TM 55-1930-209-14&P-16
CHAPTER 4 HEATING AND AIR CONDITIONING (HAC) SYSTEM
Section I. Description and data
4-1 Description. The dayroom and workshop are provided with heated and cooled air from a HAC unit on the forward
bulkhead in the workshop This unit forces either heated or cooled air through overhead ductwork into the workshop and
dayroom. Bulkheads in both rooms are well insulated so that a reasonable temperature is maintained. The control to
select either heating or air conditioning (AC) is on upper right side of box containing heating element above the AC unit
(Figure 4-1). The AC controls (Figure 4-2) are on front of the unit. The heating unit, located In ductwork above the AC
unit, uses an electrically powered element. Both heating and AC use the blower fan in the AC unit to move air into the
dayroom and workshop. The thermostat for the heating portion of this system is on the port bulkhead in dayroom near
the refrigerator receptacle. Both dayroom and workshop are also equipped with a mushroom-style, nonpowered
ventilator In the deckhouse top.
The AC unit's water cooling condenser is provided seawater from one of two sources. if seawater pumps In void 2
starboard are operating, and the proper valves open, they provide seawater for cooling the AC condenser and for cooling
the chlorination unit. When these pumps are not operating, seawater for cooling is provided by an AC cooling water
pump. This pump draws seawater from the forward searchest through a set of AC seawater strainers in void 2 port and
provides water for cooling both the AC unit and the chlorination unit. For details, see TM 55-1930-209-14&P-2, Seawater
Systems.
Installation of this system is shown in drawings referenced in Appendix A. Components are listed in Table 4-1
4-2 Capabilities. This system provides sufficient heating or cooling to maintain the dayroom and workshop at normal
working temperatures.
4-3 Special limitations. The HAC system is designed to heat and cool the workshop and dayroom only Doors from
workshop and dayroom to ROWPU space and weatherdeck must be closed when system is in operation. Failure to do so
overloads the system and will lead to Its early failure
4-4 Performance characteristics. The AC unit provides up to 60,000 Btu of cooling per hour, and the heating unit
provides heat equivalent of 15 Kw.
Table 4-1. Major Components of Heating and Air Conditioning System
Component
Qty
Function
Location
5-ton marine air
1
Provides cooled air for
On workshop forward
conditioner
workshop and dayroom
bulkhead
In-line heating
1
Heats air In workshop
In air plenum above AC
element
and dayroom
unit in workshop
Air outlets
2
Directs air flow
1 In workshop, 1 In dayroom
Air ventilators
2
Allows air to exit from
On deckhouse top, 1 in
workshop/dayroom
workshop, 1 in
dayroom
Thermostat
1
Controls heating element
On dayroom bulkhead
near refngerator
receptacle
HEAT/COOU
1
Selects heating or cooling
On side of heating
OFF switch
element housing above
AC unit in workshop
AC control unit
1
Selects AC or fan only
On front of AC unit In
workshop
Cooling pump
Controls cooling pump
On centerline bulkhead
motor controller
in void 2 port
4-1
