The Model CFC boiler is a single pass,
vertical down fired durable firetube
boiler. The internal extended-heating
surface tubes provide very high levels of
performance in a compact space,
offering over 10 square feet of heating
surface per boiler horsepower, providing
many years of trouble free performance.
Figure B5-1. AluFer Inserts
Advanced
Technology
Advanced
Construction
Tubes and tube sheets are constructed from UNS S32101 duplex stainless steel.
Tubes feature AluFer tube inserts for optimal heat transfer.
The extended heating surface design provides the ideal solution for the demands of
a condensing boiler and helps to recover virtually all the latent heat of the flue gas.
Each tube consists of an outer stainless steel tube (waterside) and the AluFer
extended surface profile on the flue gas side.
High EfficiencyWith the extended heating surface tubes the CFC boiler will provide fuel to water
efficiency of up to 99% at low fire and 97% at high fire with 80 degrees F return
water temperature.
Ease of MaintenanceThe powder coated steel casing is designed for easy removal and re-assembly. As
shown in Figure B5-2, the burner is hinged and is provided with hydraulic pistons
for simple opening for service of the spark electrode, inspection of the burner
cylinder, tubes and tube sheet on Models CFC1000 and larger. (On the CFC500 and
750, the burner is hinged only). A front mounted service platform is provided for
easy access to the burner components and controls.
Figure B5-2. Fireside Access
Quality ConstructionISO 9001:2001 certified manufacturing process ensures the highest degree of
manufacturing standards are always followed.
ASME Code construction ensures high quality design, safety, third party inspection,
and reliability, and is stamped accordingly.
Premix TechnologyThe burner utilizes "Premix" technology to mix both gas fuel and combustion air prior
to entering the burner canister, with air "leading" during burner firing transitions.
3Rev. 05-2012
Model CFCClearFire Commercial Boilers
Combined with a variable speed fan, this technology provides very low emission
levels, exceptionally safe operation, and nearly 100% combustion efficiency.
Full ModulationThe variable speed fan provides modulated firing for reduced on/off cycling,
excellent load tracking, and reduced operating costs. The burner does not require
mechanical linkage connections between the fuel input valve and air control.
Instead, the microprocessor control positions the fan speed in accordance with
system demand, and this determines the fuel input without mechanical device
positioning - that is, linkage-less fuel/air ratio control. This eliminates linkage
slippage, minimizes burner maintenance, and provides control repeatability. This is
shown schematically in Figure B5-3.
Figure B5-3. Premix Burner Technology
Designed For
Heating
Applications
The pressure vessel is designed for 125 psig MAWP (Max. Allowable Working
Pressure) and is constructed of durable ASTM Grade Steel and Stainless Steel
materials. Figure B5-4 shows the counter flow heat exchanger design that gives
optimal heat transfer. The design also prevents hot spots, does not require a
minimum flow for thermal shock protection, and does not require a minimum return
water temperature. In fact, the design carries a 20-year thermal shock warranty.
Because of its design characteristics, the Model CFC is well suited for applications
utilizing indoor/outdoor reset controls, radiant floor heating, snow melt systems,
ground source heat pump systems and systems that utilize variable speed
circulating pumps. It may also be employed in standard hot water systems that
require higher heated water at colder outdoor temperatures but then require
minimum temperatures during warmer heating days, realizing fuel efficiency savings
over traditional hot water boilers.
While the design does not lend itself to the direct supply of potable water, a separate
storage tank with an internal heat exchanger can be employed, as the
microprocessor control permits domestic water programming. Therefore, the Model
CFC can service both hydronic heating and domestic water source heating.
Dual ReturnTwo return pipes - high and low temperature - allow condensing performance with
as little as 10% return water at condensing temperature.
4Rev. 05-2012
Model CFCClearFire Commercial Boilers
Combustion Fan and
Premix Gas Valve
Safety Relief Valve
Air Vent Connection
Hot Water
Outlet
High Temp.
Return
Assembly
Burner
Canister
Control
Panel
“Finned” High
Efficiency AluFer
Tubes
Low Temp.
Return
Flue Gas
Outlet
Figure B5-4. Model CFC Heat Flow and Component Orientation
MODEL CFC PRODUCT OFFERING
Information in this section applies to condensing hot water boiler sizes ranging from
500,000 Btu input through 3,300,000 Btu input for operation on Natural Gas or
LP Gas only. Installation is for indoor use only.
Dimensions, ratings, and product information may change to meet current market
requirements and product improvements. Therefore, use this information as a guide.
ASME Code
Pressure Vessel
5Rev. 05-2012
Model CFCClearFire Commercial Boilers
Standard EquipmentEquipment described below is for the standard boiler offering:
1. The Boiler
A. Each boiler size is designed for a Maximum Allowable Working Pressure
(MAWP) of 125 psig (8.6 Bar), constructed in accordance with the ASME
Code Section IV and bear the "H" stamp.
B. The insulated boiler is mounted on a base and powder coated steel casing
provided.
C. A drain valve connection is provided at the front bottom for field piping of a
boiler drain valve, which can be furnished as an option.
2. Boiler Trim and Controls
•The following items are furnished:
•Probe Type Low Water Cutoff control, manual reset.
•Excess Water Temperature Cutoff, manual reset.
•NTC (negative temp. coefficient) sensor for hot water supply temperature.
•NTC sensor for hot water return temperature.
•ASME Safety Relief Valve set @ 125 psig. (8.6 Bar)
•Combination Temperature/Pressure Gauge.
3. Burner Control
A. The CB Falcon is an integrated burner management and modulation control
with a touch-screen display/operator interface. Its functions include the
following:
• Two (2) heating loops with PID load control.
• Burner sequencing with safe start check, pre-purge, direct spark ignition (pilot
ignition CFC-3300), and post purge.
• Electronic ignition.
• Flame Supervision.
• Safety shutdown with time-stamped display of lockout condition.
• Variable speed control of the combustion fan.
• Supervision of low and high gas pressure, air proving, stack back pressure, high
limit, and low water.
• First-out annunciator.
• Real-time data trending.
• (3) pump/auxiliary relay outputs.
• Modbus communication capability.
• Outdoor temperature reset.
• Remote firing rate or setpoint control
• Setback/time-of-day setpoint
• Lead/Lag for up to 8 boilers
6Rev. 05-2012
Model CFCClearFire Commercial Boilers
LWCO RESET
FALCON DISPLAY / OPERATOR INTERFACE
DEMAND SWITCH
Figure B5-5. ClearFire Control Panel (1500/1800 shown)
4. Forced Draft Burner
A. The burner is a "Pre-mix" design consisting of a unitized venturi, single body
dual safety gas valve, blower, and burner head.
B. Full modulation is accomplished with a variable speed fan for 5:1 turndown
ratio.
C. For near flameless combustion, the burner utilizes a Fecralloy-metal fiber
head.
D. Noise level at maximum firing is less than 70 dBA regardless of boiler size.
E. Operating on Natural Gas, NOx emissions will be less than 20 PPM
regardless of boiler size and the boiler is certified for California and Texas for
Low NOx emissions.
F. As an option, the burner is capable of direct vent combustion.
G. Ignition of the main flame is via direct spark, utilizing high voltage electrodes
and a separate electrode for flame supervision (CFC-3300 uses gas pilot
ignition and UV scanner for flame supervision).
H. To ensure adequate combustion air is present prior to ignition, and to ensure
the fan is operating, a combustion air proving switch is furnished.
I. A High Air Pressure Switch is provided to ensure burner lockout if excessive
back pressure due to a blocked stack occurs.
J. For ease of maintenance and inspection, the burner is furnished with
hydraulic rods and easy opening lockdown nuts, which permit the burner to
swing up (except 500 and 750, which are hinged only). This provides full
access to the burner and electrodes, as well, to the tube sheet and tubes.
5. Burner Gas Train
The standard gas train is equipped in accordance with UL certification and complies
with ASME CSD-1. Each burner gas train includes:
7Rev. 05-2012
Model CFCClearFire Commercial Boilers
•Low Gas Pressure Interlock, manual reset.
•High Gas Pressure Interlock, manual reset.
•ASME CSD-1 Test Cocks.
•Downstream manual ball type shutoff cock.
•Single body dual safety shutoff gas valve.
Optional EquipmentFor option details, contact the local authorized Cleaver-Brooks representative. In
summary, here are some of the options that can be provided with the boiler:
A. Dual gas train for quick and easy fuel switchover.
B. Reusable air filter.
C. Condensate neutralization tank assembly - consists of neutralizing media, filter, and PVC
condensate holding tank with integral drain trap. This assembly can be mounted beneath
the boiler.
D. Outside air intake for direct vent combustion.
E. Outdoor temperature sensor for indoor/outdoor control.
F.Header temperature sensor for multiple boiler Lead/Lag operation.
G. Auxiliary Low Water Control (shipped loose) for field piping by others into the system piping.
H. Alarm Horn for safety shutdown.
I.Relays for output signal for burner on, fuel valve open.
J.Stack Thermometer.
K. Stack temperature limit-sensor.
L.Auto air vent.
M. Boiler drain valve.
DIMENSIONS AND RATINGS
For layout purposes, the overall dimensions for the Model CFC are shown in Table
B5-1 (US Dimensions) and Table B5-2(Metric Dimensions) including the various
pipe connection sizes for supply and return water, drain, and vent. The performance
ratings for the boiler are shown in Table B5-3.
Altitude Relative to the ratings shown, installation of the boiler above 2000 feet elevation
will result in input capacity reduction. Please refer to Table B5-4 for input ratings of
the boiler at various elevations.
PERFORMANCE DATA
EfficiencyThe Model CFC is a "full condensing" boiler realizing efficiency gain at variable
operating conditions. It is designed to extract the latent heat of condensation over a
greater range than other designs. This can be seen in Figure B5-7, which depicts
nominal stack temperatures of the boiler versus other designs. The nominal point of
condensation is approximately 132
efficient heat transfer design and lower stack temperature, is able to capture the
latent heat of condensation over a broader range.
Fuel-to-water efficiency is relative to specific operating conditions. Operating
efficiency will be greater in the "condensing" mode of operation as noted above, yet
with its inherently greater heat transfer surfaces and superior pre-mix burner, the
ClearFire’s efficiency under "traditional" hot water conditions is also outstanding.
Table B5-6 throughTable B5-9 show the guaranteed efficiencies at various
operating conditions and firing rates for Natural Gas. It should be noted that the
efficiency is exceptional at high fire and low fire versus other designs where high
efficiency is realized only with low fire or minimal firing rates and low temperature
returns.
F (55.5 C). The ClearFire, due to its more
8Rev. 05-2012
Model CFCClearFire Commercial Boilers
I
Figure B5-6. Model CFC Dimensional Views
9Rev. 05-2012
Model CFCClearFire Commercial Boilers
Table B5-1. U.S. Standard Dimensions Model CFC Boiler
ITEMDIMENSIONS (inches)50075010001500180025003300
AOverall Height71.871.875.781.681.682.285.0
BOverall Width32.332.336.643.743.750.861.3
COverall Depth48.848.862.665.665.672.686.3
DWidth Less Casing26.826.831.138.238.245.355.5
EGas Connection to Top of Casing8.18.19.512.510.29.410.0
FGas Connection to Floor63.763.766.269.171.472.875.0
GSide of Casing to Gas Connection2.32.34.33.45.24.75.1
HBoiler Centerline to Air Inlet Centerline4.04.04.04.97.17.17.1
IFloor to Bottom of Base10.310.310.310.310.310.310.3
JFloor to Top of Stack Connection18.618.618.119.119.120.921.4
KCenterline to Centerline of Stack Stub15.415.416.921.021.028.135.8
LRear of Boiler to Centerline of Stack
Stub
MFront of Boiler to Rear of Casing38.838.849.449.549.556.567.0
NControl Panel Projection4.14.14.14.14.14.14.3
OCasing Height56.256.260.065.465.465.467.0
PAir Vent Line Projection from Rear of
Casing
QFloor to Centerline of Lower Return19.519.519.620.721.322.424.1
RFloor to Centerline of Upper Return28.228.730.520.332.333.835.5
SFloor to Centerline of Supply Connec-
tion
TFloor to Centerline of Air Vent59.959.962.363.163.163.666.4
Table B5-4. Altitude Correction for Input Capacity at Various Altitude Levels
Natural Gas
700' ASL2000'4000'6000'8000'10000'
CFC 33003300 kBTU/h33003300330030572930
CFC 2500250024182245208319301850
CFC 1800180018001800166615441480
CFC 1500150015001500141513111257
CFC 1000100010001000943874838
CFC 750750750750707655628
CFC 500500500490454421404
Ratings assume 35% excess air, 80F combustion air.
Blower speed adjustments should be made to match performance and local conditions accordingly.
For minimum gas supply pressures see Table B5-24. Altitude corrections for supply pressure should be made per Table B5-25.
Natural gas heating value of 1000 BTU/SCF assumed.
LP Gas
700' ASL2000'4000'6000'8000'10000'
CFC 33003300 kBTU/h33003300330030572930
CFC 2500250025002339216920101927
CFC 1800180018001800170415791514
CFC 1500150015001500150013901332
CFC 10001000100010001000926888
CFC 750750750750750695666
CFC 500500500500481445427
Ratings assume 40% excess air, 80F combustion air.
Blower speed adjustments should be made to match performance and local conditions accordingly.
For minimum gas supply pressures see Table B5-24. Altitude corrections for supply pressure should be made per Table B5-25.
LP (propane) gas heating value of 2500 BTU/SCF assumed.
13Rev. 05-2012
Model CFCClearFire Commercial Boilers
Competitor 1
Competitor 2
Clearfire
ClearFire
Efficiencies
Firing Rate
10096.094.692.089.088.588.487.9
Firing Rate
1009492.790.588.587.887.086
Figure B5-7. Competitive Condensation Analysis
The Tables below depict the operating efficiencies of each size Model CFC boiler,
including radiation losses. As the Model CFC is a fully condensing boiler, maximum
efficiency is obtained when operating within the condensing mode, utilizing the latent
heat of condensation.
EmissionsThe Model CFC Boiler has been tested by an independent testing lab for Low NOx
certification in California under the requirements of South Coast Air Quality
Management District (SCAQMD) Rule 1146. Meeting the requirements of SCAQMD
also qualifies the boiler for meeting the NOx requirements in the state of Texas.
By means of the Pre-mix burner, the Clearfire boiler provides environmentally
friendly emissions when firing natural gas; emission data are shown in Figure B5-8
through Figure B5-13.
Figure B5-8. Emissions Data Clearfire Model CFC 500
16Rev. 05-2012
Model CFCClearFire Commercial Boilers
Figure B5-9. Emissions Data ClearFire Model CFC 750
Figure B5-10. Emissions Data ClearFire Model CFC 1000
17Rev. 05-2012
Model CFCClearFire Commercial Boilers
Figure B5-11. Emissions Data ClearFire Model CFC 1500
Figure B5-12. Emissions Data ClearFire Model CFC 1800
18Rev. 05-2012
Model CFCClearFire Commercial Boilers
Figure B5-13. Emissions Data ClearFire Model CFC 2500
Figure B5-14. Emissions Data ClearFire Model CFC 3300
19Rev. 05-2012
Model CFCClearFire Commercial Boilers
Noise LevelThe Model CFC is extremely quiet at all operating levels, does not require any sound
level modifications to provide ultra low noise levels, and is virtually vibration free.
Thus, it is very suitable in applications that demand low noise levels.
Table B5-11 shows the noise levels of the Clearfire at various firing rates.
Table B5-11. Noise Level (dBA) measured 3 feet in front of boiler
ENGINEERING DATA
Boiler InformationThe Model CFC boiler is designed for service in any closed hydronic system and can
be used to augment any hot water system. It can be put into operation as a single
stand-alone unit with 5:1 turndown or in multiple units for larger turndown and
capacity.
Flow Rates and
Pressure Drops
System Operating
Parameters
Clearfire boilers may be utilized in water heating systems with temperatures from
40
F (4.4 C) to 195 F (90.5 C); ideal for ground water source heat pump
applications, etc. Because the Clearfire is a full condensing boiler, low water
temperature (below the dewpoint) restrictions do not apply. In fact, the lower the
return the better the fuel savings.
Variable temperature differentials can be designed to make use of changing outdoor
conditions and thus, the Clearfire is not restricted to a nominal 20
F (10 C)
differential. The boiler is designed to withstand thermal stresses with supply and
return temperature differences up to 100
F (55 C), without the use of a boiler-
circulating pump, blend pump or minimum water flow.
Note: The Clearfire does not require a minimum flow or continuous flow through it during operation.
However, the load imposed on the boiler must be considered when sizing the system flow so that
the flow does not exceed the capacity of the boiler or the demand.
To maintain rated capacity of the boiler, recommended flow rates should not be
exceeded as the flow will remove the heat beyond the capacity of the boiler. Table
B5-12throughTable B5-13 can be used to determine the full boiler output relative
to system temperature drop and the maximum recommended system pump flow.
Knowing the flow rate, the pressure drop through the boiler can be found in Figure
B5-14through Figure B5-19.
To prevent water flashing to steam within the boiler or system, hot water boilers
must operate with proper over-pressure. System over-pressure requirements are
shown in Table B5-14.
Note: The ASME Code Section IV limits the maximum setting of the excess temperature control to
210 F (98.9 C) for boilers constructed with stainless steel. This is to ensure that water
temperature will not reach the boiling point (steaming) and therefore, so as not to exceed the
maximum limit of this control and in compliance with the Code, the operating limit of 195 F
20Rev. 05-2012
Model CFCClearFire Commercial Boilers
(90.5 C) is set for normal boiler operation.
While proper overpressure is required, a means to relieve excess pressure at or
beyond the design pressure of the boiler must be provided. As boiler water is
heated, expansion occurs. And this expansion must be accounted for either with an
expansion tank (air filled) or with a bladder type tank. These devices permit the
water pressure to expand outside of the boiler and not impact the pressure vessel or
pressure relieving device. But, in accordance with Code, each boiler is equipped
with an ASME approved safety relieving device should pressure build-up occur (See
Table B5-16 and Table B5-15).
Air VentingThe elimination of entrained air is required. It is recommended that each unit be
piped to an expansion tank. If this is not possible, then an auto air vent should be
provided on the vent connection of the boiler. The caveat in using an auto vent is
that free oxygen can be introduced to the vesel as the boiler cools, or in some
instances the vent can become plugged.
Table B5-12. CFC Flow Rates
System Temperature Drop 0 F
102030405060708090100110120
Boiler
Size
500954833241916121110.5987
7501316644332622191615131211
10001768859443529252220181615
150026013087655243373329262423
1800351176117887059504439353230
25004702351571189579675952484339
3300620310207155124103897869625652
Flow rate as a function of Delta T at 94% efficiency and maximum firing capacity
Flow rate as a function of Delta T at 94% efficiency and maximum firing capacity
Figure B5-15. Pressure Drop Curve ClearFire Boiler Size 500
22Rev. 05-2012
Model CFCClearFire Commercial Boilers
Figure B5-16. Pressure Drop Curve ClearFire Boiler Size 750
Figure B5-17. Pressure Drop Curve ClearFire Boiler Size 1000
23Rev. 05-2012
Model CFCClearFire Commercial Boilers
Figure B5-18. Pressure Drop Curve ClearFire Boiler Size 1500
Figure B5-19. Pressure Drop Curve ClearFire Boiler Size 1800
24Rev. 05-2012
Model CFCClearFire Commercial Boilers
Figure B5-20. Pressure Drop Curve ClearFire Boiler Size 2500\
Figure B5-21. Pressure Drop Curve ClearFire Boiler Size 3300
25Rev. 05-2012
Model CFCClearFire Commercial Boilers
Table B5-14. Model CFC Minimum Over Pressure Requirements
Outlet Water Temperature 0 F (C)
80 - 180 (27 - 82)12 (0.83)
181 - 185 (83 - 85)15 (1.03)
186 - 195 (86 - 91)18 (1.24)
Table B5-15. Model CFC Boiler Safety Valve Information @ 125 PSIG
Boiler Size
5003/4”11”3364
7503/4”11”3364
10003/4”11”3364
Valve Connection
@ Boiler
No. Valves Req'dOutlet Size
Minimum System Pressure PSIG (Bar)
Valve Setting 125 psig
Relie Valve
Capacity (MBH)
15003/4”11”3364
18003/4”11”3364
25003/4”11”3364
33003/4”11”3364
Table B5-16. Model CFC Boiler Safety Valve Information @ 60 PSIG
Boiler Size
5003/4"11"1784
7503/4"11"1784
10003/4"11"1784
15003/4"11"1784
18001"11-1/4"2788
Valve Connection
@ Boiler
Valve Setting 60 psig
No. Valves Req'dOutlet Size
Relief Valve
Capacity (MBH)
25001"11-1/4"2788
33001-1/2”12”5913
26Rev. 05-2012
Model CFCClearFire Commercial Boilers
Water TreatmentEven though hot water systems are "closed", some amount of make-up water (up to
10%) will be introduced. This more often than not happens from seal leaks of
pumps, or other minimal leaks from valves etc., that go unnoticed. Therefore,
proper water chemistry of a hot water boiler is necessary for good operation and
longevity, particularly to ensure that free oxygen is removed to prevent waterside
corrosion (see Table B5-17).
Table B5-17. Model CFC Water Chemistry Requirements in accordance with ABMA
ParameterLimit
Glycol50%
pH8.3 - 9.5
Nitrates50 mg/liter
Sulphates50 mg/liter
Chloride30 mg/liter
Oxygen0.1 mg/liter
Specific Conductivity
Total Hardness<10 ppm
3500 mmho/cm
GlycolThe Model CFC boiler may be operated with a solution of glycol and water. Where
glycols are added, the system must first be cleaned and flushed. Correct glycol
selection and regular monitoring of the in-use concentration and its stability is
essential to ensure adequate, long-term freeze protection, as well as protection
from the effects of glycol-derived corrosion resulting from glycol degradation.
Typically, ethylene glycol is used for freeze protection, but other alternatives exist,
such as propylene glycol. Glycol reduces the water-side heat capacity (lower
specific heat than 100% water) and can reduce the effective heat transfer to the
system. Because of this, design flow rates and pump selections should be sized
with this in mind.
Generally, corrosion inhibitors are added to glycol systems. However, all glycols
tend to oxidize over time in the presence of oxygen, and when heated, form
aldehydes, acids, and other oxidation products. Whenever inadequate levels of
water treatment buffers and corrosion inhibitors are used, the resulting water glycol
mixture pH may be reduced to below 7.0 (frequently reaching 5) and acid corrosion
results. Thus, when pH levels drop below 7.0 due to glycol degradation the only
alternative is to drain, flush, repassivate, and refill with a new inhibited glycol
solution.
The following recommendations should be adhered to in applying ClearFire model
CFC boilers to hydronic systems using glycol:
1) Maximum allowable antifreeze proportion (volume %):
50% antifreeze (glycol)
50% water
27Rev. 05-2012
Model CFCClearFire Commercial Boilers
2) The glycol concentration determines the maximum allowable firing rate and output
of the boiler(s). Please refer to the firing rate limitation and corresponding high fire
speed settings vs. glycol % in the charts below.
3) Maximum allowable boiler outlet/supply temperature: 185 deg F (85 deg C).
4) Minimum water circulation through the boiler:
a) The minimum water circulation must be defined in such a way that the
temperature difference between the boiler outlet/supply and inlet/return is a
maximum of 40 deg F (22 deg C), defined as DT (Delta T). A DT Limit
algorithm should be enabled in the boiler controller.
b) Independent from the hydraulics of the heating system, constant water
circulation through each boiler is required. (Requires a dedicated boiler
pump if in a primary/secondary loop arrangement.) Refer to table below for
minimum boiler circulation rates.
5) Minimum over-pressure at the boiler:
For outlet temperatures up to the maximum of 185 deg F (85 deg C), a minimum
operating pressure of 30 psig (2.1 bar) is required.
6) pH level should be maintained between 8.3 and 9.5
Table B5-18. Glycol Application Guidelnes - Model CFC
Minimum required boiler circulation rate (gpm) at maximum firing rate.
1. Maximum firing rate determined by ClearFire CFC - Glycol Firing Rate Limitation chart (below).
Maximum high fire blower speed should be set according to chart.
2. Glycol concentration limit of 25%-50%. Minimum required system operating pressure is 30
psig.
3. Maximum system operating temperature of 180 ˚F. Maximum ΔT of 40˚.
4. Circulation rates correlate with boiler output based on 92% nominal efficiency.
5. Standard altitude (<1000' ASL). Contact C-B for high altitude applications.
6. Pumps should be sized based on system design ΔT and minimum required flow rates.
7. At minimum firing rate, the minimum circulation rate should correspond to the boiler's turndown.
28Rev. 05-2012
Model CFCClearFire Commercial Boilers
Table B5-19. Max Firing Rate vs. Glycol Concentration
Table B5-20. HF Speed Settings vs. Glycol Content
Condensation
As the Model CFC boiler is a full condensing boiler, condensation will develop during
startup of a cold boiler or at any time when the return water temperature is below
the dew point or approximately 132
The condensation collects in the lower portion of the boiler from the tube surfaces
and from the stack, and must be discharged to a drain. A Condensate trap must be
piped on the boiler and must be field piped to either a drain or to the optional
condensate treatment kit. Table B5-21 provides the amount of condensation that
will form when the boiler operates in the full condensing mode.
F (55.5 C).
29Rev. 05-2012
Model CFCClearFire Commercial Boilers
Table B5-21. Model CFC Maximum Condensation
Boiler Size
5003.5 (13.2)
7505 (18.9)
10007 (26.5)
15009 (34)
180012 (45.4)
250017 (64.4)
330022 (83.3)
Boiler Operating @ maximum in full condensing mode.
Gallons Per Hour - GPH
(Liters Per Hour - L/H)
As prescribed by local codes, this condensate may be discharged directly to the
drain or treated using an optional treatment assembly. Figure B5-21depicts piping
without the treatment assembly and Figure B5-22 shows the optional treatment
assembly.
Condensate Piping for Multiple Boilers
The number of condensate treatment tanks
required for multiple boiler installations depends
on the total amount of condensate produced by
the system. As a general rule, CB recommends
one tank per 5 million BTU/hr of boiler capacity
(5.0 MMBTU/hr). Model CFC capacities are in
Table B5-22.
See Figure B5-23 and Figure B5-24 for suggested
piping. A drain trap is built into the condensate
tank. Make-up water must be supplied at the
connection shown in order to prevent flue gas from
entering an idle boiler. An internal float in the condensate tank activates the makeup water valve.
If a treatment kit is utilized, clearance at the front of the boiler must be provided for
servicing the assembly and for periodically adding the neutralizing granules.
Drain trap
Float valve for makeup water
Notice
Neutralization tank
To drain
Neutralization media
1/4" O.D. Make-up Water Supply
Figure B5-24. Condensate Piping for Multiple Boilers
Condensate Drain Trap
Neutralization Tank
To Drain
31Rev. 05-2012
Model CFCClearFire Commercial Boilers
1" NPT Minimum Header Size
(Use PVC Pipe or other Nonferrous Material)
Condensate Drain Trap
Neutralization Tank
Neutralization Media
12” Minimum
Figure B5-25. Condensate Treatment Tank for Multiple Boilers
Cond. tank can be
mounted under boiler
To Drain
Gas Fuel
Connections
The local Gas Company should be consulted for the requirements for installation
and inspection of gas supply piping. Installation of gas supply piping and venting
must be in accordance with all applicable engineering guidelines and regulatory
codes. All connections made to the boiler must be arranged so that all components
are accessible for inspection, cleaning, and maintenance.
A drip leg should be installed in the supply line before the connection to the boiler.
The drip leg should be at least as large as the gas piping connection on the boiler.
SeeFigure B5-25, and Figure B5-26 for piping suggestions.
32Rev. 05-2012
Model CFCClearFire Commercial Boilers
As required
As required
Same or larger than boiler gas connection
size
Drip leg required for any vertical run of
piping
Figure B5-26. Gas Piping Schematic
Gas header - size for boiler room
capacity and to minimize pressure loss
Consideration of volume and pressure requirements must be given when selecting
gas supply piping.
Connections to the burner gas train must include a union so that the burner may be
opened for inspection and maintenance.
A. Gas supply connection is at the rear of the boiler near the top. To permit
burner opening, gas piping must not traverse the top of the boiler.
B. Table B5-23shows the gas pressure required at the inlet of the gas line.
Note: a pressure regulator is not furnished and if gas pressure exceeds 14"
W.C. a pressure regulator is recommended.
C. Table B5-24 shows the correction factors for gas pressure at elevations at
2000 feet and higher above sea level.
33Rev. 05-2012
Model CFCClearFire Commercial Boilers
From
Meter
Header Pipe
Manual Shut Off
Gas Strainer
Regulator
See Note 1
Relief Valve
See Note 5
Model
CFC
Gas Header Piping, Typical
Model
CFC
Model
CFC
NOTES:
1. Dedicated gas pressure regulator required for each boiler.
2. Refer to local fuel gas codes when applicable.
3. Header to be sized for room capacity.
4. Provision required for measuring gas supply pressure at boiler.
5. Relief valve required if gas supply pressure >1 psig.
Figure B5-27. Gas Header Piping
Model
CFC
34Rev. 05-2012
Model CFCClearFire Commercial Boilers
Table B5-24. Model CFC Minimum and Maximum Gas Pressure
Minimum pressure required at gas train connection
Boiler Model
5007" w.c.11" w.c.
7507" w.c.11" w.c.
10007" w.c.11" w.c.
150010" w.c.11" w.c.
18007" w.c.11" w.c.
25009.5" w.c.11" w.c.
33006.8" w.c.11" w.c.5 psi
Table B5-25. Model CFC Minimum Required Gas Pressure Altitude Correction
Altitude in FeetCorrection FactorAltitude in FeetCorrection Factor
10001.0460001.25
20001.0770001.3
Max. pressureNatural GasLP Gas
28” w.c.
30001.1180001.35
40001.1690001.4
50001.21
To obtain minimum required inlet pressure, select altitude of installation and multiply the pressure
shown in Table B5-24 by the correction factor corresponding to the altitude listed above.
Boiler Room
Information
The boiler must be installed on a level non-combustible surface. If the surface is not
level, piers or a raised pad, slightly larger than the length and width of the boiler
base dimensions, will make boiler leveling possible. Installing the boiler on a raised
pad or piers will make boiler drain connections more accessible and will keep water
from splashing onto the boiler whenever the boiler room floor is washed.
Note: The pad or piers must be of sufficient load bearing strength to safely support the operating
weight of the boiler and any additional equipment installed with it. Approximate operating
weights are shown in Dimensions and Ratings.
Leveling Once the boiler is placed, it must be leveled side to side and front to back using the
supply and return nozzles for horizontal and vertical positions. If shims are required
to level the boiler, the weight of the boiler must be evenly distributed at all points of
support. The legs may also be used for leveling.
ClearancesThe boiler must be installed so that all components remain accessible; ensure no
overhead obstructions so the burner may be opened. Refer to Figure B5-28.
35Rev. 05-2012
Model CFCClearFire Commercial Boilers
DIMInches
Top ClearanceA14
Side ClearanceB20
BackwayC20
FrontD36
Between Boilers E3
C
B
D
B
E
CFC 500-2500CFC 3300
Figure B5-28. Model CFC Minimum Room Clearance Dimensions
Seismic LegsSeismic mounting details shown below.
Figure B5-29. CFC Seismic Mounting
36Rev. 05-2012
Model CFCClearFire Commercial Boilers
Hot Water PipingPrimary/secondary pumps are not necessary with the Model CFC boiler. As its
design is such that no minimum flow is required, variable speed or on/off pumps
may be employed in the piping scheme.
Typical piping arrangements are shown in figures B5-33 through B5-45.
Note: These diagrams are generic and are not intended for use in a specific design without
consultation with your local Cleaver-Brooks sales representative
37Rev. 05-2012
Figure B5-33. No primary Loop with Domestic Water and 2-Way Divert Valve
ClearFire Full
Condensing
ClearFire Full
Condensing
To Condensate Drain
To Sanitary Drain
System Returns
Domestic Cold
Water In
Domestic
Water
Domestic
Water Pump
Return Header
Boiler Drain
Domestic
Water Supply
Heating System
Pumps
System Supply & Returns
System Supply
Header
Expansion
Tank
Water
Makeup
2-Way Diverting
Valve
On/Off Valve
Figure B5-36. Two Boilers and Three Variable Temperature Zones (No Primary Loop)
ClearFire
ClearFire
PP
TT
BV1 B1
TT
BV1 B1
TT
BV1 B1
CWS
Filling Loop
Removable
Tank
Expansion
Return
Return
Run condensate drain to
adjacent drain (or via optional
condensate pumping unit)
Drain
Flow
Prefabricated
Header
Back Pressure
Radiant
Heating Load
Valve
Figure B5-37. Two-Pipe Primary/Secondary Piping with Domestic Hot Water
Boiler
Heating Load
A
Heating Load
B
Heating Load
C
1
BOILER OUTLET (SUPPLY)
2
BOILER INLET (RETURN)
3
SECONDARY CONNECTION
4
ISOLATION VALVES
5
PURGE COCKS
6
AIR SEPARATOR WITH AUTOMATIC AIR VENT
7
DIAPHRAGM EXPANSION TANK WITH FILL VALVE
8
BALANCING VALVES (SQUARE HEAD COCKS)
9
SYSTEM CIRCULATOR
10
SECONDARY CIRCULATORS INJECTION PUMP
11
FLOW/CHECK VALVES (TO PREVENT GRAVITY
10
11
8
10
5
8
8
3
5
10
3
11
10
5
8
3
5
1
2
6
9
4
7
(FIXED OR VARIABLE SPEED)
OR PRESSURE-DROP-INDUCED FLOW IN
SECONDAY CIRCUITS)
12" MAX APART AT ALL SECONDARY CONNECTIONS
TO PREVENT FORCED FLOW IN SECONDARY
CAUSED BY PRESSURE DROP THROUGH PIPING
BETWEEN CONNECTIONS
TEMPERATURE CONTROL BY SECONDARY
CIRCULATION ONLY
TEMPERATURE CONTROL USING MIXING
VALVE
TEMPERATURE/HEAT INPUT CONTROL
USING INJECTION PUMPING
A
B
C
13
12
12
DOMESTIC PUMP
13
DOMESTIC WATER TANK
4
Figure B5-38. Two-Pipe Primary/Secondary Piping
Boiler
Heating Load
A
Heating Load
B
Heating Load
C
1
BOILER OUTLET (SUPPLY)
2
BOILER INLET (RETURN)
3
SECONDARY CONNECTION
4
ISOLATION VALVES
5
PURGE COCKS
6
AIR SEPARATOR WITH AUTOMATIC AIR VENT
7
DIAPHRAGM EXPANSION TANK WITH FILL VALVE
8
BALANCING VALVES (SQUARE HEAD COCKS)
9
SYSTEM CIRCULATOR
10
SECONDARY CIRCULATORS INJECTION PUMP
11
FLOW/CHECK VALVES (TO PREVENT GRAVITY
10
11
8
10
5
8
8
3
5
10
3
11
10
5
8
3
5
1
2
6
9
4
7
(FIXED OR VARIABLE SPEED)
OR PRESSURE-DROP-INDUCED FLOW IN
SECONDAY CIRCUITS)
4
12" MAX APART AT ALL SECONDARY CONNECTIONS
TO PREVENT FORCED FLOW IN SECONDARY
CAUSED BY PRESSURE DROP THROUGH PIPING
BETWEEN CONNECTIONS
TEMPERATURE CONTROL BY SECONDARY
CIRCULATION ONLY
TEMPERATURE CONTROL USING MIXING
VALVE
TEMPERATURE/HEAT INPUT CONTROL
USING INJECTION PUMPING
A
B
C
4
Figure B5-39. No Primary Loop
ClearFire Full
Condensing
ClearFire Full
Condensing
To Condensate Drain
To Sanitary Drain
System Returns
Return Header
Boiler Drain
Heating System
Pumps
System Supply & Returns
System Supply
Header
Expansion
Tank
Water
Makeup
Y10.2
Y10.1
VK-1
VK-2
Y10.1 Motorized Shutoff
Y10.2 Motorized Shutoff
VK-1 3-Way Mixed Circuit
VK-2 3-Way Mixed Circuit
Back Pressue
Valve
Figure B5-40. Domestic Water Heating, No Primary Loop
ClearFire Full
Condensing
ClearFire Full
Condensing
To Condensate Drain
To Sanitary Drain
System Returns
Boiler Drain
Expansion
Tank
Water
Makeup
Air Vent Line
Primary
Pump
Standby
Pump
Surge Tank
Figure B5-41. Domestic Water with On/Off and 3-Way Valves
ClearFire Full
Condensing
ClearFire Full
Condensing
To Condensate Drain
To Sanitary Drain
System Returns
Domestic Co
l
Water In
Domestic
Water
Domestic
Water Pump
Return Header
Boiler Drain
Domestic
Water Supply
Heating System
Pumps
System Supply & Returns
System Supply
Header
Expansion
Tank
Water
Makeup
On-Off
Valves
Figure B5-42. Piping ‘Hybrid’ Boilers
CFC
1
BOILER OUTLET (SUPPLY)
2
BOILER INLET (RETURN)
3
ISOLATION VALVES
4
PURGE COCKS
5
AIR SEPARATOR WITH AUTOMATIC AIR VENT
6
DIAPHRAGM EXPANSION TANK WITH FILL VALVE
7
FLOW/CHECK VALVES
8
SYSTEM CIRCULATOR
3
4
5
8
6
SupplyRetur
n
FLX
2
3
1
7
3
130 F
150 F
Sensor
3
3
3
3
3
3
7
Figure B5-43. ‘Hybrid’ Boilers with Domestic Water
CFC
1
BOILER OUTLET (SUPPLY)
2
BOILER INLET (RETURN)
3
SECONDARY CONNECTION
4
ISOLATION VALVES
5
PURGE COCKS
6
AIR SEPARATOR WITH AUTOMATIC AIR VENT
7
DIAPHRAGM EXPANSION TANK WITH FILL VALVE
8
FLOW/CHECK VALVES
9
SYSTEM CIRCULATOR
5
6
9
7
3
12" MAX APART AT ALL SECONDARY CONNECTIONS
TO PREVENT FORCED FLOW IN SECONDARY
CAUSED BY PRESSURE DROP THROUGH PIPING
Figure B5-44. Domestic Water with 2 Boilers and 2 Coils
To
Boilers
RTD
120V or
24V
Control
Two Stage
Cold In
Recirc Pump
Drain
Tank
Thermal Expansion
Hot Out
Thermometer
Pipe To
Safe Location
Top Relief
Pipe Per Code
Cold In
Air Purger with Vent, PRV
and Expansion Tank
Reducers
Auto Air Vent
It High Point
(Reverse Return For
Balanced Flow)
Boiler 2
Boiler 1
Circulators
Tube Bundles Can Be
In Any Location Exc
e
On Top Of Each Oth
e
Supply
Supply
Return
Heating Domestic Water with (2) Boilers and (2) Coils
Return
Model CFCClearFire Commercial Boilers
Boiler Room
Combustion and
Ventilation Air
Combustion Air
Supply - Unconfined
Spaces (For U.S.
Installations Only)
The boiler(s) must be supplied with adequate quantities of uncontaminated air to
support proper combustion and equipment ventilation. Air shall be free of chlorides,
halogens, fluorocarbons, construction dust or other contaminants that are
detrimental to the burner/boiler. If these contaminants are present, we recommend
the use of direct vent combustion provided the outside air source is
uncontaminated.
Combustion air can be supplied by means of conventional venting, where
combustion air is drawn from the area immediately surrounding the boiler (boiler
room must be positive pressure), or with direct vent (direct vent combustion) where
air is drawn directly from the outside. All installations must comply with local Codes
and with NFPA 54 (the National Fuel Gas Code - NFGC) for the U.S. and for
Canada, CAN/CGA B 149.1 and B 149.2.
Note: A boiler room exhaust fan is not recommended as this type of device can cause a negative
pressure in the boiler room if using a conventional air intake.
In accordance with NFPA54, the required volume of indoor air shall be determined
in accordance with the "Standard Method" or "Known Air Infiltration Rate Method.
Where the air infiltration rate is known to be less than 0.40 Air Changes per Hour,
the Known Air Infiltration Rate Method shall be used. (See Section 8.3 in the
NFPA54 Handbook for additional information.)
A. All Air From Inside the Building - If additional combustion air is drawn from
inside the building (the mechanical equipment room does not receive air
from outside via louvers or vent openings and the boiler is not equipped with
direct vent combustion) and the boiler is located in a unconfined space, use
the following guidelines:
1. The mechanical equipment room must be provided with two permanent
openings linked directly with additional room (s) of sufficient volume so
that the combined volume of all spaces meet the criteria for an
unconfined space. Note: An "unconfined space" is defined as a space
whose volume is more than 50 cubic feet per 1,000 Btu per hour of
aggregate input rating of all appliances installed in that space.
2. Each opening must have a minimum free area of one square inch per
1,000 Btu per hour of the total input rating of all gas utilizing equipment
in the mechanical room.
3. One opening must terminate within twelve inches of the top, and one
opening must terminate within twelve inches of the bottom of the room.
4. Refer to the NFGC, Section 8.3 for additional information.
50Rev. 05-2012
Model CFCClearFire Commercial Boilers
GAS
VENT
CLEARFIRE
BOILER
GAS
VENT
WATER
HEATER
Figure B5-45. Two Opening Outside Wall Method
12" MINIMUM
FRESH AIR OPENING
INTERIOR WALL
FRESH AIR OPENING
12" MINIMUM
B. All Air From Outdoors - If all combustion air will be received from outside the building (the mechanical
room equipment is linked with the outdoors), the following methods can be used:
1. Two Opening Method (Figure B5-45) - The mechanical equipment room
must be provided with two permanent openings, one terminating within
twelve inches from the top, and one opening terminating within twelve
inches of the bottom of the room.
2. The openings must be linked directly or by ducts with the outdoors.
3. Each opening must have a minimum free area of one square inch per
4,000 Btu per hour of total input rating of all equipment in the room,
when the opening is directly linked to the outdoors or through vertical
ducts.
4. The minimum free area required for horizontal ducts is one square inch
per 2,000 Btu per hour of total input rating of all the equipment in the
room.
51Rev. 05-2012
Model CFCClearFire Commercial Boilers
GAS
VENT
GAS
VENT
CLEARFIRE
BOILER
WATER
HEATER
Figure B5-46. Two Opening Ducted Method
12" MINIMUM
OUTLET AIR DUCT
INTERIOR WALL
EXTERIOR WALL
FRESH AIR
INLET DUCT
12" MINIMUM
C. One Opening Method (Figure B5-47) - One permanent opening,
commencing within 12 inches of the top of the enclosure, shall be provided.
1. The equipment shall have clearances of at least 1 inch from the sides and
back and 6 inches from the front of the appliance.
2. The opening shall directly communicate with the outdoors and shall have
a minimum free area of 1 square inch per 3000 BTU's per hour of the
total input rating of all equipment located in the enclosure, and not less
than the sum of the areas of all vent connectors in the confined space.
3. Refer to the NFGC, Section 8.3 for additional information.
52Rev. 05-2012
Model CFCClearFire Commercial Boilers
GAS
VENT
CLEARFIRE
BOILER
GAS
VENT
12" MINIMUM
FRESH AIR OPENING
EXTERIOR WALL
WATER
HEATER
Unconfined Space/
Engineered Design
Figure B5-47. One Opening Method
When determining boiler room air requirements for unconfined space, the size of the
room, airflow, and velocity of air must be reviewed as follows:
1. Size (area) and location of air supply openings in the boiler room.
A. Two permanent air supply openings in the outer walls of the boiler room are
recommended. Locate one at each end of the boiler room, preferably below
a height of 7 feet. This allows air to sweep the length of the boiler. See
Figure B5-48.
B. Air supply openings can be louvered for weather protection, but they should
not be covered with fine mesh wire, as this type of covering has poor air flow
qualities and is subject to clogging with dirt and dust.
C. A vent fan in the boiler room is not recommended, as it could create a slight
vacuum under certain conditions and cause variations in the quantity of
combustion air. This can result in unsafe burner performance.
D. Under no condition should the total area of the air supply openings be less
than one square foot.
53Rev. 05-2012
Model CFCClearFire Commercial Boilers
FRESH AIR OPENING
EXTERIOR WALL
GAS
VENT
CLEARFIRE
BOILER
GAS
VENT
WATER
HEATER
FRESH AIR OPENING
EXTERIOR WALL
Figure B5-48. Two Opening Engineered Method
E. Size the openings by using the formula:
Area in square feet = cfm/fpm
Where cfm = cubic feet per minute of air
Where fpm = feet per minute of air
2. Amount of Air Required (cfm).
A. Combustion Air = 0.25 cfm per kBtuh.
B. Ventilation Air = 0.05 cfm per kBtuh.
C. Total air = 0.3 cfm per kBtuh (up to 1000 feet elevation. Add 3% more per
1000 feet of added elevation).
3. Acceptable air velocity in the Boiler Room (fpm).
A. From floor to 7 feet high = 250 fpm.
B. Above 7 feet above floor = 500 fpm.
Example: Determine the area of the boiler room air supply openings for (2) Clearfire
1800 boilers at 750 feet elevation. The air openings to be 5 feet above floor level.
•Air required: 1800 x 2 = 3600 kBtuh. From 2C above, 3600 x 0.3 =
1,080 cfm.
•Air Velocity: Up to 7 feet = 250 fpm from 3 above.
Consult local codes, which may supersede these requirements.
Direct Vent
Combustion
If combustion air will be drawn directly from the outside by means of a duct
connected to the burner air intake, use the following as a guide:
1. Install combustion air vent (direct vent combustion) in accordance with the
boiler's Operating and Maintenance manual.
2. Provide for adequate ventilation of the boiler room or mechanical equipment
room.
3. In cold climates, and to mitigate potential freeze-up of the intake pipe, it is
highly recommended that a motorized sealed damper be used to prevent the
circulation of cold air through the boiler during non-operating hours.
4. Figure B5-49 shows the optional direct vent combustion kit providing easy
adaptation of the contractor supplied air duct to boiler connection. Refer to Table
B5-26 for sizing the direct vent combustion air pipe.
FAN/BLOWER
VENTURI
AIR SUPPLY LINE
Figure B5-49. Optional Direct Vent Combustion Kit
STACK/BREECHING SIZE CRITERIA
GeneralBoilers are divided into four categories based on the pressure and temperature
produced in the exhaust stack and the likelihood of condensate production in the
vent.
• Category I. A boiler which operates with a non-positive vent static pressure and
with a vent gas temperature that avoids excessive condensate production in the
vent.
• Category II. A boiler which operates with a non-positive vent static pressure and
with a vent gas temperature that may cause excessive condensate production in
the vent.
• Category III. A boiler which operates with a positive vent pressure and with a vent
gas temperature that avoids excessive condensate production in the vent.
• Category IV. A boiler which operates with a positive vent pressure and with a vent
gas temperature that may cause excessive condensate production in the vent.
Depending on the application, the Model CFC may be considered Category II, III,
or IV. The specifying engineer should dictate flue venting as appropriate to the
installation.
In some cases, PVC/CPVC material meeting ULC Type BH Class IIB specifications
may be used. Use of PVC/CPVC depends on operating conditions, specific vent
55Rev. 05-2012
Model CFCClearFire Commercial Boilers
suppliers, and any local codes having jurisdiction. Refer to vent manufacturer’s
specifications for applicability.
Proper installation of flue gas exhaust venting is critical to efficient and safe
operation of the Clearfire Boiler. The vent should be supported to maintain proper
clearances from combustible materials. Use insulated vent pipe spacers where the
vent passes through combustible roofs and walls.
The design of the stack and breeching must provide the required draft at each boiler
flue gas connection; proper draft is critical to burner performance.
Although constant pressure at the flue gas outlet is not required, it is necessary to
size the breeching and stack to limit flue gas pressure variation. Consideration of
the draft must be given whenever direct vent combustion is utilized and lengthy runs
of breeching are employed. Please note: The allowable pressure range for design of
the stack, breeching and if used, direct vent combustion pipe, is negative 0.25"
W.C. (- 62 Pa) to positive 0.25" W.C. (+62 Pa) for proper combustion and light offs.
Whenever two or more boilers are connected to a common breeching/stack, a draft
control system may be required to ensure proper draft.
Vent TerminationTo avoid the possibility of property damage or personal injury, special attention to
the location of the vent termination must be considered.
1. Combustion gases can form a white vapor plume in the winter. The plume could
obstruct a window view if the termination is installed in close proximity to
windows.
2. Prevailing winds could cause freezing of Condensate and water/ice buildup on
building, plants, or roof.
3. The bottom of the vent termination and the air intake shall be located at least
12 inches above grade, including the normal snow line.
4. Non-insulated single-wall metal vent pipe shall not be used outside in cold
climates for venting combustion gases.
5. Through the wall vents for Category II and Category IV appliances shall not
terminate over public walkways or over an area where Condensate or vapor
could create a nuisance or hazard or could be detrimental to the operation of
other equipment.
6. To prevent accidental contact by people or pets, the vent termination shall be
guarded.
7. DO NOT terminate vent in window well, alcove, stairwell or other recessed area,
unless approved by local authority.
8. DO NOT terminate above any door, window, or gravity air intake as Condensate
can freeze causing ice formation.
9. Locate or guard vent to prevent Condensate from damaging exterior finishes.
Use a 2' x 2' rust resistant sheet metal backing plate against brick or masonry
surfaces.
10. Multiple direct stack installations require four feet clearance between the stack
caps, center to center.
U.S. Installations Refer to the latest edition of the National Fuel Gas Code/NFPA 54. Vent
termination requirements are:
1. Vent must terminate at least four feet below and four feet horizontally or one foot
above any door, window or gravity air inlet to the building.
56Rev. 05-2012
Model CFCClearFire Commercial Boilers
2. The vent must be at least seven feet above grade when located adjacent to
public walkways.
3. Terminate vent at least three feet above any forced air inlet located within ten
feet.
4. Vent must terminate at least four feet horizontally, and in no case above or below
unless four feet horizontal distance is maintained, from electric meters, gas
meters, regulators, and relief equipment.
5. Terminate vent at least six feet from adjacent walls.
6. DO NOT terminate vent closer than five feet below roof overhang.
Canadian
Installations
Refer to the latest edition of CAN/CSA-B149.1 and B149.2. Vent shall not
terminate:
1. Directly above a paved sidewalk or driveway which is located between two
single-family dwellings and serves both dwellings.
2. Less than 7 feet (2.31m) above a paved sidewalk or paved driveway located on
public property.
3. Within 6 feet (1.8m) of a mechanical air supply inlet to any building.
4. Above a meter/regulator assembly with 3 feet (900mm) horizontally of the
vertical centerline of the regulator.
5. Within 6 feet (1.8m) of any gas service regulator vent outlet.
6. Less than 1 foot (300mm) above grade level.
7. Within 3 feet (1m) of a window or door which can be opened in any building,
any non-mechanical air supply inlet to any building or to the combustion air inlet
of any other appliance.
8. Underneath a Verandah, porch, or deck unless:
A. The Verandah, porch, or deck is fully open on a minimum of two sides
beneath the floor.
B. The distance between the top of the vent termination and the underside of
the Verandah, porch, or deck is greater than one foot (300mm).
Horizontal Through
the Wall Venting
Venting configurations using inside air for combustion (See Figure B5-50)
These installations utilize the boiler-mounted blower to vent the combustion
products to the outside. Combustion air is obtained from inside the room and the
exhaust vent is installed horizontally through the wall to the exterior of the building.
Adequate combustion and ventilation air must be supplied to the boiler room in
accordance with the NFGC/NFPA 54 for the U.S. and in Canada, the latest edition
of CAN/CSA-B149.1 and.2 Installation Code for Gas Burning Appliances and
Equipment.
57Rev. 05-2012
Model CFCClearFire Commercial Boilers
Inside Air
Combustion
Intake
Flue Gas Vent
(w/Screen)
12" Minimum + any
Snow Load
Figure B5-50. Horizontal Through the wall venting using inside air for combustion
The vent must be installed to prevent the potential accumulation of stack
condensate in the horizontal run of vent pipe. Therefore, it is recommended that:
1. The vent shall be installed with a slight downward slope of not more than 1/4"
per foot of horizontal run to the vent termination.
2. The vent must be insulated through the length of the horizontal run.
Horizontal Through
the Wall Stack
Venting
Note: For installations in cold/freezing climates, it is recommended that:
1. The vent shall be installed with a slight upward slope of not more than 1/4" per
foot of horizontal run to the vent termination. In this case, an approved
Condensate trap must be installed per applicable codes.
2. The vent must be insulated through the length of horizontal run.
The stack vent cap MUST be mounted on the exterior of the building. The stack vent
cap cannot be installed in a well or below grade. The stack vent cap must be
installed at least two feet above ground level and above normal snow levels.
Notice
The stainless steel direct vent cap must be furnished in accordance with AGA/CGA
requirements.
Refer to Table B5-25 for the recommended sizes of horizontal vent pipe.
Direct Vent Combustion. See Figure B5-51.
58Rev. 05-2012
Model CFCClearFire Commercial Boilers
Flue Gas Vent (w/Screen)
18" Minimum
24" Minimum
Air Intake (w/Screen)
24" Minimum
Figure B5-51. Horizontal Flue through-wall with direct vent combustion intake
These installations utilize the boiler-mounted blower to take combustion air from the
outside and vent combustion by-products to the outside.
The direct vent combustion air vent cap is not considered in the overall length of the
venting system.
The stack vent must be installed to prevent the potential accumulation of
Condensate in the stack pipes. It is recommended that:
1. The vent shall be installed with a slight downward slope of not more than 1/4"
per foot of horizontal run to the stack termination.
2. The stack vent is to be insulated through the length of the horizontal run.
Note: For installations in freezing climates, it is recommended that:
1. The stack vent shall be installed with a slight upward slope of not more than 1/
4" per foot of horizontal run to the vent termination. In this case, an approved
Condensate trap must be installed per applicable codes.
2. The stack vent is to be insulated through the length of the horizontal run.
Note: For Horizontal Stack Vent Termination:
1. The stack vent cap must be mounted on the exterior of the building. The stack
vent cap cannot be installed in a well or below grade. The stack vent cap must
be installed at least one foot above ground level and above normal snow levels.
2. Multiple stack vent caps should be installed in the same horizontal plane with
three feet clearance from side of one stack cap to the side of the adjacent vent
cap.
59Rev. 05-2012
Model CFCClearFire Commercial Boilers
3. Combustion air supplied from the outside must be free of particulate and
chemical contaminants. To avoid a blocked flue condition, keep all the vent caps
clear of snow, ice, leaves, debris, etc.
Note: Multiple direct stack vent caps must not be installed with one combustion air inlet directly above
a stack vent cap. This vertical spacing would allow the flue products from the stack vent to be
pulled into the combustion air intake installed above. This type of installation can cause nonwarrantable problems with components and poor operation of the unit due to the recirculation of
flue products.
Table B5-25. STACK DESIGN (SINGLE BOILER) USING ROOM AIR
ROOM COMBUSTION AIR -- MAXIMUM ALLOWABLE VENTING LENGTH
Boiler
CFC 5006" Standard6"80039-01704
CFC 7506" Standard6"60039-01704
CFC10006" Option6"80039-01646250880-01858
CFC10008" Standard8"140039-01647
CFC100010" Option10"200039-01705250880-01858
CFC15008" Option8"60039-01645375880-02005
CFC150010" Standard10"80039-01644
CFC150012" Option12"120039-01688375880-02005
CFC180010" Option10"60039-01644450880-02005
CFC180012" Standard12"100039-01688
CFC 250012" Standard12"110039-01688
CFC330012" Standard12"60039-01761
CFC330014" Option14"110039-01762800880-02502
Boiler Stack/Flue
Connection
Boiler
Flue/Stack
Size
Maximum length of
Flue Gas Vent in
Feet*
Flue Connection
Part No.
Room
Combustion Air
quired (CFM)
Re
125880-01858
190880-01858
250880-01858
375880-02005
450880-02005
625880-02005
800880-02502
Air Filter Kit No.
(optional)
* Each additional 90 elbow equals 5 equivalent feet of ductwork. Flue terminations may add 5-10 feet
to the equivalent length and should also be included in the equivalent length calculation.
** Increasing the diameter of the air intake will reduce the overall pressure drop and thereby allow
longer total vent lengths.
Draft tolerance at boiler flue connection during operation is +/- 0.25” WC.
60Rev. 05-2012
Model CFCClearFire Commercial Boilers
H
Table B5-26. STACK SIZING USING OUTSIDE AIR FOR COMBUSTION (DIRECT VENT COMBUSTION)
DIRECT VENT COMBUSTION AIR -- MAXIMUM ALLOWABLE VENTING LENGT
Boiler
CFC 5006" Standard4"6"7575880-01312039-01704
CFC 5006" Standard6"6"8080880-03736039-01704
CFC7506" Standard4"6"4040880-01312039-01704
CFC 7506" Standard6"6"5050880-03736039-01704
CFC10006" Option4"6"3030880-01312039-01646
CFC10006" Option6"6"4040880-03736039-01646
CFC10008" Standard4"8"5050880-01312039-01647
CFC10008" Standard6"8"6060880-03736039-01647
CFC100010" Option4"10"7070880-01312039-01705
CFC100010" Option6"10"8080880-03736039-01705
CFC15008" Option6"8"3030880-01313039-01645
CFC15008" Option8"8"4040880-02451039-01645
CFC150010" Standard6"10"4040880-01313039-01644
CFC150010" Standard8"10"6060880-02451039-01644
Boiler Stack/Flue
Connection
Combustion Air
Intake Duct &
Connection
Boiler
Flue/Stack
Size
Maximum length of
Flue Gas Vent in
Feet*
Maximum length of
Air Intake Duct in
Feet**
Direct Vent
Combustion Air Kit
Flue Connection
Part No.
CFC150012" Option6"12"6060880-01313039-01688
CFC150012" Option8"12"8080880-02451039-01688
CFC180010" Option6"10"4040880-01313039-01644
CFC180010" Option8"10"5555880-02451039-01644
CFC180012" Standard6"12"5050880-01313039-01688
CFC180012" Standard8"12"8080880-02451039-01688
CFC 250012" Standard8"12"100100880-02451039-01688
CFC330012" Standard8"12"5555880-02501039-01761
CFC330014" Option8"14"100100880-02501039-01762
* Each additional 90 elbow equals 5 equivalent feet of ductwork. Flue terminations may add 5-10 feet
to the equivalent length and should also be included in the equivalent length calculation.
** Increasing the diameter of the air intake will reduce the overall pressure drop and thereby allow
longer total vent lengths.
Draft tolerance at boiler flue connection during operation is +/- 0.25” WC.
61Rev. 05-2012
Model CFCClearFire Commercial Boilers
Vertical Venting
Inside Combustion
Air
See Figure B5-52.
10'-0" or Less
24"
Minimum
Flue Gas Vent
Termination
48"
Minimum
CFC Boiler
Figure B5-52. Inside Air - Vertical Vent
As noted in Paragraph A above, these installations use air from within the boiler
room for combustion. The same recommendations apply as noted in Paragraph A
above and also, the recommendations on flue vent sizing according to Table B5-25.
62Rev. 05-2012
Model CFCClearFire Commercial Boilers
Vertical Venting
Direct Vent
Combustion
Vent Termination
Minimum
48"
Boiler
See Figure B5-53.
Air Intake (w/Screen)
48" Minimum
12"
Minimum
above roof
or snow line
24" Minimum
Boiler
Vent Termination
36" Minimum
above intak
48" Minimum
Air Intake (w/Screen)
12" Minimum
above parapet
or snow line
With parapet wall
Figure B5-53. Vertical Stack with Direct Vent Combustion Air
As noted in Paragraph B above, these installations use air from outside the building
for combustion. The same recommendations apply as noted in B and also, the
recommendations on flue vent sizing according to Table B5-26.
ELECTRICALVoltage requirements for the Fan Motor are 115 - 120/1/60. Control Circuit voltage
is 120/1/60 for all boiler sizes. Refer to Table B5-3 "Ratings" for ampacity
requirements.
Refer to Figure B5-54 through Figure B5-56 for wiring connections and control
locations.
63Rev. 05-2012
Model CFCClearFire Commercial Boilers
Figure B5-54. Electrical Connections CFC 500-2500
64Rev. 05-2012
Model CFCClearFire Commercial Boilers
Figure B5-55. Electrical Connections CFC 3300
65Rev. 05-2012
Model CFCClearFire Commercial Boilers
Figure B5-56. CFC Rear Connections
66Rev. 05-2012
Model CFCClearFire Commercial Boilers
CB FALCON CONTROLLER
1. Control Description - The CB Falcon hydronic control is an integrated burner
management and modulation control with a touch-screen display/operator
interface.
2. Functionality - The controller is capable of the following functions:
• Flame supervision
• Burner sequencing
• Heating/modulation control
• Hot water system pump control
• High Limit temperature control
• Thermowell-mounted NTC temperature sensors to provide measured process
variable signals to the controller.
• User-friendly touchscreen interface
• Modbus communication capability
• Alarm/lockout messaging with history (last 15 messages)
• Annunciation
• Outdoor reset
• Central Heating and Domestic Hot Water loop control
• Password protection of configurable parameters
• High Stack Temperature limit
• Remote reset
• Lead/Lag sequencing
• (3) configurable pump relays
• Remote modulation/remote setpoint
• Frost protection
• Time of Day (dual setpoint) control
• Three levels of access to control configuration:
3. Safe Start Check, dynamic ILK input test (if enabled), blower switched on
4. If ILK input and CAPS switch closed and purge rate fan speed achieved, begin 15
second prepurge
5. When purge complete, blower RPM changed to lightoff speed
6. Trial for Ignition - 4 seconds*
7. Ignition and gas valve switched on*
8. Ignition turned off at the end of direct ignition period; 5 sec. stabilization time*
9. Release to modulation (Run)
10. At the end of CH heat request, burner is switched off and blower stays on for 15
sec. post purge period. Boiler enters standby mode.
*CFC 3300 uses pilot ignition - lightoff sequence will vary accordingly
3. Main Voltage Connection - 115V/single phase/60Hz
4. Local/Remote demand switch
5. Combustion Air Proving Switch - This input is used for proving airflow sufficient
for proper combustion throughout the burner run sequence.
6. High Air Pressure Switch - prevents boiler operation in the event of high stack
back pressure (blocked flue or condensate drain).
7. Gas Pressure Switch - Gas pressure switches for low gas pressure and high gas
pressure prevent the burner from being activated if either is open. Each switch
is a physical manual reset device, requiring physical depression of the reset
button if either switch is not closed prior to burner start or during burner
operation.
8. NTC (Negative Temperature Coefficient) Thermistor Inputs (10k @ 25
A.Flow Temperature (Outlet water temperature)
B.Return Temperature (Inlet water temperature)
C.Optional Domestic Water Temperature
D.Optional Outdoor Temperature
E.Optional Stack Temperature
F.Optional Header Temperature
9. System Configuration - CB Falcon configuration is arranged into the following
functional groups:
o
C)
System Identication and
Accesss
CH - Central Heat
Outdoor Reset
DHW - Domestic Hot Water
DHW Storage
DHW Plate
Warm Weather Shutdown
Demand Priority
Modulation Conguration
Pump Conguration
68Rev. 05-2012
Statistics Conguration
High Limit
Stack Limit
Delta T Limits
T-Rise Limit
Heat Exchanger High Limit
Anti-condensation
Frost Protection
Conguration
Annunciation Conguration
Burner Control Interlocks
Model CFCClearFire Commercial Boilers
10. CB Falcon Access - There are three levels of access to the CB Falcon controller:
•End User Level - read or view parameters; change setpoints. No password
required.
•Installer/Service Level - read all parameters; enables changing of most
parameters. This access level is used to configure the CB Falcon for a
particular installation, and is password-protected.
•OEM Level - read/change all parameters; for factory configuration of boilerspecific parameters. Password-protected and restricted to CB or factory
authorized service personnel.
For additional information regarding service and setup of the burner controller, refer
to CFC manual 750-263 or to the CB Falcon manual 750-265.
Figure B5-57. CB Falcon pinout
FALCON HYDRONIC CONTROL
PLUG CONNECTORS
FAN POWER (25 VDC)
FAN GND
PWM OUT
TACHOMETER
EGND
L2 FOR 120VAC OR
24VAC RETURN (OPTOS)
L1
P
PUMP A
P
PUMP B
P
PUMP C
BLOWER/HSI
EX. IGNITION
MAIN VALVE
PILOT VALVE
INTERLOCK
ALARM
PRE IGN INTLK
LCI
ANNUN 1/IAS
ANNUN 2
ANNUN 3
ANNUN 4
ANNUN 5
ANNUN 6
ANNUN 7 HFS
ANNUN 8 LFS
4
12
11
10
9
8
7
{
J4
6
5
{
4
3
{
{
HYDRONIC
2
CONTROL
1
7
6
5
4
J5
3
2
1
8
7
6
5
J6
4
3
2
1
7
6
5
J7
4
3
2
1
POWER
FLAME
ALARM
RESET
J1
LOCAL
MODBUS
A B C
1
5
2
3
6
E1
J3
GLOBAL
ECOM
MODBUS
D R C
A B C
J2
PIM
314
2
STRENGTH
FLAME
1
2
3
4
5
6
7
J8
8
9
10
11
12
1
2
3
4
J9
5
6
7
1
2
3
+
4
J10
J11
+
5
–
6
7
8
1
FUTURE
2
3
4
5
6
FUTURE
7
24 VAC
24 VAC RTN
STAT
INLET TEMP
INLET TEMP RTN
+
4-20 mA REMOTE SOURCE
_
OUTLET TEMP A
OUTLET TEMP RTN
OUTLET TEMP B
OUTDOOR TEMP
OUTDOOR TEMP RTN
DHW TEMP A
DHW TEMP RTN
DHW TEMP B
STACK TEMPA
STACK TEMP RTN
STACK TEMP B
REMOTE RESET
TOD
4 TO 20 MA
0 - 10 VDC
MA /VDC RTN
System Display
I
V
MULTIPLE
APPLIANCE
CONTROLLER
BUILDING
AUTOMATION
SYSTEM
GLOBALMODBUS
LOCALMODBUS
69Rev. 05-2012
Model CFCClearFire Commercial Boilers
70Rev. 05-2012
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