PB Heat MIH manual Expansion Tank, INDIRECT-FIRED Water Heater, Freeze Protection

WATER PIPING AND CONTROLS

D.EXPANSION TANK

1.Consult the tank manufacturer’s instructions for specific information relating to tank installation. Size the expansion tank for the required system volume and capacity. See Table 10.2 in Section 10 for boiler water content.

2.Expansion tanks are available with built-in fill valves and check valves for reducing supply water pressure and maintaining minimum system pressure. Check the design features of the tank and provide valves as necessary. Refer back to Figure 3.1 for typical expansion tank piping.

E.INDIRECT-FIRED WATER HEATER

If the boiler is to be used in conjunction with an indirect- fired water heater, refer to Figure 3.7 for typical piping. Follow the instructions provided by the water heater manufacturer. Pipe the water heater as a separate zone.

F.FREEZE PROTECTION

For new or existing systems that must be freeze- protected:

WARNING

Use only inhibited propylene glycol solutions of up to 50% by volume with water. Ethylene glycol is toxic and can attack gaskets and seals used in hydronic systems.

1.Glycol in hydronic applications is specially formulated for this purpose. It includes inhibitors which prevent the glycol from attacking metallic system components. Make certain that the system fluid is checked for the correct glycol concentration and inhibitor level.

2.The glycol solution should be tested at least once a year and as recommended by the glycol manufacturer.

3.Glycol solutions expand more than water. For example, a 50% by volume solution expands 4.8% in volume for a temperature increase from 32°F (0°C) to 180°F (82°C), while water expands 3% with the same temperature rise. Allowance must be made for this expansion in system design.

4.For more information, consult the PB Heat Water Installation Survey and the glycol manufacturer.

Figure 3.7: Typical Piping with Indirect-Fired Water Heater

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