Very hot floor near condensate return

Jim Chamberlain

I am trying to solve a problem at my church. The floor where the condensate return pipes flow into the holding tank and then the condensate pump sometimes gets extremely hot.

The system in the church is mainly one pipe steam, but there were places where someone added heat and put in a two pipe system. I turned off one part and thought that it had solved the problem. I figured the trap was bad. That seemed to solve the problem for a while, but I noticed that the floor was hot again. There are other two pipe lines that I have turned off.

Is there an inherent problem with mixing one pipe and two pipe systems. Has anyone encountered the hot floor near the condensate return pump before? I did wonder whether there was a leak, but the floor is hot not just in one spot but along what would probably be the condensate pipe line: it goes along a hallway, then the pipe makes a right angle towards the boiler and the hot floor tracts that.

Ancillary problem: boiler seems to cycle too much. The pressure drops quickly, then boiler comes on for a minute, pressure returns. Wait 20 minutes, same thing happens. Also, I think the automatic water feed goes on too often.

HELP!

Fred Harwood

Hot floor

Buried condensate returns that have been drained by a condensate pump can fill with steam and get very hot. Such returns normally are full of condensate, which keeps the steam out. Also, if the return is corroded and leaking, warm condensate will heat the leaking spot. If the whole of the return line gets hot, likely steam is in the return and heating the floor above. Do you have banging in the return? How much water does the boiler use in a week?

Jim Chamberlain

Very hot floor near condensate return

Thank you!

I don't hear any banging under the floor where the return pipes are. (There is banging in wall mounted "radiators" - they are just single pipes with heat fins and I believe some do not have the proper tilt and therefore do not drain all the time)

I cannot exactly say how much water we use since there is an automatic feed. I will say this, I can be down there for a half an hour and possibly hear the water feed go on one or two times for 30 seconds or so (and, of course, sometimes not, but it has been rare when I did not hear the feed go on at least once when I have spent any time around the boiler). The condensate pump kicks on but not nearly as often.

The system does not see water logged.

I had a plumber try to remove the strainer before the pump (he said he could not given its position, but he undid the plug and said sometimes the condensate was very little, other times, it was more "normal".) There is a master trap (which I know is taboo) between the strainer and before the condensate pump.

There are probably 50 radiators throughout the church and parish hall (there are three zones). I have replaced about4 steam vents that were locked open. That may have the cause forsome water from going out of the system; I have not checked since then, but I am not sure 4 vents could lose that much water?????

Jim

Fred Harwood

Hot floor

Jim, we would need to know more about this system. The condensate pump suggests that your buried return has steam rather than condensate in it. If so, the hot floor may not mean a leak. It might, however. Also, you need to clarify your terms on vents and traps. One-pipe steam uses main and radiator vents. Two-pipe steam uses master venting and steam traps often on both mains and radiators, which, of course, also vent air until steam arrives. The pump installation probably required the master trap, which means that your water seals have been removed. And we would like to know what pressure you're running. Finally, in a good system, even with 50 radiators, the boiler should not need more than,say, 10 gallons a month of fresh water. You need to quantify that. More means a leak, probably in the buired main. Perhaps you should find a knowledgeable heating professional for a close gander.

Jim Chamberlain

Hot floor near condensate return; mixing two and one pipe steam

Fred,

Thank you again for taking time to help me with this. I am going to write a longer response to try and be as thorough as I can.

Through the years, we have had a lot of plumbers in there looking at things but no answers yet. That is when I started to try and learn more about heating systems myself.

One-Pipe vs. Two-Pipe

The Church began as a one pipe system. The vents that I said I changed were all radiator vents for the one-pipe system. Some were clogged open and spewing out steam.

I have not been able to locate any main vents on the original one-pipe system. One plumber said they were hidden/buried in walls. That means that none has ever been inspected or changed. Could this be, or should I start looking into crawl spaces? Could a bad main vent cause water leakage? Could a system be installed without main vents?

There are three major zones, all one pipe. However, over the years, additional heating capacity was installed to certain areas using two-pipe loops with steam traps (and sometimes air vents). I don't know why someone did this since we really do need any of them. I have turned off two of the three places the two pipe is used and am thinking of shutting off the third.

A very troublesome two pipe radiator

There is one "two pipe radiator" (with a trap installed) that appears to pipe its condensate directly to one of the "one pipe" lines. This piping is 1/2 inch copper that runs about 12 feet from the trap to the one-pipe line that goes to other radiators. This 1/2 inch line is exposed and I noted that, when the heat is on, the pipe is usually very hot for the full length of the pipe. The temperature of the pipe suggests to me that it sometimes gets filled with steam - perhaps the result of a failed trap (even though the trap is new). In addition, while I cannot verify it (because the steam line to this radiator is buried in the wall), I believe that the steam line provides steam to the radiator through a DESCENDING pipe. It looks like renovations in the area could have caused someone to route an otherwise nearly horizontal steam pipe up, around and down an archway that had been built. It seems the only way the steam could get to the radiator.

This copper line was the source of a major leak of water/steam. It was disconnected from where is was "tee'd" into the one-pipe line. I had a plumber fix the leak and rerun the pipe so that it sloped better and he said he also put in a new trap. Since water was still spitting out of the vent on the radiator, he capped the vent. Thus no steam goes into the radiator. Thus, we are not using that radiator but steam is going to the trap - and perhaps beyond it into the copper pipe that leads into the one pipe system.

Condensate Returns: One pipe and two pipe

I believe that all condensate returns to the boiler through the the same condensate pump and piping. One question would be whether the two-pipe condensate lines would have been "tee'd" into existing condensate lines from the one-pipe system? Whether it would or not, what happens in this hybrid situation when one of the steam traps fails open and feeds steam into the condensate lines? Are there special challenges and requirements for the addition of two pipe steam loops to an existing one pipe system that I could verify exist on our system?

Boiler Pressure

The boiler pressure fluctuates between about 3.5 PSI and 2 PSI. The boiler can cycle every few minutes. Could this be partially the result of low load conditions when not all areas are being heated? The pressure used to be higher, but I asked a plumber to reduce to below 2 PSI, after reading Heating Help. However, he said he did not think he could lower it anymore????

I have watched the pressure rise from 2 to 3.5 in about 30 seconds, then watched the guage drop down to 2 PSI in anywhere from 10-20 minutes. If the pressure were down to 2 or less, would this help, or would the boiler cycle on and off even more frequently?

I happened to be there during a cycle when the condensate pump kicked on and the boiler pressure dropped to zero very quickly. I suspect that the master trap opened. This seems to suggest that steam may be reaching the master trap.

Water Usage

With the automatic feed, I have no way to measure the amount of make up water that goes into the boiler; however, my judgement that is that it far exceeds the 10 gallons per month you gave as a benchmark. My guess is that it would be at least a gallon a day. It is fed into the boiler through a (1/2", 3/4" ??) pipe and the water comes on for approximately 15-30 seconds each time, probably 10 times a day when the boiler is running.

In summary, I guess my principal questions are:

1) are there inherent problems adding two-pipe loops to a one-pipe system that may explain some of the problems we are having?

2) would lowering the pressure more help in anyway?

3) is there anything I have described that might indicate a potential source for a leak (e.g. a main vent or pipes near the condensate pump); if not, and a leak does exist somewhere in the condensate line under the basement floor, could it identified with an infrared device or something that would identify "hotspots" in the floor?

4) Finally, can you recommend a heating specialist in New York City (the church is located in Forest Hills Queens) that was capable of breaking the mystery?

Many thanks.

Jim