Gorman Rupp 16A20-B Pump
Spare Parts for 16A20-B Self Priming Pump
Product Summary
The Gorman-Rupp 10 Series 16A20-B is a heavy-duty self-priming centrifugal pump designed for high-capacity applications requiring reliable handling of large solids-laden liquids. As a larger variant in the proven 10 Series family, this pump excels in municipal sewage bypass, industrial waste transfer, construction site dewatering, and mining applications where exceptional solids passage and robust performance are critical.
- Superior Solids-Handling Capacity: Semi-open impeller design efficiently passes up to 2.5 inch (63.5mm) diameter spherical solids—more than double the capacity of smaller 10 Series models, making it ideal for challenging sewage and industrial applications
- Proven Self-Priming Capability: Integrated suction check valve and efficient priming design deliver reliable self-priming performance, eliminating the need for foot valves and enabling flexible above-liquid installation
- Heavy-Duty Construction: Cast iron casing with ductile iron impeller, steel wear plate, and alloy steel shaft provide exceptional durability in the most demanding municipal and industrial applications
- Field-Serviceable Design: Removable back cover provides direct access to wear plate without piping disconnection, while pedestal-mounted configuration enables complete seal and impeller service with minimal downtime
- Versatile Drive Configurations: Compatible with electric motors (single/three-phase), diesel/gasoline engines, or bare shaft options using flexible coupling or V-belt drive systems to match any power source requirement
Spare Parts List
| Select | Qty | Part Number | Description | Material / Spec |
|---|---|---|---|---|
| 1 | 7759B | Impeller | Semi-open ductile iron, 2.5" solids passage | |
| 1 | 12461 | Seal Assembly | Complete mechanical seal assembly | |
| 1 | 2545 | Wear Plate Assembly | Replaceable steel impeller wear surface | |
| 1 | 7265 | Check Valve Assembly | Suction check valve, complete assembly | |
| 1 | 38515-516 | Impeller Shaft | Alloy steel shaft with bearing journals | |
| 1 | S1030 | Ball Bearing (Inboard) | Shielded ball bearing with retaining ring | |
| 1 | S1077 | Ball Bearing (Outboard) | Shielded ball bearing | |
| 2 | 25227-534 | Oil Seal (Set of 2) | Bearing retainer & cap oil seals | |
| 1 | S1935 | Oil Seal (Seal Plate) | Seal plate oil seal | |
| 1 | 38272-517 | Seal Plate | Cast iron seal mounting plate | |
| 1 | 11907 | Shaft Sleeve | Seal shaft sleeve | |
| 1 | 34G | Casing Gasket Set | Pump casing gasket set | |
| 1 | 7668G | Back Cover Gasket | Back cover plate gasket | |
| 2 | 1679G | Flange Gasket (Set of 2) | Suction & discharge flange gaskets | |
| 1 | 38322-522 | Bearing Retainer | Inboard bearing retainer | |
| 1 | 10278 | Impeller Washer | Impeller thrust washer | |
| 1 | N0615 | Shaft Key | Drive shaft key | |
| 1 | 5091 | Impeller Shim Set | For setting impeller-to-seal plate clearance (.010-.040") | |
| 1 | S1165 | Bearing Retaining Ring | Bearing snap ring | |
| 1 | 3209 | Slinger Ring | Oil slinger |
Exploded Parts Views
Key Technical Specifications
| Parameter | Value |
|---|---|
| Model / Series | 16A20-B (10 Series) |
| Pump Type | Semi-Open Impeller, Self-Priming Centrifugal |
| Flow Performance | See performance curve (Page E-1 of manual) - Higher capacity than 14A20-B |
| Rated Power | Varies by application (Typical motor: 2.2-5.5 kW) |
| Voltage / Frequency | 240V Single-Phase / 415V Three-Phase, 50Hz (Other voltages available) |
| Suction / Discharge Connection | 3" Suction / 2" Discharge (Optional flanges available) |
| Solids Handling Capability | Up to 2.5" (63.5mm) diameter spherical solids |
| Maximum Liquid Temperature | 160°F (71°C) |
| Impeller Type | Semi-Open Ductile Iron Centrifugal |
| Rotation Direction | Per arrow on pump body (varies by configuration) |
| Seal Type | Mechanical Seal with External Lubrication (Bottle Oiler) |
| Materials of Construction | Cast Iron Casing, Ductile Iron Impeller, Steel Wear Plate, Alloy Steel Shaft |
| Installation Type | Pedestal Mounted, Self-Priming |
| Minimum Back Cover Clearance | 9 inches (228mm) minimum, 18 inches (457mm) recommended |
| Bearing Lubrication | SAE No. 30 Non-Detergent Oil (Check via sight gauge) |
Troubleshooting, Common Faults & Solutions
Pump Fails to Prime
Likely Cause: Suction check valve contaminated/damaged, air leak in suction line, collapsed suction hose lining, leaking/worn seal or gasket, suction lift/discharge head too high, strainer clogged, insufficient liquid in casing
Action / Part: Clean or replace check valve assembly (9915), correct air leaks in suction line, replace collapsed suction hose, check pump vacuum (should pull 20" Hg minimum), replace seal assembly (12446) or gaskets (2474G, 2527G), verify suction lift within rated limits, clean strainer, refill pump casing through fill cover
Pump Stops or Fails to Deliver Rated Flow/Pressure
Likely Cause: Air leak in suction, collapsed hose, worn seal/gasket, clogged strainer, suction intake not properly submerged, worn/damaged impeller or wear plate, clogged impeller, pump speed too slow, discharge/suction head too high
Action / Part: Correct suction leaks, replace hose, replace seal assembly (12446) or gaskets, clean strainer, verify proper submergence (see manual Figure 2), replace worn impeller (1692AS) and/or wear plate (2605), clear impeller debris, check driver output/belts for slippage, adjust discharge valve, measure suction lift with vacuum gauge
Pump Requires Too Much Power
Likely Cause: Pump speed too high, discharge head too low, liquid too thick, bearings frozen
Action / Part: Check driver output speed, verify sheaves/couplings correctly sized, adjust discharge valve to increase head, dilute liquid if possible, disassemble pump and check bearings (S1040, S1080)
Pump Clogs Frequently
Likely Cause: Liquid too thick, discharge flow too slow, check valve or foot valve clogged/binding
Action / Part: Dilute liquid if possible, open discharge valve fully to increase flow rate, run power source at maximum governed speed, clean check valve (9915) or foot valve
Excessive Noise / Cavitation
Likely Cause: Cavitation (excessive suction lift/friction losses), clogged/damaged impeller, pump/drive not securely mounted, pumping entrained air
Action / Part: Reduce suction lift and friction losses, record vacuum/pressure gauge readings (consult factory if needed), clean impeller debris or replace impeller (1692AS) if damaged, secure all mounting hardware, locate and eliminate air bubble source
Bearings Run Too Hot
Likely Cause: Low/incorrect lubricant, suction/discharge lines not properly supported, drive misaligned
Action / Part: Note: Bearings normally run to 160°F (71°C). Check SAE No. 30 non-detergent oil level via sight gauge (76) - maintain at middle of gauge (12.5 oz / 0.37L capacity), support piping independently, align drive properly (see manual Section B). If bearings repeatedly overheat, replace bearings (S1040, S1080), oil seals (25258-411, S1452), and bearing retainer O-ring (S2085)
Seal Leakage
Likely Cause: Worn/damaged mechanical seal, insufficient seal lubrication, contaminated seal faces, damaged shaft sleeve, worn seal plate oil seal
Action / Part: Replace complete seal assembly (12446) - never reuse old seal as wear patterns cannot realign, keep bottle oiler (S1933) full with SAE No. 30 non-detergent oil, replace shaft sleeve (3428A) if nicked or damaged, replace seal plate oil seal (S506). IMPORTANT: Impeller-to-seal plate clearance must be .020-.040" - adjust using impeller shim set (37J)
Pump Overheats
Likely Cause: Operating against closed discharge valve, insufficient flow, liquid temperature exceeds 160°F (71°C), pump running dry
Action / Part: CRITICAL: Stop pump immediately if overheated - allow complete cooling before servicing. Never remove covers/plugs from hot pump. Open discharge valve, verify sufficient flow, cool liquid if over 160°F, refill pump casing if run dry (priming). Do not operate against closed discharge valve for extended periods
Incorrect Rotation
Likely Cause: Motor wiring incorrect (three-phase motors)
Action / Part: CRITICAL: Correct rotation is indicated by arrow on pump body. Running pump in wrong direction will cause impeller to unscrew from shaft, causing severe damage. Disconnect pump from motor before checking rotation. For three-phase motors, have qualified electrician interchange any two of three phase wires to change direction. For single-phase motors, consult motor literature
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