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Pump-manufacturer compatibility
Comet Pressure Washer Pump Guide
Comet publishes detailed shaft, RPM, port, unloader and repair-kit information across ZWD, EWD, AXD and related pump families. Use the exact model and suffix before treating a pump or repair kit as compatible.
Comet model family and suffix both matter
Record the exact pump family, model and suffix before choosing a replacement or rebuild kit.
Use the Pump Parts guide for seal/valve-kit logic and the Unloader guide for K vs. non-K configurations.
Last technical review for this page: August 28, 2026.
Comet publishes several direct-gas pump families with different interfaces
Comet's current catalog makes shaft and plumbing differences visible. Some 3/4-inch pumps target smaller gas-engine classes, while 1-inch ZWD/EWD families cover higher-output professional pressure-washer ranges. The “K” suffix is also important because it can identify a built-in unloader configuration.
| Current Comet example | Published output | Shaft / RPM | Connection / control note |
|---|---|---|---|
| ZWD 2535 G (3/4) | 2.5 GPM / 3500 PSI | 3/4-in hollow gas / 3400 RPM | Current page lists 1/2-in FBSP inlet and 3/8-in FBSP outlet. |
| AXD 3/4 family | Model-specific | 3/4-in hollow gas / 3400 RPM | Built-in Uni-Flow unloader; 3/4 FNH inlet; 3/8 MNPT or M22 outlet classes. |
| ZWD-K 4040 G | 4.0 GPM / 4000 PSI | 1-in hollow gas / 3400 RPM | Built-in unloader; current listing includes Easy-Start device on the 4040 model. |
| EWD 4040 G | 4.0 GPM / 4000 PSI | 1-in hollow gas / 3400 RPM | Fully plumbed listing uses VRT3 unloader, 1/2-in FNPT inlet and 3/8-in FNPT outlet. |
Old/new part-number cross-references make Comet valuable for repair intent
Comet's current product pages often publish both legacy and replacement part numbers plus family-specific water-seal, oil-seal, valve, piston and unloader kits. That is exactly the kind of source-backed data that belongs in a pump-parts workflow.
Do not infer that a ZWD kit fits EWD or AXD because the flow/pressure class is similar. Use the exact pump family and current manufacturer kit table.
For Comet, the suffix can change the unloader decision
A model family that looks nearly identical can be supplied with or without a built-in unloader or with different fully plumbed packages. That affects both physical installation and pressure-control architecture.
Use the Unloader Valve guide before substituting one configuration for another.
No Comet-specific merchant route is forced here
The blueprint did not establish a dedicated Comet /go/ route. After verifying the exact shaft, flow, pressure and unloader class, you can compare the broader 4-GPM / 4000-PSI triplex market without implying that every listing is a Comet replacement.
Manufacturer sources
- Comet — ZWD 3/4-in — Current 3/4-in hollow-shaft ZWD models plus repair kits and old/new part numbers.
- Comet — ZWD 1-in — Current 1-in hollow-shaft ZWD gas-engine class.
- Comet — ZWD-K 1-in — Built-in-unloader ZWD-K models including current 4 GPM / 4000 PSI class.
- Comet — EWD Series — Current 1-in 4-GPM / 4000-PSI fully plumbed EWD reference.
- Comet — AXD 3/4-in — Current 3/4-in hollow-shaft pump with built-in unloader and multiple outlet formats.
- Comet — pump/regulator breakdowns — Current family breakdown and service-document index.
Sources reviewed August 28, 2026. PressureWasherMatch.com is independent and is not affiliated with or endorsed by the manufacturers referenced above.
Frequently asked questions
What Comet pressure washer pump fits a 3/4-inch gas-engine shaft?
Comet currently publishes several 3/4-inch hollow-shaft gas-engine families, including ZWD 3/4, LWD/LWD-K and AXD configurations. Exact flow, pressure, outlet and unloader setup depend on the model.
What Comet pump is rated for 4 GPM and 4000 PSI?
Current Comet examples include ZWD 4040 G / ZWD-K 4040 G and EWD 4040 G classes around 4 GPM and 4000 PSI with 1-inch hollow shafts at 3400 RPM. Their plumbing and unloader configurations differ.
What is the difference between Comet ZWD and ZWD-K?
Current ZWD-K product data explicitly includes a built-in unloader valve, while ZWD configurations may be offered with different external or plumbed unloader arrangements. Match the exact model and part number.
Can I replace an old Comet part number with the new number shown on the website?
Comet publishes old and new part numbers for many current pump and repair-kit records. Use those manufacturer cross-references, but still verify the exact model suffix and configuration before ordering.
Are Comet pump repair kits model-specific?
Yes. Current Comet pages list water-seal, oil-seal, valve, piston and unloader kits by pump family. Do not choose a seal kit by approximate dimensions alone.
Why build a Comet page if its search volume is smaller?
Comet provides unusually detailed current shaft, RPM, port, power and repair-kit data. That makes the page valuable to the replacement-pump and pump-parts ecosystem even at lower head-term volume.