Community Forums

Vern2 · 02-21-2021, 03:47 PM

Aquahot 311120 older 1997 model . Starts up and runs fine,then when temperature lo.it is reached it purges and shuts off. When temperature drops the unit never restarts on it's own. I shut the switch off and back on and it starts up. It should automatically restart. Is this the control box problem?

153stars · 02-21-2021, 11:03 PM

Sounds like it may be stopping burner at high or high high "the 2nd or safety" limit instead of first thermal shut off for up to temp. Then it would probably need to reset/restart. I may have the wording for limits description wrong per AH manuals.
There's good troubleshoot flow chart for AH online.

Vern2 · 02-23-2021, 05:12 PM

The 2 DC control limit switchs have continuity, maybe they get stuck or dont function smoothly? I just hate buying these overpriced parts if unnecessary. Just bought new controller. Now today it is running automatically, hopefully it's better. Thanks for your Input.

153stars · 02-23-2021, 07:45 PM

Oh those button snap switches are generic . Someone posted a pic with #s exact switch was $17 shipped instead of $65. First may not open the other may come in too soon. If a new controller fixed it then ,I would feel pretty good, what part is controller ...control board.
I managed to find a Webasto flame sensor for about half normal AH price. Most of the AH parts pretty over priced.