Installation and Service Manual
Boiler Flow Rate
CAUTION: The maximum flow rate for models 495,000 - 745,000 Btu/hr is 60 GPM and 90 GPM on 985,000 - 2,065,000 models. Do not exceed the maximum flow rate of the heating boiler.
If higher flow rates are required through the boiler, an optional
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.
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 is shown in Figure 30 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 degrees, Fahrenheit.
Figure 30 - Boiler Bypass Piping for High Flow Systems
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.
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
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.
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