P40 vs AR45 – My Honest Take
This has been an ongoing debate since early 2021. Depending on what side of the bed people wake up on, how they treat their equipment, and what their local supply shops are feeding into the atmosphere, it truly determines your outlook on these systems.
The AR45 was promised as the new, next best, and greatest thing to hit the market… and then slowly stopped being pushed in the years that followed. After the release of upstream pressure washing systems with electronic clutches and stainless steel components, both of these pumps are now considered “outdated” or “ancient tech” by some.
However, what few contractors fail to consider is how the price of replacement parts, availability, and operating costs of these newly pushed machines continue to climb — all while flying under the radar.
So you’re here to understand which one is better? Which one actually performs better? The real truths behind each system and whether there’s even a difference? Well, let’s get into it.
My name is Austin Pratt. I’ve been in the wash industry since Q4 of 2018. I started with a small 2.1 GPM machine in the back of a pickup truck and have since produced over 7 figures in revenue.
This experience, along with local shops falling short of promises, forced me into situations of “figure it out or you’re not getting your workload done.” This is what led to the birth of Proper Spray Equipment, which eventually grew into Overkill Wash Equipment. While working on multiple contractors’ rigs, setups, ideologies, and other inputs, I started to rapidly gain an understanding of how certain systems should be set up.
In that time, I’ve personally purchased, tested, and modified multiple soft wash systems — including metering, plumbing, wiring, and everything in between.
I’ve done fuel pump modifications, removed factory barbs on GSS units, increased RPM, and run them at full pressure with the bypass screwed all the way in. I’ve been trying to learn the weak points, the failure points, and push these systems to the limit.
Through all of that, I found noticeable performance gains, common wear items, and parts that simply aren’t holding up to the demand we put on them daily.
One important thing to keep in mind: All of these GSS pumps were originally pest control equipment. They were never designed to do what we do with them, and the way we operate them in our industry is just asking for problems.
Let’s circle back to the basics.
The Original Comet P40
The P40 was introduced as a more “chemical resistant,” bleach-friendly pump with a better warranty, components, and other “pros.” It had slightly lower performance than the AR45, but the chemical resistance claims got a lot of contractors interested.
What tends to happen is the “talk” around these units and the unverified claims coming from stores that sell and stock the equipment — not the fine print.
Contractors were told Comet would replace anything because it was a bleach-resistant pump and that most items were covered under warranty. But a quick search of the owner’s manual showed there was no warranty on consumable parts — meaning o-rings, check valves, seals, diaphragms, etc. were not covered. On the older setups, that meant about 90% of the pump wasn’t covered.
The other reality check? Getting anything through warranty required taking pictures of the damage, submitting them to Comet, and waiting weeks to months just to hear back “it’s not covered.” Then you’re stuck with the repair bill, trying to source hard-to-find parts, and dealing with the headache of getting everything to seat properly again.
Comet parts are hard to get. Plain and simple. They’re also notoriously more expensive than AR parts, and they still don’t offer any real performance gains.
Now Let’s Talk About the AR45
I think we can all agree the AR45 was the original gas soft wash system in the late 2020s era. Contractors and build companies were pushing them hard, promising their abilities and how easily you could attach a metering system and pull different chemicals, soaps, and more.
It was sold as a faster, more consistent way to apply chemical compared to a 12V system, booster pump, air diaphragm, or downstream — with better ratios, higher distances, the whole nine yards.
However, there was one slight issue: the bypass line.
You needed a 20ft+ bypass loop so the pump could offload liquid when not spraying. Once that line filled up, the pump would start building pressure and blow the weakest link. It’s the same operating concept as the unloader loop on a big-box store pressure washer.
With the original pest control setups, they batch-mixed their solutions, so the mix would get sucked into the pump and sent back to the tank when off the trigger. They had no need for a long bypass line.
As the AR45 grew in popularity, contractors started asking for changes. I met with the AR team at HUGE in 2022 and brought forward some much-needed improvements to make these pumps easier to plumb correctly and reduce headaches in the field.
Those changes finally hit the supply chain in late 2023. That became the Gen 2 AR45 — with better barbs, improved collars, no ball valve on the pump, and other small but important tweaks.
The only remaining weak point (if you can even call it that) was the head caps and outlet manifold developing spider cracks over time from bleach exposure or high-pressure environments. Eventually, we got the Gen 3 AR with upgraded stainless/aluminum head caps to distribute pressure more evenly.
Performance Reality
Running 1" plumbing is the minimum on the AR45. Anything smaller will chatter the pump hard when just the water valve is open. Even with 3/4" bulkheads and swapping to 1" hose, you can still hear a clear difference. Why set it up with the bare minimum when the price is basically the same?
The older P40 could get away with 3/4" supply lines because its performance was lower. We have to stop looking at book numbers and understand the difference between crank HP and wheel HP. Sure, the pumps are rated for 11 GPM at 300 PSI, but you’re not getting all of that down the hose.
The AR45 simply requires more volume supplied to it to run healthy.
Warranty & Parts
The AR45 never claimed to have some crazy warranty. The mentality was always: use it, fix it, reuse it. Parts are inexpensive, widely available at most local stores and online, and easy to swap in the field.
A head cap for the AR45 runs about $40 compared to $100+ for the P40. The outlet manifold was $70–$90 versus $150 for the P40.
Up until late 2025, it was split pretty evenly — half the contractors favored the AR45, half favored the P40.
Then the new P40 collector plate came out and suddenly it was the “newest and greatest” thing again. People started buying out the retrofit kits, making parts even harder to get.
As I’m writing this in April 2026, it’s still nearly impossible to get more than 1–2 retrofit kits or collectors at a time from distributors. They ship everything from Comet overseas with long lead times.
This past winter here in Middleburg, Florida (where it’s only supposed to snow once every 30 years but has snowed twice in the last two years), we had four service calls in one single day for cracked P40 collectors. All failing in the exact same spot — just northeast of the inlet port.
The Bottom Line
You can pay roughly the same amount upfront for either a P40 or an AR45 — let’s say around $2,500 when set up properly.
They now deliver very similar performance when plumbed correctly.
You basically have two roads:
- The AR45 road: Parts are about a third of the price, everyone has them in stock, they’re easier to work on and repair in the field. The only real downside is replacing the unloader more often if you crank the pressure up.
- The P40 road: Promised better chemical resistance, higher quality, better stress handling, a new manifold for even pressure distribution, and a “better warranty”… but you can’t get parts, they’re 3x more expensive, and repairs are more involved.
The choice is yours.
What will you pick?
I know what I’m going back to.