Check Valves · 52 / 65 bar

Danfoss SCA-X / CHV-X Check Valves

Danfoss Authorized Distributor (China) Wenzhou Phonetoo is an authorized Danfoss distributor in China — listed in the official Danfoss dealer directory.

SCA-X is a check valve with a built-in stop (shut-off) valve function — one valve does the work of a separate check valve plus stop valve. CHV-X is a single-function check valve. Both open at extremely low differential pressure with excellent flow characteristics, and are easy to inspect, service and overhaul. Available in angle and straight-way bodies, in 52 bar and 65 bar versions — download the datasheet matching your required pressure rating below.

Wenzhou Phonetoo Electromechanical Co., Ltd. is an authorized Danfoss distributor in China. Contact us for availability, pricing and delivery time.

Key features

Opens at only 0.04 bar (0.58 psig) differential pressure
Built-in damping chamber prevents flutter and pulsation at low refrigerant flow or density
SCA-X back-sealing: stem packing can be replaced under pressure while the system runs
Modular Flexline concept: convert to any other SVL product (regulating, stop, strainer) by replacing the complete top part — no welding
Laser-cut V-port for excellent regulating performance (SCA-X/CHV-X 50–125)
Low-temperature steel body and bonnet; 42CrMo5 high-pressure bolts
Approvals: DNV, CRN, BV, EAC, PED (contact us for the current certificate list)

Technical data

Parameter	SCA-X / CHV-X
Max. working pressure	52 bar (754 psig) / 65 bar (943 psig), depending on version
Temperature range	–60 °C to +150 °C (–76 °F to +302 °F)
Opening differential pressure	0.04 bar (0.58 psig)
Sizes	DN 6 – DN 200 (¼″ – 8″)
Connections	Butt weld DIN (EN 10220) / ANSI (B 36.10), socket weld / brazing DIN / ASME
Body	Angle or straight-way, low-temperature steel
Refrigerants	HCFC, HFC, R717 (ammonia), R744 (CO₂), flammable refrigerants
Installation	Vertical, cone pointing down

Kv values (m³/h)

DN	15	20	25	32	40	50	65	80	100	125
Angle	7.0	14.6	24.8	42.6	45.2	80	120	182	313	514
Straight-way	4.9	10.2	17.4	29.8	31.6	65	97	152	278	470

CHV-140B — 140 bar series for CO₂ transcritical

For industrial CO₂ transcritical systems, the CHV-140B series (Flexline SVL-140B platform) offers the same check-valve function at 140 bar (2030 psi): opens at 0.04 bar differential pressure, built-in damping chamber against pulsation, DN 15 – DN 100 (½″ – 4″), angle or straight-way, low-temperature steel. UL / CRN approved.

SCA-X SS / CHV-X SS — stainless steel series

For corrosive environments (coastal installations, outdoor applications, food plants with daily detergent treatment), the SCA-X SS / CHV-X SS series offers the same check (and stop-check) function in special cold-resistant stainless steel: 52 bar g (754 psig), –60 – +150 °C, butt-weld DIN / ANSI connections, DNV / CRN / BV / EAC approved. SCA-X SS retains the internal backseating for spindle-seal replacement under pressure.

Applications

Compressor discharge lines — SCA-X stop-check prevents backflow and isolates the compressor
Oil separator outlets and liquid lines requiring backflow protection
Any industrial refrigeration line needing a check valve with minimal pressure drop

Full Danfoss code numbers (148B series) are confirmed against your connection type — send the RFQ and we will quote the exact valve.

Code numbers

Ordering codes for Danfoss SCA-X stop check valves and CHV-X check valves. Confirm the exact type and code number in your RFQ and we will quote it.

Connection key: A = butt-weld ANSI; SOC = socket weld (ANSI B 16.11); ANG = angleway; STR = straightway.

Complete valves, 52 bar

Size (DN)	Type	Connection / flow	Code no.
15 (½)	SCA-X 15 A ANG	Butt-weld ANSI (B 36.10 Schedule 80), Angleway	148B5209
15 (½)	CHV-X 15 A ANG	Butt-weld ANSI (B 36.10 Schedule 80), Angleway	148B5237
20 (¾)	SCA-X 20 A ANG	Butt-weld ANSI (B 36.10 Schedule 80), Angleway	148B5309
20 (¾)	CHV-X 20 A ANG	Butt-weld ANSI (B 36.10 Schedule 80), Angleway	148B5337
25 (1)	SCA-X 25 A ANG	Butt-weld ANSI (B 36.10 Schedule 80), Angleway	148B5409
25 (1)	CHV-X 25 A ANG	Butt-weld ANSI (B 36.10 Schedule 80), Angleway	148B5437
32 (1¼)	SCA-X 32 A ANG	Butt-weld ANSI (B 36.10 Schedule 80), Angleway	148B5509
32 (1¼)	CHV-X 32 A ANG	Butt-weld ANSI (B 36.10 Schedule 80), Angleway	148B5537
40 (1½)	SCA-X 40 A ANG	Butt-weld ANSI (B 36.10 Schedule 80), Angleway	148B5609
40 (1½)	CHV-X 40 A ANG	Butt-weld ANSI (B 36.10 Schedule 80), Angleway	148B5637
50 (2)	SCA-X 50 A ANG	Butt-weld ANSI (B 36.10 Schedule 40), Angleway	148B5703
50 (2)	CHV-X 50 A ANG	Butt-weld ANSI (B 36.10 Schedule 40), Angleway	148B5737
65 (2½)	SCA-X 65 A ANG	Butt-weld ANSI (B 36.10 Schedule 40), Angleway	148B5802
65 (2½)	CHV-X 65 A ANG	Butt-weld ANSI (B 36.10 Schedule 40), Angleway	148B5837
80 (3)	SCA-X 80 A ANG	Butt-weld ANSI (B 36.10 Schedule 40), Angleway	148B5903
80 (3)	CHV-X 80 A ANG	Butt-weld ANSI (B 36.10 Schedule 40), Angleway	148B5937
100 (4)	SCA-X 100 A ANG	Butt-weld ANSI (B 36.10 Schedule 40), Angleway	148B6004
100 (4)	CHV-X 100 A ANG	Butt-weld ANSI (B 36.10 Schedule 40), Angleway	148B6037
125 (5)	SCA-X 125 A ANG	Butt-weld ANSI (B 36.10 Schedule 40), Angleway	148B6103
125 (5)	CHV-X 125 A ANG	Butt-weld ANSI (B 36.10 Schedule 40), Angleway	148B6137
50 (2)	SCA-X 50 SOC ANG	Socket welding ANSI (B 16.11), Angleway	148B5704
32 (1¼)	CHV 32 SOC ANG	Socket welding ANSI (B 16.11), Angleway	148B5539
50 (2)	CHV 50 SOC ANG	Socket welding ANSI (B 16.11), Angleway	148B5740
15 (½)	CHV-X 15 A STR	Socket welding ANSI (B 16.11), Straightway	148B6582
20 (¾)	CHV-X 20 A STR	Socket welding ANSI (B 16.11), Straightway	148B6584
25 (1)	CHV-X 25 A STR	Socket welding ANSI (B 16.11), Straightway	148B6586
32 (1¼)	CHV-X 32 A STR	Socket welding ANSI (B 16.11), Straightway	148B6588
40 (1½)	CHV-X 40 A STR	Socket welding ANSI (B 16.11), Straightway	148B6590
50 (2)	CHV-X 50 A STR	Butt-weld ANSI (B 36.10 Schedule 40), Straightway	148B6592
65 (2½)	CHV-X 65 A STR	Butt-weld ANSI (B 36.10 Schedule 40), Straightway	148B6594
80 (3)	CHV-X 80 A STR	Butt-weld ANSI (B 36.10 Schedule 40), Straightway	148B6596
100 (4)	CHV-X 100 A STR	Butt-weld ANSI (B 36.10 Schedule 40), Straightway	148B6598
125 (5)	CHV-X 125 A STR	Butt-weld ANSI (B 36.10 Schedule 40), Straightway	148B6600
15 (½)	CHV-X 15 SOC STR	Socket welding ANSI (B 16.11), Straightway	148B6601
20 (¾)	CHV-X 20 SOC STR	Socket welding ANSI (B 16.11), Straightway	148B6602
25 (1)	CHV-X 25 SOC STR	Socket welding ANSI (B 16.11), Straightway	148B6603
32 (1¼)	CHV-X 32 SOC STR	Socket welding ANSI (B 16.11), Straightway	148B6604
40 (1½)	CHV-X 40 SOC STR	Socket welding ANSI (B 16.11), Straightway	148B6605
50 (2)	CHV-X 50 SOC STR	Socket welding ANSI (B 16.11), Straightway	148B6606

SVL valve housings with different connections, 52 bar (shared by SCA-X and CHV-X)

Size (DN)	ANSI butt-weld ANG / STR		Socket weld ANG / STR		FPT ANG / STR
15 (½)	148B5254	148B5255	148B5256	148B5257	148B5258	148B5259
20 (¾)	148B5354	148B5355	148B5356	148B5357	148B5358	148B5359
25 (1)	148B5454	148B5455	148B5456	148B5457	148B5458	148B5459
32 (1¼)	148B5578	148B5579	148B5580	148B5581	148B5582	148B5583
40 (1½)	148B5654	148B5655	148B5656	148B5657	—	—
50 (2)	148B5743	148B5744	148B5745	148B5746	—	—
65 (2½)	148B5818	148B5819	—	—	—	—
80 (3)	148B5914	148B5915	—	—	—	—
100 (4)	148B6016	148B6017	—	—	—	—
125 (5)	148B6114	148B6115	—	—	—	—

Complete top parts including gaskets and bolts, 52 bar

Size (DN)	SCA-X	CHV-X
15–25 (½–1)	148B5282	148B5283
32–40 (1¼–1½)	148B5482	148B5483
50 (2)	148B5735	148B5747
65 (2½)	148B5825	148B5827
80 (3)	148B5918	148B5919
100 (4)	148B6019	148B6022
125 (5)	148B6118	148B6119

O-ring kits for R717 (ammonia heat pump) and R1270 (propylene), 52 bar

Size (DN)	R717 heat pump	R1270 propylene
15–20 (½–¾)	148B6070	148B6077
25–40 (1–1½)	148B6071	148B6078
50 (2)	148B6072	148B6079
65 (2½)	148B6073	148B6080
80 (3)	148B6074	148B6081
100 (4)	148B6075	148B6082
125 (5)	148B6076	148B6083

Replacement kits for R717 ammonia heat pump are applicable for continuous operating temperature +100 °C to 150 °C (212 °F to 302 °F).

Parts programme, 65 bar (SCA-X / CHV-X 65)

SD = socket-braze DIN (EN 1254-5); SA = socket-braze ASME (ASME B16.50).

Size (DN)	Valve housing — angleway				Valve housing — straightway				Complete top part
Size (DN)	DIN	ANSI	SD	SA	DIN	ANSI	SD	SA	SCA-X	CHV-X
6	148B6689	148B6687	148B6722	148B6711	148B6693	148B6691	148B6743	148B6732	—	—
10	148B6690	148B6688	148B6723	148B6712	148B6694	148B6692	148B6744	148B6733	—	—
15	148B6622	148B6612	148B6724	148B6713	148B6642	148B6632	148B6745	148B6734	148B5769	148B5776
20	148B6623	148B6613	148B6725	148B6714	148B6643	148B6633	148B6746	148B6735	148B5769	148B5776
25	148B6624	148B6614	148B6726	148B6715	148B6644	148B6634	148B6747	148B6736	148B5770	148B5777
32	148B6625	148B6615	148B6727	148B6716	148B6645	148B6635	148B6748	148B6737	148B5770	148B5777
40	148B6626	148B6616	148B6728	148B6717	148B6646	148B6636	148B6749	148B6738	148B5770	148B5777
50	148B6627	148B6617	—	148B6718	148B6647	148B6637	—	148B6739	148B5771	148B5778
65	148B6628	148B6618	148B6729	148B6719	148B6648	148B6638	148B6750	148B6740	148B5772	148B5779
80	148B6629	148B6619	148B6730	148B6720	148B6649	148B6639	148B6751	148B6741	148B5773	148B5780
100	148B6630	148B6620	148B6731	148B6721	148B6650	148B6640	148B6752	148B6742	148B5774	148B5781
125	148B6631	148B6621	—	—	148B6651	148B6641	—	—	148B5775	148B5782

O-ring kits and complete valves SVA / FIA, 65 bar

Size (DN)	O-ring kit for		Complete valve — SVA (cap version)				Complete valve — FIA
Size (DN)	R717 heat pump	R1270 propylene	ANG DIN	ANG ANSI	STR DIN	STR ANSI	ANG DIN	ANG ANSI	STR DIN	STR ANSI
6	—	—	148B5033	—	148B5053	—	—	—	—	—
10	148B6084	148B6085	148B5034	—	148B5054	—	—	—	—	—
15	148B6070	148B6077	148B5035	—	148B5055	—	—	—	—	—
20	148B6070	148B6077	148B5036	—	148B5056	—	—	—	—	—
25	148B6071⁽²⁾	148B6078	148B5037	—	148B5057	—	—	—	—	—
32	148B6096⁽³⁾	148B6097	148B5038	—	148B5058	—	—	—	—	—
40	—	—	148B5039	—	148B5059	—	—	—	—	—
50	148B6072	148B6079	148B5040	—	148B5060	—	—	—	—	—
65	148B6073	148B6080	148B5041	—	148B5061	—	—	—	—	—
80	148B6074	148B6081	148B5042	—	148B5062	—	—	—	—	—
100	148B6075	148B6082	148B5043	—	148B5063	—	—	—	—	—
125	148B6076	148B6083	148B5044	—	148B5064	—	—	—	—	—
150	—	—	148B6665	148B6667	148B6666	148B6668	148B6669	148B6670	148B6671	148B6672
200	—	—	148B6673	148B6675	148B6674	148B6676	148B6677	148B6679	148B6678	148B6680

(1) Repair kits for SCA-X, CHV-X and REG SA/SB (all sizes). (2) For SCA-X, CHV-X, DN 25–40. (3) For REG SA/SB, DN 25–40.

Parts programme — CHV-140B, 140 bar (2030 psi)

SA = brazing ASME B16.50; SD = brazing EN 1254-5. Note from the source: code numbers may cover more connection types (e.g. A/D) where standards and tolerances allow for it.

Size (DN)	Valve housing — angleway				Valve housing — straightway				Complete top part CHV-140B
Size (DN)	ANSI	DIN	SA	SD	ANSI	DIN	SA	SD	Complete top part CHV-140B
15 (½)	148B6863	148B6863	—	—	148B6864	148B6864	—	—	148B6873
20 (¾)	148B6865	148B6865	—	—	148B6866	148B6866	—	—	148B6873
25 (1)	148B6867	148B6867	—	—	148B6868	148B6868	—	—	148B6874
32 (1¼)	148B6869	148B6869	—	—	148B6870	148B6870	—	—	148B6874
40 (1½)	148B6871	148B6871	—	—	148B6872	148B6872	—	—	148B6875
50 (2)	148B5861	148B5861	148B6861	148B6861	148B5862	148B5862	148B6862	148B6862	148B6876
65 (2½)	148B6908	148B6910	148B6912	148B6914	148B6909	148B6911	148B6913	148B6915	148B6876
80 (3)	148B5971	148B5971	—	—	148B5972	148B5972	—	—	148B6877
100 (4)	148B6918	148B6918	—	—	148B6919	148B6919	—	—	148B6878

Complete valves, stainless steel, 52 bar — SCA-X SS / CHV-X SS

Size (DN)	Type	Connection / flow	Code no.
15 (½)	SCA-X SS 15 D ANG	Butt-weld DIN (EN 10220), Angleway	148B5293
20 (¾)	SCA-X SS 20 D ANG	Butt-weld DIN (EN 10220), Angleway	148B5381
25 (1)	SCA-X SS 25 D ANG	Butt-weld DIN (EN 10220), Angleway	148B5490
32 (1¼)	SCA-X SS 32 D ANG	Butt-weld DIN (EN 10220), Angleway	148B5585
40 (1½)	SCA-X SS 40 D ANG	Butt-weld DIN (EN 10220), Angleway	148B5664
20 (¾)	SCA-X SS 20 A40 ANG	Butt-weld ANSI (B 36.19M Schedule 40), Angleway	148B6489
25 (1)	SCA-X SS 25 A40 ANG	Butt-weld ANSI (B 36.19M Schedule 40), Angleway	148B6480
32 (1¼)	SCA-X SS 32 A40 ANG	Butt-weld ANSI (B 36.19M Schedule 40), Angleway	148B6490
40 (1½)	SCA-X SS 40 A40 ANG	Butt-weld ANSI (B 36.19M Schedule 40), Angleway	148B5687
65 (2½)	SCA-X SS 65 A40 ANG	Butt-weld ANSI (B 36.19M Schedule 40), Angleway	148B7012
15 (½)	CHV-X SS 15 D ANG	Butt-weld DIN (EN 10220), Angleway	148B5294
20 (¾)	CHV-X SS 20 D ANG	Butt-weld DIN (EN 10220), Angleway	148B5382
25 (1)	CHV-X SS 25 D ANG	Butt-weld DIN (EN 10220), Angleway	148B5491
32 (1¼)	CHV-X SS 32 D ANG	Butt-weld DIN (EN 10220), Angleway	148B5586
40 (1½)	CHV-X SS 40 D ANG	Butt-weld DIN (EN 10220), Angleway	148B5665
20 (¾)	CHV-X SS 20 A40 ANG	Butt-weld ANSI (B 36.19M Schedule 40), Angleway	148B6491
25 (1)	CHV-X SS 25 A40 ANG	Butt-weld ANSI (B 36.19M Schedule 40), Angleway	148B6481
32 (1¼)	CHV-X SS 32 A40 ANG	Butt-weld ANSI (B 36.19M Schedule 40), Angleway	148B6492
40 (1½)	CHV-X SS 40 A40 ANG	Butt-weld ANSI (B 36.19M Schedule 40), Angleway	148B5688
15 (½)	CHV-X SS 15 D STR	Butt-weld DIN (EN 10220), Straightway	148B5678
20 (¾)	CHV-X SS 20 D STR	Butt-weld DIN (EN 10220), Straightway	148B5679
25 (1)	CHV-X SS 25 D STR	Butt-weld DIN (EN 10220), Straightway	148B5680
32 (1¼)	CHV-X SS 32 D STR	Butt-weld DIN (EN 10220), Straightway	148B6544
40 (1½)	CHV-X SS 40 D STR	Butt-weld DIN (EN 10220), Straightway	148B6566
20 (¾)	CHV-X SS 20 A40 STR	Butt-weld ANSI (B 36.19M Schedule 40), Straightway	148B6608
25 (1)	CHV-X SS 25 A40 STR	Butt-weld ANSI (B 36.19M Schedule 40), Straightway	148B6609
32 (1¼)	CHV-X SS 32 A40 STR	Butt-weld ANSI (B 36.19M Schedule 40), Straightway	148B6610
40 (1½)	CHV-X SS 40 A40 STR	Butt-weld ANSI (B 36.19M Schedule 40), Straightway	148B6611

O-ring kits for R717 (ammonia heat pump) and R1270 (propylene), stainless steel, 52 bar

Size (DN)	R717 heat pump	R1270 propylene
15–25 (½–1)	148B6070	148B6077
32–40 (1¼–1½)	148B6071	148B6078
65 (2½)	148B6073	148B6080

Replacement kits for R717 ammonia heat pump are applicable for continuous operating temperature +100 °C to 150 °C (212 °F to 302 °F).

Datasheet downloads

Frequently asked questions

What is the Danfoss CHV-X check valve used for?

The CHV-X is a check valve that prevents refrigerant backflow in industrial refrigeration systems — for example stopping high-pressure gas flowing back to the compressor on shutdown.

What is the difference between CHV-X and SCA-X?

The CHV-X is a check valve only. The SCA-X combines a check valve with a built-in shut-off valve, so it can also isolate the line for service.

At what pressure does the CHV-X open?

The CHV-X is designed to open at a very low differential pressure of 0.04 bar, minimizing pressure loss in normal flow.

What pressure is the CHV-X rated for?

The standard CHV-X range is rated 52 bar; a 65 bar version is also available. Older documentation without a pressure marking refers to the 52 bar version — confirm the rating when ordering. We also supply 65 bar and 120 bar versions — contact us if you need them.

Which refrigerants is the CHV-X suitable for?

The CHV-X is applicable to HCFC, HFC, R717 (ammonia) and R744 (CO2).

What sizes are available?

The CHV-X range covers DN 15 to DN 125 (1/2 to 5 in.).

Where is a check valve typically installed?

Typical locations include compressor discharge lines, hot gas lines and liquid lines where reverse flow must be prevented — for instance between the compressor and the oil separator or condenser.

Is this a genuine Danfoss product? How long is delivery?

Yes. We are an authorized Danfoss industrial refrigeration distributor in China, listed in Danfoss China’s official authorized dealer directory. All valves are brand-new, genuine stock with valid warranty. We ship from China; express delivery takes about 1–2 weeks to most destinations worldwide.