Install Instructions

37
4 Water connections (continued)
Installation with a chilled water
system
Pipe refrigeration systems in parallel. Install duct coil
downstream at cooling coil. Where the hot water heating
boiler is connected to a heating coil located in the air handling
units which may be exposed to refrigeration air circulation, the
boiler piping system must be equipped with flow control valves
or other automatic means to prevent gravity circulation of the
boiler water during the cooling cycle.
The coil must be vented at the high point and hot water from the
boiler must enter the coil at this point. Due to the fast heating
capacity of the boiler, it is not necessary to provide a ductstat to
delay circulator operation. Also, omit thermostat flow checks
as the boiler is cold when heating thermostat is satisfied. This
provides greater economy over maintaining standby heat.
Boiler flow rate
Typical heating boiler installations
General plumbing rules:
1. Check all local codes.
2. For serviceability of boiler, always install unions.
3. Always pipe pressure relief valve to an open drain.
4. Locate system air vents at highest point of system.
5. Expansion tank must be installed near the boiler and on the
suction side of the system pump.
6. Support all water piping.
⚠ CAUTION
Do not exceed the maximum flow rate of the
heating boiler.
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.
Installation & Service Manual
TABLE - 4C
BOILER TEMPERATURE RISE AT MAXIMUM FLOW
Temperature Rise at Full Rate Fire
Maximum Flow
Model Temperature Rise °F
497 15 @ 55 GPM
647 20 @ 55 GPM
747 23 @ 55 GPM
987 19 @ 90 GPM
1257 24 @ 90 GPM
1437 27 @ 90 GPM
1797 34 @ 90 GPM
2067 39 @ 90 GPM
TABLE - 4D
MAXIMUM WATER FLOW
The maximum flow rate through a water heater with
a copper heat exchanger must be set to provide and not exceed
the following flow:
Model Maximum Flow
Maximum Flow for
CuNi Heat Exchanger
497, 647, and 747 55 GPM 75 GPM
987, 1257, 1437, 1797, and 2067 90 GPM 115 GPM
⚠ CAUTION: