SPC DERV, DERVDX, DERVCHW Installation, Operating And Maintenance Instructions

INSTALLATION, OPERATING
AND MAINTENANCE INSTRUCTIONS

DERV(DX/CHW)

C/W CHILLED WATER AND SPLIT SYSTEMDX COOLING

QA/IOM/63 ISSUE 2 – DERV

UNITS

1 General Description

SPC DERV(DX/CHW) units are heat recovery ventilator units incorporating heat recovery heat
pipes, dehumidifier heat pipes and an active DX cooling coil or chilled water cooling coil. DX units
are supplied with a matched condensing unit for external mounting and for piping to the DERVDX
unit which acts as the indoor unit in the split system.

The units are intended to fully condition outside air by taking advantage of the cooling potential of
dirty extract air and the cooling and dehumidifying potential of a DX evaporator coil or chilled
water cooling coil.

The units are constructed in two halves; one half incorporating the extract fan(s) and extract
section of the heat recovery heat pipe, the other half contains the supply fan(s), supply section of
the heat recovery heat pipe plus chilled water/DX cooling coil c/w heat pipe wrapped around it.
The wrap around heat pipe precools the air prior to the cooling coil and reheats it after the cooling
and dehumidifying process to generate neutral ventilation air.

Units incorporate filtration on both the supply and extract side and are designed to be mounted
out of sight above false ceilings, suspended from the ceiling slab.

The supply and extract sections terminate in sheet metal flanges for the attachment of ducting.
Ducting design will be to suit the desired distribution within the premises and is largely beyond the
scope of this manual.

Units are supplied with an on/off and three speed controller to control the rotational speed of the
backward curved centrifugal fans and hence control the throughput of air on both the supply and
extract side. Further control of the air throughput must be made as part of the ducting design with
branch sizes matched to air volumes and manual volume control dampers fitted where
necessary. DX versions supplied with matched outdoor units incorporate a relay for switching of
the compressor and an additional temperature setting switch.

2 Technical Details

The table below gives details of the nominal operating characteristics of the DERV units along
with pertinent weights and dimensions. Operating limits for the units are as follows:

Maximum outside air temperature: 55°C
Minimum outside air temperature: 5°C
Maximum extract air temperature: 40°C
Minimum extract air temperature: 5°C
Units should be installed in a non-condensing environment.
Minimum outside air temperature for condensing unit operation of DX model: 20°C

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DERV chilled water units

Unit size 80 150 250
Nominal supply volume (litres/s) 107 155 236
Nominal extract volume (litres/s) 107 155 236
Nominal supply external static (Pa) 80 80 80
Nominal extract external static (Pa) 80 80 80
Total net cooling (W) 6375 9788 15127
Sensible cooling (W) 3313 4929 7561
Cooling coil total capacity (W) 5150 7779 11462
Supply air dry bulb (°C) 20.2 19.5 19.3
Supply air wet bulb (°C) 17.1 16.0 15.7
Heat recovery heat pipe cooling load saving (W) 1225 2009 3665
Wraparound heat pipe precool load saving (W) 622 1040 1660
Wraparound heat pipe reheat load saving (W) 622 1040 1660
Power supply (V/Ph/Hz) 230/1/50 230/1/50 230/1/50
Nominal current draw (A) 0.6 1.0 1.7
Nominal power draw (W) 138 230 391
Weight (kg) 75 100 130
Water flowrate (litres/s) 0.22 0.33 0.51
Water pressure drop (kPa) 10 9 18
Coil inlet connection size (mm) 15 22 22
Coil outlet connection size (mm) 15 22 22

The conditions upon which the above data is based are as follows:
Outside air @ 46/30°C
Extract air @ 25°C
CHW flow/return @ 7.2/12.8°C

500
473
473

80

80
30310
15155
23970

19.3

15.7
6340
3320
3320

230//1/50

3.4
782
190

1.02
19
28
28

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DERV DX version

Unit size 150 250

Nominal supply volume (litres/s) 155 236

Nominal extract volume (litres/s) 155 236

Nominal supply external static (Pa) 80 80

Nominal extract external static (Pa) 80 80

Total net cooling (W) 9788 15127

Sensible cooling (W) 4929 7561

Supply air dry bulb (°C) 19.5 19.3

Supply air wet bulb (°C) 16.0 15.7

Cooling coil total capacity (W) 7779 11462

Heat recovery heat pipe cooling load saving (W) 2009 3665

Wraparound heat pipe precool load saving (W) 1040 1660

Wraparound heat pipe reheat load saving (W) 1040 1660

Power supply (V/Ph/Hz) 230/1/50 230/1/50

Nominal current draw (A) 1.0 1.7

Nominal power draw (W) 230 391

Weight (kg) 100 130

Suction connection (“) 7/8 7/8

Liquid connection (“) 3/8 3/8 5/8 5/8

Outdoor unit power supply (V/Ph/Hz) 230/1/50 230/1/50 400/3/50 400/3/50

Outdoor unit nominal power draw (A) 13.1 18.0 8.4 8.4

Outdoor unit nominal power draw (W) 3013 4140 4143 4143

Compressor Reciprocating Reciprocating Scroll Scroll

Refrigerant R22 R22 R22 R22

Expansion device Capillary Capillary Valve Valve

Outdoor unit size WxHxD (mm) 1020x954x406 1020x954x406 1020x1270x406 1020x1270x406

Outdoor unit weight (kg) 80 90 110 120

375 500

358 473

358 473

80 80

80 80

22907 30310

11470 15155

19.3 19.3

15.7 15.7

18125 23970

4782 6340

2504 3320

2504 3320

230/1/50 230/1/50

2.0 3.4

460 782

170 190

1,1/8 1,1/8

The conditions upon which the above data is based are as follows:
Outside air @ 46/30°C
Extract air @ 25°C

Table1: Technical data

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Detailed unit dimensions and construction information is highlighted on the figure below:

igure 1: Physical unit data

F

Outdoor unit sizes for DERVDX models are given in the performance table above.

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3 Reception & storage

DERV units are delivered in purpose made cardboard containers, if ordered as a DX version with
outdoor unit then this will be packaged separately. Upon receipt of the units the packaging should
be checked for any obvious damage and the labeling checked against the project requirement.
Any damage or delivery discrepancy should be reported to the SPC local office immediately. After
checking the packaging the units should be removed and a visual inspection carried out and any
damage reported immediately. If the units are not to be installed immediately then they should be
returned to the packaging for storage.

It is recommended that the units be stored in a safe location away from site activity and they must
not be exposed to the ambient. Units must be stored in non-condensing atmospheres where
temperatures cannot exceed 50°C.

4 Installation

4.1 Mounting of Indoor Unit

DERV and DERVDX indoor units must be installed horizontally and are intended to be fitted in a
concealed location, ideally above a false ceiling. The units must be suspended from the concrete
ceiling slab or other fixed and firm horizontal steelwork. Care must be taken to ensure that the
DERV(DX) unit is fixed to a structure that will accept the unit weight as shown in the above table
and that vibrations are not transmitted.

DERV(DX) units are supplied with 4-off robust fixing lugs at each of the corners of the unit (6-off
on the size 500). Each of these lugs incorporates a rubber bush to prevent unit vibrations being
directly transmitted to the mounting/support rods. The units should be mounted from the
ceiling/steelwork using threaded drop-rods. These drop-rods are not supplied with the units but
we recommend the use of M8 threaded rod.

The ceiling or support structure should first be marked out to match the position of the holes in
the DERV(DX) unit fixing lugs. The structure should then be drilled and fitted with suitable
anchors capable of accepting the weight of the DERV(DX) unit. Brackets can then be secured to
the ceiling anchors for securing the threaded drop rods. The rods should be cut to length and
secured to the ceiling bracket or supporting steelwork and the other end passed through the fixing
lugs on the DERV(DX) unit.

The drop-rods should be secured with suitable nuts on either side of the fixing lugs around the
anti-vibration bushes. It is important that the unit is fitted level in both directions so that correct
operation and drainage are ensured. A maximum deviation of 3mm from the horizontal should be
maintained and checked on installation using a spirit level and adjusted using the retaining nuts
on the fixing lugs.

4.2 Mounting/Location of Outdoor Unit (DERVDX only)

Outdoor units supplied with DERVDX are suitable for floor mounting and are side discharge
models. It is important that there is no obstruction on the air inlet and outlet sides of the unit and
that there is no possibility of hot discharge air being drawn back into the inlet.

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