Thermo Pride MHA1-50N Installation And Service Manual page 50

All installations and services must be performed by qualified service personnel.
Yes
After pre-purge,does the
hot surface ignitor energize
and glow?
Yes
After hot surface ignitor
warm-up, does gas valve
open?
Yes
Yes
Is there 120 VAC across draft
inducer power terminals "IND"
& "IND N" at the ignition control
module?
Yes
Check wiring to draft inducer.
If okay, replace inducer assembly.
No
Is there voltage present at the
hot surface ignitor terminals
"IGN" & "IGN N" at the ignition
control module?
Yes
Check wiring to hot surface
ignitor. If okay, replace hot
surface ignitor assembly.
No
Check across "MV" terminals
on ignition control module for 24
VAC during the 4 second flame
proving period after ignitor
warm-up. Is there 24 VAC?
Check wiring to gas valve.
If okay, Replace gas valve.
46
No
Yes
No
Check the ignition control module
diagnostic LED lamp. Reset the
module by interrupting power to
system for more than one second.
If LED stays on continuously, replace
ignition control module.
No