Russ
Lifetime Supporting Member
I have a honeywell purple peeper at a clients site and noticed an issue about eight months ago. The relay module (ST 7800 A 1039 /9645) wouldn't always initiate the pilot during start up. The LED for the pilot wouldn't always turn on (on the module), and when it failed to turn on I'd get a fault once the pilot timer completed. This weird condition only happened during start up. Once the burner was lit there were no further odd behaviors.
This lighting issue could happen upwards of a dozen times in a row then disappear for another dozen lights. At the time once the burner was lit, it stayed on. I noted the issue, and recommended troubleshooting the cause with the likely possibility of having to replace the module.
However, about six months ago I added a utility savings program to the equipment. This required the burner to be turned off on a daily basis. I got my chance to troubleshoot.
When troubleshooting the module issue, I noticed leakage voltage, and believed that was possibly a factor in the pilot issue. I connected the keyboard display module (S7800 1001) to verify the exact sequence of events and found that once connected the relay module worked perfectly. The load the keyboard module added seemed to offset the effects of the leakage voltage. There were no further pilot issues. It lit every time. Before connecting the keyboard module I was going to recommend replacing the main relay module.
Every morning the unit automatically lights off, and for the past six plus months there hasn't been a single flame failure.
Why?
This lighting issue could happen upwards of a dozen times in a row then disappear for another dozen lights. At the time once the burner was lit, it stayed on. I noted the issue, and recommended troubleshooting the cause with the likely possibility of having to replace the module.
However, about six months ago I added a utility savings program to the equipment. This required the burner to be turned off on a daily basis. I got my chance to troubleshoot.
When troubleshooting the module issue, I noticed leakage voltage, and believed that was possibly a factor in the pilot issue. I connected the keyboard display module (S7800 1001) to verify the exact sequence of events and found that once connected the relay module worked perfectly. The load the keyboard module added seemed to offset the effects of the leakage voltage. There were no further pilot issues. It lit every time. Before connecting the keyboard module I was going to recommend replacing the main relay module.
Every morning the unit automatically lights off, and for the past six plus months there hasn't been a single flame failure.
Why?
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