Lochinvar 399 Boiler Flow Rate, Placing the Boiler in Operation, Boiler Bypass Requirements

CAUTION:

Hydronic Heating Boilers and Domestic Water Heaters

INSTALLATION Continued

Boiler Flow Rate

The maximum flow rate through the boiler with a copper heat exchanger MUST NOT exceed the following:

Input - Btu/hr		Maximum Flow Rate
399,999	- 750,000	55 GPM
990,000	- 2,070,000	90 GPM

If higher flow rates are required through the boiler, an optional Cupro-Nickel heat exchanger is available. Consult the factory for specific application requirements.

The heat exchanger is generally capable of operating within the design flow rates of the building heating system. Should the flow rate exceed the maximum allowable flow rate through the boiler an external bypass must be installed. The bypass should be fully sized with a balancing valve to allow for proper adjustment of flow. Flow rate can be determined by measuring the temperature rise through the boiler.

Placing the Boiler in Operation

Filling the System

All air must be purged from the system for proper operation. An air scoop and air vent must be located close to the boiler outlet and there should be a minimum distance between the cold water feed and the system purge valve.

1.Close all drain cocks and air vents.

2.Open the makeup water valve and slowly fill the system.

3.If a makeup water pump is employed, adjust the pressure to provide a minimum of 12 psi at the highest point in the system. If a pressure regulator is also installed in the line, it should be adjusted to the same pressure.

4.Close all valves. Purge one circuit at a time as follows:

A.Open one circuit drain valve and let the water drain for at least five minutes. Ensure that there are no air bubbles visible in the water stream before closing the drain valve.

B.Repeat this procedure for each circuit.

Boiler Bypass Requirements

The installer must ensure that the boiler is supplied with adequate flow without excessive temperature rise. It is recommended that this boiler be installed with a bypass in the piping if the maximum recommended flow rate is exceeded. The bypass will help to ensure that the boiler can be supplied with adequate water flow. Flow rates exceeding the maximum recommended flow will result in erosion of the boiler tubes. A typical bypass with a valve as shown in FIG. 40 will allow control of boiler flow.

Temperature/Pressure Gauge

This boiler is equipped with a dial type temperature/pressure gauge. This gauge is factory installed in the outlet side of the heat exchanger. The gauge has one scale to read system pressure and a separate scale to read water temperature in °F.

FIG. 40 Boiler Bypass Piping for High Flow Systems

5.Open all valves after all circuits have been purged. Make sure there are no system leaks.

CAUTION: Do not use petroleum based stop leak products. All system leaks must be repaired. The constant addition of make-up water can cause damage to the boiler heat exchanger due to scale accumulation. Scale reduces flow and heat transfer, causing overheating of the heat exchanger.

6.Run the system circulating pump for a minimum of 30 minutes with the boiler turned OFF.

7.Open all strainers in the system and check for debris.

8.Recheck all air vents as described in step 4.

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