Hello
A few years ago I replaced (and rewired & changed back plate) a Honeywell ST7100 with a new Honeywell st9400c for a gravity system. The reason was that the old controller was coming ON at random times (both HW and CH) when it should have been OFF.
However, this problem has persisted for a few years with the new honeywell st9400. I have lived with it because it does not happen often, but sometimes it seems to get worse. These are a few facts/synptoms:
-The honeywell st9400c number is 4214, so in theory it is not part of the bad batch (1037 - 1139)
-The unit randomly changes from Auto mode, to Cont or Once modes (so it turns itself ON when the Auto timer is OFF), for one of both HW and/or CH
-Unlike many other users with the bad batch, I can run both HW and CH at the same time, no problem.
-This happens anytime of the year , regardless of outside temperatures (there's a HW thermo, but not for CH)
I would be happy to buy a replacement unit, either the same model or a different brand. However the fact that the same symptoms have appeared on both units could mean that something is wrong elsewhere (wiring?), and I dont want to spend the money on a new unit if the problem will stay the same. Have I just been unlucky with the units or is there an underlying problem ?
A few years ago I replaced (and rewired & changed back plate) a Honeywell ST7100 with a new Honeywell st9400c for a gravity system. The reason was that the old controller was coming ON at random times (both HW and CH) when it should have been OFF.
However, this problem has persisted for a few years with the new honeywell st9400. I have lived with it because it does not happen often, but sometimes it seems to get worse. These are a few facts/synptoms:
-The honeywell st9400c number is 4214, so in theory it is not part of the bad batch (1037 - 1139)
-The unit randomly changes from Auto mode, to Cont or Once modes (so it turns itself ON when the Auto timer is OFF), for one of both HW and/or CH
-Unlike many other users with the bad batch, I can run both HW and CH at the same time, no problem.
-This happens anytime of the year , regardless of outside temperatures (there's a HW thermo, but not for CH)
I would be happy to buy a replacement unit, either the same model or a different brand. However the fact that the same symptoms have appeared on both units could mean that something is wrong elsewhere (wiring?), and I dont want to spend the money on a new unit if the problem will stay the same. Have I just been unlucky with the units or is there an underlying problem ?