To set high and low fire on the Photon heater you can use a handheld signal generator producing between 1 and 10 volts. This can be purchased online through various websites. Please see the Photon Installation Manual (https://www.reznor.co.uk/wp-content/uploads/2025/05/Reznor-Photon-Installation-Manual-EN-2025-05-D301310-Iss-6.pdf) for more information.
What can be used to set high and low fire on the Photon heater?
Information on Reznor's range of warm air heaters