d,
bypass damper that can be used to enhance convection
heat transfer.
With the damper open the recuperator functions
primarily as a radiation type with some assist by convec-
tion transfer to a secondary surface suspended in the
flue gas passage.
With the bypass damper closed, flue gas pressure
drop and convection heat transfer are at maximum values
while radiation transfer is only slightly reduced. Total
heat transfer and air preheat temperature are highest in
this condition.
While on some applications preheat temperature of
more than 1000 F can be realized, it is suggested that
temperature be limited to a nominal maximum of 900 F
unless testing or observation of radiant tube temperature
profile under operating conditions is possible. If the air
preheat obtained with the given flue temperature is too
high, open the bypass damper to lower preheat air
temperature.
Metric Conversions
1 scfh = 0.028 26 sm
3
/h = 0.026 86 nm
3
/h
1 " w c = 25.40 mm H
2
O
C =
5
/
9
(F 32)
1" = 25.40 mm
1 lb = 0.4536 kg
WARNING: Situations dangerous to personnel and property can develop from incorrect operation of combustion equipment.
North American urges compliance with National Safety Standards and Insurance Underwriters recommendations, and care in operation.
DIMENSIONS SHOWN ARE SUBJECT TO CHANGE. PLEASE OBTAIN CERTIFIED PRINTS FROM NORTH AMERICAN MFG. CO.
IF SPACE LIMITATIONS OR OTHER CONSIDERATIONS MAKE EXACT DIMENSION(S) CRITICAL.
CAPACITIES:
2000 to 4000 scfh air
FLUE GAS TEMPERATURE:
2000 F maximum
TYPE:
Single tube – counterflow
Weight: 70 pounds
8484-3000 OVERALL DIMENSIONS
6"
8
7
/
16
"
(Typ.)
Flue Outlet O.D.
1
13
/
16
"
35
5
/
16
"
Insulation applied
to this surface
by customer
3
/
8
-16
×
2
1
/
2
" Hex Bolts
(6) req'd
(by customer)
2
1
/
2
"
9" O.D. Flange
(8)
3
/
8
" Hex Bolts and
Nuts equally spaced
on 7
5
/
8
" BC as shown
2
1
/
2
" Pipe Size
Air Outlet
2" Pipe Size
Air Inlet
6
1
/
2
" Flue Inlet I.D.
3
/
8
-16
×
5
1
/
4
"

Hex Bolts
(2) req'd
(by customer)
1
/
8
" Gasket and
1
/
2
" Thk.
Flange (by customer)
30
3
/
8
" Printed in USA
NA101-8484-1
Selection Procedure
Given:
scfh preheated air
flue gas temperature
1. Enter selection chart at scfh air, and locate intersection with flue gas temperature line.
2. Read available air preheat temperature and total pressure drop directly from curves.
Given:
scfh, 3000
flue gas temperature, 1600 F
1. Enter chart at 3000 scfh.
2. Locate intersection with 1600 F flue gas temperature on grid.
3. Read air preheat achieved (about 730 F).
4. Read total pressure drop (about 5.3 inches wc).
8484-3000 With Bypass Damper Closed
For most applications North American recommends 900 F maximum preheat air temperature.
Total Pressure Drop





P "wc, Air Side
3.0
4.0
5.0
6.0
7.0
8.0
900 F
800 F
700 F
600 F
500 F
4000
3500
3000
2500
2000
1500
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
Air Capacity, scfh
Flue Gas T
emperature, F
900 F
(Bypass Damper
Fully Open)
1000 F
Maximum Recommended
Preheat T
emp.
Sheet 8484-1
Page 2
North American Mfg. Co., 4455 East 71st Street, Cleveland, OH 44105-5600 USA, Tel: +1.216.271.6000, Fax: +1.216.641.7852
email: sales@namfg.com
l
www.namfg.com