Does my termovar need cleaning and dare I do it? Thinking I need a plumber to do it with some replacement fittings on hand, here is backgrond. My questions are around a "cleaning screen" (where should it be?) and the effect of old antifreeze on a termovar. Here is the longer story: I have a Solo 40 plus installed in late 2008. It replaced a cira 1940 coal/coverted to oil boiler. The system had antifreeze in it and I decided for several reasons not to add any more after adding the Solo. Now I wondering if I should have drained all of it and flushed the system. Is it corrosive? I can still smell it when I bleed the radiators. The symptoms: We are starting our heating season here in NH, most of the summer the Solo has given us hot house water and the heat is turned off. All night the boiler was/is at 175 and the cold return around 80. The house has called for heat since 6 and it is 11 AM. I have hot water past the backflow value between the hot water feed and house, so I am figuring the termovar is dirty and not enough. I do have a gas boiler backup and it is a balmy 45 today. As the initial installer put it, the Termovar is "tender" and prone to leak if the cold return pipe is banged. This has happened in the past but the leak stopped. Leak being something hot water would take care of without any drips to the ground. Today it started up again but now it is a drip ever 10 seconds and as usually seems to come from the cold water side. The pipes/fitings below it appear mildly rusted, so I am afraid of putting a pipe wrench on it Or even trying to turn off all the values if I cool down the Solo to look at the termovar. So I am thinking better pay someone take the temovar a part, with some new fittings on hand. I don't remember the installer mentioning a screen to keep debris out of the termovar and rest of the system. We did have major work done on our town water system and while we tried to be careful, it is possible something got into the furnace loop. Otherwise I am happy with my Solo. Comments? I see a similar closed post back in 2010, so started a new one.