NorAire NC-FE series, Installation & Operating Instructions Manual

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05/16/2014 7 NI216
Mechanical Installation – Hydronic/Warm Water Output
Use standard water heating loop parts/components and piping/plumbing best practices as if this NorAire IDU is
a “boiler”. Using a buffer tank, the input plumbing can be viewed as the “primary loop”. If a single radiant heat
loop is sized for the Btu output of the boiler, no primary loop is required, simply plumb direct to the loop
manifolds.
Drawing HX103 provides suggested piping for ten possible hydronic heat/cool arrangements. Potentially there
can be various combinations of these ten suggestions, but with an experienced hydronic installer, the
information on the HX103 drawing set should provide adequate details to design and install an appropriate
hydronic heat/cool supply arrangement. The upper left introductory statements and the notes on each page are
very important. Do not overlook the intended application associated with its suggested plumbing/piping. This
is specifically true with the chilled water direct supply output going to the water coil and whether or not the
forced air water coil can be used for both heat and cool.
Note: As these heat/cool configurations lead to control complexity, Electro Industries’ Buffer Tank
Controller is recommended and in the case of forced air water coil heat and cool the BTC is required
(order HP-BTC). The BTC has a special operating mode (mode D) designed just for proper interface
with this IDU and this IDU controller must have J3 jumper pulled.
This IDU has an internal circulator hydronic pump with one water
return female NPT port and two water
supply NPT female ports – warm and chilled water are separate.
This NorAire heat pump has separate heating water and chilled water piped outputs. This is an important
feature typically not provided with other air to water (or even water to water) heat pumps. A few of these
benefits include – chilled water does not go through the boiler, the internal pump can be a direct output to the
forced air water coil (often the forced air water coil is a zone from the buffer tank, this inefficient and harder to
control with the radiant floor zone), either the hottest or the coldest water will always get to the forced air water
coil without the buffer tank, etc.
The return/supply piping and external hydronic load components must be sized to maintain the minimum water
flow stated in the Specification Chart. For design planning purposes the IDU external pumping allowed
pressure drop is the Specification Chart
pump feet of head minus the internal pressure drop feet of head.
Since this is primarily a heat pump compressor energy generating product, provisions must be made in the
external hydronic arrangement to make sure a small heating zone does not short cycle the compressor. In other
words, if the smallest zone cannot use or absorb the Btu capacity of the ODU, a buffer tank type arrangement is
required. This same requirement relates to cooling or chilled water direct output. If the forced air water coil
cannot absorb or use the cooling Btu/h of the ODU, piping and system design will require a buffer tank (single
tank will result in heat/cool switchover) or dedicated cooling buffer tank.
Note: The IDU control system is limited, when the system involves buffer tank (single or dual) various
thermostats, air handler, etc. the option Electro Buffer Tank Controller (HP-BTC) is strongly
recommended.
Disclaimer – the intent of the HX103 drawing set is suggested application and system concepts. The end use
designer and installing contractor have the responsibility for all equipment, any additional components not
shown, and detailing required system performance and local codes.
Flow switch – there is a built-in safety flow switch at the internal pump return. Typically this will indicate flow
above 2.0 GPM. The contacts of the flow switch feed into the controller board at the OPT tab.