I’m going to add a couple of things that need to be done for people newly implementing recirculation control via the HotButton feature, that I didn’t really see documented elsewhere.
-
By default, HotButton will only trigger the unit to run ~10s or so, a pretty useless amount. You need to go into the installer menu (holding M and back-button for ~5 secs, default pin code 1234) → Application Settings → Hot Button, and configure the furthest fixture setting from the default of 30 ft to something many times what’s realistic. For instance, my furthest fixture is probably 40-50 ft, but I have to use a setting of ~200 ft for it to work long enough for the recirc return temp to rise to an acceptable level.
-
Also by default, regardless of the length of the setting above, the recirc will stop when the return temp reaches 100F. To get around this, turn on dipswitch 2 on the HotButton PCB to disable Energy Savings Mode. On my A2 model, the dipswitches are upside down, so it’s the 2nd switch from the right, and you push it down to turn it on. This then allows the recirc to run until the return reaches the default of 9F from the set temp, just like how the other recirc modes behave.
Edit: For #1, even 200 ft doesn’t allow it to run long enough when warming up for the first time after a cold night. I would recommend a setting of 500+ ft, but I’m on copper piping. CPVC or PEX would probably come up to temp a lot faster.