Geez, mate, give it a rest! Since you readily admit you are not a heating engineer or electrician or anything else vaguely related (nor am I) you have no way of knowing HOW MUCH oil should be in it. ALL oil heaters are partly filled, perhaps for reasons I have theorised before. I also doubt you could buy less than a rather large drum of it, if you could find it. Tell me - any signs of a leak? Do you have an identical heater? If so, weigh both with good scales. That would indicate if oil was low. As I've said before, oil-filled heaters have a very gentle heat, so may not feel as 'warm' as others, still, with a little time they will fill a smaller room with a nice all-over heat. If you could compare identical heaters you might be able to say one was hotter than another.....I suspect it's fine apart from the thermostat, and, chances are, you're on the low setting. I don't think running it without a thermostat is safe, even if you do watch it..... Trust me, I've seen/bought/used a lot of heaters in my day, probably more than most posters here, since I lived in Australia and portable heaters are all 99% of the population use, since few people have central heat. Just chuck it. Get another sort, if you don't like the oil heat type. Personally I like them almost as much as baseboard heaters (and they're easier to cover up accidentally, although I don't know how much risk of fire they pose) - I bought an oil heater for both my daughter's rooms since they were the safest we could find, and they may well have been Delonghis. For us, they worked well but to this day, they still make a hot paint smell when they run. DON'T BOTHER ABOUT THE OIL - YOU CAN'T RESEAL IT, AND YOU HAVE NO IDEA WHETHER MORE OIL WILL HELP OR WILL EXPAND AND CAUSE LEAKAGE ETC.

I turned on the heat and the zone valve on my baseboard heater is warm but my baseboard heater is not getting any heat, it's ice cold. I can move the lever at the bottom of the valve (I'm guessing it's the end switch?) freely. I think there's a problem with the motor in the valve but I'm not sure. Does anyone know? Is there anything I can do to get heat to flow into the heater right now?

I don't know what the Runtal radiators look like. These are cast iron radiators? If they are normally mounted flush with the wall then attaching them to the baseboards will leave an unwanted gap, won't it? If they are not supposed to be flush and a space is normally present, a little wider won't matter. There are more than one reason to close the gap between the drywall and the floor. If it can't be seen, it does not matter much how you close it. Quarter round with some caulk sealant should work fine. I don't entirely understand what mean by "bleed the baseboards..." If you have radiators, a baseboard is superfluous. Bleeding them in in the vertical direction will look too busy for me. On the other hand, you won't have radiators along the entire length of the walls so you will want a baseboard where there is no radiator and you want the transition to look pleasing. That is a judgement call and depends on what else you are doing with the room. In general, however, I'd probably like to line up the top of the rads with something that resembles them very much even if it does not stand as far proud of the wall. That is just my preference and it assumes a boxy radiator with a pretty modern look. Matching it might mean some custom millwork.

I had a cabin with electric baseboard heaters. The heaters were located under windows. If I did not use the heaters in the winter, the windows would get condensation. Which wall heater, a gas wall heater would cost $2-3k with installation.