Heatcraft Refrigeration Products 4346B001 User Manual

Bulletin H-IM-71A

Part No. 4346B001

August 2002

(Replaces H-IM-71, August 1996)

Air Handler Unit

Installation & Operations Manual

TABLE OF CONTENTS

Coil Stacking ........................................................................................ 5

Condensate Drain Traps .......................................................................

Direct Expansion Coils .........................................................................

Filter Quantities ....................................................................................

Freezing Temperatures ........................................................................

Inspection ............................................................................................

Installation ...........................................................................................

Internal Isolation ..................................................................................

Maintenance ........................................................................................

Motors & Drives ...................................................................................

Replacement Parts ...............................................................................

Section Assembly .................................................................................

Shipment of Sections ...........................................................................

Start-up ................................................................................................

Steam Coils ...........................................................................................

Water Coils ...........................................................................................

Weights ................................................................................................

4
3
8
6
2
2
4
4
2
8
5
7
4
2, 3
3
7

Inspection

Shipment should be checked against the bill of lading to
verify that all items listed have been received.

All parts should be carefully inspected to determine if
any damage was incurred in shipment.

Any shortage and/or claims for damage should be
immediately reported to the delivering carrier followed
by filling a claim for shortages and/or damages.

Shipment of Units

Depending on the unit size and accessories included,
the shipment may be made in two or more sections.

Handling

Special care should be taken when handling and
assembling component sections of the unit. Rough
handling at the job site can result in damaged bearings,
bent shaft, etc.

All units are shipped on wooden skids. It is
recommended that units not be moved removed from
skids until they are at a place of installation. The
mounting legs/rails provided for isolators should be used
when lifting units into place.

Suspended Units

Unit sizes 03 through 41 may be ceiling suspended from
the mounting legs/based rails with 5/8” diameter rods
(furnished by others). These rods will pass through the
11/16” diameter mounting holes provided.

Unit sizes 50, 65, and 75 cannot be ceiling suspended.

Installation

It is very important that the unit be installed in a level
position to prevent distortion and to insure proper
damper operation and coil drainage.

Allow sufficient space around the unit for proper
maintenance. Major factors to be considered are
filter removal for cleaning or replacement, access
to all removal panels, removal of coils and shaft if
ever necessary, lubrication access and motor belt
adjustment.

Canvas duct connections should be used between the
unit and both supply and return air ducts.

Units are furnished with 1 1/4” F.P.T. Drain connection
on each side of the coil section. The drain line from
the drain pan connection must be adequately pitched

and should have a water seal of sufficient depth to
compensate for the air pressure within the units.
(See Condensate Drain Traps on page 4.)

When the unit is located on the roof, it must be mounted
on support beams that span load bearing walls. If this
is not done, excessive vibration may occur due to the
resiliency of the roof.

Fan noise is a function of the fan design, volume flow,
pressure, and the efficiency of the fan. Present methods
of measuring fan noise do not evaluate the pure tones
generated by some fans and these tones can be
objectionable when radiated into occupied spaces.

Therefore, on critical applications we recommend extra
sound attention in the octave band containing the tone.

Motors & Drives

All units will normally be shipped with motor and drive
installed.

When mounting a motor on the adjustable base (Installed
on the unit) extreme care should be taken to insure
proper alignment and belt tension.

All electrical work should be done in strict accordance
with local codes and regulations.

Steam Coils

Type “J” and “NFS” coils have supply and return
connections on the same end. Types “R”, “S”, and “RA”
coils have supply and return connections on opposite
ends.

Type “NFD” coils have supply connections one each end
of the coil , with a single return connection, one end only.

All piping should be in accordance with accepted
industry standards and local codes. Support all piping
independent of coil and provide adequate swing joints in
all piping to absorb expansion and contraction strains.

Run return piping the full size of the coil return connection
from the coil to a dirt pocket. (do not use reducing
fittings.)

Install drip traps in steam mains ahead of coils. Do not
drip steam mains through the coils.

Install a vacuum breaker (1/2” 15º check valve) ahead of
the trap on low pressure open gravity return systems and
on high pressure systems. Install a 1/2” 15º swing check
valve in a 1/2” vacuum equalizing line, bypassing the
condensate trap, on low pressure vacuum systems.

2

When two or more steam coils are furnished in a unit,
provide separate traps for each coil. Size traps with
ample capacity using the maximum heating load and
service factor recommended b y the trap manufacturer.

Select control valves in accordance with the
recommendations of the control manufacturer using
actual heating loads.

Install suitable strainer ahead of all automatic valves and
traps to catch dirt and scale. Provide adequate air vents
to expel air and other non-condensable.

Control valves used for Type “J”, “NFS”, “RA” and
“NFD” coils must be gradual acting modulating type with
veeport.

Where a control valve is used for Type “S” or “R” coils
and when the entering air temperature is below 35ºF.,
use a two position valve. Locate control element in the
entering air stream so that valve will remain open with
a minimum of five pounds steam pressure when the
entering air temperature is below 35ºF.

Typical Steam Coil Piping

Low Pressure Open Gravity Return System

Steam Main

Gate Valve

12” Minimum

High Pressure System

12” Minimum

Control Valve

Union

Vacuum Breaker
1/2”-15” Check Valve

Vent

Gate Valve

Union

Strainer

Dirt Pocket

Control Valve

Union

Vacuum Breaker

Vent

1/2”-15” Check Valve

Gate Valve

Union

Strainer

Dirt Pocket

Strainer

Combination Float

Thermostatic Trap

Strainer

Union

and

Return Main

Gate Valve

Union

Float or

Bucket Trap

Return Main

Open Vent

Steam Main

When the system is started up the damper should remain
closed for approximately ten minutes after the steam
valve is opened.

Properly locate all temperature sensing elements at a
point of true average air mixture temperature.

Refer to “Typical Steam Coil Piping Diagrams” for
controls positioning and piping configuration.

When face and bypass dampers are used, it is good
practice to install on the coil a valve which closes as
the face damper closes to prevent over heating due to
damper leakage or heat picked up by the air wiping the
exposed coil face.

Water Piping

All piping must be supported independent coils.

Swing joints or flexible fittings must be provided to absorb
expansion and contraction strains. Rigid piping may also
reduce effectiveness of vibration isolators.

The water supply should always be connected to the
bottom inlet of the coil. The coil connections are identified
with stickers.

Water coils , 3 through 10 rows, are supplied with a vent
and drain connection (1/4” MPT) which extends through
the unit casing.

For protection of coils exposed to freezing temperatures,
refer to page 6.

Coils must be adequately vented in order to prevent air
binding.

Direct Expansion

Both the liquid distributor and the suction line extend
through the casting.

The expansion valve utilized must be of the external
equalizer tube type. The expansion valve bulb must be
located on the suction line between the coil and the 1/4”
external equalizer tube. Never locate the bulb in a trap.

All refrigerant piping practices used should be in
accordance with local codes and latest ANSI Standard
B9 Safety Code. Hard drawn type “L” or “K” copper tubing
should be used. Soft tubing where bending is required
may be used provided it is protected in accordance with
local code restrictions.

Good Practice should be followed as to pulling adequate
vacuum, tubes cleaned of foreign material, etc.

3