Before and After

A typical Catholic parish in Cincinnati had a steam boiler in the basement of either the church or the grade school, feeding steam underground to heat the other building plus the rectory, where the priests lived. If there were nuns at the parish, they got steam underground to heat their convent. The boiler was in the school at the parish I attended. The snow melted in a direct line across the parking lot. We thought it was divine intervention.

In both photos, you can still see the old steam line coming through the basement wall in the lower left, with the pink stuff around the insulated pipe and the gauge on top in the before shot, but not in the after. I guess somebody is saving old gauges.

The steam stopped coming through this pipe years ago, since we were there to look at the steam boiler now used for heat located in the other part of the basement that had recently sprung a leak. Steam boilers do that after so many years.

Before the steam was cut off to the rectory, the rest of the equipment in the before picture was used to pump the condensate back underground to the church. After the steam was cut off, it was used to pump the condensate over to the boiler in the other part of the basement. The equipment consisted of the large tank with a gauge glass, a float style water feeder, and a base mounted pump.

Back then the installer cobbled together parts from different manufacturers, while today we would use a boiler feed unit from one manufacturer. That could simplify things if the return system needed to be replaced, but we were thinking of something even simpler. At this point, you have noticed that the after picture looks like a hot water boiler.

The existing steam system was two pipe with easy to convert cast iron radiators. The current homeowner was interested in decreasing operating costs and having equipment that is easy to repair, so my contractor quoted the steam to hot water conversion. Turns out last year he converted the first floor to forced air heating and cooling, but this year he wanted to put in a high efficiency hot water boiler to heat the second and third floors.

That is what you see in the after picture hanging on the wall. The expansion tank is almost as large as the boiler, since in this case there are still radiators with a lot of water content plus the water content of the original distribution piping that is still used. Not many jobs have an expansion tank that is larger than the boiler.

Other items in the before picture that were removed include a steam control valve (that regulated  temperature in the rectory), one steam trap (that functioned as a condensate drip trap to keep condensate from accumulating in front of that control valve), and one steam trap at the end of the rectory’s steam main (to keep steam from entering the tank).

Besides the boiler and expansion tank, the items added to make it a hot water system include a circulating pump that is barely seen in the ceiling directly above the boiler, an air separator that cannot be seen, and the fill valve-backflow preventer combination in the new fill line seen just above the expansion tank. Upstairs, each radiator was drilled, tapped and fitted with a 1/8” manual air vent.

So, all the equipment shown in the before shot plus the boiler in the other part of the basement were removed. This freed up the space to install the high efficiency wall hung boiler in this part of the basement, which had much better access to the supply and return piping, since that was where the original underground connections were located.

Now, the simplified system has fewer and more readily available parts to maintain if anything breaks.  The homeowner will be enjoying lower operating costs and more even heat from the radiators. Customers that have their system operating with a reset water temperature are commenting that the room temperature is very steady, rather than the temperature swings that they experienced with either steam or fixed temperature hot water in their radiators.

This will be the last column about steam to hot water conversions for a while. Next month I’ll write about my upcoming high efficiency hot water boiler to high efficiency hot water boiler conversion at my house. What could go wrong when I do it myself?

Patrick Linhardt is a thirty-seven-year veteran of the wholesale side of the hydronic industry who has been designing and troubleshooting steam and hot water heating systems, pumps and controls on an almost daily basis. An educator and author, he is currently Hydronic Manager at the Corken Steel Products Co.