Lochinvar Crest 751 Owner's manual

DIR #2000508187
D
IR
#
2
000508
This manual must only be used by
a qualified heating installer / service
technician. Read all instructions,
including this manual along with
the Crest Installation and Operation
Manual, and the Crest Service Manual,
before installing. Perform steps in the
order given. Failure to comply could
result in severe personal injury, death,
or substantial property damage.
WARNING
Save this manual for future reference.
100268179_2000509263 Rev A
Dual Fuel Supplemental Manual
Models: FBD 751 - 2001

2
CONTENTS
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.
HAZARD DEFINITIONS .................................................... 2
PLEASE READ BEFORE PROCEEDING ........................ 3
THE CREST -- HOW IT WORKS ...................................... 4
RATINGS........................................................................... 5
1. GAS CONNECTIONS
Check Inlet Gas Supply ..................................................... 6
Gas Pressure ..................................................................... 7
Gas Valve Replacement ................................................... 7
2. START-UP
Start the Boiler ................................................................... 8
Check System and Boiler....................................................8
Operating Instructions........................................................ 9
Check Flame and Combustion......................................... 10
Dual Fuel Switching Instructions ................................ 10-11
3. DIAGRAMS.............................................................12-13
Revision Notes.................................................. Back Cover

Dual Fuel Supplemental Manual
Please read before proceeding
Installer – Read all instructions, including
this manual, the Crest Installation and
Operation Manual and the Crest Service
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 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.
Failure to adhere to the guidelines on this
page can result in severe personal injury,
death, or substantial property damage.
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.
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.
Any claims for damage or shortage in
shipment must be filed immediately
against the transportation company by
the consignee.
Factory warranty (shipped with unit) does
not apply to units improperly installed or
improperly operated.
3
If the information in this manual is not
followed exactly, a fire or explosion may
result causing property damage, personal
injury or loss of life.
This appliance MUST NOT be installed in
any location where gasoline or flammable
vapors are likely to be present.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electric switch; do
not use any phone in your building.
• Immediately call your gas supplier
from a near by phone. Follow the
gas supplier’s instructions.
• If you cannot reach your gas supplier,
call the fire department.
• Installation and service must be
performed by a qualified installer,
service agency, or the gas supplier.
WARNING
NOTICE
WARNING
WARNING

Dual Fuel Supplemental Manual
4
The Crest Dual Fuel - How it works...
1. Propane gas connection
The propane gas connection pipe is a threaded black iron pipe
connection. This pipe should be connected to the incoming gas
supply to deliver propane gas to the boiler.
2. Natural gas connection
The natural gas connection pipe is a threaded black iron pipe
connection. This pipe should be connected to the incoming gas
supply to deliver natural gas to the boiler.
3. Fuel selection switch
Switches the unit between natural and propane gas.
4. Natural gas indicator light (green)
Indicates that natural gas operation has been selected.
5. Propane gas indicator light (red)
Indicates that propane gas operation has been selected.
6. Small natural gas valve (Valve 1 Natural)
The small natural gas valve senses the negative pressure
created by the blowers, allowing gas to flow only if the gas
valves are powered and combustion air is flowing.
7. Small propane valve (Valve 1 Propane)
The small propane gas valve senses the negative pressure
created by the blowers, allowing gas to flow only if the gas
valves are powered and combustion air is flowing.
8. Large natural gas valve (Valve 2 Natural)
The large natural gas valve senses the negative pressure created
by the blowers, allowing gas to flow only if the gas valves are
powered and combustion air is flowing.
9. Large propane gas valve (Valve 2 Propane)
The large propane gas valve senses the negative pressure created
by the blowers, allowing gas to flow only if the gas valves are
powered and combustion air is flowing.
10. Natural shutoff valve
The natural shutoff valve is used to isolate the boiler gas
train from the gas supply.
11. Propane shutoff valve
The propane shutoff valve is used to isolate the boiler gas
train from the gas supply.
5
4
3
DIR #2000508194
Models FBD 751 - 2001
2
1
DIR #2000508187
Front View Left Side (inside unit)
1
2
10
8
6
11
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DIR #2000508206

Dual Fuel Supplemental Manual
Ratings
Crest
AHRI Rating
Model Number
Note: Change “N” to
“L” for L.P. gas models.
Input
MBH
(Notes 4 - 8)
Min Max
Gross
Output
MBH
(Note 1)
Net
AHRI
Ratings
Water,
MBH
(Note 2)
FB(N,L,D)0751 50 750 720 626
FB(N,L,D)1001 50 1000 960 835
FB(N,L,D)1251 62 1250 1200 1043
FB(N,L,D)1501 60 1500 1440 1252
FB(N,L,D)1751 70 1750 1680 1460
FB(N,L,D)2001 80 2000 1920 1670
Maximum allowed working pressure is located on the rating plate.
NOTICE
Figure A High Altitude Label Location 5
Other Specifications
Appliance
Water
Content
Gallons
Pipe
Size
Outlet
Pipe
Size
Inlet
Gas Inlet
Size
Air
Size
Vent
Size
(Note 3)
Weight
w/Water
(lbs.)
73 3" 3" 1 1/4" 6" 6" 1768
77 3" 3" 1 1/4" 6" 6" 1838
87 3" 3" 1 1/4" 6" 8" 1975
94 4" 4" 1 1/2" 8" 8" 2307
106 4" 4" 1 1/2" 8" 8" 2458
111 4" 4" 1 1/2" 8" 8" 2570
Notes:
1. The ratings are based on standard test procedures
prescribed by the United States Department of Energy.
2. Net AHRI ratings are based on net installed radiation of
sufficient quantity for the requirements of the building
and nothing need be added for normal piping and
pickup. Ratings are based on a piping and pickup
allowance of 1.15.
3. Crest boilers require special gas venting. Use only
the vent materials and methods specified in the Crest
Installation and Operation Manual.
4. Standard Crest boilers are equipped to operate from sea
level to 4,500 feet only. The boiler will de-rate by 1.4%
for each 1,000 feet above sea level up to 4,500 feet.
5. High altitude Crest Models are equipped to operate from
3,000 to 12,000 feet only. e boiler will not de-rate up
to 5,500 feet and will de-rate by 1.6% for each 1,000 feet
above 5,500 feet. e operation given in this manual
remains the same as the standard boilers. A high altitude
label (as shown in FIG A.) is also axed to the unit.
De-rate values are based on proper combustion
calibration and CO2 ’s adjusted to the recommended
levels.
UNIT EQUIPPED FOR
HIGH ALTITUDE
3,000 FT. TO 12,000 FT.
IMG01026

6
Table 1A First Stage Piping at High Pressure_10 PSI
The gas piping must be sized for the proper flow and length of
pipe, to avoid excessive pressure drop. Both the gas meter and
the gas regulator must be properly sized for the total gas load.
If you experience a pressure drop greater than 1 inch w.c.
(249 Pa), the meter, regulator, or gas line is undersized or in
need of service. Perform the steps below when checking inlet
gas supply:
1. Turn the main power switch to the “OFF” position.
2. Shut off gas supply at the manual gas valve in the gas
piping to the appliance.
3. Remove the 1/8" pipe plug on the flange to the factory
supplied gas shutoff valve and install a suitable 1/8"
fitting (field supplied) for the manometer tubing. Place the
tubing of the manometer over the tap once the 1/8"
fitting is installed as shown in FIG.’s 1-1 and 1-2.
4. Slowly turn on the gas supply at the factory installed
manual gas valve.
5. Turn the power switch to the “ON” position.
6. Adjust the temperature set point on the control panel of
the SMART TOUCH control module to call for heat or
utilize Service Mode, see page 10 of this manual.
7. Observe the gas supply pressure as the burner fires at
100% of rated input. Percent of burner input will be
displayed on the Modulation Screen.
8. Ensure inlet pressure is within specified range.
Minimum and maximum gas supply pressures are
specified in this section of the manual.
9. If gas supply pressure is within normal range and no
adjustments are needed, proceed on to Step 11.
10. If the gas pressure is out of range, contact the gas utility,
gas supplier, qualified installer or service agency to
determine the necessary steps to provide proper gas
pressure to the control.
11. Turn the power switch to the “OFF” position.
12. Shut off the gas supply at the manual gas valve in the gas
piping to the appliance.
13. Remove the manometer from the pressure tap on top of
the gas valve. Remove the 1/8" (3 mm) field supplied
fitting and reinstall the pipe plug removed in Step 3.
DO NOT adjust or attempt to measure gas
valve outlet pressure. Attempting to alter
or measure the gas valve outlet pressure
could result in damage to the valve, causing
potential severe personal injury, death, or
substantial property damage.
WARNING
Check inlet gas supply
1 Gas connections
Dual Fuel Supplemental Manual
The Dual Fuel Crest is equipped with
two (2) inlet gas connections. Each
connection must be checked to ensure
proper operation.
NOTICE
Table 1B Second Stage Piping at Low Pressure_1/2 PSI
10 20 30 40 50 60 70 80 90 100 125 150
1/2 2442 1885 1580 1382 1240 1133 1048 979 921 872 775 703
Pipe 3/4 4831 3812 3230 2842 2561 2346 2175 2035 1917 1816 1618 1470
Size 1 8531 6916 5939 5270 4776 4392 4083 3829 3614 3429 3063 2789
(I.D.) 1 1/4 16626 13771 11963 10691 9736 8987 8378 7872 7443 7074 6336 5779
1 1/2 23670 19957 17510 15749 14407 13341 12470 11740 11119 10581 9501 8682
2 42521 36514 32398 29359 27001 25104 23538 22216 21082 20097 18104 16580
Nominal Iron Pipe
Size Inches
Length of pipe or tubing, feet
Maximum Capacities of Pipe in KBTUH/Hr
Notice: Capacities show n are for Natural Gas. Please consult supplier for proper gas pipe sizing for propane.
10 20 30 40 50 60 70 80 90 100 125 150
1 1/4 2205 1496 1212 1039 913 834 771 724 677 630 567 511
Pipe 1 1/2 3307 2299 1858 1559 1417 1275 1181 1086 1023 976 866 787
Size 2 6221 4331 3465 2992 2646 2394 2205 2047 1921 1811 1606 1496
(I.D.) 2 1/2 10140 7046 5695 4778 4343 3908 3618 3329 3160 2991 2654 2412
3 17990 12510 10110 8481 7708 6936 6422 5908 5608 5309 4711 4281
4 36710 25520 20620 17300 15730 14150 13100 12050 11440 10830 9613 8736
Nominal Iron Pipe
Size Inches
Length of pipe or tubing, feet
Maximum Capacities of Pipe in KBTUH/Hr
Notice: Capacities show n are for Natural Gas. Please consult supplier for proper gas pipe sizing for propane.

7
Dual Fuel Supplemental Manual
WARNING Do not check for gas leaks with an open
flame -- use the bubble test. Failure to
use the bubble test or check for gas leaks
can cause severe personal injury, death, or
substantial property damage.
14. Turn on the gas supply at the manual gas valve.
15. Turn the power switch to the “ON” position.
16. Adjust the temperature set point on the control panel of
the SMART TOUCH control module to the desired
water temperature so the appliance will call for heat.
17. Check burner performance by cycling the system while
you observe burner response. The burner should ignite
promptly. Flame pattern should be stable. Turn system
off and allow burner to cool, then cycle burner again to
ensure proper ignition and flame characteristics.
18. Repeat Steps 1 - 17 for both natural and LP gas supply.
Ignition problems are especially noticeable in NEW LP
installations and also in empty tank situations. This can
also occur when a utility company shuts off service to an
area to provide maintenance to their lines.
Gas valve replacement
The gas valve MUST NOT be replaced with a
conventional gas valve under any circumstances. As
an additional safety feature, the gas valves have flanged
connections to the venturis and blowers.
Figure 1-1 Inlet Gas Supply Check_Natural
DIR #2000508192
DO NOT adjust or attempt to
measure gas valve outlet pressure.
Attempting to alter or measure
the gas valve outlet pressure could
result in damage to the valve,
causing potential severe personal
injury, death, or substantial property
damage.
Failure to follow all precautions
could result in fire, explosion, or
death!
WARNING
WARNING
1 Gas connections (continued)
Gas Pressure
The gas pressure must remain between 4 inches w.c. (.99 kPa)
minimum and 14 inches w.c. (3.5 kPa) maximum for Natural
gas and between 4 inches w.c. (.99 kPa) minimum and 14
inches w.c. (3.5 kPa) maximum for LP gas during standby
(static) mode and while in operating (dynamic) mode. If an
in-line regulator is used, it must be a minimum of 10 feet (3 m)
from the Crest boiler. It is very important that the gas line is
properly purged by the gas supplier or utility company. Failure
to properly purge the lines or improper line sizing, will result
in ignition failure.
Figure 1-2 Inlet Gas Supply Check_Propane
DIR #2000508193

8
Dual Fuel Supplemental Manual
2 Start-up
Final checks before starting the boiler
Read the Crest Service Manual to familiarize yourself
with SMART TOUCH control module operation. Read
this manual, page 9 for proper steps to start boiler.
Verify the boiler and system are full of water and all
system components are correctly set for operation.
Verify the preparation procedures of Section 9 of the
Crest Installation and Operation Manual have been
completed.
Verify electrical connections are correct and securely
attached.
Inspectvent pipingand airpiping forsigns ofdeterioration
from corrosion, physical damage or sagging. Verify air
piping and vent piping are intact and correctly installed
per this manual.
Start the boiler
1. Read and follow the Operating instructions in FIG. 2-1,
page 9.
If boiler does not start correctly
1. Check for loose connections, blown fuse or service switch
off?
2. Is external limit control (if used) open? Is boiler water
temperature above 200°F (93°C)?
3. Is the boiler receiving a call for heat?
4. Is gas turned on at meter and boiler?
5. Is incoming gas pressure less than 4 inches w.c. (.99 kPa)?
If none of the above corrects the problem, refer to the
Troubleshooting Section of the Crest Service Manual.
Check system and boiler
Check water piping
1. Check system piping for leaks. If found, shut down the
boiler and repair immediately. (See WARNINGS in
the Crest Installation and Operation Manual (startup)
regarding failure to repair leaks.)
2. Vent any remaining air from the system using manual
vents. Air in the system will interfere with circulation
and cause heat distribution problems and noise.
Check vent piping and air piping
1. Check for gastight seal at every connection, seam of air
piping, and vent piping.
Venting system must be sealed gastight
to prevent flue gas spillage and carbon
monoxide emissions, which will result in
severe personal injury or death.
Check gas piping
1. Check around the boiler for gas odor following the
procedure in the Crest Installation and Operation
Manual (connecting gas supply piping).
If you discover evidence of any gas leak,
shut down the boiler at once. Find the
leak source with a bubble test and repair
immediately. Do not start the boiler again
until corrected. Failure to comply could
result in severe personal injury, death, or
substantial property damage.
WARNING
WARNING

9
Dual Fuel Supplemental Manual
FOR YOUR SAFETY READ BEFORE OPERATING
WARNING: If you do not follow these instructions exactly, a fire or explosion
may result causing property damage, personal injury, or loss of life.
A. This appliance does not have a pilot. It is
equipped with an ignition device which
automatically lights the burner. Do not try
to light the burner by hand.
B. BEFOR E OPER ATING sme ll a ll ar ound
the appliance are a for gas. Be sure to
smell next to the floor because some gas
is heavier than air and will settle on the
floor.
WHAT TO DO IF YOU SMELL GAS
•D o no t tr y to light any appl iance.
•Do not touch any electric switch; do
not use an y ph one i n your b ui ldi ng .
•Immediately call your gas supplier from a
neighb or ’s phone. Fol low the gas supplier’s
instructions.
•If yo u can not re ach you r ga s suppl ier , ca ll
the fire department.
C. Use only your hand to turn the gas control knob.
Never use tools. If the handle will not turn by
hand, don’t try to repair i t, call a qualified service
technician. Force or attempted repair may
result in a fire or explosion.
D. Do not use this a ppliance if any part has be en
under water. Imm ediate ly call a qual ified
ser vice technician to inspect the applianc e and
to replace any part of the control system and
any gas contr ol w hich has been under water.
OPERATING INSTRUCTIONS
1. STOP! Read the safety information
above on this label.
2. Set the thermostat to lowest setting.
3. Turn off all electric power to the
applia nc e.
4. This appliance is equipped with an
ignition device which automatically lights
the burner. Do not try to light the burner
by hand.
5. Remove front door.
6. Turn gas shutoff valve counterclockwise
to “ OFF”. H an dle wil l be pe rp endicu la r to
pipe. Do not force.
7. Wait five (5) minutes to clear out any gas.
If you then smell gas, ST OP ! Follow “B”
in the safety information above this label.
If you don’t smell gas, go to next step.
8. Tur n g as sh utoff val ve clockwise to “ ON”.
Handle will be parallel to pi pe.
9. Instal l fr ont door.
10. Turn on all electric power to appliance.
11. Set th er mostat to desired setti ng .
12. If the ap pl ian ce w ill n ot op erate, fol low the
instr uctions “T o Tu rn Off Gas T o Appliance” and
call your service technician or gas supplier.
TO TURN OFF GAS TO APPLIANCE
1. Set the thermostat to lowest setting.
2. T urn off all e lectric po wer to the appl iance
if se rvice i s to be pe rfor me d.
3. Remove front door.
4. Turn gas shut off valve counterclockwise to
“OFF”. Handle will be perpendicular to pipe.
Do not force.
5. Instal l fr ont door.
L BL2 005 3 REV B
Figure 2-1 Operating Instructions
2 Start-up (continued)

10
Dual Fuel Supplemental Manual
2 Start-up
Dual fuel switching instructions
1. Turn the main power off to the boiler by placing the “On/
Off” switch in the OFF position (FIG. 2-2).
2. Using the fuel selector switch (FIG. 2-2), select the desired
fuel.
Figure 2-2 Fuel Selector Switch
IMG00063
NATURAL PROPANE
DETAIL
FUEL SELECTION
SWITCH
NATURAL PERSONALITY I.D.
PROPANE PERSONALITY I.D.
MAIN POWER
SWITCH
DIR #2000508194
Check flame and combustion
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 Maintenance Screen from the
Home Screen by pressing the SETUP button, enter the
installer password, and then using the scrolling menu
feature on the left side, scroll down to the SERVICE
MAINTENANCE button.
5. On the Service Maintenance Screen place heater into
Service Mode by selecting the START button, then
selecting Set Gas Valve 1 - High.
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 2A below. CO levels should be less than 200
ppm for a properly installed unit. If the combustion is
not within range reference the Troubleshooting Section
in the Crest Service Manual for possible causes and
corrective actions.
Table 2A Flue Products Chart
Flue Products Natural Gas
Gas Valve
CO2 (%) O2 (%)
Valve 1 High 9.2 4.6
Valve 1 Low 9.0 4.9
Valve 2 High 9.3 4.4
Valve 2 Low 8.7 5.5
Propane
Valve 1 High 11.0 4.1
Valve 1 Low 10.0 5.6
Valve 2 High 11.1 4.0
Valve 2 Low 10.7 4.6
**All set points should be within +/- 0.2%**
8. Once the heater analysis is complete, test the safety shutoff
device by turning the manual shutoff valve to the OFF
position and ensuring the heater shuts down and registers an
alarm. Open the manual shutoff valve and reset the control.
9. Turn the main power off to the boiler and replace the
fitting into the flue pipe connection.
10. Place the boiler back into normal operation.
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.
WARNING