For Units 2, 3, 4, and 5:

System Operation

5) Run the 4-pin connector of Communication Cable B (9.8 ft, 3 m cable) up through the cable access in the bottom of

Unit 1’s cabinet.

6)Connect the connector of the Communication Cable B to socket 2 on the Control Board. The Communication Cable B ground wire terminals should be grounded with the MSB ground wire and Communication Cable A ground wire terminal.

Ground wires of Communication Cable B

7) Run the other end of Communication Cable B through the cable access in the bottom of Unit 2’s cabinet.

•The Control Board can electronically connect up to 25 water heaters.

•When multiple water heaters are operating, they will attempt to supply equal amounts of hot water.

•On initial water flow demand, from 1 to 3 units which can be determined by Dip SW setting of Master MSB board will open their servos valves until flow demand is determined. See Dip SW table for open water flow valve. Only the necessary number of water heaters will begin to fire to meet demand.

Water heaters not firing will close their valves.

•As the default setting, 3 units will open its servo valve until flow demand is determined.

•It is recommended that the dip switch settings on MSB boards other than the Master MSB board be set for 1 unit ready.

•When installation is completed, do a test run for all units.

•After the test run, check and clean the water filter on all units.

•The temperature setting for all of the connected water heaters is controlled by the temperature controller connected to the water heater with the Master MSB Board. Temperature controllers connected to the other units will provide maintenance codes for their respective units.

•If water heaters do not use a temperature controller, the temperature setting for the water heater with the Master MSB board is used.

•If a water temperature over

140 degree F is desired, then an MCC-91 controller needs to be connected to Master Control Board.

•For proper operation, it is not recommended that different models be connected together. Combining different models may result in lower performance.

•The order in which each water heater operates is occasionally rotated to ensure equal usage among the entire system.

8)Connect the 4-pin connector from Communication Cable B to the 4-pin socket located at the top of the water heater control board of Unit 2. Communication Cable B ground wire terminal should be grounded with the PC board ground wire.

Ground wire of

Communication Cable B

9)Attach the cable tie bracket to the bottom of the water heater cabinet using the existing screw. Pull all of the excess cable up into Unit 2’s cabinet, and then secure it tightly to the bracket using the cable tie.

10)Repeat steps 5 to 9 for Units 3, 4, and 5, as applicable.

Note: Communication Cable B for Unit 3 plugs into socket 3, Unit 4 plugs into socket 4, etc.

11)After making all of the connections to the Control Board, tighten all of the cable ties used to secure the Communication Cables.

12)Place the front cover panels back on each of the water heaters using (4) screws.

13)Restore power to the water heaters.

Dip SW table for open water flow servo valve

When viewing the installed MSB board, the dip switch will be as shown below (upside down).

 

3 units ready (default)

2 units ready

1 unit ready

 

 

 

 

 

No1 OFF

No1 ON

No1 ON

Dip SW

No2 OFF

No2 OFF

No2 ON

 

 

 

setting

 

 

 

 

 

 

 

NOTE: In a recirculation system, in order to increase the tempera- ture setting, it is necessary to turn off the power supply to the circulation pump, increase the temperature setting, and then turn the pump back on. No additional action is necessary when decreasing the temperature setting.

Indicator lights on the Control Board indicate the status of each of the water heaters as follows:

LED 6

(Working with multiple MSB boards)

LED 1 ~ 5

 

LED 1 ~ 5

EXPLANATION

 

 

 

 

Solid

Water flow servo valve is open when water

 

 

heater is in standby or working.

 

 

 

 

Flashing Slowly (1.2

Water flow servo valve is closed when water

 

sec on / 0.5 sec off)

heater is not operating.

 

 

 

 

Flashing Quickly

An error is detected. A temperature controller

 

(0.5 sec on / 0.5 sec

must be connected to this unit to read the

 

off)

error code.

 

 

 

 

Off

No unit detected at this connection.

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Rinnai MSB-C1, MSB-M For Units 2, 3, 4, System Operation, Dip SW table for open water flow servo valve, Led, Explanation
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MSB-M, MSB-C1 specifications

The Rinnai MSB-C1 and MSB-M are cutting-edge gas condensing boilers designed to deliver exceptional heating and hot water performance for residential and commercial applications. Rinnai, a leading manufacturer known for its innovation in heating technology, has equipped these models with advanced features that enhance energy efficiency and user comfort.

One of the standout features of the MSB-C1 and MSB-M is their ability to provide high energy efficiency ratings. These condensing boilers utilize a heat exchanger that captures and reuses exhaust gases, maximizing energy output while minimizing waste. This innovative design not only reduces fuel consumption but also lowers greenhouse gas emissions, making these models an environmentally friendly choice.

The MSB-C1 and MSB-M are equipped with intelligent control systems that allow users to easily manage heating and hot water needs. The integrated control panel offers user-friendly operation, enabling precise temperature adjustments and scheduling options. This level of control ensures that users can optimize energy usage based on their specific requirements.

Safety is a top priority in Rinnai’s designs, and both models come with numerous safety features. The built-in pressure relief valve and flame failure safety mechanism provide peace of mind, ensuring the boilers operate safely under various conditions. Moreover, the models are constructed with durable materials that enhance longevity while minimizing maintenance needs.

The Rinnai MSB-C1 is ideal for larger homes or commercial spaces, offering a robust output to efficiently meet significant heating demands. Conversely, the MSB-M is designed for smaller environments, providing flexibility without compromising on performance. Each model is capable of delivering hot water on demand, reducing the waiting time for users and ensuring comfort at all times.

Installation has been simplified with the MSB-C1 and MSB-M models, as their compact design allows for versatile placement within buildings. They can be easily integrated into existing heating systems, facilitating upgrades without extensive modifications.

In summary, the Rinnai MSB-C1 and MSB-M are sophisticated condensing boilers that combine efficiency, safety, and user-friendly features. Their advanced technology and environmentally conscious design make them an excellent choice for those seeking reliable and sustainable heating solutions. These systems not only fulfill heating requirements but also promote energy conservation, making them a forward-thinking option for any space.
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