I have wanted some kind of heater in my attached garage (demoted to glorified storage" since building my detached one) because the adjoining rooms are usually cold as though the rest of the house is heated, (of course) and at least in my attic, well insulated. Why they would insulate the whole house except the unheated part is beyond me. 2 winters ago, I tore the drywall out insulated heavily and sheathed everything incl the ceiling with OSB/ as well as "catching up" the ceiling with the rest of the house insulation wise, and putting a subfloor just over the garage part of the attic,
It helped but not completely, that unheated space still robs the heat from the house. When I used to work out there, I had a few different portable heaters over the years and I found out "heat the garage, keep the rest of the house warmer"
This past summer I found a 10K BTU ventless heater cheap at a garage sale. Mind you, the idea wasn't to make the garage "shirt sleeve" comfortable, but just to take the edge off, to help the rest of the house retain its heat; so i figured this should at least do that; nope.
The flame did not extend beyond the burner, barely made the burner itself glow blue.
I took the cover off and cleaned the burner and took the supply line off, blew it out too. Same result.
This ventless heater has 2 gas ports ; you use whichever one is appropriate for whatever gas (NG or LP) you plumb to it. The PO had the fitting in the NG side, which is what I run.(OK there)
I gave up and bought a new ventless heater today. my garage sale one did not come with the instructions, the new one did. The new one is same brand but I got the 30K version because they had them on a helluva sale, got the 30K for the same price as the 10K usually sells for...
I put the new one in, and saw in the instructions where you gotta take off an access plate to flip a switch to which ever gas you are running, in addition to using only the inlet port marked likewise...
Well, the sheet said that they come shipped ready to run propane; I had to pull the access cover, and flip it to NG on the new heater... could it be?
Yup, I plumbed NG to the garage sale heater, in the NG port/ but the flip valve (that I didn't know existed) under the access plate, was on LP...
I knew that the garage sale heater seemed unusually weak looking at the flame; especially knowing people that have these heaters and seeing how theirs burn (height of flame etc) but didn't know that there was a valve to switch... The new heater is 30K BTU, vs the garage sale one's 10K BTU; 10K is a little "light" for the square footage of the attached garage, but had I known this I think it would have taken the edge off the cold out there, which is all I was after... $120 for a new heater I didn't need to buy