Monarch ESP & UP & FR Effluent Series Pumps
- ESP33 (1/3 HP) and ESP50 (1/2 HP) submersible sump and effluent pumps
- Piggyback float, vertical float or manual versions of each
- ESP33S-FP pump and 5.5 gallon tank for laundry trays
- UP16M utility pump clears water to 1/4 inch from the floor
- ESP33, ESP50 and UP16 names continue under Little Giant
- Send the model and switch type, and we will find the match
A sump pit only 10 inches across leaves no room for a float on a swinging cord. That detail, along with horsepower and lift, decides which Monarch sump pump version you need. Here is how the ESP33, ESP50, ESP33S-FP package and UP16M utility pump compare, and which job each one fits.
All four run on 115 V with oil-free, continuous duty motors and thermal overload protection.
ESP33 or ESP50: Which Monarch Sump Pump Fits?
Choose the ESP33 for a basement sump with a short lift: it is 1/3 HP, passes 1/2 inch solids, and stops pumping at 17.5 feet of head. Choose the ESP50 when water has to climb higher or carries more debris: it is 1/2 HP, passes 3/4 inch solids, and reaches 31 feet of shut-off head.
Submersible Sump Pump Specs Side by Side
Figures come from Monarch's datasheets. Flow is in gallons per minute at the listed head.
| Spec | ESP33 | ESP50 | UP16M |
|---|---|---|---|
| Horsepower | 1/3 HP | 1/2 HP | 1/6 HP |
| Full load amps | 5.6 | 6.7 | 2.1 |
| Solids | 1/2 in | 3/4 in | 1/8 in |
| Flow | 44 GPM at 5 ft, 13 GPM at 15 ft | 61 GPM at 15 ft, 36 GPM at 25 ft | 20 GPM at 5 ft, 7 GPM at 15 ft |
| Shut-off head | 17.5 ft | 31 ft | 19 ft |
| Discharge | 1 1/2 in NPT, 1 1/4 in bushing included | 1 1/2 in NPT | 3/4 in NPT, garden hose adapter |
| Cord | 10 ft | 20 ft | 10 ft |
| Build | Cast iron motor housing and casing; P models thermoplastic | Cast iron motor housing, polypropylene pump body | Aluminum casing |
Pick the Switch: Piggyback, Vertical or Manual
A piggyback float hangs on a cord and plugs in behind the pump plug, so you can test the pump by plugging it straight into the outlet. A vertical float rides up and down a rod, which suits a narrow basin where a tethered float could catch on the wall.
| Model | Order no. | Switch | Motor cover |
|---|---|---|---|
| ESP33AM | 620186 | Piggyback float | Cast iron |
| ESP33AM-P | 620185 | Piggyback float | Thermoplastic |
| ESP33AV | 620120 | Vertical float | Cast iron |
| ESP33AV-P | 620121 | Vertical float | Thermoplastic |
| ESP33M | 620089 | Manual | Cast iron |
| ESP50AM | 620187 | Piggyback float | Cast iron |
| ESP50AV | 620178 | Vertical float | Cast iron |
| ESP50M | 620174 | Manual | Cast iron |
ESP33S-FP: Laundry Tray and Bar Sink Package
The ESP33S-FP (620098) sets an ESP33AV-P pump inside a 5.5 gallon polypropylene tank that sits on the floor. It lets you add a laundry tray, a bar sink, or a dehumidifier drain where there is no drain line below the floor.
The vertical float starts the pump as the tank fills and stops it once the tank empties. It handles 1/2 inch solids, which covers lint and small debris from a utility sink.
UP16M: A Portable Water Removal Pump
The UP16M draws water from the bottom, so it can pump a flat surface down to 1/4 inch. A built-in strainer and a removable screen keep debris out of the impeller.
Use it to clear a flat roof, a pool cover, a window well, or a water heater you are draining. It is a manual pump with no float, so someone has to start and stop it.
Where These Pumps Do Not Belong
- Toilet waste. None of these pumps pass the 2 inch solids that raw sewage needs. A basement toilet calls for the WS sewage series.
- Long septic runs or mounds. The ESP50 can move light effluent, but its shut-off head is 31 feet. For more lift, compare the WS50H and WS100H effluent pumps.
For grinder pumps and the full job-by-job chart, go back to the Monarch sump and sewage section.
Same Model Names Under Little Giant
Little Giant, a Franklin Electric brand, still sells the ESP33, the ESP50 and the UP16 under those names. So a worn ESP33AM-P or ESP50AV can be replaced by name.
See current Little Giant sump and effluent pumps, or send us your old model number and we will confirm the match.
Frequently Asked Questions
Should I get a 1/3 hp or 1/2 hp sump pump?
Get a 1/3 hp sump pump when the lift is short, and a 1/2 hp sump pump when the water climbs higher. Monarch's 1/3 HP ESP33 moves 44 GPM at 5 feet but only 13 GPM at 15 feet, and stops at 17.5 feet. The 1/2 HP ESP50 still moves 61 GPM at 15 feet and reaches 31 feet. Measure from the pump to the highest point of the discharge pipe, then add some head for pipe friction.
Is a vertical float switch better?
Yes, a vertical float switch is better in a narrow sump pit, because it rides straight up and down instead of swinging on a cord. A tethered float can catch on the side of a small basin and keep the pump from starting or stopping. Our listing for the Monarch ESP50AV notes it fits basins as small as 10 inches across. In a wide pit, a piggyback float works too, and it lets you test the pump by plugging it in directly.
Can I use a utility pump as a sump pump?
No, a utility pump is not a good permanent sump pump. A pump like the Monarch UP16M has no float switch, so it cannot start on its own when the pit fills. It also passes only 1/8 inch solids and draws through a bottom screen made for clear water. Use it for draining jobs you watch, and put an automatic pump such as an ESP33AM or ESP33AV in the sump.
Are cast iron sump pumps good?
Yes, cast iron sump pumps are a good choice where heat and wear matter. Monarch built the ESP33 with a cast iron motor housing and casing because the metal draws heat away from the motor. Its "P" models swap in a thermoplastic motor cover and casing, which resists corrosion and ships a pound lighter. Both versions use the same 1/3 HP motor, 1/2 inch solids rating and flow, so pick by pit conditions and weight.
Request a quote with the model or order number from your ESP or UP pump, and we will confirm the match.