I will try to keep this brief, but it will take a little explaining. History: 9 year Old Weil McLain Boiler (Ultra 80) which I have had problems with every year from day one. Leak of factory pipe (thin wall at bend) directly out of heater at about the 5 year point. Firing issue for a couple years. All zone valves had to be replaced and a multitude of other issues. Finally most items have been nailed down and things were running pretty smooth last year. Then had a FillTrol tank go bad (mounted sideways so air caused corrosion) late last winter and we limped along till summer to get it fixed. Once installed and system refilled and air bleed it was doing great. Expansion tank pressure holding steady at about 60 psi and the boiler and FillTrol tank pressure and boiler pressure holding between 12-15 PSI. Since the system is in my workshop, I try to check it weekly and most of the time I do. Last week was really cold (-3 degrees) and the system was running better than ever and here is where I should have knocked on wood. About 3 days ago, I started noticing the condensate pump running more. Did not concern me at all, because with it being so cold, it is likely to condensate more, so my thinking goes. I even remarked to my wife that the condensate pump was running more and that the heater must be running more efficiently. More on this later in Theory #2 .... One day later we hear gurgling (air in the lines) in the afternoon and when I check the Expansion tank it as at 0 psi and the boiler as well was at 0 psi. Ugg! So, I started looking for pipe leaks and could not find any (scoured the visible pipes at least three times now). The entire in-floor part is covered with Reflextix and insulation, but can be easily inspected from below in the basement. The up stairs is radiant baseboard and most of it can be visually inspected easily as well. So after thinking it over, I decided to pressurize the system again, this time without the boiler firing (read no evaporation thus making it easier to spot any leaks). Unfortunately without the proper pumps to quickly purge the system of air, I have to rely on the "Spirovents" located near the boiler (out and return lines) to eventually get the air purged out which takes a lot more time than the other way. They do not seem to be functioning as efficiently as when new. Went to bed with the Expansion tank at 70 psi and it was down to 40 psi by morning, but less air in the lines at least according to my ears. Boiler never dropped below 12 psi all night and all pumps still running with natural gas off to test my theory. So, throughout the day, I have been making sure the Expansion tank that feeds the FillTrol tank is around 70 psi and 24 hours later I still have air in the line. Although less than before. My current thinking is that the Expansion tank is only providing replacement water for the purging air. We will see. If not, perhaps I will at least be able to locate the leak once enough water leaks out. [B]Theory #1:[/B] Leak in one of the lines and just have not found it yet. Once I get the air purged, if the lines hold pressure for a few days, I will rule this one out. [B]Theory #2:[/B] I have an internal crack in the heat exchanger causing the water to get pumped out through the condensate pump when the boiler comes up to temp. Note that the boiler is currently within the pressure loop and there is no water leaking into the condensate trap at this time. Anyone been in this situation before? What are your thoughts? Any help or additional troubleshooting tips would be greatly appreciated. Thanks, SDesign Edited original post to reflect proper tank naming FillTrol was used incorrectly etc.

hi folks- I ran out of oil, and thus hot water, since I have the tankless coil for domestic hot water. My supplier can’t get here for some time. Would this plan be OK: 1. Get two 5-gallon yellow cans specifically made for diesel fuel. 2. Go to the local gasoline service station and fill up the cans with diesel fuel straight from the pump. (Do I make sure the pump says number “n”, or are they all the same?) 3. Pour the fuel down the same filler pipe that the delivery guy uses (I can’t get the plugs open on the top of my oil tanks, no way. Another bad story! Lol) I don’t use that much fuel for hot water so I figure 10 gals would be OK for a while. I could get 20 gals or even more if that would be a better course. Was wondering if you could even get the system primed with only 10 gals in a 275 gal tank? Or is that irrelevant? I thought diesel fuel was OK but here is a link below which talks about bleeding? I guess that means you could see leaks with diesel fuel? I also heard somewhere that your flame might need adjustment because of a difference in the burn? I would hate to mess with that. lol I know how to bleed the pump for priming, I’ve done that many times. Any thoughts would be greatly appreciated! [url]http://www.doityourself.com/forum/gas-oil-home-heating-furnaces/425758-can-i-use-diesel-place-furnace-oil.html#b[/url]