SEQUENCE OF OPERATION

Non-Simultaneous and Simultaneous Operation

Double element electric water heaters are designed to operate in a Non-Simultaneous or Simultaneous mode.

Non-Simultaneous Mode: Allows only one heating element to operate at a time. For example, when the tank is cold, the upper element is energized first, heating the top of the tank. Only when the upper thermostat is satisfied, the upper element is de-energized and power is directed to the lower thermostat, energizing the lower element and heating the bottom portion of the tank until the lower thermostat is satisfied. As hot water is drawn off the tank, it is replaced with cold water delivered through the dip tube to the bottom of the tank. The bottom of the tank cools, the lower thermostat will call for heat energizing the lower element. If enough hot water is drawn from the tank, the top portion of the tank cools and the upper thermostat will call for heat, de-energizing the lower element and allowing only the top element to energize until the upper thermostat is satisfied.

Simultaneous mode: allows both heating elements to operate at the same time. That is, if either thermostat (upper or lower) is calling for heat, the corresponding heating element is energized independent of the other.

Sequence of Operation- Double Element, Non-Simultaneous Operation, Single Phase.

1Line voltage is applied across terminals

L1 & L3 of the upper thermostat. ECO is closed, so there is voltage at terminal L4 and to one side of the upper and lower elements.

2Tank is cold therefore both thermostats

are closed at terminal T2 & 2 (calling for heat). The circuit is complete through the upper thermostat only, allowing current to flow through upper element.

3When upper thermostat is satisfied, it opens at terminal T2 interrupting current flow through upper element, and closes at terminal T4 allowing voltage to pass to terminal 1 of lower thermostat. This completes the circuit through the lower thermostat and allows current flow through lower element.

4When the lower thermostat is satisfied, it opens at terminal 2 interrupting current flow through lower element. The system is now in stand-by mode waiting for the next call for heat

1

2

ECO

 

Closed

Thermostat closed

 

at terminal T2

Upper

Upper

T’stat

T’stat

Upper

Upper

Element

Element

 

Thermostat closed

 

at terminal 2

Lower

Lower

T’stat

T’stat

Lower

Lower

Element

Element

5The lower thermostat/element combination will generally cycle on and off more often then the upper. In some cases, such as a cold tank or in high

3

4

5

demand periods, the upper

thermostat will call for heat

(opening at terminal

Thermostat closed

T4 and closing at

at terminal T4

 

terminal T2) prior to the lower thermostat being satisfied. This will interrupt current flow through the lower thermostat and element and allow current to flow through the upper element only. When the upper thermostat is satisfied, it resumes operation as described in sequence #3 above.

Upper

T’stat

Upper

Element

Lower

T’stat

Lower

Element

Thermostat open between terminals 1 and 2

 

Thermostat closed

 

at terminal T2

Upper

Upper

T’stat

T’stat

Upper

Upper

Element

Element

 

Thermostat closed

 

between terminals

 

1 and 2

Lower

Lower

T’stat

T’stat

Lower

Lower

Element

Element

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Bradford-White Corp M-2-50T6DS service manual Non-Simultaneous and Simultaneous Operation
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M-2-50T6DS specifications

Bradford-White Corp is renowned for its commitment to quality and innovation in water heating solutions, and the M-2-50T6DS model exemplifies this philosophy. Designed to meet the needs of both residential and light commercial applications, this 50-gallon gas water heater is engineered for efficiency, reliability, and ease of use.

One of the standout features of the M-2-50T6DS is its high recovery rate, which is achieved through a powerful atmospheric vent design that allows for quick heating of water. The heater’s 40,000 BTU per hour input ensures that there is always a sufficient supply of hot water available when needed. This makes the unit ideal for households with multiple bathrooms or for commercial settings where high hot water demand is common.

The Bradford-White M-2-50T6DS incorporates a state-of-the-art ignition system known as the Direct Spark Ignition (DSI). This technology provides a reliable start-up with minimal energy consumption, enhancing both safety and efficiency. The DSI system reduces the risk of pilot light outages and simplifies the ignition process, making it user-friendly.

In terms of construction, the M-2-50T6DS is built with a robust design featuring a glass-lined tank for superior corrosion resistance. This durable tank is insulated with CFC-free foam, ensuring optimal heat retention and minimizing energy loss. Coupled with the unit's Energy Factor rating, it reflects Bradford-White's dedication to energy efficiency, offering long-term savings on utility bills.

Another notable characteristic is the heater's integrated thermal expansion tank, which helps manage water pressure and reduces damage to your plumbing system, thereby enhancing the overall longevity of both the heater and your home’s plumbing infrastructure.

Safety is a priority with the M-2-50T6DS as well. The model is equipped with a dual-sensor thermostat that monitors the temperature and adjusts accordingly to prevent overheating. Additionally, it features a temperature and pressure relief valve for added safety, ensuring that the unit operates within safe parameters.

In summary, the Bradford-White M-2-50T6DS water heater epitomizes advanced engineering and high performance. With a focus on efficiency, reliability, and safety, this model is an excellent choice for anyone in need of a dependable source of hot water, demonstrating Bradford-White's unwavering commitment to quality in the water heating industry.
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