new oil boiler commissioning

[what..the?]

Can an oil boiler system be fitted by a plumber untrained in oil?

If it can, but the system needs to be finally commissioned by a trained oil person does this have to happen before the boiler can be used by the customer?

I have been using my boiler for a month now should it have been commissioned by now or before I moved in and used it?

Thanks in advance

[The Builder]

Ideally Mrs What, commissioning should take place at the time of installation. However, several times my Engineer has installed, got it running safely, but returned a week or so later to officially commission and enter up the relevant readings and test results when he has more time. That's ok because it's the same guy.
I worry that your guarantee may be compromised if it's left any longer. It's (possibly) giving the manufacturers ammunition to wriggle out of their legal obligations.
I'm guessing that your installer hasn't filled out the paperwork and instigated the guarantee.