Heatilator, pilot starts, main burner not

[Jaste]

I have a Heatilator NBV 4842i 2013. Hardly ever used, not started in 2 years, when I tried to start it this year, it would not start. I have a remote control to start it.
Symptoms:
Ignitor module fires the igniter with 3 sparks.
Pilot flame lit, and stays on for a split second.
No flame in the main burner
Tried to do this several times, on off on off, it finally fires the main burner.

Anyone experienced this symptom, and have an idea what the problem is.
Thanks

 

[DAKSY]

Are you sure of the Model Number? I can't find an NBV unit. NDV is all I found.

 

[Jaste]

I believe so. I attach an image of the label inside the fire place

 

[DAKSY]

OK. Found it. This is from your Manual: