My minimax NT 400 heater will not ignite. The fan turns on. The start sequence proceeds as it should. Gas flow starts (I can smell it), but there is no ignition. The sequence repeats 3 times, and then the heater goes into lockout. Error code E4 comes up on the display, indicating fan failure, but the fan is blowing. The air vacuum switch appears to work (vacuum hose not leaking, crimped, etc), and the switch registers + Ohms when vacuum is applied. Is it a bad ignitor? Other ideas?
Pool & Spa - Pentair - Minimax NT Heater
Answers & Comments
Many things can cause this, including the ignitor as you mentioned. You can ohm out the ignitor, and that should tell you if the ignitor is capable of heating up. But this ignitor also has a built in flame sensor in it. That part of it can also be bad. If the heater has worked before, then i would probably say it is not the gas pressure. More likely clogged orifice or bad ignitor. You will not be able to check the pressures at the gas valve without a manometer.
You may have low gas flow. This is tough to check but if you have a manometer you can check gas pre on the back side of the gas valve with heater off and then while it is trying to start. If you don't have a large enough meter or gas line this will often be the problem and give you the gas smell since it will feed gas but not enough to light.Good luck.
YOU CAN PULL THE BURNER ORFICES WITHOUT PULLING THE BURNER TRAY. FLEX UP THE SHEET METAL TRAY AND PULL THE ORFICES AND CLEAN WITH #12 SOLID WIRE. SPIDER WEBS ARE BLOCKING ONE OR MORE ORFICES. IF ITS A MIDDLE ONE OVER THE HOT SURFACE IGNITER IS PLUGGED THIS IS A TYPICAL SYMPTOM. GOOD LUCK.