Dth 101 pool heater installation issue

terzene1

Member
May 20, 2025
5
newton nj
Hi there, saw the other treads on this and I believe the dth 101 is installed correct. I have the same Hayward pool heater at this guys:

I the device is connected to the app but it’s not actually turning off or no the heater. I have it connected to the middle com and the end pool as instructed…. Not sure what to do, thank you!
 
Welcome to TFP.

Show us pictures of your equipment and wiring with the problem. Not someone else’s.
 
Show us the other end of where the black and red wire goes to.

Why are you calling a Hayward H400FDN heater dth101?

If you short the black and red wire together does the heater turn on?

Is the heater in bO mode?

A bO code is a normal display on the heater when it is controlled by automation. It indicates that the heater is in remote control mode.

To put your heater in bypass you:

  1. Press the Mode button to place the heater in Standby Mode
  2. Hold the Down Arrow and Mode buttons simultaneously for 3 seconds for Bypass operation. “bO” will be displayed on the screen
  3. Heater must then be in the Spa or Pool Mode for operation. The heater will fire when instructed by the external control.
To remove your heater from bypass mode, you:

  1. Press and hold the DOWN key and
  2. Then press and hold the MODE key
  3. Hold down both keys for 3 seconds until the indication ‘‘bO’’ is removed from the display.
 
Understood, I’ll try to put it into bypass mode. The dth101 is a wireless remote controller. Wi-Fi Remote Gas pool Sauna Hot tub Heater Smart Thermostat/Timer program Temperature Contr

With the DTH101 you will have no thermostat control over the H400FDN heater in bO mode.

The heater will continually heat until 104F.

The DTH101 web page says:

You need to change the pool thermostat with this wifi thermostat. The pool thermostat is in circuit that turn your heater on or off and normally you can easily change the thermostat, but please check the pool heater thermostat before buying the unit.

The H400FDN Manual says:

2-wire remote control connection:
To configure the heater for 2- wire remote thermostat control, use the “MODE” key on the heater keypad
to put the control into “STANDBY” mode. Then press and hold both the “( - )” and “MODE” keys for 3 seconds
until the display shows the code “bo”.
On the remote control wiring terminal block (Figure 18), connect the appropriate wires from the remote
control to the terminals adjacent to the ORANGE wire (“POOL”) and WHITE wire (“24V”).
To operate the heater by remote thermostat, the heater’s control must be in either “POOL” or “SPA”
mode. The display will show “bo”. The “POOL” or “SPA” LED will be illuminated. The remote thermostat
will operate the heater. The heater’s thermostat will function to limit the water temperature to a maximum of
104°F.
 
With the DTH101 you will have no thermostat control over the H400FDN heater in bO mode.

The heater will continually heat until 104F.

The DTH101 web page says:

You need to change the pool thermostat with this wifi thermostat. The pool thermostat is in circuit that turn your heater on or off and normally you can easily change the thermostat, but please check the pool heater thermostat before buying the unit.

The H400FDN Manual says:

2-wire remote control connection:
To configure the heater for 2- wire remote thermostat control, use the “MODE” key on the heater keypad
to put the control into “STANDBY” mode. Then press and hold both the “( - )” and “MODE” keys for 3 seconds
until the display shows the code “bo”.
On the remote control wiring terminal block (Figure 18), connect the appropriate wires from the remote
control to the terminals adjacent to the ORANGE wire (“POOL”) and WHITE wire (“24V”).
To operate the heater by remote thermostat, the heater’s control must be in either “POOL” or “SPA”
mode. The display will show “bo”. The “POOL” or “SPA” LED will be illuminated. The remote thermostat
will operate the heater. The heater’s thermostat will function to limit the water temperature to a maximum of
104°F.
Thanks for this, sorry for my ignorance, based on the photos above does it look like it’s wired correctly? If so it just seems like I just need to put the heater into pool BO mode?
 
Thanks for this, sorry for my ignorance, based on the photos above does it look like it’s wired correctly? If so it just seems like I just need to put the heater into pool BO mode?
It is easy enough to give it a try and find out.