A.Y. McDonald · Effluent Pump
Thermoplastic High Head Effluent Pumps, 20 GPM (P Series)
4 in multistage effluent pumps with Baker stainless steel motors, 1/2 to 1-1/2 HP, for pressure distribution, mound and drip systems: shut-off heads 146 to 358 ft.
146-358 ft (63-154 PSI) Max Head · 20 GPM Nominal
1/2-1-1/2 HP
115V or 230V 1Ph, 2-Wire
10 to 100 ft Lead
1-1/4 in FNPT Discharge
Stainless Steel Shell and Shaft
Internal Check Valve (Standard Models)
4 in Diameter, 12.5-20.0 in Long
23-41 lb Weight
What Ships and What It Needs to Run
Included: the pump end and Baker stainless steel motor, assembled, with the lead length of the model. Standard models include the internal check valve, cable guard and cable guard screws; X99x models ship less check valve, cable guard and screws, with a hole drilled in the center of the discharge, for drain-back dosing.
Control panel required, ordered separately. Two-wire motors start directly from a dosing control panel or timer with level floats.
Sized at install: flow inducer or pump vault, effluent screen, discharge and manifold piping.
Overview
Reinforced thermoplastic motor bracket and discharge with a built-in guide bearing, assembled with Baker stainless steel motors from 1/2 to 1-1/2 HP. Two-wire, single-phase models include the pump, motor and a 10 ft lead; 25, 50 and 100 ft leads are available. All 4 in submersibles carry grounded leads meeting the National Electrical Code.
Why multistage: each stage adds head, so these pumps reach hundreds of feet at low flow. That suits pressure-dosed laterals, mounds and long uphill runs, where a single-stage effluent pump runs out of head.
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Stainless steel pump shell and shaft; reinforced thermoplastic diffusers and impellers.
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Internal anti-spin check valve standard (standard-lead models).
- Thermoplastic intake screen.
- 1-1/4 in FNPT discharge.
Genuine A.Y. McDonald equipment, factory-new in original packaging — sold and supported by Watermain Supply, an independent industrial supplier. Watermain Supply is an Authorized Stocking A.Y. McDonald and Baker Water Systems Distributor.
3-Year A.Y. McDonald Warranty
Covered for 3 years from the date of manufacture under Baker Manufacturing’s published limited warranty (A.Y. McDonald Pumps & Accessories price list, effective 7/1/26). This is Baker’s term for assembled submersible pumps with Baker motors up to 80 GPM pump ends. Per Baker’s terms, the warranty does not cover failure caused by sand or abrasive materials in the water.
Outgrow It and You Don’t Replace It
Single pump. Duplex dosing tanks use two pumps and an alternating dosing panel.
Models & Ratings (60 Hz)
| Model |
Part Nos. (10 ft, 10 ft X996, 25, 50, 100 ft) |
HP |
Volts |
Stages |
Shut-off |
Max Flow |
Length A |
Weight |
| 22050P2AJ |
6634-183 / 6634-186 / 6634-184 / 6634-185 / 6634-281 |
1/2 |
115 |
5 |
146 ft (63 PSI) |
30 GPM |
12.5 in |
23 lb |
| 22050P2J |
6634-314 / 6634-188 / 6634-187 / 6634-275 / 6634-267 |
1/2 |
230 |
5 |
146 ft (63 PSI) |
30 GPM |
12.5 in |
23 lb |
| 22075P2J |
6634-315 / 6634-271 / 6634-228 / 6634-316 / 6634-317 |
3/4 |
230 |
7 |
203 ft (87 PSI) |
32 GPM |
14.6 in |
27 lb |
| 22100P2J |
6634-318 / 6634-278 / 6634-273 / 6634-272 / 6634-319 |
1 |
230 |
9 |
261 ft (112 PSI) |
32 GPM |
16.8 in |
31 lb |
| 22150P2J |
6634-320 / 6634-321 / 6634-322 / 6634-237 / 6634-323 |
1-1/2 |
230 |
12 |
358 ft (154 PSI) |
33 GPM |
20.0 in |
41 lb |
Source: A.Y. McDonald Pumps by Baker catalog, rev 3/26, and Pumps & Accessories price list, effective 7/1/26.
Shared Specifications
| Nominal flow |
20 GPM |
| Motor |
Baker 4 in stainless steel, 2-wire, single phase |
| Discharge |
1-1/4 in FNPT |
| Diameter |
4 in |
Performance — Will It Do What You Need?
| Flow, GPM → |
0 |
5 |
10 |
15 |
20 |
25 |
30 |
| 1/2 HP, 5 stages |
151 |
141 |
128 |
112 |
93 |
72 |
43 |
| 3/4 HP, 7 stages |
209 |
196 |
179 |
161 |
136 |
103 |
62 |
| 1 HP, 9 stages |
258 |
247 |
230 |
204 |
165 |
122 |
74 |
| 1-1/2 HP, 12 stages |
358 |
344 |
323 |
286 |
235 |
173 |
100 |
Total head in feet at each flow, digitized from the published curve in the A.Y. McDonald Pumps by Baker catalog, rev 3/26, p. 323, and rounded down. A dash is beyond the end of the published curve.
Printed shut-off heads: 1/2 HP 146 ft (63 PSI), 3/4 HP 203 ft (87 PSI), 1 HP 261 ft (112 PSI), 1-1/2 HP 358 ft (154 PSI).
Before You Buy — The Limits That Decide the Fit
| Water |
Screened septic effluent. Use an effluent screen or flow inducer ahead of the intake. |
| Head |
Choose the HP whose curve shows at least your total head at the design flow, including the distal pressure at the laterals. |
| Drain-back |
X99x models ship less check valve, for lines that must drain back to the tank. |
| Power |
115V (A models) or 230V single phase, 2-wire. |
| Pairing |
Single pump. |
Materials of Construction
| Pump shell and shaft |
Stainless steel |
| Diffusers and impellers |
Reinforced thermoplastic |
| Motor bracket and discharge |
Reinforced thermoplastic, built-in guide bearing |
| Intake screen |
Thermoplastic |
Accessories
| Accessory |
Code |
Description |
| Effluent pump lead, 2-wire |
3132-538 / 539 / 540 / 541 |
10, 25, 50 and 100 ft replacement leads |
| Pump end only |
22050KAJ and others |
Thermoplastic pump ends, listed separately |
