Venmar HEPA 4000 Specifications download pdf (Page 24)

Appendix C: Water Source Heat Pump (WSHP)

Water Line Piping Requirements and Options

Water Supply and Return Piping Requirements

Recommended and required WSHP water line piping com-

ponents with a detailed functional description are outlined

below:

• Manual shut-off valves in supply and return water

lines are recommended for isolation and service.

• Pressure and temperature gauge connections in the

supply and return water lines are recommended for

testing and service.

• A water strainer (16–20 mesh minimum) in the sup-

ply water line is recommended on open loop systems

to eliminate contaminants.

• Air vents are required on the high side of the water

supply or inlet line to discharge the non-condensable

air in order to avoid unexpected high head pressure

and poor cooling/heating performance. Manual air

vents are factory installed on the water condenser

and economizer coil (if equipped).

• A balancing valve with pressure and temperature

gauge connections in the return water lines is recom-

mended for balancing and service.

• A two-way motorized on/off water shut-off valve

is recommended to isolate water ﬂowing through

both the economizer coil (if equipped) and water-to-

refrigerant condenser for conservation when the unit

is off. The motorized water valve must open 90 sec-

onds prior to compressor start-up and remain open

ﬁve seconds after the compressor is shut off.

• A waterside economizer coil, a three-way modulating

water economizer valve and a temperature sensor

on the water inlet or supply line and downstream of

the economizer coil is required for energy conserva-

tion. The water temperature sensor is input to the

DDC Control System which determines when to

divert water to the economizer coil for energy con-

servation in cooling mode. The three-way motorized

economizer valve and the inlet water temperature

sensor are included with the WSHP WiSE coil option

and factory provided and installed in the compressor

compartment.

• A three-way modulating head pressure control valve

is required to maintain stable operation of the re-

frigeration systems when operated on ground loop

water systems when the design inlet water tempera-

ture is below 65°F [18°C] in the cooling mode. A

refrigerant pressure transducer on the compressor

discharge is used to modulate the water ﬂow to the

condenser using a 2 to 10 VDC signal to prevent the

compressor discharge pressure from falling below the

compressor operating limit. The three-way motorized

valve and the pressure sensor option is factory pro-

vided and installed in the compressor compartment

if the design inlet water temperature is below 65°F

[18°C] in the cooling mode.

• A ﬂow switch is required on the water return or leav-

ing side of the condenser to monitor the presence or

absence of ﬂow which will shut down the compres-

sor and unit if no ﬂow is present. The water ﬂow

switch option is factory provided and installed in the

compressor compartment.

• A water temperature sensor is required on the water

return or leaving side of the condenser to monitor

the water temperature which will shut down the

compressor and unit for freeze protection if the leav-

ing water temperature drops below 35°F [2°C]. The

water temperature sensor option is factory provided

and installed in the compressor compartment on

100% water systems.

• A relief valve must be installed in the water supply or

inlet line if the maximum pressure of components is

less than the water supply pressure to prevent dam-

age, injury or death due to instantaneous release of

high pressure water.

Factory Installed Piping Options and

Physical Description

Some of the recommended and required components in

the water supply and return line are available or included

as factory installed and pre-wired options. When the fac-

tory installed options are selected the piping schematic,

component size and C

rating will be included based on

compressor selected with the submittals. These compo-

nents are mounted inside the compressor compartment,

piped in copper lines with sweat or threaded connections

as indicated in the submittals. Physical description, opera-

IMPORTANT

WSHP external water supply and return piping shall be in

accordance with National and Local Codes. Line sizing,

pressure limiting devices, backﬂow preventers, strainers,

valves, ﬂow temperature and pressure measuring, freeze

protection, all other safety or control piping requirements

for system operation are the sole responsibility of the

Installing Contractor and/or Design Engineer. The water

supply must be sized for the minimum ﬂow as indicated

on the mechanical drawings.

WARNING

Prior to connection of water supply or inlet line, verify

water pressure is less than the maximum pressure for

components in the water line. To prevent injury or death

due to instantaneous release of high pressure water,

relief valves must be installed in system water supply or

inlet piping.

VCES-VHC72-IOM-1H

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Venmar HEPA 4000 Specifications Page 24

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