Bradford White U2TW75T*RN, Руководство по обслуживанию

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Sequence of Operation
Thermostat Calls for Heat.
Pr i or to e n er gi z ing b lo w er , g as c o n trol c he c ks safet y ci r cui t to in s u re the ci r cui t i s o p e n . Normal s wi t c h p os i t i o n s
in the safet y ci r cui t are as follo w s:
a) Press u re s wi t c h n ormall y o p e n .
b ) B lo w er tem p erat u re s wi t c h n ormall y c lose d .
If the safet y ci r cui t i s c lose d, the c o n trol w a i ts 4 se c o nd s , g as c o n trol L E D flashes
2 times
wi th 3 se c o nd p a u se.
G as c o n trol w a i ts 2 m inu tes the n, b lo w er r un s for 30 se c o nd s. Th i s cyc le re p eats un t i l safet y ci r cui t o p e n s.
Po w er up S e qu e nc e
1
S tart U p .
U p o n p o w er up, the c o n trol r un s a safe-start c he c k wi th a t ypic al start- up d ela y of 1 -5 se c o nd s.
2
Si m u late d R es i st i ve Loa d Dev ic e Che c k.
To assure no outputs are energized if the “Simulated Resistive device” is out of range , the c o n trol wi ll test the
the d ev ic e for p ro p er o p erat ing ra ng e. If the d ev ic e i s wi th in ra ng e the c o n trol res u mes n ormal o p erat i o n wi th n o
p er c e i va b le d ela y . If the d ev ic e i s o u t of ra ng e , the c o n trol L E D i mme di atel y flashes
7 times
wi th 3 se c o nd p a u se.
Normal Heat ing S e qu e nc e
1
2
B lo w er En er gi zes.
3
Press u re Swi t c h Proves B lo w er/Ve n t Sy stem O p erat i o n .
If the p ress u re s wi t c h d oes n ot c lose wi th in 30 se c o nd s , the c o n trol L E D Flashes
3 times
wi th 3 se c o nd p a u se.
The b lo w er r un s for 30 se c o nd s ever y 2 m inu tes tr ying to g et the p ress u re s wi t c h or b lo w er tem p erat u re s wi t c h to
c lose. Th i s cyc le re p eats as lo ng as there i s a c all for heat.
4
B lo w er Pre- pu r g e Per i o d (2 se c o nd s)
5
Tr i al for P i lot I gni t i o n ( 90 se c o nd s).
a) The g as c o n trol l ig hts the pi lot by a c t i vat ing s p ark igni ter a nd g as flo w to pi lot bu r n er.
b ) If flame i s n ot se n se d wi th in 90 se c o nd s , igni ter a nd g as flo w are d ea c t i vate d, b lo w er wi ll p ost pu r g e a nd
c o n trol L E D flashes
6 times
wi th 3 se c o nd p a u se.
6
M a in Bu r n er I gni t i o n
A fter pi lot flame i s se n se d, g as c o n trol a c t i vates ma in valve for ma in bu r n er igni t i o n . The g as c o n trol wi ll ign ore
flame a nd p ress u re s wi t c h s ign als for 3 se c o nd s allo wing for ma in bu r n er to sta bi l i ze.
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