Steam heat with hot water loop

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    • #274740
      MasterPlumbers
      Keymaster

      We just moved into a 100+ year old home that has steam heat with a Bell & Gossett hot water zone that heats our family room/kitchen (which was installed by the previous owners 5 years ago). A few months ago a company came to service our boiler. They tried to bleed the hot water loop, and ended up messing up the system (by letting air into the hot water loop). We didn’t realize why we were so cold for 2 months, or why our steam system was so loud – major banging. Just figured it out by doing some research, and they came out to fix it. The technician had not dealt with hot water zones before, so my confidence level in his work is kind of low. Now our baseboard hot water zone works great, and we don’t have any more knocking, but the rest of the house – the regular steam radiators – don’t seem to be heating our second floor as well as they once did. Could they have messed up something on the steam side when resetting the hot water loop? What can I look for?

    • #290341
      Guest
      Participant

      Check to see if the technician connected the hot water circulator to run constantly. This would prevent the hot water loop from settling air in the highest location while the circulator was off, making the hot water loop quiet. However, while the circulator runs, the steam side output is reduced as the hot water loop draws heat from the water that is reaching boiling temperature. Set the control to turn the hot water loop circulator on and off with the thermostat.

      If this is not the problem, the steam burner input may have originally been sized to the steam system and drawing more heat for a hot water loop may reduce the amount of heat to the steam system to a marginal condition. You do not state what fuel you are using. Oil input can usually be increased a bit to handle the additional load – gas less so.

    • #290342
      Guest
      Participant

      quote:


      Originally posted by Harold hydronic.net:
      Check to see if the technician connected the hot water circulator to run constantly. This would prevent the hot water loop from settling air in the highest location while the circulator was off, making the hot water loop quiet. However, while the circulator runs, the steam side output is reduced as the hot water loop draws heat from the water that is reaching boiling temperature. Set the control to turn the hot water loop circulator on and off with the thermostat.

      If this is not the problem, the steam burner input may have originally been sized to the steam system and drawing more heat for a hot water loop may reduce the amount of heat to the steam system to a marginal condition. You do not state what fuel you are using. Oil input can usually be increased a bit to handle the additional load – gas less so.


      Thanks Harold. The hot water loop circulator is set to turn on and off with the thermostat. What temp should the hot water be set at – it is currently set at 160. If that was slightly lower would the hot water drain less from the steam side of the system? To answer your other question, the system is run with gas, not oil.

    • #290343
      SylvanLMP
      Participant

      Harold far be it for a “plumber” to ask this but,

      I was curious about the following.

      As we know a lot of losers especially non licensed folks or “plumbers” who cannot make a living doing plumbing resort to dabbling in the non licensed field of heating as they have no formal knowledge of codes plumbing or heating and thus go about their way causing damage

      Now considering this is a steam system and someone made a connection to the wet return several questions just came to mind.

      1- Did the “technician” take a branch before or after the Hartford loop?

      2-Did this technician use thin copper tubing like M knowing most steam condensate is highly acidic and will possibly eat this piping up causing a leak.

      3- Did this “heatin” guy size the circulator to prevent excessive velocity in these hydronic lines?

      4- Did this plumber/heating person bother to lower the hot water temperature below 180 degrees as water in excess of this temperature will erode the copper tubing if the velocity is over 2-3 FPS? AND even 4-5 FPS on hot water is (160) is not that great for this kind of piping (SEE CDA)

      5-Did this heating person read the boiler plate for EDR or horse power or even check the firing rate and convert it back to BTU’s

      to make sure it can carry the extra load?

      6- Now that this is a duel type of heat what provisions are there for the “relief” of excessive hot water pressure as the circulator and zone valves can act as checks

      Or is this system only protected by a pop safety valve?

      7- Since there is air in the system did the new zone installer use a Hoffman #75 air vent, If not then what provisions did this heating person allow for the possibility of the trapped air in this system from causing a severe rupture due to excessive pressure

      ( called pressure/ temperature relationship huh?)

      Considering this system is “gas” and Not high temperature oil was this system converted?

      After all 1 gal of oil is 138,000-140,000 BUT per gal and a cubic foot of “natural gas” is only 1,000- 1,200

      So there maybe a problem of causing excessive thermo stress due to wide temperature fluctuations ( heatin guys call this DELTA HUH? LOL

      if the firing rate cannot keep up I would assume.

      Metal fatigue comes to mind and dangeriously low stack temperatures.

      I hope someone installed a low water cut off “even though it is residential” as some misfits feel only “commercial” accounts should have better plumbing and heating.

      Harold thankfully I know nuthin about heating BUT if I did I would inspect this house ASAP Or call a licensed mechanical engineer who knows the ASME section IV code just to make one on sight inspection for peace of mind.

      Unfortunately a lot of folks dabble in the piping trades as they can get away in most area’s without bothering to actually learn these professions.

      One person on this list said

      “If it isn’t inspected why do it up to code”?

      Another brain dead P&H guy gives quality ONLY to commercial accounts BUT I am sure this BBC doesn’t give a discount to the residential accounts by telling them

      “IM going to do a cheap job using lousy materials barley legal BUT ILL give you something off the price”

      I yet to find any of my accounts saying Hey do it cheap and illegal.

      Then again I do take these trades seriously.

      Harold I think you should explain in a private E mail to these fine folks about protecting “pressure vessels” legally and what to look for.

      Drain cleaner… Sylvan

    • #290344
      Guest
      Participant

      Sylvan, I know you are illustrating a point here that inexperienced installers can do a lot of damage, and that the owner of this system can have some serious mistakes built into the system,; but, knowing that you are a licensed boiler inspector, former stationary high-pressure engineer, and experienced heating contractor, most followers of this forum are enjoying the humor without believing the feigned inexperience.

      Sully would do well to have every question you pose in your post examined to make sure there is nothing that is wrong and potentially dangerous.

      The temperature of the heating loop, if running through a heat exchanger is going to depend upon whatever radiation is available to take heat away from the transfer rate of the heat exchanger, so the setting cannot be determined without the data. This would require innumerable posts to describe a situation that is better discovered by a competent heating/plumbing repairman who can visit the site to know the nature of the equipment through observation.

    • #290345
      Guest
      Participant

      Harold and Sylvan,
      Thanks for your comments – our biggest problem is finding a competent repairman to check out the system. The repairman that originally messed up the system by “bleeding” the hot water loop was from the company that installed the system 5 years ago. Either of you live in the Chicago area, or know anyone competent in this area that does?

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