Oil Burner not firing

Pressing the red button or turning on the heating , nothing , no pump sound

Worth checking with a multimeter if power is going to the burner ?, it has a black control box , few junction boxes on the wall , everything is working in the boiler room

This is in the garage outside (boiler room) , all the oil burners are in there ; no idea why they have two in this house , the big blue one and another smaller for the main house (is working fine), the control box for the septic tank is in there , working fine

I have never seen so many pumps , property must have at least 5-6 pumps I have seen , at least 3 in the house , 3-4 in the boiler room

Will try get another plumber, 2nd plumber I had out, replaced an expansion vessel, 272 euro fir 10 to 15mins work and I had to supply the parts, he never braced it, so I had to redo, feckin thing was leaking at more than 1 point (obviously the previous plumbers fault, who touch it a few years back) , I was left without water as he forgot to turn on a valve, when I asked if he checked the psi on the expansion vessel, he got annoyed, he just slapped it up

1st plumber was back n forth to the house 6 times, kept telling me its working, when I tried, heatimg, hot water, nothing... No idea why lads don't verify everything is working before they leave, no leaks.. It takes them more time and frustration on both sides, do it once, do it right

Really is difficult to get a person to do it correctly, I have to spend my time on forums, YouTube tutorials, reading manuals

Thanks Jim