Sterling SR-A / SRG-A Convectors

Submittal Specification

Product Overview

The Sterling SR-A and SRG-A series convectors are designed for commercial hydronic heating applications. They feature a flat top cabinet with semi-recessed installation and a 3-sided overlap design. Available options include open inlets (SR-A) or louvered inlets (SRG-A).

Specifications

General

Cabinet Type: Flat Top, Semi-Recessed, 3 Sided Overlap
Front and Liner Style: Front Outlet, Stamped Louvers, Pencil Proof
Element: Bronze Header 3/4" NPT with Copper Tube/Alum Fins (Mechanically Expanded)
Lengths: Available in 20" through 64" in 4" increments.

Materials & Finishes

Cabinet Front and Liner Material Options:
- CRS (Cold Rolled Steel): 18 Ga./20 Ga. (Standard), 18 Ga./18 Ga. (Optional), 16 Ga./20 Ga. (Optional), 16 Ga./18 Ga. (Optional), 16 Ga./16 Ga. (Optional), 14 Ga./20 Ga. (Optional), 14 Ga./18 Ga. (Optional), 14 Ga./16 Ga. (Optional), 14 Ga./14 Ga. (Optional).
- *Liner is Galvannealed Steel.
- SS (Stainless Steel): 18 Ga./20 Ga. (Optional), 18 Ga./18 Ga. (Optional), 16 Ga./20 Ga. (Optional), 16 Ga./18 Ga. (Optional), 16 Ga./16 Ga. (Optional).
Finish Options: Baked Powder Prime (Standard), Baked Powder Color (Optional).

Connections & Options

Header Connections: Single Header Both Ends (Standard), Single Inlet 1 End / Dual Inlet 1 End (Optional), Dual Inlet Both Ends (Optional).
Optional Accessories: 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). Note: Adding end pockets increases the overall physical length by 4" per pocket, while the coil length remains standard.
Perforated Front: Consult Factory (16 Ga. Optional, 14 Ga. Optional).

Model Dimensions (Type SR-A / SRG-A)

MODEL	D	L	H	B	J
4xx-16	16	20,24,28, 32,36,40, 44,48,52, 56,60,64,	16	18	2
4xx-18	18			2-1/8
4xx-22	4-1/4		22
4xx-24	24		24
4xx-30	30		30
6xx-16	16	20,24,28, 32,36,40, 44,48,52, 56,60,64,	16	18	4
6xx-18	18			3-1/8
6xx-22	6-1/4		22
6xx-24	24		24
6xx-30	30		30
8xx-16	16	20,24,28, 32,36,40, 44,48,52, 56,60,64,	16	18	6
8xx-18	18			4-1/8
8xx-22	8-1/4		22
8xx-24	24		24
8xx-30	30		30

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

Performance Ratings

The following tables provide Steam Ratings in BTU/H for 215°F at 65°F Entering Air Temperature (EAT) for Type SR-A and Type SRG-A convectors.

Type SR-A Steam Ratings (BTU/H)

DEPTH INCHES	FRONT OUTLET, NOMINAL LINER HEIGHT *TYPE SR-A
DEPTH INCHES	16"	18"	22"	24"	30"
20	2230	2495	2830	2930	3120
24	2760	3145	3625	3720	3985
28	3310	3815	4345	4465	4775
32	3865	4490	5110	5255	5665
36	4370	5160	5880	6025	6505
40	4895	5810	6600	6790	7320
44	5425	6480	7390	7560	8160
48	5950	7105	8110	8350	8975
52	6550	7800	8855	9070	9745
56	7030	8450	9625	9865	10630
60	7655	9120	10345	10610	11400
64	8135	9790	11135	11400	12290
20	3240	3625	4250	4390	4850
24	4030	4560	5375	5570	6170
28	4850	5520	6480	6670	7370
32	5615	6480	7610	7870	8690
36	6430	7390	8690	9025	9935
40	7250	8375	9815	10200	11230
44	8065	9290	10920	11350	12480
48	8880	10250	12025	12455	13705
52	9745	11185	13105	13535	14905
56	10510	12145	14230	14735	16225
60	11400	13055	15310	15840	17425
64	12190	14040	16440	17065	18770
20	4030	4535	5040	5135	5570
24	5110	5760	6360	6575	7105
28	6385	6960	7680	7895	8520
32	7560	8185	9025	9310	10055
36	8710	9385	10390	10705	11545
40	9865	10630	11760	12070	13055
44	11040	11830	13055	13440	14545
48	11950	12935	14400	14810	16080
52	13465	14230	15670	16105	17425
56	14615	15505	17090	17570	19010
60	15770	16655	18335	18840	20375
64	16775	17880	19750	20330	21960

Type SRG-A Steam Ratings (BTU/H)

DEPTH INCHES	FRONT OUTLET, NOMINAL LINER HEIGHT *TYPE SRG-A
DEPTH INCHES	16"	18"	22"	24"	30"
20	2163	2420	2773	2871	3089
24	2677	3051	3553	3646	3945
28	3211	3701	4258	4376	4727
32	3749	4355	5008	5150	5608
36	4239	5005	5762	5905	6440
40	4748	5636	6468	6654	7247
44	5262	6286	7242	7409	8078
48	5772	6892	7948	8183	8885
52	6354	7566	8678	8889	9648
56	6819	8197	9433	9668	10524
60	7425	8846	10138	10398	11286
64	7891	9496	10912	11172	12167
20	3046	3408	4038	4171	4753
24	3788	4286	5106	5292	6047
28	4559	5189	6156	6337	7223
32	5278	6091	7230	7477	8516
36	6044	6947	8256	8574	9736
40	6815	7873	9324	9690	11005
44	7581	8733	10374	10783	12230
48	8347	9635	11424	11832	13431
52	9160	10514	12450	12858	14607
56	9879	11416	13519	13998	15901
60	10716	12272	14545	15048	17077
64	11459	13198	15618	16212	18395
20	3667	4127	4687	4776	5403
24	4650	5242	5915	6115	6892
28	5810	6334	7142	7342	8264
32	6880	7448	8393	8658	9753
36	7926	8540	9663	9956	11199
40	8977	9673	10937	11225	12663
44	10046	10765	12141	12499	14109
48	10875	11771	13392	13773	15598
52	12253	12949	14573	14978	16902
56	13300	14110	15894	16340	18440
60	14351	15156	17052	17521	19764
64	15265	16271	18368	18907	21301

Correction factors for BTU performance at different Average Water Temperatures should be applied using Table 3. For other applicable correction factors, refer to the Correction Factors page. For assistance with ratings and selection, please use the Sterling online Specifier.

Correction Factors

Table 3: Convector Correction Factors (Based on ASHRAE)

These factors adjust BTU performance based on Average Water Temperature and Entering Air Temperature (EAT).

AVERAGE WATER TEMPERATURE (°F)	ENTERING AIR TEMPERATURE (°F) (STD)
AVERAGE WATER TEMPERATURE (°F)	55°	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 Other Than 1 PSI Gauge

PRESSURE PSI GAUGE	FACTOR
PRESSURE PSI GAUGE	5	10	15	20	25	50
*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.

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

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.

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

Additional Correction Factors are available on the next page.

Table 7: Gallons Per Minute of Hot Water Required

This graph illustrates the relationship between Gallons Per Minute (GPM) and MBH (Thousands of BTU per Hour) for different temperature drops (10°F, 20°F, 30°F, 40°F).

[Graph showing GPM vs MBH for various temperature drops]

Table 8: Output-Flow Rate Corrections

This table shows MBH which result at specific water temperature drops and minimum water flow rates required to maintain turbulent flow within element tubes.

Convector Depth	Tubes per Element	Min. Flow Rate (0.25 Ft./Sec.) GPM	MBH Based on T.D. & Min. Flow Rate
Convector Depth	Tubes per Element	Min. Flow Rate (0.25 Ft./Sec.) GPM	10TD	20TD	30TD	40TD
4"	2	.15	0.750	1,500	2,250	3,000
6"	3	.225	1.125	2,250	3,375	4,500
8"	4	.30	1.500	3,000	4,500	6,000

Convector Coil Details

The convector coil is constructed with copper tubes and aluminum fins, mechanically expanded for optimal heat transfer. Coil fins are 2-1/2" high and bonded to copper tubes at 6 fins per inch.

Coil Configurations:
- 4" Depth: 2 Tube Element (3 3/4" width)
- 6" Depth: 3 Tube Element (5 3/4" width)
- 8" Depth: 4 Tube Element (7 3/4" width)

Diagram Description: A diagram illustrates the convector coil assembly. It shows the end-to-end length (liner length less 1/2"), riser centers (liner length less 2 1/2"), and a 3/4" NPT typical connection. Details include a vent plug (CAT-53045A) and a 3-position hanger welded to the liner (CAT-53086C).

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.

	Sterling Convector PW-A/PWG-A Submittal Specification Detailed specification submittal for Sterling Convector models PW-A and PWG-A, including product features, materials, dimensions, steam ratings, and correction factors for hydronic heating applications.
	Sterling FWG-A Convector: Submittal Specification and Technical Data Detailed submittal specification and technical data for the Sterling FWG-A Front Outlet Recessed Convector, including BTU ratings, correction factors, material options, dimensions, and performance data.
	Sterling Convectors FS-A/FSG-A Submittal Specification Technical submittal specification for Sterling Convectors FS-A and FSG-A series, featuring flat top cabinets for wall or floor mounting. Includes detailed product specifications, materials, finishes, optional accessories, and comprehensive BTU rating tables and correction factors for HVAC applications.
	Sterling SF-A/SFG-A Convectors: Submittal Specification and Performance Data Detailed submittal specification for Sterling SF-A and SFG-A slope top cabinet convectors, including dimensions, materials, finishes, BTU ratings, and correction factors for HVAC applications.
	Sterling Convectors: Steam and Hot Water Radiation Catalog A comprehensive catalog detailing Sterling Convectors for commercial hydronic heating systems, covering product types, specifications, installation data, and selection guides for steam and hot water radiation.
	Sterling Convectors RF-A/RFG-A Specification and Ratings Detailed specifications, steam ratings, and correction factors for Sterling Convectors RF-A and RFG-A flat top recessed cabinets.
	Sterling W-A Convector Submittal Specification Technical specification and submittal data for the Sterling W-A Flat Top Cabinet Wall Mounted Convector, detailing materials, dimensions, performance ratings, and correction factors for HVAC applications.
	Sterling SW-A Slope Top Convector Specifications and Ratings Detailed specifications, BTU/H ratings, and correction factors for Sterling SW-A Slope Top Wall Mounted Convectors, including material, finish, and performance data.