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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 Cupro-Nickel heat exchanger is
available. When using a Cupro-Nickel heat
exchanger, GPM can be increased by 30 percent.
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.
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.
Installation and
Service Manual
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 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.
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