this appliance is an irritant; when handling or replacing the ceramic
materials it is advisable that the installer follow these safety guidelines.

Avoid breathing dust and contact with skin and eyes.

• Use NIOSH certified dust respirator (N95). This type of respirator is based on the OSHA
requirements for cristobalite at the time this document was written. Other types of respirators may
be needed depending on the job site conditions. Current NIOSH recommendations can be found on
the NIOSH website at http://www.cdc.gov/niosh/homepage.html. NIOSH approved respirators,
manufacturers, and phone numbers are also listed on this website.

• Wear long-sleeved, loose fitting clothing, gloves, and eye protection.

Apply enough water to the combustion chamber lining to prevent airborne dust.

 Remove the combustion chamber lining from the appliance and place it in a plastic bag for disposal.

 Wash potentially contaminated clothes separately from other clothing. Rinse clothes washer

thoroughly.

NIOSH stated First Aid.

 Eye: Irrigate immediately.
 Breathing: Fresh air.

3

Please read before proceeding

When servicing boiler –

• To avoid electric shock, disconnect electrical supply
before performing maintenance.

• To avoid severe burns, allow boiler to cool before
performing maintenance.

Boiler operation –

• Do not block flow of combustion or ventilation air to
the boiler.

• Should overheating occur or gas supply fail to shut off,
do not turn off or disconnect electrical supply to
circulator. Instead, shut off the gas supply at a location
external to the appliance.

• Do not use this boiler if any part has been under water.
The possible damage to a flooded appliance can be
extensive and present numerous safety hazards. Any
appliance that has been under water must be replaced.

Service Manual

Boiler water –

• Thoroughly flush the system (without boiler
connected) to remove sediment. The high-efficiency
heat exchanger can be damaged by build-up or
corrosion due to sediment.

• Do not use petroleum-based cleaning or sealing
compounds in the boiler system. Gaskets and seals in
the system may be damaged. This can result in
substantial property damage.

• Do not use “homemade cures” or “boiler patent
medicines”. Serious damage to the boiler, personnel,
and/or property may result.

• Continual fresh make-up water will reduce boiler life.
Mineral buildup in the heat exchanger reduces heat
transfer, overheats the stainless steel heat exchanger, and
causes failure. Addition of oxygen carried in by makeup
water can cause internal corrosion. Leaks in boiler
piping must be repaired at once to prevent the
introduction of makeup water.

Freeze protection fluids –

• NEVER use automotive antifreeze. Use only inhibited
propylene glycol solutions which are specifically
formulated for hydronic systems. Ethylene glycol is
toxic and can attack gaskets and seals used in hydronic
systems.

4

What is in this manual?

Service Manual

Service

Near boiler piping

• Typical system components

The Crest boiler display

• Display panel readout, buttons and their functions

Control module inputs

• Control module inputs and options

Control module outputs

• Control module outputs and options

General

• How the boiler operates

• How the control module operates

• Access modes -- user and installer

• Sequence of operation -- HW/space heating

Control panel menu access

• Accessing programming mode and locating menus
(See separate guide covering the PC interface.)

Maintenance

• Service and maintenance schedules

• Address reported problems

• Inspect boiler area and boiler interior

• Clean condensate trap

• Check all piping for leaks

• Check air openings

• Flue vent system and air piping

• Check water system

• Check expansion tank

• Check boiler relief valve

• Inspect ignition electrode

• Check ignition ground wiring

• Check all boiler wiring

• Check control settings

• Perform start-up and checks

• Check burner flame

• Check flame signal

• Check flue gas temperature

• General maintenance

• Review with owner

• Cleaning boiler heat exchanger

• Oiled bearing circulators

Control panel parameter access

• Accessing and changing parameters from the display panel

Quick start information -- parameter
table

• An index of available adjustments and readouts, where to
access them and where to find detailed information.

Crest boiler operation

• Initial Setup

• Set Points

• Outdoor Reset

• Ramp Delay

• BMS

• Advanced Setup

• SH Night Setback

• HW Night Setback

• Cascade

• Pumps

• Service Notification

Troubleshooting

• Troubleshooting table - No display

• Checking temperature sensors

• Sensor tables

• Troubleshooting table - Fault messages displayed on
boiler interface

• Combustion analysis procedure

• Gas valve adjustment procedure

5

Service Manual

1 Service

Boiler piping

This piping reference is included to specify the Boiler Piping specific to the Crest boiler. This piping scheme is important for
proper operation of the SMART TOUCH control. See the Crest Installation and Operation Manual for more detailed piping
diagrams.

Single Boiler - Recommended - Primary / Secondary Piping with a Hot Water Generator

FROM SYSTEM

SYSTEM RETURN

HOT WATER

GENERATOR

RELIEF

VALVE

SENSOR

12"

MAX

BALL VALVE
(TYPICAL)

AIR SEPERATOR

DRAIN PORT
(TYPICAL)

SYSTEM SUPPLY
SENSOR

SYSTEM
CIRCULATOR

BOILER

DRAIN

WATER

GENERATOR

CIRCULATOR

FLOW CHECK
VALVE (TYPICAL)

BOILER PUMP

Single Boiler - Alternate - Full Flow System Piping

RELIEF

VALVE

BALL VALVE

(TYPICAL)

FROM SYSTEM

BOILER DRAIN

Y-STRA INER

(RECOMMENDED)

Y-STRA INER
(RECOMMENDED)

EXPANSION

TANK

PRESSURE
REDUCING VALVE

PRESSURE
GAUGE

AIR SEPERATOR

DRAIN PORT
(TYPICAL)

SYSTEM
CIRCULATOR

BACK FLOW
PREVENTER

TO SYSTEM

MAKE UP
WATER

IMG01035

PRESSURE REDUCING VALVE

(OPTIONAL)

BYPASS

EXPANSION

TANK

PRESSURE

GAUGE

PRESSURE
REDUCING VALVE

BACK FLOW
PREVENTER

TO SYSTEM

MAKE UP
WATER

IMG01038

6

Service Manual

1 Service (continued)

w/CON•X•US Interface

The Home Screen displays status, modulation rate, outlet water temperature, inlet water temperature, flue temperature, system
supply temperature, system return temperature, outdoor air temperature, and domestic hot water tank temperature.

The boiler can be started and stopped by pressing the ON/OFF button. The Boiler Status Screen and Main Menu Screen can be
accessed by pressing the appropriate button.

Figure 1-1 Home Screen

When the ON/OFF switch is turned to the ON position,
the first screen visible on the LCD display will be the Home
Screen. This screen displays the current status of the Crest
boiler. The following items can be viewed or interacted with
on the Home Screen:

On/Off button - Pressing this button allows the boiler to be
placed in either Manual Shutdown Mode or Standby Mode.

Status - This line shows the current operating status of the
Crest boiler and the current set point.

Outlet Water Temperature - This is the boiler outlet
temperature.

Inlet Water Temperature - This is the boiler inlet temperature.

System Supply Temperature - This is the water temperature

as measured by the system supply sensor located in the
downstream piping (if connected).

System Return Temperature - This is the water temperature
measured by the system return sensor located in the upstream
piping (if connected).

Outside Air Temperature - This is the outdoor air temperature
(if connected).

HW Temperature - This is the temperature as measured by the
tank sensor in the hot water storage tank (if connected).

Flue Temperature - Temperature measured by the flue sensor.

Time - The time is displayed in the lower left-hand corner

of the display. Reference this manual for Night Setback
parameters and more information regarding adjusting the date
and time.

Modulation Percentage - Displays the current boiler firing
rate.

7

1 Service

General Operation

Service Manual

How the boiler operates

The Crest uses an advanced stainless steel heat exchanger
and electronic control module that allows fully condensing
operation. The blowers pull in air and push flue products out
of the boiler through the heat exchanger and flue piping. The
control module regulates blower speeds to control the boiler
firing rate. The gas valves sense the amount of air flowing into
the boiler and allow only the right amount of gas to flow.

How the control modules operate

The Crest boiler is equipped with a SMART TOUCH
CON•X•US Interface. The control module receives inputs
from boiler sensors and external devices. The control module
activates and controls the blowers and gas valves to regulate
heat input and switches the boiler, Hot Water Generator
(HW), and system pumps on and off as needed. The user
programs the control module to meet system needs by adjusting
control parameters through the SMART TOUCH CON•X•US
Interface. These parameters set operating temperatures and
boiler operating modes.

Sequence of operation

Table 1A (page 11) shows control module normal
sequences of operation for space heating and HW
operation. The combined operation sequence is for a
typical application, programmed to provide HW priority.

Access modes

User

The USER can set the SH set point, HW set point, turn the
unit OFF and ON and set up WiFi.

Installer

Most parameters are available only to the INSTALLER,
accessible only by entering the installer password (5309)
when selecting the Setup Section.

Note: The password will timeout after an hour from
entry.

8

1 Service

1 Service (continued)

Control inputs

HWG THERMOSTAT /

SENSOR

ENABLING DEVICE

CASCADE

LOUVER PROVING SWITCH

SYSTEM SENSOR -

SUPPLY

SYSTEM SENSOR -

RETURN

Service Manual

LOW VOLTAGE

CONNECTION

BOARD

OUTDOOR SENSOR

SEQUENCER / BUILDING

MANAGEMENT SYSTEM

AUX SWITCH 1 & 2

0-10 INPUT FROM

SYSTEM PUMP

INLET TEMPERATURE

SENSOR

OUTLET TEMPERATURE /

HI-LIMIT SENSOR

FLUE GAS SENSOR

INLET AIR SENSOR

AIR PRESSURE SWITCH

MANUAL RESET

HIGH LIMIT

FLAME SENSOR 1 & 2

BLOCKED DRAIN SWITCH

BAS BOARD

SMART CONTROL

MODULE

GAS PRESSURE SWITCHES

LOW WATER CUTOFF

AIR METERING VALVE
PRESSURE SWITCH

VENT DAMPER

PROVING SWITCH

AIR METERING VALVE
PROVING SWITCHES

DISPLAY PANEL

PC INTERFACE

9

1 Service

1 Service

Control outputs

Service Manual

0-10V OUTPUT TO

BOILER PUMP

ALARM CONTACTS

LOW VOLTAGE

CONNECTION

BOARD

LINE VOLTAGE

TERMINAL

STRIP

NL

SUPPLY

120V

SYSTEM PUMP BOILER PUMP DHW PUMP

MAX. 1.5 AMPS PER CONNECTION

FIELD SUPPLIED CONTACTOR MUST

BE INSTALLED

LOUVER RELAY

RUN TIME CONTACTS

BOILER RATE OUTPUT

SEQUENCER / BUILDING

MANAGEMENT SYSTEM

BOILER PUMP

CONTACTOR

SYSTEM PUMP

CONTACTOR

HWG PUMP

CONTACTOR

IGNITOR

BLOWER

GAS VALVES

10

SMART CONTROL

MODULE

VENT DAMPER

DISPLAY PANEL

PC INTERFACE

AIR METERING VALVE

Service Manual

1 Service (continued)

Table 1A Sequence of Operation

Sequence of operation

Note: This unit is equipped with two (2) gas train systems. Gas Train 1 will fire first. If the demand cannot be met by the first
gas train, the second gas train (Gas Train 2) will fire.

Upon a call for heat, the control turns on the appropriate pumps (system and boiler pumps for a space heating call,

1.

HW pump for a hot water generator call).

The control confirms that the low water cutoff contacts are closed and energizes the louvers (optional) and damper

2.

(optional) relays.

The control confirms that the gas pressure switch, blocked drain switch, limits, louver proving switch (optional) and

3.

damper proving switch (optional) contacts close. The Pre-Purge cycle begins.

The control confirms the blower is up to the desired speed, and the air pressure switch is closed.

4.

5.

6.

7.

8.

9.

10.

11.

Once the Pre-Purge cycle is complete, the control lowers the blower speed, closes the air metering valve, initiates
sparking of the ignition electrode, and opens gas valve 1.

After a short wait, the control stops sparking and checks for the presence of flame current through the flame sense
electrodes.

If flame is not detected after the sparking ends, the control will perform a postpurge, then start another prepurge cycle
and try to light the burner again.

If the control detects flame current, the control will hold the blower speed constant for a few seconds to allow the
flame to stabilize, then begin modulating the firing rate in order to maintain the controlling sensor to the desired set
point temperature.

If the current call for heat is for space heating and a HW call for heat becomes active, the control will turn on the HW
pump relay output, then turn off the boiler pump. It will then modulate the blower speed in order to maintain the
outlet temperature to the desired HW outlet set point temperature (Normal Mode Only).

If the boiler is unable to maintain the desired set point using gas valve 1, control will transition to the larger gas valve

2. The blower will modulate to a fixed speed and the air metering valve will start to open. As it opens, gas valve 2 will
be turned on and gas valve 1 will be turned off. If the flame should be lost at any time during this process, the control
will immediately try to reignite the burner. Once the air metering valve is fully open and the flame is confirmed to
be present, the control will hold the fan speed constant for a few seconds in order to allow the flame to stabilize. The
fan speed will then modulate as needed to maintain the set point. If the flame is not present when the air metering
valve is fully open, the boiler will go through a complete shutdown and restart of the burner. If the heat load should
decrease sufficiently, a similar process is used to transition from gas valve 2 to gas valve 1.

Once both the space heating and HW calls for heat are satisfied, the control will turn off the gas valve and begin the
Post-Purge cycle. Any pumps that are running will begin their respective Pump Delay cycles. The air metering valve
will be opened.

12.

13.

At the end of the Post-Purge cycle, the louver relay contacts will de-energize.

At the end of the Pump Delay cycle(s), the pump(s) will be turned off.

11

1 Service

Initial Setup Screen

Figure 1-2 Rapid Setup A

Service Manual

Initial Setup

Clock and Date

The control uses an internal clock for the night setback
feature and for logging of events. For these features to
work correctly, the clock must be set when the boiler is first
installed or anytime the boiler has been powered off for more
than four (4) hours. This parameter must be accessed to set
the clock. If the unit is connected to the internet, the time will
adjust based on the time zone selected.

Temperature units (°C / °F)

The control can be configured to display temperature in
either °C or °F.

12

Service Manual

1 Service (continued)

Viewable and changeable control parameters

CAUTION

Set Point Screens

Figure 1-3 Set points HW_Screen A

Before changing parameters, note the settings so that the unit can be returned to its original operating
parameters.

Figure 1-4 Set points HW_Screen B

13

1 Service

Figure 1-5 Set points SH_Screen A

Service Manual

Table 1B Set Points (This table lists control module parameters; use the sub-tab under the Setup tab to access

them.

Menu

SET POINTS

Parameter Name

(as shown on the LCD screen)

Space Heat 1 Set point: Set point 32 185 120

Space Heat 1 Set point: Min 32 185 32

Space Heat 1 Set point: Max 32 185 185

Space Heat 1 Set point: Offset 0 36 9.9

Space Heat 1 Set point: Diff 0 72 19.8

System Pump Anti-Seize Time 0 40 0.33

High Limit: ARHL 32 200 199.4

High Limit: MRHL 0 90 0

HW Boiler Set point: Set point N/A N/A N/A

HW Boiler Set point: Offset N/A N/A N/A

HW Boiler Set point: Differential N/A N/A N/A

HW Tank Set pont: Set point N/A N/A N/A

HW Tank Set point: Min N/A N/A N/A

Min

Value Value Value

Max

Default

HW Tank Set point: Max N/A N/A N/A

HW Tank Set point: Diff N/A N/A N/A

14

1 Service (continued)

Service Manual

Set Points

Space Heat 1 Set Point: Set point

The SH set point sets the water temperature set point used
during space heating calls.

Space Heat 1 Set Point: Min

The SH minimum set point sets the minimum water
temperature set point that can be used for space heating
operation. The user or installer will not be able to
program the control with a lower SH set point.

Space Heat 1 Set Point: Max

The SH maximum set point sets the maximum water
temperature set point that can be used for space heating.
The user or installer will not be able to program the
control with a higher SH set point.

Space Heat 1 Set Point: Offset

The SH offset sets how many degrees above set point the
temperature can go before the boiler will shut off.

Space Heat 1 Set Point: Differential

The SH differential sets how many degrees below the
offset the temperature has to drop before the boiler turns
back on.

High Limit: ARHL

The SMART TOUCH control contains an integral Auto
Reset High Limit (ARHL) on the outlet of the heat
exchanger. Once the outlet temperature exceeds the
ARHL set point, the boiler will shut down and lock out.
Once the outlet temperature has dropped below this
set point, the RESET button on the LCD display can be
pressed to reset this lockout. If RESET is not pressed, the
control will automatically reset the lockout after five (5)
minutes.

HW Boiler Set Point: Set point

When a HW call for heat becomes active, the control will use
the HW boiler set point to determine the firing rate of the
boiler based on the boiler outlet water temperature.

HW Boiler Set Point: Offset

This parameter reflects the degrees above HW boiler set point
the outlet temperature can go before the boiler will shut off.

HW Boiler Set Point: Differential

This parameter reflects the degrees below HW boiler offset the
outlet temperature has to go before the boiler turns on.

HW Tank Set Point: Set Point

By installing a tank sensor, the SMART TOUCH control can
perform the tank thermostat function. The SMART TOUCH
control automatically detects the presence of this sensor, and
generates a call for heat when the tank temperature drops
below the tank set point minus the differential, and finishes the
call for heat when the tank temperature reaches tank set point.

HW Tank Set Point: Min

This setting controls the minimum user set point for the tank
temperature.

HW Tank Set Point: Max

This setting controls the maximum user set point for the tank
temperature.

HW Tank Set Point: Differential

When a tank sensor is installed, the tank temperature must
drop this amount below the tank set point before the boiler
will turn on.

High Limit: MRHL

The SMART TOUCH control contains an integral
Manual Reset High Limit (MRHL) on the outlet of the
heat exchanger. Once the outlet temperature exceeds
the MRHL set point, the boiler will shut down and lock
out. Once the outlet temperature has dropped below this
set point, the RESET button on the LCD display must be
pressed to clear this lockout.

15

1 Service

Outdoor Reset Screen

Figure 1-6 Outdoor Reset A

Service Manual

Table 1C Outdoor Reset (This table lists control module parameters; use the sub-tab under the Setup tab to access

them.)

Max

Default

Menu

Set point Max 32 185 180

Set point Min 32 185 68

Outdoor Temperature: Min -22 86 23

Outdoor Temperature: Max -22 86 86

Outdoor Temp: Shutdown 32 122 79.7

Outdoor Temp: Diff 32 122 79.7

Shift OA Reset Curve -27 27 0

OUTDOOR RESET

Boost Time 0 250 20

Boost Temperature 0 25 0

Parameter Name

(as shown on the LCD screen)

Min

Value Value Value

16

1 Service (continued)

Service Manual

Outdoor Reset

Outdoor Reset Curve

The Outdoor Temp Min and Set Point Max define the
upper point of the Outdoor Reset Curve. The lower point
is defined by the Outdoor Temp Max and Set Point Min.
The curve will level out at Set Point Min for temperature
warmer than Outdoor Temp Max. The curve will continue
on if the set point (set on Set Points Screen) is above the Set
Point Max. The curve will be shortened if the set point is
below Set Point Max.

Outdoor Temperature: Shutdown

When the outdoor temperature rises above this point, the
control will block all SH demands (HW demands will still
be active).

Outdoor Temperature: Differential

The outdoor air shutdown differential parameter is the
number of degrees below parameter the outdoor air
temperature must go before the boiler will respond to a SH
demand.

Boost Temperature

If a SH demand lasts longer than the programmed boost time
delay setting and there have been no HW demands, the control
will increase the water temperature set point by the amount in
this parameter. If the SH demand continues through another
time period, the set point will be increased again. This will
continue until either the SH demand ends, a maximum of 20
increases has occurred, or the maximum set point has been
reached. Once the SH demand has been satisfied the set point
will revert back to its calculated setting.

Shift OA Reset Curve

The shift reset curve parameter shifts the actual set point
above or below the calculated set point by the number of
degrees in this parameter.

Boost Time

The boost time parameter sets the amount of time that must
elapse with a SH demand before the water temperature
calculated set point will be increased.

17

1 Service

Ramp Delay Screen

Figure 1-7 Ramp Delay

Service Manual

Table 1D Ramp Delay (This table lists control module parameters; use the sub-tab under the Setup tab to access

them.)

Max

Default

Menu

RAMP DELAY

Parameter Name

(as shown on the LCD screen)

Ramp Delay Mode N/A N/A N/A

Step 1: Ramp Delay Time 1 40 2

Step 1: Ramp Delay Limit (%) 10 100 20

Step 2: Ramp Delay Time 1 40 2

Step 2: Ramp Delay Limit (%) 10 100 30

Step 3: Ramp Delay Time 1 40 2

Step 3: Ramp Delay Limit (%) 10 100 40

Step 4: Ramp Delay Time 1 40 1

Step 4: Ramp Delay Limit (%) 10 100 55

Step 5: Ramp Delay Time 1 40 1

Step 5: Ramp Delay Limit (%) 10 100 75

Step 6: Ramp Delay Time 1 40 1

Step 6: Ramp Delay Limit (%) 10 100 100

Min

Value Value Value

18

1 Service (continued)

Ramp Delay

Ramp Delay (Enable / Disable)

This parameter allows the installer to enable or disable the SH
ramp delay.

SH Ramp Delay

The SMART TOUCH CON•X•US Interface can be
programmed to limit the firing rate for a fixed period of time at
the start of a space heating demand. There are six (6) possible
limits, each with their own time delay. The first limit applies
as soon as the burner starts. Once its time delay expires, the
second limit is applied and its timer begins. The control steps
through these limits until the 6th (sixth) limit expires. Note,
however, that the 6th limit will also limit the rate for the rest of
that heat demand.

Service Manual

19

1 Service

BMS Screens

Figure 1-8 BMS_Screen A

Service Manual

Figure 1-9 BMS_Screen B

20

Service Manual

1 Service (continued)

Table 1E BMS / BAS (This table lists control module parameters; use the sub-tab under the Setup tab to access

them.)

Menu

BMS

Parameter Name

(as shown on the LCD screen)

BMS Status ACTIVE INACTIVE INACTIVE

BMS Mode POWER SETPOINT POWER

Power (%): Min 4 POWER MAX 4 or 5

Power (%): Max POWER MIN 100 100

Volts: Min 0 VOLTS MAX 2

Volts: Max VOLTS MIN 10 10

Set point (F): Min 32 SET POINT MAX 69.8

Set point (F): Max SET POINT MIN 185 179.6

Volts: Min 0 VOLTS MAX 2

Volts: Max VOLTS MIN 10 10

Volts to Enable / Disable BMS: Enable 0 10 2

Volts to Enable / Disable BMS: Diff. to Stop 0 10 0.5

BMS TSAT ENABLE DISABLE DISABLE

BAS Active / Inactive ENABLE DISABLE DISABLE

Min

Value Value Value

Max

Default

BAS

BAS Out of Order Timer 5 120 30

BMS

BMS (Active / Inactive)

The set point or modulation of the boiler may be controlled
through the 0 - 10V Building Management System (BMS)
input. When the parameter is set to INACTIVE, the 0 - 10V
input will be ignored. When set to ACTIVE, the set point or
modulation will be controlled by the voltage on the 0 - 10V
input, as described below.

BMS Mode (Power / Set Point)

When BMS is set to ACTIVE, this parameter will determine
if the voltage on the 0 - 10V BMS input is converted to
modulation or a set point. When set to POWER, the
voltage determines the modulation of the boiler. When set
to SETPOINT, voltage determines the set point used by the
boiler.

BMS Volts at Minimum (Power or Set Point)

When BMS is set to ACTIVE, this parameter will determine
the voltage on the 0 - 10V BMS input that represents the
minimum modulation or set point. Any voltage less than
this value will not change the modulation or set point used
by the boiler.

BMS Volts at Maximum (Power or Set Point)

When BMS is set to ACTIVE, this parameter will determine
the voltage on the 0 - 10V BMS input that represents the
maximum modulation or set point. Any voltage above this
value will not change the modulation or set point used by the
boiler.

BMS Rate at Minimum Volts

This parameter is visible only when BMS Mode is set
to POWER. The value of this parameter determines the
modulation rate when the voltage on the 0 - 10V BMS input
is equal to or less than the BMS Volts at Minimum parameter
value.

BMS Rate at Maximum Volts

This parameter is visible only when BMS Mode is set
to POWER. The value of this parameter determines the
modulation rate when the voltage on the 0 - 10V BMS input is
equal to or more than the BMS Volts at Maximum parameter
value.

21

1 Service

Service Manual

BMS Set Point at Minimum Volts

This parameter is visible only when the BMS Mode is set to
SETPOINT. The value of this parameter determines the set
point when the voltage on the 0 - 10V BMS input is equal to
or less than the BMS Volts at Minimum parameter value.

BMS Set Point at Maximum Volts

This parameter is visible only when BMS Mode is set to
SETPOINT. The value of this parameter determines the set
point when the voltage on the 0 - 10V BMS input is equal to
or more than the BMS Volts at Maximum parameter value.

BMS Volts to Enable

When BMS is set to ACTIVE, the boiler may be enabled
either through the ENABLE input, or by the voltage on the
0 - 10V BMS input (see BMS Tstat Enable Mode below). If
enabled through the voltage on the 0 - 10V BMS input, the
value of this parameter determines the voltage at which the
boiler becomes enabled.

Differential to Stop BMS Demand

When BMS is set to ACTIVE, and the boiler is enabled
through the voltage on the 0 - 10V BMS input, the voltage
must go below the BMS Volts to Enable value by this amount
in order to end the demand.

BAS

BAS Active / Inactive

The boiler is capable of being monitored and/or controlled
by a Building Automation System (BAS) through either a
ModBus RTU or BACnet MS/TP communication system.
In addition, it can communicate through a BACnet TCP/IP
system with the use of an optional gateway. See the Crest
ModBus Manual (100161012) for details on the points that
are available. If the boiler is to be monitored by the BAS
system, the BAS Active / Inactive parameter should be set to
INACTIVE. If the boiler is to be controlled through a BAS
system, the BAS Active / Inactive parameter must be set to
ACTIVE.

BAS Out of Order Timer

When the boiler is being controlled by the BAS system,
the commands it sends to the boiler must be refreshed
periodically. If the boiler does not receive a command for
too long, the boiler will revert to its local readings (e.g.,
enable input, temperatures, etc. ) until a new command is
received from the BAS system. For most commands, this
timeout is fixed at 10 minutes. Certain commands (0 - 10V
BMS voltage, system supply temperature, system return
temperature, and tank temperature) can change quickly, so
they need to be refreshed more often. The timeout for these
commands is controlled by the BAS Out of Order Timer.

BMS Tstat Enable Mode

In order to use the ENABLE input to enable the boiler, this
parameter must be set to ACTIVE. To use the voltage on the
0 - 10V BMS input to enable the boiler, this parameter must
be set to INACTIVE.

22

1 Service (continued)

Advanced Setup Screen

Figure 1-10 Advanced Setup

Service Manual

Table 1F Advanced Setup (This table lists control module parameters; use the sub-tab under the Setup tab to

access them.)

Max

Default

Menu

Freeze Protection; Pump On -22 45 44.6

Freeze Protection; Burner On -22 45 37.4

Freeze Protection; Burner Off -22 45 5

Anti-Cycling Time 0 40 10

Anti-Cycling Diff 0 54 1

ADVANCED SETUP

Controlling Sensor 0 4 2

Parameter Name

(as shown on the LCD screen)

Min

Value Value Value

Advanced Setup

Freeze Protection Pump On

The SMART TOUCH control will turn on the boiler and
system pump outputs whenever the inlet temperature drops
below this setting. This is done to prevent the water in
the heat exchanger from freezing. Certain low-temperature
applications (such as snow melt) can operate at temperatures
around freezing, so this setting needs to be lowered in these
cases. The temperature at which the pump outputs are turned
on, can be accessed through the Freeze Protection Pump On
parameter.

Freeze Protection Burner On

If running the pumps does not prevent the inlet
temperature from falling closer to freezing, the SMART
TOUCH control will fire the burner at low fire if in the
ON state. The installer can adjust the temperature at
which the burner fires by adjusting the Freeze Protection
Burner On parameter.

23

1 Service

Freeze Protection Burner Off

Once the burner has started firing due to a low inlet
temperature, the inlet temperature must increase by this
amount before the burner turns back off. The installer can
adjust this differential by accessing the Freeze Protection
Burner Off parameter.

Anti-Cycling Time

Once a SH demand has been satisfied, a set amount of
time must elapse before the control will respond to a new
SH demand. The control will block the new heat demand
and anti-cycling will be shown in the display until the time
has elapsed or the water temperature drops below the anti­cycling differential. This parameter can be changed by the
installer by accessing the Anti-Cycling Time parameter.

Anti-Cycling Differential

The control will bypass the anti-cycling time if the inlet
water temperature drops too much. The control will use
the inlet water temperature at the time the boiler shut off as
the starting point. If the inlet temperature drops below this
temperature parameter the control will abort anti-cycling
and allow the boiler to fire. This parameter can be changed
by the installer by the Anti-Cycling Differential parameter.

Service Manual

Controlling Sensor

The SH controlling sensor parameter selects the sensor
the control will use to regulate the boiler firing rate. This
parameter is adjustable by accessing the Controlling Sensor
parameter. The sensor selections are as follows: The outlet
sensor regulates the firing rate based on the outlet water
temperature of the boiler and the inlet sensor regulates the
firing rate based on the inlet water temperature of the boiler.
If the outlet sensor is selected, and the optional system
supply sensor is connected, the control will regulate the
firing rate based on the system supply sensor temperature.

24

1 Service (continued)

Night Setback Screen

Figure 1-11 SH Night Setback

Service Manual

Table 1G SH/HW Night Setback (This table lists control module parameters; use the sub-tab under the Setup tab

to access them.)

Max

Default

Menu

NIGHT

SH/HW

Parameter Name

(as shown on the LCD screen)

Offset Temperature (F) 0 90 0

SETBACK

Min

Value Value Value

SH/HW Night Setback

Offset Temperature

Once the internal clock has been set correctly, the SH night setback feature can be used to program a lower set point. The
value of this parameter will be subtracted from the normal set point to determine the set point used during night setback. The
temperature range for this parameter is 0°F to 90°F (50°C). The feature is turned off with a setting of 0°F.

25

Pump Screen

Figure 1-12 Pump

Service Manual

Table 1H Pumps (This table lists control module parameters; use the sub-tab under the Setup tab to access them.)

Max

Default

Menu

PUMPS

SETUP

HW PUMP

HW

SETUP

Parameter Name

(as shown on the LCD screen)

System Pump Mode N/A N/A N/A

Boiler Pump Delay 0:00 40:00 0:30

Boiler Pump Anti-Seize Time 0:00 40:00 0:33

System Pump Mode N/A N/A N/A

System Pump Delay 0:00 40:00 0:30

System Pump Anti-Seize Time 0 40:00 0:33

Delta T Set point 0 60 0

HW System Pump Mode N/A N/A N/A

HW Pump Delay 0.5 2400 30

HW Pump Anti-Seize Time 0 40 0.33

HW Type NORMAL ZONE NORMAL

HW/SH Switching Time 0 240 30

SH/HW Switching Time 0 240 30

HW Max Fan Speed 10 100 100

Min

Value Value Value

26

1 Service (continued)

Pumps

Service Manual

HW System Pump Mode

System Pump Mode

The SMART TOUCH control is able to control the system
pump in 5 different ways. The options are as follows:

1. ON with a call for heat, with a constant speed.

2. ON with a call for heat, with a variable speed input.

3. Always ON, with a constant speed, except during
outdoor shutdown.

4. Always ON, with a variable speed input, except during
outdoor shutdown.

5. Always OFF (not connected).

For options 2 and 4, the speed of the system pump is
controlled by a separate control system. The pump speed is
sent to the 0-10V pump speed input on the boiler.

Boiler Pump Delay

The SH pump delay parameter sets the length of time the
boiler pump will run after a SH demand has been satisfied.

Boiler Pump Anti-Seize Time

If the boiler pump does not run for 24 hours, it will be turned
on briefly to prevent it from seizing. The length of time it
runs is determined by the Boiler Pump Anti-Seize Time
parameter.

Boiler Pump Mode

The SMART TOUCH control is able to control the boiler
pump in 3 different ways. The options are as follows:

This parameter allows the installer to determine how the system
pump responds to a HW call for heat. The parameter can be
adjusted through the HW System Pump Mode parameter.
Select Always Off if you want the system pump to always turn
off during a HW call for heat. Select Always On if you want
the system pump to always turn on during a HW call for heat.
Select Normal if you want the system pump to ignore the HW
call for heat and operate based on the System Pump Mode
setting only.

HW Pump Delay

The HW pump delay parameter sets the length of time the
HW pump (if connected) will run after a HW demand has
been satisfied. This parameter is adjustable by the installer by
accessing the HW Pump Delay parameter.

HW Pump Anti-Seize Time

If the boiler pump does not run for 24 hours, it will be turned
on briefly to prevent it from seizing. The length of time it runs
is determined HW Pump Anti-Seize Time.

HW Type

This parameter gives the installer a choice of piping the Hot
Water Generator (HW) directly to the boiler, or as a zone in
the heating system. This parameter can be adjusted through
the HW Type parameter. For direct HW select Normal, for
treating the HW as a zone, select Zone.

1. ON with a call for heat, with a constant speed.

2. ON with a call for heat, with a variable speed
output.

3. Always OFF (not connected).

System Pump Delay

The system pump delay parameter sets the length of time the
system pump (if connected) will run after a SH demand has
been satisfied.

System Pump Anti-Seize Time

If the boiler pump does not run for 24 hours, it will be turned
on briefly to prevent it from seizing.

ΔT Set Point

The SMART TOUCH control includes a 0 - 10Vdc output
for controlling the speed of a variable speed boiler pump.
This feature can be used with primary - secondary piping
systems only. The speed is regulated in order to, among
other things, maintain a minimum delta T across the heat
exchanger. This helps reduce the electrical consumption
of the boiler pump when the boiler is firing at less than its
maximum rate. (This feature is active only when a system
supply sensor is installed).

HW/SH Switching Time

When a boiler has a HW demand and it receives a space heating
demand, the SMART TOUCH control will start a timer. Once
the timer expires, it will stop the HW demand and service the
space heating demand. This feature does not apply when the
HW is programmed as a zone, or in Cascade. The installer can
adjust the length of time the boiler will service the HW demand
by accessing the HW/SH Switching Time parameter.

SH/HW Switching Time

When a boiler has a space heating demand and it receives a HW
demand, it will immediately switch to the HW demand and
start a timer. Once the timer has expired, the boiler will switch
back to the space heating demand and start another timer.
Once this timer expires, it will switch back to the HW demand.
This feature does not apply when the HW is programmed as a
zone, or in Cascade. The installer can adjust the length of time
the boiler will service the space heating demand by accessing
the SH/HW Switching Time parameter.

HW Rate Limiting

This parameter determines the maximum rate to be used when
heating a HW tank. This setting may be used when the tank
is unable to accept all of the BTU’s available from the boiler.
This parameter may be adjusted by the installer by accessing
the HW Rate Limiting parameter.

27

1 Service

Cascade Screens

Figure 1-13 Cascade Setup Screen A

Service Manual

Figure 1-14 Cascade Leader Setup

28

Service Manual

1 Service (continued)

Table 1I Cascade (This table lists control module parameters; use the sub-tab under the Setup tab to access them.

Menu

CASCADE

Cascade

Parameter Name

(as shown on the LCD screen)

Cascade Address 0 7 1

Cascade Status ENABLE DISABLE DISABLE

Cascade Type N/A N/A N/A

Cascade Set point: Offset 0 40 10

Cascade Set point: Differential 0 72 20

Max Cascade Cond. Set point (F) 32 185 185

Max Cascade Non-Cond Set point (F) 68 260 185

Block Time Switching Boiler On / Off 0 4:15 60

Minimum Next On Time 0 4:15 60

Number of Boiler Pumps Always On 0 8 0

Rate % to Switch On Next Boiler 1 100 80

Rate % to Switch Off Last Boiler 1 100 10

Legacy Boiler Size Code* 0 255 0

Min

Value Value Value

Max

Default

Cascade Address

The boiler designated as the Leader needs to be programmed
with address 0. All the Member boilers require addresses
from 1 to 7, and the addresses must be different for each
Member. The addresses can be in any order, regardless of
the order in which the units are wired together. The outdoor
air (if used) and system supply sensor must be connected to
the Leader boiler.

Cascade Status

The boiler is part of a group of units sequenced together. The
designated Leader unit determines the total output needed
from the group based on the set point and controlling sensor
reading. It assigns portions of the output to itself (Leader)
and the Member units. When Cascade is active, each boiler
in the group requires a unique address.

Cascade Type

The two (2) types of Cascade control are listed below:

Efficiency Optimization

This method is used when it is desired to have the most efficient
system. When the first boiler reaches a certain rate (default =
80%), it lowers its rate to 40% and turns on the next boiler at
40%. The two (2) boilers then modulate at the same rate. As
the calculated load increases further and both boilers ramp
up to 80%, it lowers the rate of the first two (2) boilers to 53%
and brings the next boiler on at 53%. The three (3) boilers
then modulate together. As the calculated load decreases, the
boilers will reach a lower threshold (default = 10%), at which
time the last boiler (the third one in this example) will turn off
and the Cascade will increase the rates of the remaining boilers
to provide the equivalent total output as before ((3 x 10%) / 2 =
15% in this example).

29

1 Service

Service Manual

L/L: Lead/Lag

This method is used when it is desired to run the least
number of boilers as possible. When the first boiler reaches
100% and calculated demand is still greater, the Cascade will
bring on boiler number two. At the same time the first boiler
will reduce its firing rate by an amount equal to the initial
firing rate of the second boiler. As the calculated demand
continues to increase, the first boiler will go to high fire,
followed by ramping up the second boiler. If the calculated
demand is still increasing once the second boiler reaches
100%, the Cascade will bring on boiler number three and
reduce the firing rate of boiler number two by an amount
equal to the initial firing rate of the third boiler.

This sequence will continue until the load is matched or all
boilers are firing at 100%. When the load begins to decrease,
the last boiler to fire will modulate down to low fire and hold
there. As the calculated demand continues to decrease, the
second to the last boiler will modulate down to low fire. If
calculated demand is still decreasing, the last boiler will shut
down and the next to the last boiler will increase its firing rate
to make up the lost BTU’s of the last boiler. If the calculated
demand continues to decrease, it will modulate down to low
fire and hold there while the next previous boiler starts to
modulate down, as before. This will continue until either

demand is matched or all boilers have shut down.

Cascade Set point Offset

This parameter determines how much the temperature can
go above set point before the lead boiler will turn off.

Cascade Set point Differential

This parameter determines how much the temperature must
go below the turn off temperature (Set point + Offset) before
the lead boiler turns on.

Maximum Cascade Cond / Non-Cond Set point (F)

These types of parameters determine the set point used
by the individual boilers in a Cascade. When a boiler is
commanded to fire by the Leader boiler, it will attempt to
achieve this temperature at its outlet. If any of the boiler
outlet temperatures reach the maximum cascade set point,
the boiler will then modulate down on its own in order to
keep its outlet temperature within the maximum cascade set
point. Therefore, these parameters can be used to limit the
outlet temperatures of all the boilers in a Cascade. Note that
these parameters do not apply when the boiler is heating an
indirect HW tank.

Blocking Time Switching Boiler On / Off

In order to prevent units in a Cascade from short cycling,
this parameter defines the minimum ON and OFF time for
each unit. The installer can adjust this time by accessing the
Blocking Time Switching Boiler On / Off parameter.

Minimum Next On Time

In order to reduce the risk of temperature overshoot with a
Cascade, this parameter defines the minimum time delay from
starting one unit until the next unit may be started.

Number of Boiler Pumps Always On

When multiple Crest boilers are connected in a Cascade, the
SMART TOUCH control can keep a minimum number of the
boiler pumps running, regardless of how many of the boilers
are firing. This is useful in full flow systems where the system
flow is provided by the individual boiler pumps.

Rate % to Switch on Next Boiler

When the Cascade is programmed in the Efficiency
Optimization Mode, the currently running boilers must ramp
up to a certain firing rate before the next boiler in the Cascade
will start.

Rate % to Switch off Last Boiler

When the Cascade is programmed in the Efficiency
Optimization Mode, the currently running boiler will stop.

Legacy Boiler Size Code

The legacy boiler size code parameter is used to determine the
maximum power and priority of legacy boilers (i.e., Power-fin)
in cascade with the Crest Boiler. The default value for this
parameter is 0. When this value is left unchanged, the SMART
TOUCH control will automatically assume that any member(s)
of the Cascade not communicating their size will be 1,500,000
Btu. The lowest priority will always be given to these units
because the SMART TOUCH control will assume they are non­condensing boilers. Changing this parameter is not necessary
for Cascade operation. However, the installer can adjust this
code by using the PC program. The PC program will calculate
the proper code based on the information provided.

30

Service Manual

1 Service (continued)

Service Screens

 e Service Screen allows the integrated control to override all other heat demands and operate Valve 1 and Valve 2 at high  re and
low  re conditions. To place the boiler into Service Mode, press the START button. As speci ed above the integrated control will
override all other heat demands, however, all safeties will be active. If no buttons are pressed, the integrated control will automatically
revert back to its original status a er the “Remaining time in Service” counter expires.

Once the boiler has been placed into Service Mode it will light and modulate to low  re. At any time a er that point there are two (2)
ways to adjust the  ring rate.  e  rst way is by pressing one of the six (6) preset buttons.  e second way is by manually adjusting
the  ring percentage using the “+” and “-“ buttons. When Service Mode is no longer needed press the STOP button to return to
normal operation.

Figure 1-15 Service Maintenance A

31

1 Service

Figure 1-16 Service Notification

Service Manual

Table 1J Service Notification (This table lists control module parameters; use the sub-tab under the Setup tab to access them.

Menu

SERVICE

NOTIFICATION

Maintenance Notice By: Months 0 36 12

Maintenance Notice By: Running Hours 0 100,000 10,000

Maintenance Notice By: Cycles 0 100,000 10,000

Maintainer Information: Name N/A N/A N/A

Maintainer Information: Phone N/A N/A N/A

Parameter Name

(as shown on the LCD screen)

Service

Maintenance Notice By: Months

When the boiler control determines that a scheduled service
is due based on the months of installation, the boiler display
will turn yellow and a new status screen will appear informing
the installer that maintenance is required.

Maintenance Notice By: Running Hours

When the boiler control determines that a scheduled service
is due based on the hours of actual operation, the boiler
display will turn yellow and a new status screen will appear
informing the installer that maintenance is required.

Min

Value Value Value

Maintenance Notice By: Cycles

When the boiler control determines that a scheduled service is
due based on the number of boiler cycles, the boiler display will
turn yellow and a new status screen will appear informing the
installer that maintenance is required.

Maintainer Information: Name and Phone Number

When a Maintenance Reminder timer or counter has expired,
a Maintenance Reminder screen will appear on the display.
By programming the installer’s name and phone number, this
information will appear on the Maintenance Reminder Screen
at that time. This can be programmed by accessing parameters
L4 and L5. When selected, another menu will appear with
PHONE and NAME. Note that the phone number is limited to
10 characters, and the name is limited to 26 characters. Only 0 ­9, A - Z (CAPS only), &, (,), +, and - are permitted.

Max

Default

32

Service Manual

1 Service (continued)

Graph Screens

 e Graph Screen consists of two (2) di erent types of screens.  e  rst screen Short Term Data Screen (three minutes in one
second intervals) and the Long Term Data Screen (32 days, 233 average minutes). If a parameter is selected by mistake, it can be
de-selected by re-selecting the parameter. A maximum of eight (8) items can be graphed at one time.

Figure 1-17 Graph Select

Once the items to be graphed are selected, press the OK button to view the graph. Each item graphed will have a di erent color line
to represent it.  e items selected will be shown below the graph along with their corresponding color.

Figure 1-18 Graph Screen

33

Service Manual

1 Service

History Screen

 e History Screen shows the status of various counters and faults. Within the History Screen there are two separate screens.  ese
screens are the “Lockout Blocking Fault” and “Runtime History”.

 e default screen is the “Lockout Blocking Fault” screen.  is screen allows you to view the last 20 lockout/blocking faults.
Succeeded by each fault is the date and time of when the fault occurred. A three (3) minute graph of sensor data before the fault can
be viewed by selecting the VIEW button..

Figure 1-19 History Fault

34

Service Manual

1 Service (continued)

 e third screen is the “Runtime History”.  ere are several pieces of information that are displayed on this screen. Items that can
be viewed on this screen are as follows:

• Power hours – Shows the number of hours the control has been powered on since the last reset.

• Running hours – Shows the number of hours that the boiler has been  ring since the last reset.

• Ignition attempts – Shows the number of times the control has attempted to ignite since the last reset.

• Successful Ignition attempts - Shows the number of times the control has successfully ignited since the
last reset.

• Total Power hours – Show the total number of hours the control has been powered.

• Total Running hours – Show the total number of hours that the boiler has been  ring.

• Total ignition attempts – Show the total number of times the control has attempted to ignite.

• Total Successful ignition attempts – Show the total number of times the control has successfully ignited.
 e top le of this screen details the running hours based on 4 di erent running positions.

Figure 1-20 History Screen_Runtime History

35

2 Maintenance

Maintenance and annual startup

Table 2A Service and Maintenance Schedules

Service Manual

Service technician

(see the following pages for instructions)

General:

• Address reported problems, if any

• Inspect interior; clean and vacuum if
necessary;

• Clean condensate trap and fill with fresh
water

• Check for leaks (water, gas, flue,
condensate)

• Verify flue and air lines in good condition
and sealed tight

• Check system water pressure/system
piping/expansion tank

• Check control settings

• Check the ignition and both flame sense
electrodes (sand off any deposits; clean
and reposition)

• Check wiring and connections

Owner maintenance

(see the Crest User’s Information Manual for

instructions)

• Check boiler area

Daily

Monthly

• Check pressure/temperature
gauge

• Check vent piping

• Check air piping

• Check air and vent termination
screens

• Check relief valve

• Check condensate drain system

• Perform start-up checkout and
performance verification per Section 9 of

ANNUAL START-UP

the Crest Installation and Operation
Manual.

• Flame inspection (stable, uniform)

• Check both flame signals (at least 10
microamps at high fire)

• Test low water cutoff.

If combustion or performance
indicate need:

• Clean heat exchanger

• Remove and clean burner using
compressed air only

• Clean the blower wheels

36

Every

6 months

End

of season

months

• Test low water cutoff

• Reset button (low water
cutoff)

• Check boiler piping (gas and
water) for leaks

• Operate relief valve

• Shut boiler down (unless boiler
used for domestic hot water)

2 Maintenance (continued)

Service Manual

 WARNING

 WARNING

 WARNING

Follow the service and maintenance procedures given throughout this manual and in component literature
shipped with the boiler. Failure to perform the service and maintenance could result in damage to the boiler
or system. Failure to follow the directions in this manual and component literature could result in severe
personal injury, death, or substantial property damage.

The boiler should be inspected annually only by a qualified service technician. In addition, the maintenance
and care of the boiler designated in Table 2A and explained on the following pages must be performed to
assure maximum boiler efficiency and reliability. Failure to service and maintain the boiler and system could
result in equipment failure.

Electrical shock hazard – Turn off power to the boiler before any service operation on the boiler except as
noted otherwise in this instruction manual. Failure to turn off electrical power could result in electrical shock,
causing severe personal injury or death.

Address reported problems

1. Inspect any problems reported by the owner and correct
before proceeding.

Inspect boiler area

1. Verify that boiler area is free of any combustible materials,
gasoline and other flammable vapors and liquids.

2. Verify that air intake area is free of any of the contaminants
listed in Section 1 of this manual. If any of these are
present in the boiler intake air vicinity, they must be
removed. If they cannot be removed, reinstall the air and
vent lines per this manual.

Inspect boiler interior

1. Remove the front access covers and inspect the interior
of the boiler.

2. Vacuum any sediment from inside the boiler and
components. Remove any obstructions.

Clean condensate trap

1. Inspect the condensate drain line, vent line, condensate
PVC fittings, and condensate trap.

Flush condensate trap with water

1. Remove the four (4) screws securing the top cover to the
condensate trap and remove the cover (FIG. 2-1).

2. Locate the plastic ball inside the float tube. Verify there

is nothing under the ball causing it to not seat properly.

3. Fill with fresh water until the water begins to pour out of

the drain.

4. Replace the top cover and the screws removed in Step 1.

Figure 2-1 Condensate Trap

FROM CONDENSATE
VENT ON BOILER

FROM CONDENSATE

TO FLOOR DRAIN
OR NEUTRALIZER KIT
1” PVC / CPVC CONNECTION

DRAIN ON BOILER

Check all piping for leaks

 WARNING

1. Inspect all water and gas piping and verify to be leak free.

2. Look for signs of leaking lines and correct any problems
found.

3. Check gas line using the procedure found in Section 6

- Gas Connections of the Crest Installation and Operation
Manual.

Eliminate all system or boiler leaks.
Continual fresh makeup water will
reduce boiler life. Minerals can build up,
reducing heat transfer, overheating heat
exchanger, and causing heat exchanger
failure. Leaking water may also cause
severe property damage.

Flue vent system and air piping

1. Visually inspect the entire flue gas venting system and air
piping for blockage, deterioration or leakage. Repair any
joints that show signs of leakage. Verify that air inlet pipe
is connected and properly sealed.

2. Verify that boiler vent discharge and air intake are clean
and free of obstructions.

 WARNING

Failure to inspect for the above conditions
and have them repaired can result in
severe personal injury or death.

Check water system

1. Verify all system components are correctly installed and
operational.

2. Check the cold fill pressure for the system. Verify it is
correct (must be a minimum of 12 psi (82.7 kPa)).

3. Watch the system pressure as the boiler heats up (during
testing) to ensure pressure does not rise too high.
Excessive pressure rise indicates expansion tank sizing
or performance problem.

4. Inspect automatic air vents and air separators. Remove
air vent caps and briefly press push valve to flush vent.
Replace caps. Make sure vents do not leak. Replace any
leaking vents.

37

2 Maintenance

Check expansion tank

1. Expansion tanks provide space for water to move in and
out as the heating system water expands due to temperature
increase or contracts as the water cools. Tanks may be
open, closed or diaphragm or bladder type. See Section
5 - Hydronic Piping of the Crest Installation and Operation
Manual for suggested best location of expansion tanks and
air eliminators.

Check boiler relief valve

1. Inspect the relief valve and lift the lever to verify flow.
Before operating any relief valve, ensure that it is piped with
its discharge in a safe area to avoid severe scald potential.
Read Section 5 - Hydronic Piping of the Crest Installation
and Operation Manual before proceeding further.

 WARNING

 WARNING

2. After following the above warning directions, if the relief
valve weeps or will not seat properly, replace the relief valve.
Ensure that the reason for relief valve weeping is the valve
and not over-pressurization of the system due to expansion
tank waterlogging or undersizing.

Safety relief valves should be re-inspected
AT LEAST ONCE EVERY THREE YEARS,
by a licensed plumbing contractor or
authorized inspection agency, to ensure
that the product has not been affected by
corrosive water conditions and to ensure
that the valve and discharge line have not
been altered or tampered with illegally.
Certain naturally occurring conditions
may corrode the valve or its components
over time, rendering the valve inoperative.
Such conditions are not detectable unless
the valve and its components are physically
removed and inspected. This inspection
must only be conducted by a plumbing
contractor or authorized inspection agency
– not by the owner. Failure to re-inspect the
boiler relief valve as directed could result in
unsafe pressure buildup, which can result in
severe personal injury, death, or substantial
property damage.

Following installation, the valve lever must
be operated AT LEAST ONCE A YEAR to
ensure that waterways are clear. Certain
naturally occurring mineral deposits may
adhere to the valve, rendering it inoperative.
When manually operating the lever, water
will discharge and precautions must be taken
to avoid contact with hot water and to avoid
water damage. Before operating lever, check
to see that a discharge line is connected to
this valve directing the flow of hot water
from the valve to a proper place of disposal.
Otherwise severe personal injury may result.
If no water flows, valve is inoperative. Shut
down the boiler until a new relief valve has
been installed.

Service Manual

Inspect ignition and flame sense
electrodes

1. Remove the ignition and both flame sense electrodes from
the burner plate.

2. Remove any deposits accumulated on the ignition/flame
sense electrodes using sandpaper. If the electrodes cannot
be cleaned satisfactorily, replace with new ones.

3. Replace ignition/flame sense electrodes, making sure the
gaskets are in good condition and correctly positioned.

Check ignition ground wiring

1. Inspect boiler ground wire from the heat exchanger access
cover to ground terminal strip.

2. Verify all wiring is in good condition and securely attached.

3. Check ground continuity of wiring using continuity meter.

4. Replace ground wires if ground continuity is not
satisfactory.

Check all boiler wiring

1. Inspect all boiler wiring, making sure wires are in good
condition and securely attached.

Check control settings

1. Navigate to the Setup Screen and check all settings. See
Section 1 of this manual. Adjust settings if necessary. See
Section 1 of this manual for adjustment procedures.

2. Check settings of external limit controls (if any) and adjust
if necessary.

Perform start-up and checks

1. Start boiler and perform checks and tests specified in

Section 9 - Start-up of the Crest Installation and Operation
Manual.

2. Verify cold fill pressure is correct and that operating

pressure does not go too high.

Check burner flame

1. Inspect flame through observation windows.

2. If the flame is unsatisfactory at either high fire or low

fire, remove and clean the burner. Clean the burner
thoroughly using a vacuum cleaner or compressed air. Do
not use compressed air to clean the burner if cleaning is
performed inside a building.

• Shut down the boiler:

- Follow the “To Turn Off Gas to Appliance”

instructions for the boiler in Section 9 - Startup
of the Crest Installation and Operation Manual.

- Do not drain the boiler unless it will be

exposed to freezing temperatures. If using
freeze prevention fluid in system, do not drain.

3. Allow time for the boiler to cool to room temperature if it

has been firing.

38

2 Maintenance (continued)

Y

A

Service Manual

4. Remove the top access panel(s) to gain access to the
gas/air manifold assembly.

5. Remove the gas/air manifold burner access cover
(FIG. 2-2).

6. Using care, remove the transition gas line from the
gas/air manifold and orifice assembly.

7. Remove the orifice assembly from inside the burner.

8. Remove the nuts/washers holding the burner to the
gas/air manifold assembly.

9. Remove the burner baffle and the burner from the
gas/air manifold assembly.

NOTICE

The burner gasket, burner, burner
baffle, and gas/air manifold access
cover can only be installed in one
orientation. All of these parts will
have to be re-installed correctly.
To ensure all of these parts are

Figure 2-2 Burner Assembly

NOTE: Be sure to pay close
attention to the Lochinvar logo.

lign the logo with the Lochinvar
logo on the gas/air manifold to
ensure proper assembly.
Pay close attention to the bolt
pattern, as the gas/air manifold
assembly can only be installed
one way.

LOCHINVAR LOGO

GAS/AIR MANIFOLD COVER

GAS/AIR MANIFOLD GASKET

BURNER

PILOT ASSEMBLY

BURNER GASKET

GAS/AIR MANIFOLD

GAS/AIR MANIFOLD GASKET

BURNER TOP PLATE ASSEMBL

FIBERBOARD

GASKET

re-installed correctly, align the
logo on top of the gas/air manifold
cover with the logo on the gas/air
manifold as shown in FIG. 2-2. Be

IMG01141

certain to pay close attention to the
bolt pattern when re-installing the
above parts.

10. When replacing the burner, ensure gaskets are in good
condition and positioned correctly (FIG. 2-2).

11. When securing the burner and manifold, be sure to
tighten the nuts as follows:

a. Tighten the nuts in a star pattern sequence.
b. Tighten the 7/16" nuts, securing the

burner to the cast manifold to a torque of 8 ft.-lbs.

12. Re-install the orifice assembly and the transition gas
line removed in Steps 6 and 7.

13. Re-install the gas/air manifold burner access cover.
Tighten 3/8" nuts to 8 ft.-lbs. using the star pattern
sequence.

14. After firing the unit, re-tighten the nuts to the above
torque specifications.

Check flame signal

1. At high fire of each combustion system, the flame signal
shown on the display should be at least 10 microamps.

2. A lower flame signal may indicate a fouled or damaged
flame sense electrode. If cleaning the flame sense electrodes
does not improve, ground wiring is in good condition, and
ground continuity is satisfactory, replace the flame sense
electrode.

3. See Section 3 - Troubleshooting in this manual for other
procedures to deal with low flame signal.

Review with owner

1. Review the Crest User’s Information Manual with the
owner.

2. Emphasize the need to perform the maintenance schedule
specified in the Crest User’s Information Manual (and in
this manual as well).

3. Remind the owner of the need to call a licensed contractor
should the boiler or system exhibit any unusual behavior.

 WARNING

Failure to follow the torqueing
specifications listed above could result
in severe personal injury or death.

4. Remind the owner to follow the proper shutdown procedure
and to schedule an annual start-up at the beginning of the
next heating season.

39

2 Maintenance

Service Manual

Cleaning boiler heat exchanger

1. Shut down boiler:

• Follow the “To Turn Off Gas to Appliance” instructions
for the boiler in Section 9 - Startup.

• Do not drain the boiler unless it will be exposed to
freezing temperatures. If using freeze prevention fluid
in system, do not drain.

2. Allow time for the boiler to cool to room temperature if
it has been firing.

3. Remove the top access panel to remove the gas/air
manifold assembly.

4. Remove the nuts securing the burner to the burner
mounting plate. Remove the burner (reference FIG. 2-2
and follow the steps in Check Burner Flame on pages
33-34).

5. Remove the nuts securing the burner mounting plate
from the heat exchanger and set aside. Remove the
entire burner mounting plate assembly.

 WARNING

6. Use a vacuum cleaner to remove any accumulation on
the tube sheet surfaces. Do not use any solvent.

7. Brush the heat exchanger (tube sheet, combustion
chamber walls, and tube entry) while dry using a nylon
bristle brush. Caution: DO NOT use a metal brush.
Re-vacuum the heat exchanger.

8. Finish cleaning using a clean cloth dampened with warm
water.

9. Temporarily remove the condensate drain line from the
condensate trap and route directly to a drain.

10. Rinse out debris with a low pressure water supply. The
water will drain through the condensate connection.

11. Allow the heat exchanger to thoroughly dry.

12. Reconnect the condensate drain line to the condensate
trap.

13. Close isolation valves on piping to isolate boiler from
system. Attach a hose to the boiler drain and flush boiler
thoroughly with clean water by using purging valves to
allow water to flow through the water make-up line to
the boiler.

14. When securing the burner, be sure to tighten the nuts as
instructed in the “Check Burner Flame” section on pages
33 and 34 of this manual.

15. Replace the burner mounting plate assembly and gas/
air manifold assembly. Ensure gaskets are in good
condition and positioned properly. Restore boiler to
operation.

16. Perform start-up and check-out procedures in the Check
Flame and Combustion - Section 9 - Startup of the Crest
Installation and Operation Manual.

The boiler contains ceramic fiber
materials. Use care when handling these
materials per instructions on this page.
Failure to comply could result in severe
personal injury.

Handling ceramic fiber materials

REMOVAL OF COMBUSTION CHAMBER
LINING

 WARNING

The combustion chamber insulation
in this appliance contains ceramic fiber
material. Ceramic fibers can be converted
to cristobalite in very high temperature
applications. The International Agency for
Research on Cancer (IARC) has concluded,
“Crystalline silica in the form of quartz
or cristobalite from occupational sources
is carcinogenic to humans (Group 1).”
Normal operating temperatures in this
appliance are below the level to convert
ceramic fibers to cristobalite. Abnormal
operating conditions would have to be
created to convert the ceramic fibers in this
appliance to cristobalite.
The ceramic fiber material used in this
appliance is an irritant; when handling
or replacing the ceramic materials it is
advisable that the installer follow these
safety guidelines.

Avoid breathing dust and contact with

skin and eyes.

• Use NIOSH certified dust respirator
(N95). This type of respirator is
based on the OSHA requirements for
cristobalite at the time this document
was written. Other types of respirators
may be needed depending on the job
site conditions. Current NIOSH
recommendations can be found on
the NIOSH website at http://
www.cdc.gov/niosh/homepage.
html. NIOSH approved respirators,
manufacturers, and phone numbers
are also listed on this website.

• Wear long-sleeved, loose fitting
clothing, gloves, and eye protection.

Apply enough water to the combustion

chamber lining to prevent airborne
dust.

 Remove the combustion chamber lining

from the boiler and place it in a plastic
bag for disposal.

 Wash potentially contaminated clothes

separately from other clothing. Rinse
clothes washer thoroughly.

NIOSH stated First Aid.

 Eye: Irrigate immediately.
 Breathing: Fresh air.

40

2 Maintenance (continued)

A

Test low water flow conditions

Service Manual

NOTICE

This test is to be carried out once the
Crest boiler is completely piped in with
adequate gas and water flow. Once
the test is completed, ensure that the
isolation valve is opened up to allow full
water flow.

Test procedure

1. Place the unit into Service Mode. Navigate to the Service
Screen from the Home Screen by pressing the MAIN
MENU button and then the SERVICE button.

2. On the Service Screen place heater into Service Mode by
selecting the START button. In Service Mode the boiler
will fire at ignition speed and will then modulate up to full
fire.

3. Allow the unit to progress through its normal diagnostics
and pre-purge programming.

4. Allow the unit to fire and operate until the temperatures
stabilize. This occurs when the inlet and outlet
temperatures are rising together and the Delta T ( T) is
maintained.

5. When the unit stabilizes, begin to slowly shut off the
isolation valve on the outlet piping of the boiler (see FIG.
2-3). This will begin to restrict the flow and simulate a
low flow condition.

6. While slowly shutting off the isolation valve, refer to the
Status Screen to watch the behavior of the boiler. This
screen allows you to monitor the inlet temperature, outlet
temperature, and T.

7. When the  T reaches 70˚F, the control will attempt to
modulate the firing rate down to protect it from low flow
conditions.

8. When the T reaches 80°F, the control module will turn
off the burner. If the control module shuts down, the test
was successful.

9. Completely open the isolation valve on the outlet piping
of the boiler.

10. Resume operation.

Figure 2-3 Adjust outlet isolation valve

DJUST OUTLET
ISOLATION VALVE
ONLY

IMG01035

41

3 Troubleshooting

Service Manual

 WARNING

 WARNING

Label all wires prior to disconnection
when servicing controls. Wiring
errors can cause improper and
dangerous operation. Always
disconnect power to the boiler
before servicing. Failure to comply
could result in severe personal
injury, death, or substantial
property damage.

Never jumper (bypass) any device
except for momentary testing as
outlined in the Troubleshooting
chart. Severe personal injury, death,
or substantial property damage can
result.

Before troubleshooting:

1. Have the following items:
a. Voltmeter that can check 120 vac, 24 vac, and
12 vdc.
b. Continuity checker.
c. Contact thermometer.

2. Check for 120 vac (minimum 102 vac to maximum

132 vac) to boiler.

3. Make sure thermostat is calling for heat and

contacts are closed. Check for 24 vac between
enable input and ground.

Check control module fuses

NOTICE

1. Turn OFF the power to the boiler at the external line
switch.

2. Remove the upper and lower doors.

3. Remove the four (4) screws securing the control panel cover to
the unit to gain access to the control module.

4. Inspect fuses F2, F4, and F5, see FIG 3-1 below.

Figure 3-1 Control Module Fuses

F2 - 3.15 AMP
BLOWER RELAYS

F4 - 5 AMP
PUMP RELAYS

F5 - 5 AMP
IGNITOR OUTPUT

F6 - 5 AMP
NOT USED
(SPARE)

ALWAYS check control module fuses before
replacing c
ontrol module or any major components
(blower, etc.). If one of these fuses is blown,
it can prevent the control module or other
components from operating.

4. Make sure all external limit controls are installed

and operating.

Check the following:

1. Wire connectors to control module are securely

plugged in at the module and originating control.

2. Gas pressures:

• Maximum: 14 inches w.c. (3.5 kPa) (natural and
LP) with no flow (lockup) or with boiler on

• Minimum: 4 inches w.c. (1.0 kPa) (natural and
LP), with gas flowing (verify during boiler
startup)

42

5. The boiler is shipped with four (4) spare fuses in a plastic bag
located inside the control panel.

6. If necessary, replace open fuse (F2 is 3.15 amps, F4, F5 and F6
are 5 amps each).

Note: Fuses F2, F4, F5 and F6 are all slow blow fuses.

 WARNING

7. Re-install the control panel cover using the four (4) screws
removed in Step 3. Re-install the upper and lower doors after
fuse inspection.

8. Restore power to the boiler at the external line switch and verify
boiler operation (Section 9 - Start-up in the Crest Installation
and Operation Manual) after completing boiler service.

Do not jumper fuse or replace with any fuse
except as specified. Failure to comply could
result in severe personal injury, death, or
substantial property damage.

Service Manual

3 Troubleshooting (continued)

Table 3A Troubleshooting Chart - No Display

FAULT CAUSE CORRECTIVE ACTION

No Display

No Burner

Operation

- No power supplied to the unit.

- No LED’s illuminated on the CON•X•US
Interface control board.

- Bad display, no LED’s illuminated. • Check connection.

- Bad display. • Replace the display.

- Main control board temperature set point
satisfied.

- Remote thermostat satisfied. • Review remote thermostat setting.

- Outside air temperature above Warm
Weather Shutdown (WWSD) set point for
main control board.

• Check external line switch, fuse, or breaker.

• Check position of ON/OFF switch. Turn switch to the
ON position.

• Check 120 vac through the ON/OFF switch.

• Check wiring harness connection between display
board and main control board. Connect
harness at both points.

• Review temperature setting.

• Check location of outside air sensor. Check
resistance of outdoor air sensor and compare to Table
3C on page 39 of this manual.

Unit Does Not

Modulate

Up to 100%

- Unit locked out on fault. • Consult display for specific fault. Refer to fault
descriptions on page 41 of this manual for corrective
actions.

- Ramp delay active. • Check ramp delay parameter settings. Optional PC
software required.

• Turn ramp delay feature off. See page 20 of this
manual for instructions on how to turn this feature off.

- Boiler controlled by BMS.

• Check BMS parameter settings.

43

Service Manual

3 Troubleshooting

Checking temperature sensors

The boiler temperature sensors (inlet water, outlet water, system water, flue, and outdoor air) are all resistance type devices. The
following tables show the correct values for the sensors at various temperatures. Use an ohmmeter to read the resistance of the
sensor at a known temperature. If the resistance of the sensor does not closely match its corresponding table, replace the sensor

It is important to note that the flue and outlet water sensors each have two temperature sensing devices in one housing. These
devices are designated as S1/S9 - outlet sensor and S3/S10 - flue sensor. Please reference the wiring diagram in the Crest
Installation and Operation Manual for correct terminal location.

Table 3B - Inlet Water/System Sensor Resistance vs.

Temperature

Temperature Resistance Temperature Resistance

50 18,780 158 1,990

68 12,263 176 1,458

86 8,194 194 1,084

104 5,592 212 817

122 3,893

140 2,760

Table 3D - Outlet Water Sensor Resistance vs. Temperature

Outlet S1 R/Y

Pre-Mix Air S11 GY/Y

Temperature Resistance Temperature Resistance Temperature Resistance Temperature Resistance

50 19,553 158 2,004 50 40,030 158 3,478

68 12,690 176 1,464 68 25,030 176 2,492

86 8,406 194 1,084 86 16,090 194 1,816
104 5,715 212 816 104 10,610 212 1,344
122 3,958 122 7,166
140 2,786 140 4,943

Table 3C - Outdoor Air Sensor Resistance vs. Temperature

Temperature Resistance Temperature Resistance

-50 490,813 20 46,218

-40 336,606 30 34,558

-30 234,196 40 26,099

-20 165,180 50 19,900
10 118,018 60 15,311

0 85,362 70 11,883

10 62,465 80 9,299

Outlet S9 RW/Y

Table 3E - Flue Sensor Resistance vs. Temperature

Flue S3 GY/Y Flue S10 W/Y

Temperature Resistance Temperature Resistance Temperature Resistance Temperature Resistance

50 40,030 158 3,478 50 258,500 158 16,870

68 25,030 176 2,492 68 125,500 176 12,000

86 16,090 194 1,816 86 80,220 194 8,674
104 10,610 212 1,344 104 52,590 212 6,369
122 7,166 122 35,270
140 4,943 140 24,160

44

Service Manual

3 Troubleshooting (continued)

Table 3F Troubleshooting Chart - Noisy System

FAULT CAUSE CORRECTIVE ACTION

Noisy

Operation

- Supply gas problem. Natural and LP gas
pressures should be between 4 inches w.c.
(1.0 kPa) and 14 inches w.c. (3.5 kPa).

- Gas/air mixture problem. • Refer to the Gas Valve Adjustment Procedure on

- Dirty/damaged burner. • Refer to page 34 in this manual for the burner removal

- Air in the piping system. • Properly purge all air from the piping system.

- Blown fuse.

• Refer to Section 6 - Gas Connections of the Crest
Installation and Operation Manual for detailed
information concerning the gas supply.

page 53 of this manual for the proper gas valve setting.
Verify that the vent/air intake lengths do not exceed the
maximum listed in the General Venting section of the
Crest Installation and Operation Manual.

and inspection procedure. Clean or replace the burner
as necessary.

• Replace fuse F4 on the control board, see page 37 of
this manual.

No Pump

Operation -

Boiler Pump

System Pump

or

HW Pump

Relief Valve

Opening

- Faulty pump.

- Internal fault on control board.

- Faulty pump relay.

- Incorrect parameter setting.

- System pressure exceeds relief valve
setting.

• Replace pump.

• Replace main control board.

• Replace relay.

• Reference the Boiler Pump Mode and System
Pump Mode parameters in the Service section of this
manual.

• Lower the system pressure below the rating of
the supplied relief valve or replace the standard relief
valve with a higher rated valve up to the maximum
pressure of the heat exchanger 160 psi (40 kPa).

• Improperly sized expansion tank.

45

Service Manual

3 Troubleshooting

Table 3G Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

Gas Pressure SW

Open

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the
SMART TOUCH

to reset.)

display

Low Water

Cutoff Open

(will require a manual

reset once condition has

been corrected. Press
the RESET button on the
SMART TOUCH display

to reset.)

Blocked Drain SW

Open

(will require a manual

reset once condition has

been corrected. Press
the RESET button on the
SMART TOUCH display

to reset.)

Either the low gas pressure switch or the high
gas pressure switches tripped.

The low water cutoff is not making.

Blown fuse.

The blocked drain switch has detected
excessive condensate build up inside the
unit.

• Measure the supply gas pressure to determine cause
of failure. Natural and LP gas pressures should be
between 4 - 14 inches w.c. (1.0 - 3.5 kPa).

• Refer to Section 6 - Gas Connections of the
Crest Installation and Operation Manual for detailed
information concerning the gas supply.

• Correct the supply gas pressure if necessary.

• Reset the LWCO from the RESET button on the front
control panel.

• Verify system is full of water and all air has been
purged from the system.

• Check for loose or misplaced jumpers if flow switch or
LWCO is not installed.

• Replace fuse F2 on the control board, see page 37
of this manual.

• Check condensate tube from unit to floor drain for
proper installation and obstructions.

• Inspect condensate trap for blockage. Clean if
necessary.

• Check for loose wiring connection at wire harness
plug.

• Bad blocked drain switch. Replace switch.

APS

Open

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the
SMART TOUCH

to reset.)

display

46

Blocked flue/inlet pressure switch contacts
are open.

• Check the wiring connections to switch. Wires should
be connected to the common and normally closed
terminals.

• Vent/air intake lengths exceed the maximum allowed
lengths. Refer to Section 2 - General Venting of the
Crest Installation and Operation Manual for
proper lengths.

• Check for obstruction or blockage in the vent/air
intake pipes or at terminations.

• Check reference hose and tubing connected to the
pressure switch for blockage or obstruction.

• Inspect the burner. Reference page 34 of this manual
for removal and cleaning procedures. Replace if
necessary.

• Inspect the heat exchanger. Reference page 35 of
this manual for removal and cleaning procedures.
Replace if necessary.

• Faulty air pressure switch. Replace switch.

• Verify combustion air blower is operating. Replace if
necessary.

Service Manual

3 Troubleshooting (continued)

Table 3G (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

Anti-cycling

Flame Failure

1 Ignition/

Flame Failure 2

Ignition

(will require a manual

reset once the condition

has been corrected.

Press the RESET button

on the SMART TOUCH

display to reset.)

The main control board has received a call
for heat too quickly after the previous call for
heat has ended.

The unit has failed to prove main burner
ignition. It will require a manual reset before
attempting to fire again.

• The control board will release the call for heat after a
set time period.

• The control board will release the call for heat if the
outlet temperature drops too quickly.

• Inspect spark electrode and associated wiring for
damage and connection. Reference page 33 of this
manual for removal and cleaning procedures.
Replace if necessary.

• Visually check for presence of a spark from the view
port.

• Check for proper electrical grounding of the unit.

• Check incoming supply gas pressure. Natural and
LP gas pressures should be between 4 - 14 inches w.c.
(1.0 - 3.5 kPa). Refer to Section 6 - Gas Connections
of the Crest Installation and Operation Manual for
detailed information concerning the gas supply.

• Verify that the plastic hose from gas valve 1 to the air
inlet is connected and is not damaged.

• Verify that the vent/air intake pipes are correctly
installed and that there are no obstructions.

• If 120 vac is present at the main control board, check
the wiring between the main control board and the gas
valve. Replace the wiring if necessary. Do not
disconnect the wiring from the gas valve and attempt to
measure voltage at that point. The main control board
can detect if the gas valve is not connected and will
display the Gas Valve / Connection fault.

• If 120 vac is present, check the outlet of the valve to
ensure the valve is flowing gas. With a manometer
connected to the outlet tap of the gas valve, when the
unit is in the prepurge period, there should be a
negative pressure present. When the valve is
energized a change in pressure should occur. If the
pressure change does not occur, the gas valve is not
opening. Replace the gas valve.

• Inspect flame sensors and associated wiring.
Reference page 33 of this manual for removal and
cleaning procedures. Replace if necessary.

• Inspect the burner. Reference page 34 of this manual
for removal and cleaning procedures. Replace if
necessary.

47

Service Manual

3 Troubleshooting

Table 3G (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

• Inspect flame rod 1 and associated wiring for damage
and connection. Reference page 33 of this manual for
removal and cleaning procedures. Replace if necessary.

• Check for proper electrical grounding of unit.

• Check incoming supply gas pressure. Natural and

Flame Failure 1

Running

(will require a manual

reset once the condition

has been corrected.

Press the RESET

button on the SMART

TOUCH

display to

reset.)

The unit was running and lost the flame
signal.

L.P. gas pressures should be between 4 - 14 inches w.c.
(1.0 - 3.5 kPa). Refer to Section 6 - Gas Connections of
the Crest Installation and Operation Manual for detailed
information concerning the gas supply.

• Verify that the plastic hose from the gas valve to the air
inlet is connected and is not damaged.

• Verify that the vent/air intake pipes are installed correctly
and there are no obstructions.

• Inspect flame sensor and associated wiring. Reference
page 33 of this manual for removal and cleaning
procedures. Replace if necessary.

• Check combustion.

Flame Failure 2

Running

(will require a manual

reset once the condition

has been corrected.

Press the RESET

button on the SMART

TOUCH

display to

reset.)

The unit was running and lost the flame
signal.

• Inspect the burner. Reference page 34 of this manual for
removal and cleaning procedures. Replace if necessary.

• Inspect flame rod 2 and associated wiring for damage
and connection. Reference page 33 of this manual for
removal and cleaning procedures. Replace if
necessary.

• Check for proper electrical grounding of unit.

• Check incoming supply gas pressure. Natural and
L.P. gas pressures should be between 4 - 14
inches w.c. (1.0 - 3.5 kPa). Refer to Section 6 - Gas
Connections of the Crest Installation and Operation
Manual for detailed information concerning the gas
supply.

• Verify that the plastic hose from the gas valve to the air
inlet is connected and is not damaged.

• Verify that the vent/air intake pipes are installed correctly
and there are no obstructions.

• Inspect flame sensor and associated wiring. Reference
page 33 of this manual for removal and cleaning
procedures. Replace if necessary.

• Check combustion.

• Inspect the burner. Reference page 34 of this
manual for removal and cleaning procedures. Replace
if necessary.

Flame Failure 2

Transition

(will require a manual

reset once the condition

has been corrected.

Press the RESET button

on the display to reset.)

48

The unit was running and lost the flame
during a transition from one gas valve to the
other.

• Check the transition gas valve.

Service Manual

3 Troubleshooting (continued)

Table 3G (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

Gas Valve / Relay

Failure 1

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the
SMART TOUCH

to reset.)

display

Gas Valve / Relay

Failure 2

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the
SMART TOUCH

to reset.)

display

The main control board did not detect gas
valve 1.

The main control board did not detect gas
valve 2.

• Check wiring harness connection at the gas valve and
at the main control board.

• Replace the wire harness.

• Replace the gas valve.

• Replace the control board.

• Check wiring harness connection at the gas valve and
at the main control board.

• Replace the wire harness.

• Replace the gas valve.

• Replace the control board.

• Verify that the system is full of water and that all air
has been properly purged from the system.

• Verify that the boiler is piped properly into the heating
system. Refer to Section 5 - Hydronic Piping of the
Crest Installation and Operation Manual
for the proper piping methods for the Crest boiler.

Auto Reset

High Limit

The outlet water temperature has exceeded
the setting of the automatic reset high limit.

• Check 120 vac to boiler pump motor on a call for
heat. If voltage is not present, check wiring back to
the main control board.

• Check the ARHL set point.

• If 120 vac is present on a call for heat and the boiler
pump is not operating, replace the pump.

• If the system pump is a variable speed pump, ensure
that the system flow is not less than the boiler flow.

• If operating on something other than an outlet sensor,
check temperature setting of the main control board.

• If the optional manual reset high limit has tripped,
check setting of the device.

• Check resistance of water sensors and compare to
Table 3B on page 39 of this manual. Replace
sensor if necessary.

• Replace the main control board.

49

Service Manual

3 Troubleshooting

Table 3G (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

Transition Gas

Valve / Relay

Failure

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the
SMART TOUCH

to reset.)

display

Manual Reset

High Limit Open

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the
SMART TOUCH

to reset.)

display

The main control board did not detect the
transition gas valve.

The outlet water temperature has exceeded
the setting of the high limit.

• Check the wiring harness connection at the gas valve
and the control board.

• Replace the wire harness.

• Replace the gas valve.

• Replace the control board.

• Verify that the system is full of water and that all air
has been properly purged from the system.

• Verify that the boiler is piped properly into the heating
system. Refer to Section 5 - Hydronic Piping of the
Crest Installation and Operation Manual
for the proper piping methods for the Crest boiler.

• Check voltage to boiler pump motor on a call for
heat. If voltage is not present, check wiring back to
the main control board.

• Replace the pump relay if necessary.

• If 120 vac is present on a call for heat and the boiler
pump is not operating, replace the pump.

• If the system pump is a variable speed pump, ensure
that the system flow is not less than the boiler flow.

• If operating on either an inlet or system supply sensor,
check temperature setting of the main control board.

• If the high limit has tripped, check setting of the
device and the MRHL set point.

• Check resistance of water sensors and compare to
Table 3B on page 39 of this manual. Replace
sensor if necessary.

• Replace high limit (if equipped).

• Replace main control board.

Fan Speed Low

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the
SMART TOUCH

to reset.)

display

50

The actual fan RPM is 30% lower than what
is being called for.

Blown fuse.

• Vent/air intake lengths exceed the maximum allowed
lengths. Refer to Section 2 - General Venting of the
Crest Installation and Operation Manual for
proper lengths.

• Check for obstruction or blockage in the vent/air
intake pipes or at terminations.

• Check the wiring connections at the fan and at the
main control board.

• Replace the fan.

• Replace fuse F2 on the control board, see page 37
of this manual.

Service Manual

3 Troubleshooting (continued)

Table 3G (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

• Vent/air intake lengths exceed the maximum allowed

Fan Speed High

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the
SMART TOUCH

to reset.)

display

Louver Proving

Sw Open

The actual fan RPM is 30% higher than what
is being called for.

An optional remote proving switch is not
making.

lengths. Refer to Section 2 - General Venting of the
Crest Installation and Operation Manual for
proper lengths.

• Check for obstruction or blockage in the vent/air
intake pipes or at terminations.

• Check the wiring connections at the fan and at the
main control board.

• Replace the fan.

• Check function of remote devices.

• Check for loose or misplaced jumper if proving switch
is not installed.

Flue Temp High

Delta T High

The stack temperature has exceeded the set
parameters for the boiler.

The temperature rise across the heat
exchanger has exceeded the set parameters
for the boiler.

• Inspect the heat exchanger. Reference page 35 of
this manual for the procedure on how to clean the flue
side of the heat exchanger.

• Inspect the flue sensor and associated wiring.
Measure the resistance of the flue sensor and
compare to Table 3E on page 39 of this manual.
Replace the sensor if necessary.

• Verify that the vent/air intake pipes are properly
installed and that there are no obstructions.

• Verify that the system is full of water and that all air
has been properly purged from the system.

• Verify that the boiler is piped properly into the heating
system. Refer to Section 5 - Hydronic Piping of the
Crest Installation and Operation Manual
for the proper piping methods for the Crest boiler.

• Check for 120 vac to the boiler pump motor on a call
for heat. If voltage is not present, check the wiring
back to the main control board. Replace the main
control board if necessary.

• If 120 vac is present on a call for heat and the boiler
pump is not operating, replace the pump.

• Verify that the boiler pump is set to the proper speed
or that the pump is the proper size. Reference
Section 5 - Hydronic Piping of the Crest
Installation and Operation Manual for boiler
pump specifications.

• Inspect the inlet and outlet sensors and associated
wiring. Measure the resistance of the sensors and
compare to the tables on page 39 of this manual.

51

Service Manual

3 Troubleshooting

Table 3G (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

• Verify that the system is full of water and that all air
has been properly purged from the system.

• Verify that the boiler is piped properly into the heating
system. Refer to Section 5 - Hydronic Piping of the
Crest Installation and Operation Manual
for the proper piping methods for the Crest boiler.

• Check for 120 vac to the boiler pump motor on a call
for heat. If voltage is not present, check wiring back
to the main control board. Replace the main control

Outlet Temp

High

Outlet water temperature has exceeded the
maximum outlet water temperature.

board if necessary.

• If 120 vac is present on a call for heat and the boiler
pump is not operating, replace the pump.

• Verify that the boiler pump is set to the proper speed
or that the boiler pump is the proper size. Reference
Section 5 - Hydronic Piping of the Knight Boiler
Installation and Operation Manual for boiler pump
specifications.

• Inspect the outlet sensors and associated wiring.
Measure the resistance of the sensors and compare to
the tables on page 39 of this manual.

Parameter

Programming

Complete

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the

SMART TOUCH

to reset.)

display

Sensor Open

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the

display to reset.)

Sensor Shorted

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the

display to reset.)

Flue Sensor

Open

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the

display to reset.)

After downloading parameters from a laptop,
the main control board must be reset.

Either the inlet water or outlet water
temperature sensor has been disconnected.

Either the inlet water or outlet water
temperature sensor has been shorted.

The flue sensor has been disconnected or
removed from the flue.

• Press the RESET button on the SMART
TOUCH display panel.

• Check the sensors and their associated wiring.
Repair or replace the sensor or wiring if damaged.

• Measure the resistance of the sensors and compare
the resistance to the tables on page 39 of this
manual.

• Replace the sensor if necessary.

• Check the sensors and their associated wiring.
Repair or replace the sensor or wiring if damaged.

• Measure the resistance of the sensors and compare
the resistance to the tables on page 39 of this
manual.

• Replace the sensor if necessary.

• Check the sensor and its associated wiring. Repair
or replace the sensor or wiring if damaged.

• Measure the resistance of the sensors and compare
the resistance to the tables on page 39 of this
manual.

• Replace the sensor in flue.

• Replace the sensor if necessary.

52

Service Manual

3 Troubleshooting (continued)

Table 3G (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

Flue Sensor

Shorted

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the

display to reset.)

Too Many

Resets - Try Later

Internal Fault

Flue Temp

Shutdown

The flue sensor has been shorted.

Too many manual resets have occurred
during a 15 minute period.

The main control board has detected an
internal fault.

The stack temperature has exceeded the
set parameters for the boiler.

• Check the sensor and its associated wiring. Repair
or replace the sensor or wiring if damaged.

• Measure the resistance of the sensors and compare
the resistance to the tables on page 39 of this
manual.

• Replace the sensor if necessary.

• Wait 15 minutes and try again.

• Turn power off to unit, wait 30 seconds and then turn
power back on.

• Replace the main control board.

• Inspect the heat exchanger. Reference page 35 of
this manual for the procedure on how to clean the
flue side of the heat exchanger.

• Inspect the flue sensor and associated wiring.
Measure the resistance of the flue sensor and
compare to Table 3E on page 39 of this manual.
Replace the sensor if necessary.

• Verify that the vent/air intake pipes are properly
installed and that there are no obstructions.

• Replace the main control board.

Delta T

Shutdown

The temperature rise across the heat
exchanger has exceeded the set parameters
for the boiler.

• Verify that the system is full of water and that all air
has been properly purged from the system.

• Verify that the boiler is piped properly into the heating
system. Refer to Section 5 - Hydronic Piping of the
Crest Installation and Operation Manual
for the proper piping methods for the Crest boiler.

• Check for voltage to the boiler pump motor on a call
for heat. If voltage is not present, check the wiring
back to the pump relay. Replace the pump relay if
necessary.

• If 120 VAC is present on a call for heat and the boiler
pump is not operating, replace the pump.

• Verify that the boiler pump is set to the proper speed
or that the pump is the proper size. Reference
Section 5 - Hydronic Piping of the Crest
Installation and Operation Manual for boiler
pump specifications.

53

Service Manual

3 Troubleshooting

Table 3G (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

• Verify that the system is full of water and that all air
has been properly purged from the system.

• Verify that the boiler is piped properly into the heating
system. Refer to Section 5 - Hydronic Piping of the
Crest Installation and Operation Manual

Outlet Temp

Shutdown

Outlet water temperature has exceeded the
maximum outlet water temperature.

for the proper piping methods for the Crest boiler.

• Check for voltage to the boiler pump motor on a call
for heat. If voltage is not present, check wiring back
to the pump relay. Replace the pump relay if
necessary.

• If 120 VAC is present on a call for heat and the boiler
pump is not operating, replace the pump.

Writing/
Programming
EEProm Error

CRC Parameter

Error

Wrong Error

Code

Flame Sense Out

of Sequence 1

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the

display to reset.)

Flame Sense Out

of Sequence 2

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the

display to reset.)

Flue Damper

Switch Open

The main control board has detected an
internal fault.

The main control board has detected an
internal fault.

The main control board has detected an
internal fault.

Flame Sensor 1 senses a flame while gas
valve 1 and gas valve 2 are turned off.

Flame Sensor 2 senses a flame while all gas
valves are turned off.

The flue damper proving switch is not closed
when the flue damper is energized.

• Turn 120V power OFF and back ON.

• Replace the main control board.

• Turn 120V power OFF and back ON.

• Replace the main control board.

• Press the RESET button on the SMART TOUCH
display panel.

• Clean Flame Sensor 1.

• Replace control board.

• Clean Flame Sensor 2.

• Replace control board.

• Check that the flue damper is connected to the 3-pin
connector on the rear of the boiler.

• Check the wiring between the flue damper connector
and the control board.

• Check for 24VAC from the output of the flue damper
transformer when the fan is running.

• Check for 120VAC from the output of the flue damper
transformer when the fan is running.

• Check the wiring between the flue damper transformer
and the control board.

• Check fuse F4 on the control board.

• Replace the flue damper.

• Replace the control board.

54

Service Manual

3 Troubleshooting (continued)

Table 3G (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

IO Expander Out

Error

Wrong

Personality Plug

Air Metering

Valve Stuck

Closed

(will require a manual

reset once the condition
has been corrected. Press
the RESET button on the

display to reset.)

Air Metering

Valve Stuck

Open

(will require a manual

reset once the condition
has been corrected. Press
the RESET button on the

display to reset.)

The control board detected an internal fault.

The personality plug does not match the
personality plug value stored in memory.

The air metering valve did not open when
needed.

The air metering valve did not close when
needed.

• Turn the 120V power OFF. Wait 15 seconds, then turn
the 120V power back ON.

• Replace the control board.

• Remove the lower front jacket and compare the
personality plug value shown on the display with the
value on the personality plug label. If the two values
match, accept the new personality plug value.

• Check the connections at the personality plug
connector.

• Check the voltage at connector X6, pin 13 at the start of
PrePurge. If not 24VAC, replace the control board.

• Check the wiring between the control board and the air
metering valve.

• Replace the air metering valve.

• Replace the control board.

• Check the slide switch on the inside of the air metering
valve actuator.

• Check the voltage at connector X6 pin 13 during the last
part of PrePurge. If 24VAC, replace the control board.

• Check the wiring between the control board and the air
metering valve.

• Replace the control board.

Failure ADC

Controller

(will require a manual

reset once the condition
has been corrected. Press
the RESET button on the

display to reset.)

A problem was detected with measuring one
or more temperature sensors.

The control board has detected an internal
fault.

• Check all connections between the temperature sensors
and the control board. Make sure all connections are
dry and secure.

• Connect a PC to the control board and open the Status
window. Look for temperature readings that are jumping
by more than 1°F.

• Check the resistance of all sensors (see page 39).

• Replace the control board.

• Turn the 120V power OFF. Wait 15 seconds, then turn
the 120V power back ON.

• Replace the control board.

55

Service Manual

3 Troubleshooting

Table 3G (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT DESCRIPTION CORRECTIVE ACTION

Outlet Sensor

Differential

(will require a manual

reset once the condition
has been corrected. Press
the RESET button on the

display to reset.)

Flue Sensor

Differential

(will require a manual

reset once the condition
has been corrected. Press
the RESET button on the

display to reset.)

The readings from the two outlet temperature
sensors are too far apart.

The readings from the two flue temperature
sensors are too far apart.

• Check all connections between the outlet temperature
sensors and the control board. Make sure all
connections are dry and secure.

• Check the resistance of the two outlet sensors (see
page 39).

• Replace the control board.

• Check all connections between the flue temperature
sensors and the control board. Make sure all
connections are dry and secure.

• Check the resistance of the two flue sensors (see page

39).

• Replace the control board.

56

3 Troubleshooting (continued)

Service Manual

Combustion Analysis Procedure

1. Turn the main power off to the boiler by placing the
“On/Off” switch in the OFF position.

2. Remove the fitting from the flue collector. Note:
Combustion measurements will be made at this point.

3. Turn the main power on to the boiler by placing the
“On/Off” switch in the ON position.

4. Navigate to the Service Screen (FIG. 3-2) from the
Home Screen by pressing the MAIN MENU button
and then the SERVICE button.

5. On the Service Screen place heater into Service Mode
by selecting the START button, then selecting Set Gas
Valve 1 - High as shown in FIG. 3-2.

6. Insert the probe from a combustion analyzer into the
hole left by the removal of the fitting.

7. Once the boiler has modulated up to rate, measure the
combustion. The values should be in the range listed
in Table 3H. CO levels should be less than 200 ppm
for a properly installed unit. If the combustion is not
within range reference the Troubleshooting Chart on
page 58 (Table 3I) for possible causes and corrective
actions.

Table 3H Flue Products

Flue Products

Gas Valve

Valve 1 High 9.5 4.0

Valve 1 Low 9.0 4.9

Valve 2 High 9.5 4.0

Valve 2 Low 9.0 4.9

Valve 1 High 11.0 4.1

Valve 1 Low 10.2 5.3

Valve 2 High 11.2 3.8

Valve 2 Low 10.5 4.9

**All set points should be within +/- 0.2%**

Natural Gas

CO2 (%) O2 (%)

Propane

Figure 3-2 Service Screen

57

3 Troubleshooting

8. After Gas Valve 1 is set, repeat the same procedure for the
second gas train by selecting Set Gas Valve 2 - High on the
Service Screen (FIG. 3-2).

9. Once the heater analysis is complete, test the safety shutoff
device by turning the manual shutoff valve to the OFF
position and ensuring that the heater shuts down and
registers an alarm. Open the manual shutoff valve and reset
the control.

10. Turn the main power off to the boiler and replace the
fitting into the flue pipe connection.

11. Place the boiler back into normal operation.

Service Manual

 WARNING

Table 3I Troubleshooting Chart - Combustion Levels

You must replace the fitting to prevent
flue gas spillage into the room. Failure
to comply could result in severe personal
injury, death, or substantial property
damage.

POSSIBLE CAUSE CORRECTIVE ACTION

Vent/Air Intake Length

or Obstruction

Gas Supply Pressure

Dirty/Damaged Burner

Gas Valve Adjustment

• Refer to Section 2 - General Venting of the Crest Installation and Operation Manual
for the proper venting and air intake methods for the Crest boiler.

• Check for obstructions at the vent/air intake terminals.

• Refer to Section 6 - Gas Connections of the Crest Installation and Operation
Manual for the proper gas supply for the Crest boiler.

• Refer to page 34 of this manual for burner removal and cleaning procedures.

• Replace burner if necessary.

• Refer to page 53 of this manual for the gas valve adjustment procedure.

58

3 Troubleshooting (continued)

Gas valve adjustment procedure

Service Manual

CAUTION

Locate the throttle adjustment screw on the gas valve (see
FIG. 3-3). Using a screwdriver, turn the screw a 1/4 turn

counterclockwise to increase CO2 levels or a 1/4 turn
clockwise to decrease CO2 levels. After one adjustment on

the valve, follow the Combustion Analysis Procedure on
pages 57 and 58 of this manual to measure the combustion.

If combustion is still not within the specified range,
repeat the procedure. This procedure SHOULD NOT
be performed more than four (4) times. If after four (4)
adjustments and the combustion is still not within the
specified range, revisit the possible causes in Table 3I on
page 58 or replace the gas valve.

Figure 3-3 Gas Valve Adjustment

Under normal operating conditions this
valve should not need adjusting.

IMG01142

GAS VALVE 1

GAS VALVE 2

59

Revision Notes: Revision A (ECO #C17106) initial release.

Revision B (ECO C17419) reflects the addition of the large Crest models
(1501 - 2001).

Revision C (Change #500001029) reflects the addition of the Crest
CON•X•US Interface.

Revision D (PCP# 3000002050 / CN# 500002334) reflects updates
made to the BMS and BAS instructions on pages 21-22.

Revision E (PCP# 3000002544 / CN# 500002701) reflects updates
made to ΔT Set Point under Pumps on page 27, step 10 under
Sequence of Operation on page 11, and the second paragraph on page

44.

Revision F (PCP# 3000002426 / CN# 500003006) reflects an update to
the Crest home screen image on the manual cover.

FBII-SER _MM #100208044_DIR #2000004590_Rev F

05/16