Page 115 - HVAC Pump Handbook

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Physical Description of HVAC Pumps

112 HVAC Pumps and Their Performance

Figure 5.4 In-line pumps. (From Patterson Pump Company HVAC Pumps and Systems
Manual, 2004.)

This pump was built in small motor sizes initially, but it is now
available in motor sizes as large as 400 hp. Great care must be taken
with these pumps to ensure that the piping does not impose stress on
the pump connections. If this happens, excessive maintenance on
bearings and mechanical seals will result.
This pump can save considerable floor space in an HVAC equip-
ment room. It can be mounted directly in the pipeline, or it can be
mounted on a base like any other pump.
5. Multistage (Fig. 5.5). This single-suction pump is often mis-
named as a multistage horizontal split case pump, a name that does
not recognize that it is a single-suction pump. This pump has two to
five stages with internal passages that carry the water from one stage
to the next. The pump is flexibly coupled to a standard motor when
mounted horizontally. It can be mounted vertically and still be flexi-
bly coupled to a vertical, solid-shaft motor.
This pump is not seen often on HVAC water systems. Its principal
use is in pumping condenser water in tall buildings with indoor
sumps that require high pump heads.
6. Self-priming (Fig. 5.6). The self-priming pump is always a single-
suction type. It can be close coupled or flexibly coupled to the motor
like other single-suction pumps.
The principal feature that these pumps have is the ability to prime
themselves. Water can be lifted from below-grade tanks into the pump

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