Walk enough quarry sites and you will eventually see the same problems: an oversized pump running flat out, moving less water than expected, and consuming more power than it should. Or a perfectly good pump working in the wrong water, wearing through impellers every few months while everyone accepts it as the cost of doing business.
Usually, the pump is not the problem. It was simply never matched to the duty.
Audex offers two pump ranges for this work. Choosing the wrong range can be a much more expensive mistake than choosing the wrong size within that range. So let us start with the most important question.
How dirty is the water?
Not how much water. Not how far it needs to travel. How dirty is it?
The AS range is designed for water: rainwater, groundwater, runoff and wash plant discharge. The water may be cloudy and carry some fines, but it is still primarily water. These high-speed pumps operate at 3,450 rpm and are built to generate head — up to 433 feet on the largest units.
The AW range is designed for dirty water: silt, sludge, settling-pond bottoms and anything approaching slurry. Every AW pump includes an agitator that keeps solids suspended at the suction point, preventing material from packing around the inlet and choking the pump. AW models can pass solids up to 30 mm, compared with a maximum of 20 mm for the AS range. They also operate at 1,750 rpm — roughly half the shaft speed of an AS pump.
That difference in speed matters. In abrasive water, wear increases sharply with impeller-tip speed. The lower operating speed of the AW range helps it survive gritty service that can wear out an AS pump within months. That is not a marketing claim; it is simply physics.
The trade-off is head. The AW range tops out at 104 feet, while the AS range reaches 433 feet.
In simple terms:
AW pumps move dirty water over shorter distances.
AS pumps move cleaner water against greater head.
The two ranges are not interchangeable, and adding horsepower will not make one perform the job of the other.
Sizing an AW pump
The AW range divides into three general groups, but only one is intended for demanding quarry applications.
The AW 2-040 and AW 3-075 are 115 V single-phase pumps with aluminium motor bodies. They are useful on construction sites but are not built for aggregate operations.
The AW 2-150 and AW 2-220 step up to full cast-iron construction with high-chrome impellers and agitators. These are well suited to smaller, silty duties requiring a 2-inch discharge.
The quarry range begins with the AW 3-400. From that model upward, every pump operates at 1,750 rpm, passes solids up to 30 mm, and uses a high-chrome impeller, agitator and inlet plate.
Model | Discharge | Power | Maximum head | Maximum flow |
|---|---|---|---|---|
AW 3-400 TC | 3 in. | 5 HP | 48 ft | Approx. 435 gpm |
AW 4-600 TC | 4 in. | 8 HP | 55 ft | Approx. 635 gpm |
AW 6-900 TC | 6 in. | 12 HP | 70 ft | Approx. 845 gpm |
AW 8-1500 TC | 8 in. | 20 HP | 72 ft | Approx. 1,640 gpm |
AW 8-2200 TC | 8 in. | 29 HP | 104 ft | Approx. 1,585 gpm |
Another useful feature is the side-flow, top-discharge design of the AW range. It keeps the motor cool even when the pump is operating out of the water, and allows for a very low continuous running level.
If you need to draw a settling pond or sump close to the bottom, that matters. An AS pump requires proper submergence to keep its motor cool.
Sizing an AS pump: start with head, not horsepower
One of the most common mistakes when selecting an AS pump is buying horsepower and expecting more water.
That is not how pump selection works.
Consider the 6-inch models. The AS 6-4500 is a 60 HP pump capable of moving 872 gpm. Step up to the 100 HP AS 6-7500 and maximum flow actually falls to 740 gpm. The additional horsepower does not buy more flow — it buys more head: 433 feet instead of 295 feet.
Begin by calculating the static lift. Then add the friction loss through the hose or pipe run. Once you know the total dynamic head, you can select the appropriate pump.
Shallow sumps and surface water
For low-head, moderate-flow applications, consider the AS 4-370 and AS 4-550. These models provide 61 to 80 feet of head and approximately 420 to 450 gpm of flow. They are also light enough to be handled by two people using an appropriate lifting strap.
For smaller catch basins, look at the AS 2-220 or AS 3-550.
General pit dewatering
The AS 4-1100 and AS 4-1500 provide maximum heads of 159 and 183 feet respectively. At comparable power levels, the 6-inch models offer more flow but less head.
Deep pits and long lifts
When pumping from a working face, the static lift can exceed 150 feet before friction losses are considered. These applications call for models such as the AS 4-2200, AS 4-3000, or one of the high-head 6-inch pumps.
Bulk transfer and wash plant feed
High-volume applications with modest lift generally belong in 8-inch territory. The AS 8-3700 and AS 8-4500 both move up to 1,347 gpm, while the AS 8-5500 reaches 1,717 gpm.
The mistake people make within the AS range
A bigger, more powerful pump is not necessarily better when the water contains solids. Often the opposite is true.
The 15 HP AS 6-1100 passes solids up to 19.5 mm. The AS 6-4500, with four times the horsepower, passes only 6 mm. Producing higher head requires tighter clearances, and tighter clearances leave less room for grit and solids.
If the water contains significant solids and an AS pump is still the right choice, the 8-inch family is worth considering. Every 8-inch AS model passes solids up to 20 mm.
For smaller models, always check the solids-handling specification before ordering.
Two practical checks before you buy
1. Generator sizing
If the pump will run on temporary power, confirm the generator requirements before placing the order.
Across both ranges, the recommended generator capacity is approximately four and a half times the motor rating. A 60 HP pump may require a 270 kW generator, while a 120 HP pump may require 540 kW.
Starting current is the important factor. Overlooking it can turn a straightforward installation into a serious problem on delivery day.
2. Weight and handling
Do not assume that pumps with the same discharge size will have similar handling requirements.
The AS 4-1500 weighs 317 lb. The AS 4-2200, despite having the same discharge size, weighs 815 lb. There is a significant design change between these models, and it directly affects the lifting equipment and site preparation required.
All models discussed here are available in 575 V three-phase 60 Hz configurations — the standard supply used at many Ontario industrial sites.
What matters after the sale
Choosing the right pump is important. What happens eighteen months later, when a wear part fails and the plant is down, matters just as much.
That is why we stock Audex parts here in Ontario instead of routing every order through an overseas supplier. It is also the reason behind our 48-hour parts guarantee. Even a perfectly sized pump becomes a liability if you have to wait three weeks for an impeller.
If you are not sure which range fits your application, send us three things:
The required head
The desired flow
A description of the water and the solids it contains
That is usually enough information to narrow the selection to two options. We would rather have that conversation before you buy than after the pump is already on site.