Lennox MLA018S4S-1P - Page 146

146
Error Code: P1
Description: HighorLowvoltageprotection
General Note: Anabnormalvoltageriseordropisdetectedbycheckingthespeciedvoltagedetectioncircuit.
Voltage protection
Checkthevoltageofoutdoorunitpower
supply,thevoltagebetween
L(L1)andN(L2)rangemin.187~max
253VAC
Yes
CheckwhetherthevoltageofIPMboard
PandNisnormal?277-356VDCfor
18-30KBtu/h;277-410VDCfor36KBtu/h.
No
Replacebridgerectiers,andthen
checkwhetherthesystemcanrun
normally(Onlyfor4-zone)
No
ReplaceIPMboard,andthencheck
for normal unit operation
No
Replaceoutdoormainboard.
Problem Solved.
Yes
Yes
Checktheprimarypowersupply.
No