Harry Taylor HT2000, Installation & Servicing Manual

Page: 14 / 56

14
2.9.2.2 Natural Ventilation Openings
to Enclosures
For enclosure applications the minimum free
area of ventilation opening shall be:
•
At high level 5 cm
2
for each kW of
rated heat input.
•
At low level 10 cm
2
for each kW of
rated heat input.
The high level ventilation opening should be
sited on an external wall and positioned as
high as is practical and always within the top
15% of the wall height
The low level natural ventilation opening
should be situated on an external wall and
be within 1000 mm of floor level for natural
gas and ideally at floor level for l.p.g gas
installations but in any event no higher than
250 mm.
The table in the next column provides
specific data for each heater model as -
2.9.2.3 Mechanical Ventilation to a
Plant Room or Enclosure.
In the event that the installer prefers to
mechanically ventilate the plant room or
enclosure rather than provide ventilation
openings then -
•
The plant room or enclosure needs to
be mechanically ventilated at the rate
of 4.14 m
3
/h of fresh air per kW or
rated heat input.
•
It is a requirement that the mechanical
ventilation shall be of the ’input’ type
with either natural or mechanical
extraction. Where mechanical
extraction is selected then the
extraction rate should be 5%-10% less
than the input rate.
•
Systems of mechanical extraction with
a natural inlet shall not be used
•
It is necessary to provide an automatic
means to safely inhibit heater(s)
operation should mechanical air
supply fail for any reason
Minimum Free Area of
ventilation opening
High Level Low Level
cm
2
cm
2
30 64 128
35 79 158
40 97 194
60 127 254
75 160 320
85 193 386
120 257 514
135 291 582
180 386 722
205 460 920
235 515 1030
275 623 1246
350 769 1538
375 847 1694
Model
Minimum Free Area of
ventilation opening
High Level Low Level
cm
2
cm
2
30 159 318
35 198 396
40 244 488
60 317 634
75 400 800
85 483 966
120 643 1286
135 726 1452
180 965 1930
205 1152 2304
235 1287 2574
275 1558 3116
350 1922 3844
375 2118 4236
Model