No ignition and E04 Code

The HSI (ignitor) has 2 wires, its like a cigeratte lighter, power is applied and it heats then glows red, the single wire you mention is the flame sensor, used by the control board (igntion module) to ensure the burner has lit or it shuts the power to the gas valve off but keeps the fan operating for a period of 1 hour till it resets.

It sounds like your ignitor is defective, it happens often, depending on your location, you may be able to purchase one, but I would advise having a service tech do it.

The manual for troubleshooting and repair can be found at this link:

http://www.staritepool.com/pdfs/MiniMaxNTServiceManual.pdf