SQN Construction and Drive Options
The SQN housing is G-90 galvanized steel with an aluminum wheel and integral inlet and outlet duct collars. It carries the shortest depth of any square inline fan, with universal position mounting feet for vertical or horizontal installs, multiple access doors for service, and built-in lifting lugs.
SQN-B belt drive uses regreasable air-handling ball bearings, an adjustable motor plate, and a belt tunnel. SQN-D direct drive couples the motor to the wheel for fewer moving parts. SQN-D VF adds a Vari-Flow EC motor for higher efficiency and speed control. Standard units handle air to 180°F, with an alternate build to 200°F.
SQN Models, Sizes, and Wheel Types
The SQN comes in 3 wheel types so you can match the fan to your pressure. Standard SQN covers most jobs, SQNHP is the high pressure wheel, and SQNXP is the extended pressure wheel.
| Wheel |
Belt drive sizes |
Direct drive sizes |
Max static |
Max airflow |
| SQN (standard) |
60 to 402 |
70 to 365 |
4 in. wg |
31,000 CFM |
| SQNHP (high pressure) |
135 to 402 |
180 to 365 |
5 in. wg |
31,600 CFM |
| SQNXP (extended pressure) |
Not offered |
180 to 365 |
5 in. wg |
11,500 CFM |
The full SQN model lineup is below. Find your size in the left column, then read across to the drive and wheel you need. A dash means that build is not offered in that size.
| Size |
Belt (SQN-B) |
Direct (SQN-D) |
HP Belt (SQNHP-B) |
HP Direct (SQNHP-D) |
XP Direct (SQNXP-D) |
| 60 |
60SQN-B |
– |
– |
– |
– |
| 70 |
70SQN-B |
70SQN-D |
– |
– |
– |
| 80 |
80SQN-B |
– |
– |
– |
– |
| 90 |
– |
90SQN-D |
– |
– |
– |
| 100 |
100SQN-B |
100SQN-D |
– |
– |
– |
| 120 |
120SQN-B |
120SQN-D |
– |
– |
– |
| 135 |
135SQN-B |
135SQN-D |
135SQNHP-B |
– |
– |
| 150 |
150SQN-B |
150SQN-D |
150SQNHP-B |
– |
– |
| 165 |
165SQN-B |
165SQN-D |
165SQNHP-B |
– |
– |
| 180 |
180SQN-B |
180SQN-D |
180SQNHP-B |
180SQNHP-D |
180SQNXP-D |
| 195 |
195SQN-B |
195SQN-D |
195SQNHP-B |
195SQNHP-D |
195SQNXP-D |
| 210 |
210SQN-B |
210SQN-D |
210SQNHP-B |
210SQNHP-D |
210SQNXP-D |
| 225 |
225SQN-B |
225SQN-D |
225SQNHP-B |
225SQNHP-D |
225SQNXP-D |
| 245 |
245SQN-B |
245SQN-D |
245SQNHP-B |
245SQNHP-D |
245SQNXP-D |
| 270 |
270SQN-B |
270SQN-D |
270SQNHP-B |
270SQNHP-D |
270SQNXP-D |
| 300 |
300SQN-B |
300SQN-D |
300SQNHP-B |
300SQNHP-D |
300SQNXP-D |
| 330 |
330SQN-B |
330SQN-D |
330SQNHP-B |
330SQNHP-D |
330SQNXP-D |
| 365 |
365SQN-B |
365SQN-D |
365SQNHP-B |
365SQNHP-D |
365SQNXP-D |
| 402 |
402SQN-B |
– |
402SQNHP-B |
– |
– |
Overall dimensions in inches are below. Use them to confirm the fan fits your space before you order, and call 773-774-8616 if you need a submittal drawing.
| SQN-B Size |
Height |
Length |
Width |
| 60 |
26 1/2 |
22 |
14 |
| 70 |
26 1/2 |
22 |
14 |
| 80 |
26 1/2 |
22 |
14 |
| 100 |
26 1/2 |
22 |
14 |
| 120 |
30 15/16 |
22 |
18 7/16 |
| 135 |
33 1/4 |
22 1/4 |
20 3/4 |
| 150 |
35 3/4 |
23 7/8 |
23 |
| 165 |
40 1/16 |
27 |
25 5/16 |
| 180 |
42 3/8 |
30 |
27 5/8 |
| 195 |
44 15/16 |
32 1/4 |
29 15/16 |
| 210 |
46 1/4 |
35 |
31 1/4 |
| 225 |
48 3/4 |
37 1/4 |
33 1/2 |
| 245 |
53 1/4 |
38 |
36 |
| 270 |
56 15/16 |
41 1/2 |
39 11/16 |
| 300 |
61 1/4 |
42 |
44 |
| 330 |
65 11/16 |
45 3/4 |
48 7/16 |
| 365 |
67 1/4 |
46 |
50 |
| 402 |
72 3/8 |
50 1/4 |
55 1/8 |
| SQN-D Size |
Height |
Length |
Width |
| 70 |
14 |
14 |
14 |
| 90 |
14 |
17 |
14 |
| 100 |
14 |
22 |
14 |
| 120 |
18 7/16 |
22 |
18 7/16 |
| 135 |
20 3/4 |
22 1/4 |
20 3/4 |
| 150 |
23 |
23 7/8 |
23 |
| 165 |
25 5/16 |
27 |
25 5/16 |
| 180 |
27 5/8 |
30 |
27 5/8 |
| 195 |
29 15/16 |
32 1/4 |
29 15/16 |
| 210 |
31 1/4 |
35 |
31 1/4 |
| 225 |
33 1/2 |
37 1/4 |
33 1/2 |
| 245 |
36 |
40 13/16 |
36 |
| 270 |
39 11/16 |
45 |
39 11/16 |
| 300 |
44 |
50 |
44 |
| 330 |
48 7/16 |
55 |
48 7/16 |
| 365 |
50 |
60 13/16 |
50 |
SQN Motor, Wheel, and Bearing Parts
Many buyers reach this page looking for a part, not a whole fan. Heinlein stocks and sources Loren Cook replacement parts for every SQN size, including the motor, aluminum wheel, drive belt, and regreasable ball bearings. The SQN is a long-service commercial unit, and the right part keeps an installed fan running instead of forcing a full replacement.
As an authorized Loren Cook distributor, Heinlein can supply SQN parts even for older units that are no longer in production, the ones whose parts are hardest to track down.
We can quote a single part or a complete replacement fan for any issue. Have the model and serial number from the unit tag ready and call 773-774-8616.
Frequently Asked Questions
What is the difference between the SQN-B and SQN-D?
SQN-B is belt drive, which lets you set fan speed through the drive selection and reaches the full size range to 402. SQN-D is direct drive, with the motor coupled to the wheel for fewer moving parts and less maintenance. SQN-D VF adds a Vari-Flow EC motor for efficiency and speed control. Call 773-774-8616 to match the drive to your duty.
What is the difference between SQN, SQNHP, and SQNXP?
These are the three wheel types. Standard SQN runs to 4 inches of static pressure and covers most jobs. SQNHP is the high pressure wheel and runs to 5 inches. SQNXP is the extended pressure wheel, offered on direct drive sizes 180 to 365. Tell us your airflow and static and we will pick the wheel.
Can the SQN discharge from the side?
Yes. The square housing supports single or dual side discharge, which can replace a system elbow or tee, cut static pressure, and raise flow up to 10 percent. The unit also installs vertical or horizontal with the universal mounting feet.
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