Buying task · Couplers, adapters and swivels
Couplers, adapters and swivels
Identify each end (standard, size, male or female, M22 bore), find an adapter whose maker names both ends, check its rating, and know how each joint seals.
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Short answer
Name both ends before you buy a pressure washer adapter. For each side, know the standard (M22, quick-connect, NPT, garden-hose thread or a brand fitting), its size, whether it is male or female and, for M22, its 14 mm or 15 mm bore. Then buy an adapter whose maker names both ends, and check its pressure rating against your machine.
What this topic covers
An adapter joins two different connections. This topic covers quick-connect plugs and couplers, M22 adapters, inlet fittings and swivels. The two ends of one adapter are often different standards, which is the whole point of it and also the easiest place to buy wrong.
MTM Hydro, for example, sells an M22 14 mm plug by 3/8 in quick-connect coupler: an M22 thread on one end and a quick-connect on the other.[1]
The decisions, in order
1. Identify each end. "M22" alone is not enough. In the name M22, the M means a metric thread and 22 is the outside thread diameter in millimeters.[2] M22 14 mm and M22 15 mm fittings share the same outside thread and differ only in the inner stem diameter, so they can screw together and still not seal.[2] AR Blue Clean says a 14 mm stem in a 15 mm bore will leak, and a 15 mm stem will not fit into a 14 mm bore.[2] To tell them apart, AR recommends measuring the inner bore of the male M22 connection or checking the product documentation.[2] The fitting identifier and the guide to identifying your connections go through each end.
2. Find an adapter whose maker names both ends. Good listings name the standard, size and gender on each side. AR Blue Clean's PW554-B is a transfer M22 swivel adapter with a 15 mm M22 swivel inlet and a male M22 x 14 mm outlet.[3] MTM names its adapters by inner size, such as an M22 female 15 mm twist coupler by 3/8 in stainless QC plug,[1] and sells separate M22 adaptor kits for 14 mm and 15 mm connections.[1] A listing that says only "M22" leaves the bore to you.
3. Check the rating against your machine. An adapter is part of the pressure line. Some makers state a rating: ECHO lists its kit of two adapters, which convert M22 to 3/8 in male or female connectors, for operation up to 4,000 PSI.[4] RYOBI rates its 7-piece RY31QCK01 quick-connect kit for pressure washers up to 4,000 PSI.[5] Others do not: AR Blue Clean lists no pressure rating for the PW554-B and tells buyers to check their hose's PSI rating.[3] Cat Pumps advises that a high-pressure system is only as strong as its weakest component.[6] Where no rating is stated, you cannot know the adapter's limit.
4. Know how the joint seals. Swagelok says tapered pipe threads seal on the threads and always need a sealant, while straight threads seal with a gasket, O-ring or metal contact, so sealant is not required or recommended on them.[7] An M22 or quick-connect joint seals on its O-ring. Champion's manual says never to repair leaking connections with sealant but to replace damaged O-rings.[8] The leaking fitting guide covers the causes.
Brand adapters and kits
Picks that fit3 products
Choose by your machine's brand. Sun Joe's SPX-M22M2F is Sun Joe's own M22 adapter for its SPX-series washers.
More on choosing
Westinghouse's WPWFIT2KIT (4-piece) and WPWFIT3KIT (6-piece) are Westinghouse's own kits for its ePX and WPX machines. Read the ends and any rating on the maker's page against your hose and machine before you order; where no rating is stated, the weakest-part rule applies. On Amazon, check that 'Ships from / Sold by' shows Amazon.com or the brand.
Sun Joe's own M22 adapter for its SPX series
Sun Joe SPX‑M22M2F 14 mm M22 male to 15 mm M22 female high-pressure hose adapter, brass
Westinghouse hose-and-gun quick-connect kit
Westinghouse WPWFIT2KIT 4‑piece M22‑14 mm hose/gun quick-connect kit, brass
Westinghouse's larger quick-connect kit
Westinghouse WPWFIT3KIT 6‑piece quick-connect kit for garden hose and M22‑14 mm hose/gun, brass
Sun Joe's manual tells owners to use only hoses, fittings and couplings the manufacturer recommends and to contact Sun Joe if unsure.[9] A maker's own adapter is the first place to look on a machine like that.
Every connection standard
Each standard has its own page with how to recognize it, how it seals and which makers use it:
| Standard | Page |
|---|---|
| M22, 14 mm stem | M22 14 mm |
| M22, 15 mm stem | M22 15 mm |
| 3/8 in quick-connect | 3/8 in QC |
| 1/4 in quick-connect | 1/4 in QC |
| NPT pipe thread | NPT |
| BSPP and BSPT | BSP |
| Garden-hose thread | GHT |
| Kärcher bayonet and quick connect | Kärcher bayonet |
Every page on couplers, adapters and swivels
Start here
Guides
- M22 14 mm vs 15 mm fittings
- Pressure washer fitting types explained
- 3/8 vs 1/4 in quick-connect
- NPT vs BSP vs M22 threads
- Adapters: M22 to quick-connect
- Water inlet fittings
- Live swivels
- Why a fitting leaks
Tools
Key terms
M22 thread, quick-connect, male thread, female thread, O-ring, thread sealant, NPT and live swivel.
Everything in this topic
Guides
- 3/8 vs 1/4 in pressure washer quick-connectsHelps you pick the right quick-connect size and gender, and read the thread behind it.
- M22 14 mm vs 15 mm pressure washer fittingsHelps you find the M22 bore on both ends before you buy a hose, gun or adapter.
- NPT vs BSP vs M22 pressure washer threadsHelps you identify a thread on a gun, wand or adapter before ordering a matching part.
- Pressure washer adapters: M22, quick-connect and brand fittingsHelps you choose an adapter whose two ends and rating are stated, not guessed.
- A leaking fitting: wrong bore, worn O-ring or a hose to replaceHelps owners find why a pressure washer connection leaks and fix it the way the makers allow, without holding or taping a pressurized fitting.
- Pressure washer fitting types explainedHelps you name the standard at each joint of your machine before you buy a part.
- Live swivels and swivel fittings: what their ratings coverHelps owners tell a live swivel from a swivel nut and check its threads and rating before adding one to the line.
- Pressure washer water inlet fittingsHelps you connect the water supply within the maker's limits, without using inlet parts on the high-pressure side.
Shortlists
- M22 and quick-connect adapters with both ends namedPoints owners of Sun Joe and Westinghouse machines to their maker's own adapters, and shows what to check on any adapter's two ends.
Tools
- Pressure washer fitting identifierHelps you put a name, size and gender on a fitting you are holding, so you can buy the part or adapter that matches it.
Common questions
What is the difference between 3/8 and 1/4 quick connect?
Size and job. In the maker documents we read, 3/8 in quick-connects join hoses to pumps and guns, and 1/4 in quick-connects take nozzles and attachments at the wand. One does not fit the other. More in 3/8 vs 1/4 in pressure washer quick-connects
Which end is the plug and which is the coupler?
The plug (male, also called a nipple in industrial catalogs) pushes into the coupler (female), which has a sliding collar or sleeve. SIMPSON's 41028 hose has a 3/8 in male plug on one end and a female socket on the other. More in 3/8 vs 1/4 in pressure washer quick-connects
Are brass quick connects rated lower than stainless?
In Dixon's industrial H-Series, a 3/8 in brass coupler is rated 2,500 PSI against 3,500 for 303 stainless and 4,000 for steel. Those are industrial parts; for any pressure-washer quick-connect, read that part's own rating. More in 3/8 vs 1/4 in pressure washer quick-connects
Do I need thread tape on a quick-connect?
Never on the quick-connect itself; it seals with an O-ring. Tapered pipe threads on the back of a fitting seal on the thread and need sealant, per Swagelok. More in 3/8 vs 1/4 in pressure washer quick-connects
What is the difference between M22 14 mm and 15 mm?
Both have the same 22 mm outside thread. They differ in the inner stem diameter, 14 mm or 15 mm, which is where the O-ring seals. More in M22 14 mm vs 15 mm pressure washer fittings
Why does my M22 fitting screw on but leak?
The thread can match while the stem does not. AR Blue Clean says a 14 mm stem in a 15 mm bore will leak, and a 15 mm stem will not go into a 14 mm bore. Do not force or over-tighten it; find the right part. More in M22 14 mm vs 15 mm pressure washer fittings
How do I know if my pressure washer is 14 mm or 15 mm?
Measure the inner bore of the male M22 end, or read the maker's documentation for that model. We do not name a size for a whole brand, because no maker document we read does. More in M22 14 mm vs 15 mm pressure washer fittings
Can I use a 14 mm hose on a 15 mm machine?
Only through an adapter whose maker states both ends, such as AR Blue Clean's PW554-B (15 mm swivel inlet, 14 mm male outlet). Check that the adapter's rating covers your machine; AR states none for the PW554-B. More in M22 14 mm vs 15 mm pressure washer fittings
Questions
What is the most common pressure washer fitting?
No source we read counts them. AR Blue Clean offers only a general observation about where 14 mm and 15 mm M22 fittings tend to appear, with no model list. Identify the fittings on your own machine instead.[2]
Do I need thread tape?
It depends on the thread. Swagelok says tapered pipe threads such as NPT seal on the threads and always need a sealant, while straight threads seal with a gasket, O-ring or metal contact, so sealant is not required or recommended on them. M22 and quick-connect joints seal on O-rings.[7]
What is the difference between M22 14 mm and 15 mm?
The same 22 mm outside thread with a different inner stem. AR Blue Clean says a 14 mm stem in a 15 mm bore will leak, and a 15 mm stem will not fit into a 14 mm bore. The M22 14 mm vs 15 mm guide explains how to tell them apart.[2]
Can I convert my machine to quick-connect?
Some makers sell kits for it. RYOBI's RY31QCK01 is a 7-piece quick-connect kit rated for washers up to 4,000 PSI, and ECHO's kit converts M22 to 3/8 in male or female connectors for operation up to 4,000 PSI. Active, by contrast, says not to convert the Active 2.0's inlet or outlet to a direct quick connect, so check your own maker's guidance first.[5][4][10]