Well, that title will get your attention. You’re wondering if the large sum of money will land somehow in your lap or will it unfortunately fly out of your checkbook. Actually, this column will be a continuation of June’s column discussing the merits of converting a steam heating system to a hot water heating system. In other words, one system that is full of just water and one system that is full of steam, water and/or air, depending on where in the system or when in the steam cycle.
If you are a Steely Dan fan, you recognize the title from a line in the song, Bad Sneakers. I’ve always liked the portion of the line, large sum of money to spend. I won’t even speculate what it meant to the songwriters Walter Becker and Donald Fagen back in the mid 1970s, but when it comes to steam-to-hot water conversions, it’s not what the homeowner wants to hear. It’s also not what you want to hear if the conversion isn’t going well.
To avoid mistakes that cost you money, make sure there is a clear plan that makes sense to both you and the homeowner. Any job of this type is going to have a few bumps. My job is to help you recognize the bumps before they cost you a large sum of money. Your job is to make sure the bumps don’t bust the budget.
In some cases, the cost of the conversion is actually cheaper than the cost of the repair to the existing steam system. Let’s re-visit the job mentioned in the previous column with the rattling noise in the master bedroom. When I originally looked at the job, the complaint was for a flooded steam boiler, possibly from an automatic feeder sticking open.
Turned out that the wet return, that ran the full length of the basement behind new walls and cabinetry, was plugged with the accumulation of 90 plus years of muck (or whatever you call it). The large amount of money to replace that pipe and then replace the walls and cabinetry was more than the smaller amount of money to convert from steam to water.
Like other jobs of the 1920s in my area, this system had a steam main that ran the length of the house. The boiler is on one side of the basement while the end of the steam main is on the other. Almost everyone utilizes parallel flow, which means the condensate flowing in the bottom of the steam main needs to find its way back across the basement to the boiler room.
With a hot water system, there is no need for a vent or a way to return the water from the end of the main like in the steam system. In a hot water system, the water from the supply main needs to flow up to the radiators, not back to the boiler. This fact allowed us to abandon in place the clogged wet return, avoiding that large sum of money.
I recommend that a valve or removable cap be installed where the end of steam main is modified during the conversion. Use this point in the system and any other available to flush the muck out of the remaining pipe(s). You normally don’t find much muck in pipes above the waterline, but always plan for the possibility, since the one time you don’t, you’ll get stuck by the muck.
Like other jobs, the returns from the radiators pipe together in a dry return that ends in the boiler room. It is called a dry return, but that just means it’s above the water line. In a steam system, it carries the air and the condensate from the radiators. This is the piping that might seem smaller than normal for a hot water job, but remember that the supply pipe is much larger than normal for a hot water job. The Law of Averaging comes into play, in this case to our advantage.
The beauty of converting this type of steam system is not much has to be done to the return piping when changing to hot water. The less disturbance to the piping, the better. Again, add flush points where you can and always add a strainer to pick up the big chunks. While you are at it, also use a dirt separator with a magnet to pick up the small stuff. The high efficiency boiler going in won’t like the residual muck, no matter what size.
Back at the radiators, the valves were replaced and the manual air vents installed. Everything was gravy until the one steam trap started to rattle, in the middle of the night when the world is quiet, sorta like Murphy’s Law. Fortunately it was an easy extraction. Steam traps are designed to be taken apart. In this case to remove the bellows assembly that had broken off inside. But, sometimes, it can be 90 to 100 years since the cap’s threads moved. Make sure to have a back-up wrench on the bottom hex of the trap.
Well, I’m out of space again. Converting to hot water has plenty of benefits and plenty of different approaches, probably more than I could bore you with. For those of you that are making book on my retirement date, I now have no idea. Life is dynamic and ever changing.
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.