A.Y. McDonald · Backup Sump Pump
Guardian Water-Powered Backup Sump Pumps
A backup sump pump that runs on municipal water pressure, with no battery to maintain; standard and radon-ready, with alarm or RPZ backflow options.
390-1,110 GPH at 10 ft Lift (30-80 PSI Supply)
No Battery or Power Needed
29-90 PSI Supply Pressure
3/4 in FNPT Inlet
1-1/4 in PVC Sch 80 Discharge
Brass and PVC
Made in the USA
10-16 lb Weight
What Ships and What It Needs to Run
Included: the Guardian water-powered pump with its patented activation valve and a single check valve; alarm and RPZ models add the Tank Alert alarm or a 3/4 in reduced pressure backflow assembly, per the model.
Pressurized water supply required. 29 to 90 PSI. Most codes call for backflow protection on the supply; the -0001 models include an ASSE 1013 RPZ assembly.
Sized at install: supply line, discharge pipe and drain for the water the pump uses.
Overview
When the power goes out, the Guardian takes over. It uses the pressure of your water supply to lift water out of the pit, so it needs no electricity and no battery. Designed for groundwater and sump crocks in homes, motels, hotels, schools, hospitals, industrial buildings, computer and record storage rooms.
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Patented activation valve — positive on, positive off.
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Intermittent or continuous use, designed for dewatering.
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Brass and PVC for corrosion resistance.
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Radon Ready models suit basins with a sealed radon mitigation lid.
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RPZ models (-0001) — 3/4 in reduced pressure assembly, ASSE 1013, approved by the USC Foundation for Cross-Connection Control and Hydraulic Research.
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.
1-Year A.Y. McDonald Warranty
Covered for 1 year from the date of installation, or 2 years from the date of manufacture, whichever comes first under Baker Manufacturing’s published limited warranty (A.Y. McDonald Pumps & Accessories price list, effective 7/1/26). 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 unit, installed beside the primary electric sump pump.
Models & Ratings (60 Hz)
| Model |
Part No. |
Configuration |
Option |
Weight |
| 747H20 |
6225-000 |
Standard |
Base Unit |
10 lb |
| 747H20A |
6225-011 |
Standard |
Tank Alert Alarm |
14 lb |
| 747H20-0001 |
6225-006 |
Standard |
RPZ Backflow Assembly |
16 lb |
| 747H20RR |
6225-009 |
Radon Ready |
Base Unit |
10 lb |
| 747H20RRA |
6225-012 |
Radon Ready |
Tank Alert Alarm |
13 lb |
| 747H20RR-0001 |
6225-010 |
Radon Ready |
RPZ Backflow Assembly |
16 lb |
Source: A.Y. McDonald Pumps by Baker catalog, rev 3/26, and Pumps & Accessories price list, effective 7/1/26.
Shared Specifications
| Supply pressure |
29 to 90 PSI |
| Inlet |
3/4 in FNPT |
| Discharge |
1-1/4 in PVC Sch 80 (IPS) |
| Minimum water temperature |
32°F |
| Construction |
Brass and PVC |
Performance — Will It Do What You Need?
| Supply pressure |
30 PSI |
40 PSI |
60 PSI |
80 PSI |
| GPH removed at 10 ft lift |
390 |
630 |
906 |
1,110 |
Gallons per hour removed at 10 ft of lift, by inlet supply pressure, as printed by A.Y. McDonald. Source: Pumps by Baker catalog, rev 3/26, p. 306.
Reading it: on a 60 PSI city supply the Guardian removes about 906 GPH, roughly 15 GPM, at 10 ft of lift.
Before You Buy — The Limits That Decide the Fit
| Water supply |
Municipal or well water at 29 to 90 PSI. Output rises with supply pressure. |
| Backflow |
Check your local code; RPZ models include an ASSE 1013 assembly. |
| Water use |
The pump uses supply water to move pit water; both leave through the discharge. |
| Temperature |
Minimum water temperature 32°F. |
Materials of Construction
| Body and valve |
Brass and PVC |
Accessories
| Accessory |
Code |
Description |
| Guardian float only |
747FLT |
Replacement float, listed with Guardian repair parts |
