Sterling SW-A Slope Top Convector Specifications and Ratings

Product Overview

The Sterling SW-A Slope Top Convector is a wall-mounted unit designed for efficient hydronic heating. This document provides detailed specifications, performance ratings, and correction factors for various configurations.

Specifications

Front and Liner

Style: Slope Outlet
Outlet: Stamped Louvers, Pencil Proof

Material (Cabinet Front and Liner)

18 Ga./20 Ga. CRS (Standard)
18 Ga./18 Ga. CRS (Optional)
16 Ga./20 Ga. CRS (Optional)
16 Ga./18 Ga. CRS (Optional)
16 Ga./16 Ga. CRS (Optional)
14 Ga./20 Ga. CRS (Optional)
14 Ga./18 Ga. CRS (Optional)
14 Ga./16 Ga. CRS (Optional)
14 Ga./14 Ga. CRS (Optional)
18 Ga./20 Ga. SS (Optional)
18 Ga./18 Ga. SS (Optional)
16 Ga./20 Ga. SS (Optional)
16 Ga./18 Ga. SS (Optional)
16 Ga./16 Ga. SS (Optional)

Finish

Baked Powder Prime
Baked Powder Color (Optional)

Coil

Bronze Header 3/4" NPT w/Copper Tube/Alum Fins (Mechanically Expanded).

Header Connections

Single Header Both Ends (Standard)
Single Inlet 1 End / Dual Inlet 1 End (Optional)
Dual Inlet Both Ends (Optional)

Optional Accessories

Damper: Damper Blades Factory Installed, Knob Damper (Optional), Tamper Resistant (Optional)

Access Doors

Optional

Insulation

Back Only (Optional)
Back, Sides, Top (Optional)

Piping Knockout

Optional

4" End Pockets

LH (Optional)
RH (Optional)
Both Ends (Optional)

Perforated Front

Consult Factory (16 Ga. or 14 Ga. Optional)

Model Dimensions

Model Series	D (Depth)	L (Length)	H (Height)	B	J
4xx	4-1/4"	20", 24", 28", 32", 36", 40", 44", 48", 52", 56", 60", 64"	14"	2-1/8"	2"
4xx			18"
4xx			20"
4xx			26"
4xx			32"
6xx	6-1/4"	20", 24", 28", 32", 36", 40", 44", 48", 52", 56", 60", 64"	14"	3-1/8"	4"
6xx			18"
6xx			20"
6xx			26"
6xx			32"
8xx	8-1/4"	20", 24", 28", 32", 36", 40", 44", 48", 52", 56", 60", 64"	14"	4-1/8"	6"
8xx			18"
8xx			20"
8xx			26"
8xx			32"

NOTE: When adding end pockets, liner and front length increase.

Steam Ratings in BTU/H (215°F at 65°F EAT)

DEPTH IN INCHES	LENGTH IN INCHES	SLOPE TOP, WALL MOUNTED, NOMINAL HEIGHT TYPE SW-A
DEPTH IN INCHES	LENGTH IN INCHES	14"	18"	20"	26"	32"
4	20	2930	3120	3215	3335	3505
4	24	3720	3960	4080	4250	4415
4	28	4490	4775	4895	5110	5305
4	32	5305	5640	5760	6050	6290
4	36	6070	6455	6625	6960	7250
4	40	6840	7320	7510	7850	8110
4	44	7630	8135	8350	8735	9070
4	48	8400	8975	9190	9625	9985
4	52	9145	9745	9935	10440	10850
4	56	9935	10655	10850	11400	11830
4	60	10705	11400	11615	12190	12815
4	64	11495	12310	12530	13150	13920
6	20	4510	4970	5090	5425	5690
6	24	5710	6290	6480	6960	7175
6	28	6890	7560	7750	8330	8690
6	32	8110	8905	9120	9840	10130
6	36	9290	10175	10490	11255	11615
6	40	10490	11470	11810	12670	13150
6	44	11665	12790	13105	14160	14665
6	48	12840	14040	14470	15550	16105
6	52	14015	15290	15720	16895	17590
6	56	15215	16655	17135	18410	19150
6	60	16345	17880	18360	19730	20570
6	64	17570	19270	19775	21265	22080
8	20	5760	6120	6310	6770	7030
8	24	7345	7825	8040	8665	9000
8	28	8880	9410	9650	10415	10825
8	32	10440	11135	11400	12310	12790
8	36	12050	13250	13105	14135	14690
8	40	13560	14425	14830	15985	16585
8	44	15120	16030	16510	17760	18430
8	48	16680	17710	17905	19610	20375
8	52	18190	19250	19750	21335	22225
8	56	19750	21000	21550	23255	24215
8	60	21290	22510	23110	24960	26040
8	64	22895	24265	24935	26880	28010

Correction factors for BTU performance at different Average Water Temperatures, use correction factors from Table 3 of the Correction Factors page.

For other applicable correction factors see the Correction Factors page.

For assistance with ratings and selection, please use our online Specifier.

Correction Factors

Table 3: Convector Correction Factors

Based on Section 35.4 ASHRAE HVAC Systems and Equipment

AVERAGE WATER TEMPERATURE (°F)	ENTERING AIR TEMPERATURE (°F)
AVERAGE WATER TEMPERATURE (°F)	55° (STD)	60°	65°	70°	75°
100°	0.17	0.14	0.12	0.09	0.07
110°	0.23	0.20	0.17	0.14	0.12
120°	0.29	0.26	0.23	0.20	0.17
130°	0.35	0.32	0.29	0.26	0.23
140°	0.43	0.39	0.35	0.32	0.29
150°	0.50	0.46	0.43	0.39	0.35
160°	0.58	0.54	0.51	0.47	0.43
170°	0.67	0.63	0.58	0.54	0.51
180°	0.76	0.71	0.67	0.63	0.58
190°	0.85	0.81	0.76	0.71	0.67
200°	0.95	0.90	0.85	0.81	0.76
210°	1.05	1.00	0.95	0.90	0.85
215° (STD)	1.10	1.05	1.00	0.95	0.90
220°	1.15	1.10	1.05	1.00	0.95
230°	1.26	1.20	1.15	1.10	1.05
240°	1.37	1.32	1.26	1.21	1.15
250°	1.47	1.43	1.37	1.32	1.27

Table 4: Correction Factors for Steam Pressures

CORRECTION FACTORS FOR STEAM PRESSURES OTHER THAN 1 PSI GAUGE*

PRESSURE PSI GAUGE	5	10	15	20	25	50
FACTOR	1.12	1.25	1.36	1.46	1.56	1.93
BTU PER SQ. FT.	269	301	327	351	374	463

*Apply factors shown above to the ratings shown on the 215°F ratings page.

Note: Max Recommended operating pressure 150 PSIG, (365.9°F).

For conversion from steam to hot water, use correction factors shown in Table 3.

Table 5: Correction Factors for Access Doors

Length	Free Standing, Non-Recessed Non-Standard Access Door Locations				Semi-Recessed or Fully Recessed Non-Standard Access Door Locations
Length	3 or 4	3 & 4	5 or 6	5 & 6	3 or 4	3 & 4	5 or 6	5 & 6
20"	0.940	0.880	0.820	0.650	0.975	0.950	0.925	0.850
24"	0.950	0.910	0.860	0.720	0.980	0.960	0.940	0.880
28"	0.960	0.920	0.890	0.770	0.982	0.968	0.948	0.902
32"	0.970	0.940	0.890	0.800	0.985	0.972	0.955	0.918
36"	0.970	0.940	0.920	0.830	0.988	0.975	0.962	0.925
40"	0.970	0.950	0.920	0.850	0.990	0.978	0.970	0.932
44"	0.980	0.950	0.930	0.860	0.990	0.980	0.970	0.940
48"	0.980	0.960	0.940	0.880	0.990	0.982	0.970	0.948
52"	0.980	0.960	0.950	0.890	0.992	0.985	0.978	0.955
56"	0.980	0.960	0.950	0.890	0.992	0.985	0.978	0.955
60"	0.980	0.970	0.950	0.900	0.992	0.985	0.978	0.955
64"	0.980	0.970	0.950	0.910	0.992	0.988	0.978	0.962

Note: Derating factors do not apply to units with end pockets.

Table 6: Pressure Loss in Feet of Water

WATER FLOW IN GPM	4 INCH MODELS	6 INCH MODELS	8 INCH MODELS
.25	0.044	--	--
.50	0.160	0.070	0.046
1	0.597	0.270	0.167
2	2.220	1.047	0.616
3	--	2.260	1.367
4	--	3.793	2.380
5	--	--	3.673

Charted figures showing pressure drop through Convectors with forced hot water. Used for determining pressure head requirement. Based on 64" length units, but applicable to shorter units, as most loss is due to headers.

Output-Flow Rate Corrections

Table 7: Gallons Per Minute of Hot Water Required

This section contains a graph illustrating Gallons Per Minute (GPM) of hot water required versus MBH (Thousands of BTU per Hour) for different temperature drops (10°F, 20°F, 30°F, 40°F). The lines show the relationship between flow rate and heat output for various temperature differentials.

Table 8: Output-Flow Rate Corrections

Convector Depth	Tubes per Element	GPM (Min. Flow Rate 0.25 Ft./Sec.)	MBH Based on T.D. & Min. Flow Rate
Convector Depth	Tubes per Element	GPM (Min. Flow Rate 0.25 Ft./Sec.)	10TD	20TD	30TD	40TD
4"	2	0.15	0.750	1,500	2,250	3,000
6"	3	0.225	1.125	2,250	3,375	4,500
8"	4	0.30	1.500	3,000	4,500	6,000

NOTE: Table 8 shows MBH which result at specific water temperature drops and minimum water flow rates which are required to maintain turbulent flow within element tubes.

Convector Coil Details

Diagram illustrating the convector coil construction. It details the coil's tube elements, specifying options for 2 tubes (3 3/4" width), 3 tubes (5 3/4" width), or 4 tubes (7 3/4" width). The diagram shows the end-to-end length is the liner length minus 1/2 inch, and riser centers are the liner length minus 2 1/2 inches. It also indicates a typical 3/4" NPT connection for risers. Visual elements include a vent plug, a 3-position hanger welded to the liner, and a dual inlet header. Coil fins are 2-1/2" high and mechanically bonded to copper tube at 6 fins per inch.

Note: When ordering convectors with end pockets, always refer to the standard unit length. The overall physical length will increase by 4" for each end pocket. The coil length will remain the standard size.

Manufacturer Information

Sterling Commercial Hydronic Products

260 North Elm St., Westfield, MA 01085

(413) 564-5535

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Sterling SW-A Slope Top Cabinet Wall Mounted Convector