Weather-Rite TT Series, Инструкция по установке, эксплуатации и обслуживанию

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SECTION 23: D
IRECT FIRED PROCESS AIR HEATERS
113 of 198
the process air heater in compliance w ith:
United States: Refer to NFPA 86 - latest re v ision,
O v ens and F u rnaces /ANSI Z83.25 - latest re v ision,
Direct Gas-Fired Process Air Heaters.
Canada: Refer to CSA 3.19 - latest re v ision, Direct
Gas-Fired Process Air Heaters.
23.1 Direct Fired Process Air Heater Models
• 100% O u tside Air - Ventilating and Baking Cycle
Mode
• 100% O u tside Air - Ventilating w ith Red u ced
Airflo w for Bake Cycle Mode
• 100% O u tside Air - Ventilating w ith Recirc u lation
for Baking Cycle Model (80% Recirc u lated Air
after the bu rner and 20% O u tside Air)
• 100% O u tside Air - Ventilating w ith Recirc u lation
for Baking Cycle Model (90% Recirc u lated Air
across the bu rner and 10% O u tside Air)
Other terms may b e u sed to descri b e the b ake cycle
mode s u ch as; C u re or C u re Time Cycle, Dry or
Drying Cycle, and Flash Kick Cycle. Ventilation air
and the term o
u tside air are also u sed
interchangea b ly.
All process heaters come eq u ipped w ith t w o High
Limit discharge controllers, one for the v entilation
cycle - maxim u m 160 °F (71 °C) (a u tomatic reset)
and one for the b ake cycle mode - maxim u m 300 °F
(149 °C) (man u al reset). The discharge temperat u re
controller limits the temperat u re to a maxim u m
250 °F (121 °C).
23.2 Installer's Responsibilities
1. All access opening(s) to the heated space,
ser v ed b y the Process Heater that can b e u sed
b y personnel to enter the space, m u st ha v e
door interlock s w itch or s w itches to sh u t do w n
the Process Heater if entry is attempted d u ring
the b ake cycle.
2. On recirc u lation Process Heaters, the ret u rn air
d u ct from the ser v ed space m u st ha v e filters
installed to pre v ent partic u late matter from
entering the heater. If not s u pplied b y the Pro-
cess Heater, then the installer m u st s u pply
them. These filters m u st b e appro v ed b y the
a u thority ha v ing j u risdiction of the installation.
3. The ret u rn air d u ct system m u st b e installed
w ith doors, panels or other means for access to
facilitate inspection, maintenance, cleaning
and access to fire protection de
v ices.
4. Instr u ctions m u st b e pro v ided to req u ire peri-
odic inspection and cleaning of the recirc u la-
tion air d u ct. The installer m u st s u pply this
information.
5. The gas piping installer m u st locate a man u al
emergency gas sh u toff v al v e in an appropriate
location that allo w s access to sh u t off the flo w
of gas to the Process Heater in case of an
emergency.
6. If a post p u rge (cool-do w n) cycle is not s u p-
plied w ith the Process Heater, then the installer
m u st s u pply a timing circ u it that allo w s 100%
v entilation air of the space to cool the prod u cts
do w n and p u rge any air b orne contaminants.
See Page 113, Figure 94
FIGURE 94: Cool Down Cycle Circuit
7. It is also s u ggested that the follo w ing B u rn
Hazard Warning b e installed at all access
opening(s) to the heated space, ser v ed b y the
Process Heater, that can b e u sed b y personnel
to enter the space. If additional bu rn hazard
w arnings are needed, contact Weather-Rite
-
f
-
-
A
B
TO MAI N PO W ER
f f
f
f
f
f f
f
FUSE F2 FUSE F3
120 V
CO N TROL TRA N SFORMER
COOL DO WN
TIMER COIL*
HEATER
RU N CO N TACT
BAKE CYCLE
AUXILARY CO N TACT
SUMMER/OFF/ W I N TER S W ITCH*
1
1
15
16
17
3
4
13
5
15
COOL DO WN TIMER CO N TACT
SUPPLY FA N O V ERLOADS
SUPPLY FA N CO N TACTOR COIL
SUPPLY FA N AUXILIARY CO N TACT
SUPPLY FA N AIR FLO W S W ITCH
V OLUME AIR FLO W S W ITCH
TERMI N AL LOCATED O N MAI N PA N EL
TERMI N AL LOCATED O N REMOTE STATIO N
FIELD W IRI N G
KEY;
W I N . SUM.
OFF
13 5
FUSE F1
2
2