Electric is probably the most expensive method of heating that there is. You need to do some serious price investigation before you make this switch.

I can understand your wanting to help as perhaps with all the combos the tech may not have the correct nozzle with him. At the same time if you have chosen a good service co that sent a quality tech for other reasons such as wanting to install an 80 degree instead of a 90 because it was impinging on the side of the target wall or because oil boilers are sold by # of sections that can take several different nozzles. He or she may have chosen one that wont short cycle the burner, based on your system. Sometimes even the manufacturer may state to use a hollow however the boiler will rumble and a semi-solid clears that up. My answer, I should clarify is to put your trust into the tech, however question perhaps why they used the nozzle they did.

The SSII is stainless steel construction, as is the backward inclined material handling fan. The entire operating guts of the unit will slide right out the back of the box if necessary. Keep in mind that the boiler/furnace/power venter must be set-up correctly with a tech who owns and knows how to operate digital combustion analyzers. If your oil company doesn't think they need them, get another oil company. If you go this way, the furnace/boiler should be thoroughly cleaned and set up at the time of installation of the power venter. Get a fresh start.

At the very least, your shutoff valve pressure rating must be significantly higher than the rating of the system's pressure relief valve so that pressure relief, should it become necessary, happens in controlled fashion. You need to know what the pressure requirement is for your system in order to know whether or not the new valve's pressure rating is adequate. That will depend upon your boiler/heater, temperature, pressure drop and operating pressure, plus the safety margin required by code.