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MCDONNELL & MILLER Low Water Cut-Off, 120V - Replacement HVACR Pumps, Valves & Tubing
MCDONNELLReplacement HVACR Pumps, Valves & Tubing

MCDONNELL & MILLER Low Water Cut-Off, 120V

MCDONNELL Replacement HVACR Pumps, Valves & Tubing. Specifications: Product Type: Low Water Cut-Off.

SKU 3G-OTH-77737

Also listed as: RB122E · RB 122E

Brand
MCDONNELL
Item
& MILLER Low Water Cut-Off, 120V
Category
Replacement HVACR Pumps, Valves & Tubing
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Delivery
Worldwide DHL shipping from Singapore; 7–14 business days door-to-door for most destinations.
Payment
Invoicing in USD. Bank transfer (SWIFT) and corporate PO accepted.

Technical Specifications

MCDONNELL
Manufacturer Part Number
RB-122E
Product Type
Low Water Cut-Off

Technical Documents

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MCDONNELL Products
3G Electric (S) Pte. Ltd. — Singapore

Product Description

MCDONNELL Replacement HVACR Pumps, Valves & Tubing. Specifications: Product Type: Low Water Cut-Off.

Frequently Asked Questions

What is the MCDONNELL & MILLER RB-122E low water cut-off used for?

The RB-122E is a residential low water cut-off that protects hot water boilers from damage caused by low water conditions. It automatically shuts down the burner when water level drops, preventing overheating and potential system failure in hydronic heating applications.

What are the specifications of the MCDONNELL & MILLER RB-122E?

The RB-122E is a low water cut-off with a 120V power supply, designed for residential hot water boilers. It is manufactured by McDonnell & Miller under part number RB-122E and is a direct replacement for compatible systems requiring float-type level sensing.

Where to buy the MCDONNELL & MILLER RB-122E worldwide?

3G Electric supplies the McDonnell & Miller RB-122E low water cut-off to customers worldwide. As a global industrial sourcing partner, we handle logistics, customs clearance, and delivery to your location. Contact us for a quote and lead time on this replacement part.

How to install the MCDONNELL & MILLER RB-122E low water cut-off?

Installation typically requires mounting the RB-122E on the boiler supply line above the water line, wiring the 120V control circuit to the burner safety circuit, and verifying proper float operation. Always follow the manufacturer's instructions and local codes for safe boiler operation.

Used in

Common applications for MCDONNELL
Steam boiler low-water cutoff — McDonnell & Miller 61 level control
Condensate receiver level monitoring — McDonnell & Miller RS-4-BR-1 4-level sensor
HVACR pump suction filtration — McDonnell & Miller 340700 strainer basket assembly
Flow switch head replacement — McDonnell & Miller 63-HD head mechanism
Boiler control circuit safety — McDonnell & Miller 7-BM electrical switch with manual reset
Field servicing of flow switches — McDonnell & Miller 310452 cartridge kit

MCDONNELL Products

3G Electric supplies MCDONNELL replacement hvacr pumps, valves & tubing. We supply genuine products with in-stock availability on common SKUs, technical documentation, commissioning support, and warranty service — worldwide.

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Compatible alternatives & equivalents

Cross-referenced by specification & description
This low water cut-off is designed for use in steam and hot water boilers to protect against low-water conditions. It automatically shuts down the burner when the water level drops, preventing dry-fire damage. Suitable for commercial and industrial HVAC systems
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