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

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TT-S
ERIES
I
NSTALLATION
, O
PERATION AND
S
ERVICE
M
ANUAL
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19.5 Safety Systems
Safety systems are req u ired for proper performance
of the air handler. The air handler shall not b e
permitted to operate w ith any safety system disa b led.
If a fa u lt is fo u nd in any of the safety systems, then
the system shall b e repaired only b y a contractor
q u alified in the installation and ser v ice of gas fired
heating eq u ipment, u sing only components that are
sold and s u pplied b y Weather-Rite LLC. See Page
86, Figure 36 for a b rief description of each safety
de v ice, its location and its s w itching v oltage.
Table 36: Safety Systems
19.5.1 Manual Reset Hi g h Temperature Limit
Switch
If for any reason, the temperat u re of the air at the
discharge of the b lo w er reaches the limit set point of
160 °F (71.1 °C), the high temperat u re limit s w itch w ill
open the circ u it to the bu rner system and discontin u e
all bu rner f u nctions. E v ents that co u ld res u lt in
excessi v e discharge air temperat u res incl u des
defecti v e bu rner mod u lation system or a s u rge in gas
press u re reaching the bu rner. Restarting the bu rner
can only b e accomplished after the limit has cooled
do w n and the reset bu tton on the s w itch has b een
depressed. This s w itch is located in the air handler
control enclos u re.
19.5.2 Airflow Pressure Switches
The lo w airflo w v elocity press u re s w itch monitors the
airflo w (differential press u re) across the bu rner.
When the airflo w across the bu rner reaches the
proper v elocity ( v ol u me) for com bu stion, the s w itch
closes. When the s w itch closes, it permits the flame
safeg u ard relay to b egin ignition. This s w itch is
factory set at 0.2 in w .c. The high v elocity press u re
s w itch w ill open if the airflo w across the bu rner
exceeds its maxim u m allo w a b le limit. When the
s w itch opens, it sh u ts do w n the flame safeg u ard
relay. This s w itch is factory set at 1.0" w c The
press u re s w itch is a safety de v ice, w hich can b e field-
adj u sted.
19.5.3 Gas Pressure Switches
The high gas press u re s w itch is standard on all
models. The lo w gas press u re s w itch is standard on
certain models. (ANSI and FM compliant gas trains
a
b o v e 2,500 MBH and XL compliant gas trains a b o v e
400 MBH) and are also a v aila b le as an option on the
others.
The f u nction of the gas press u re s w itches is to
protect against either a lack of gas or an excessi v e
press u re in the system.
On the lo w gas press u re s w itch side, this s w itch
opens its internal s w itch w hich sh u ts the bu rner do w n
and pre v ents its operation d u e to ins u fficient gas
press u re.
On the high gas press u re side, its internal s w itch w ill
open, sh u tting do w n the bu rner d u e to excessi v e gas
press u re passing thro u gh the gas train.
The settings of the gas press u re s w itches are field
adj u sta b le. The one monitoring the incoming gas
press u re is the lo w gas press u re s w itch. The lo w gas
press u re s w itch m u st b e set to 2" w c to
accommodate the s u rge drop w hen the v al v es of the
gas train open.
The high gas press u re s w itch m u st b e set to 8" w c to
accommodate the s u rge increase w hen the gas train
v al v e opens.
If either s w itch senses a press u re w hich is lo w er (lo w
gas press u re s w itch) or higher (high gas press u re
s w itch) than its set point, then the s w itch w ill open
and lock o u t, sh u tting the bu rner do w n. The s w itch
w ill ha v e to b e reset man u ally, once the condition has
b een corrected.
19.5.4 Flame Control
This de v ice w ill check for b oth pilot flame and main
flame w ithin the bu rner. When a flame signal from the
pilot flame is a v aila b le, it w ill allo w the main gas v al v e
to open. If a pilot flame is not present, the electrical
signal cannot
b e sent and the pilot gas v al v e w ill
close. The relay is eq u ipped w ith a trial for ignition. If
ignition does not occ u r, the flame safeg u ard relay w ill
try to relight or locko u t (depending on model u sed),
and m u st b e man u ally reset. (See Tro ub leshooting
G u ide - Page 156, Section 27 ).
Safety Controls Location Volta g e
Man u al Reset High-Temp
Limit (All Models)
Air Handler
Control
Enclos u re
120V
Press u re S w itches (All
Models)
Air Handler
Control
Enclos u re
120V
Flame Control (All Models) 120V