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  • #46
    Re: My boiler is short cycling

    Originally posted by NHMaster3015 View Post
    If all that stuff checks out, go to the part in my post about cleaning the pig tail.
    If it were the pigtail, the system would NOT be shutting off, it would keep on running most likely until the relief valve blew.

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    • #47
      Re: My boiler is short cycling

      Originally posted by DuckButter View Post
      Steam systems run best at a max of 2psi.
      I noticed in the pics that the guage was at or near zero, was it operating at the time?
      Also I noticed the pressuretrol was all the way down to .5, maybe a little increase might slow the frequency it cycles..don't go more than 2 psi, in fact only a small amount per try until it either stops short cycling or you're @ 2psi on the boiler guage when it shuts off.

      My #1 guess is whats already been mentioned, the pigtail feed to the pressuretrol might be clogged, thats very common.
      Usually it's good measure to replace both pigtail and presuretrol at the same time while you're at it.

      IF any of this sounds confusing, please consider getting a pro to look at it, if you mistake one thing for another and accidently alter/damage a safety, you could create a hazardous situation.
      Originally posted by zuffy View Post
      The Honeywell control was never touched. It has always been at the same level. There is line that says 2 and below is .5, the indicator is in between.

      If the Honeywell thing is the pressuretrol, I will get a pro to replace it if he agree that is the problem. I know better than to try to fix something I'm not comfortable doing.

      Thanks for the help.
      The pressuretrol is NOT the problem, Its an air problem, the AIR vents are not working properly. If the air cant escape the steam cant get in. Replace the main air vents and the radiator air vents.

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      • #48
        Re: My boiler is short cycling

        You need to go back thorugh the posts, It was the thermostat all along. Exactly what the first part of my original post said.
        sigpic

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        • #49
          Re: My boiler is short cycling

          Originally posted by Masterplumb View Post
          The pressuretrol is NOT the problem, Its an air problem, the AIR vents are not working properly. If the air cant escape the steam cant get in. Replace the main air vents and the radiator air vents.
          True, he mentioned after the fact that the boiler had been working fine at the same setting before, if it were a ceased pressuretrol, or clogged pigtail, the boiler wouldn't start at all.
          You're right, if the pressuretrol were short cycling the boiler it would be a venting issue (I'd been semi-guessing the setting had been tampered with).
          In the real world, we'd probably jump the tt connections, or pressuretrol to conclude this.
          I'm pretty sure he'd mentioned the vents were working, like NH said:
          Originally posted by NHMaster3015 View Post
          You need to go back thorugh the posts, It was the thermostat all along. Exactly what the first part of my original post said.
          ...but I'm not up to reading back.
          I think NH got it, but we don't get the luxury of jumping the connections to find out for sure.

          Comment


          • #50
            Re: My boiler is short cycling

            Originally posted by NHMaster3015 View Post
            You need to go back thorugh the posts, It was the thermostat all along. Exactly what the first part of my original post said.
            Actually, it's not the thermostat. I think it was the default CPH set at 6. Since changing it to 1 CPH, it's not short cycling anymore. BTW, I did replace the thermostat with a Honeywell VisionPro TH8110. With the CPH at 1, it's functioning the same as with the old thermostat.

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            • #51
              Re: My boiler is short cycling

              Originally posted by Masterplumb View Post
              The pressuretrol is NOT the problem, Its an air problem, the AIR vents are not working properly. If the air cant escape the steam cant get in. Replace the main air vents and the radiator air vents.
              Just curious, where can I find the main air vents and do they look like the ones found in the radiators?

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              • #52
                Re: My boiler is short cycling

                Originally posted by zuffy View Post
                Just curious, where can I find the main air vents and do they look like the ones found in the radiators?
                The main vents are usually at the end of the main(s) right before they drop down into a return.

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                • #53
                  Re: My boiler is short cycling

                  Originally posted by DuckButter View Post
                  True, he mentioned after the fact that the boiler had been working fine at the same setting before, if it were a ceased pressuretrol, or clogged pigtail, the boiler wouldn't start at all.
                  You're right, if the pressuretrol were short cycling the boiler it would be a venting issue (I'd been semi-guessing the setting had been tampered with).
                  In the real world, we'd probably jump the tt connections, or pressuretrol to conclude this.
                  I'm pretty sure he'd mentioned the vents were working, like NH said:

                  ...but I'm not up to reading back.
                  I think NH got it, but we don't get the luxury of jumping the connections to find out for sure.
                  You said if it was a clogged pigtail the boiler wouldnt start? I believe you have it backwards, if the pigtail was clogged the pressure-trol would never get a reading, making the boiler cycle LONGER and build up the steam pressure, most likely until the relief valve blew.

                  The thermostat is hardly ever an issue with cycling, its usually a pressure problem, i.e. the air cant escape from the vents fast enough and this will make the pressure rise faster then normal.

                  If the rad. vents work but the main vent(s) dont, it takes way too long to vent the system. A usual sign of this is a very audible hissing coming from the radiator vents.

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                  • #54
                    Re: My boiler is short cycling

                    Originally posted by Masterplumb View Post
                    The main vents are usually at the end of the main(s) right before they drop down into a return.
                    Can you please translate that into normal conversation language? I don't understand the plumbing terminology. Got a pic of how a normal main vent looks like?

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                    • #55
                      Re: My boiler is short cycling

                      Originally posted by zuffy View Post
                      Can you please translate that into normal conversation language? I don't understand the plumbing terminology. Got a pic of how a normal main vent looks like?
                      Coming from the top of your boiler you have either one or two pies coming out. They combine into one common pipe. This pipe will usually run along each side of the basement or directly down the middle, in either scenario at the furthest end of these pipes you will usually see these pipes turn down towards the floor(or just trace the pipes until they go from horizontal to vertical). You will usually see the main air vent(s) before the pipes head toward the floor. I hope I explained myself better!

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                      • #56
                        Re: My boiler is short cycling

                        i never seen a air vent at the end of a main there should be a end of the main trap before it changes back to water .
                        not saying there should not be one just never seen one
                        Charlie

                        My seek the peek fundraiser page
                        http://observatory.mountwashington.o...nal&fr_id=1040


                        http://www.mountwashington.org/weather/conditions.php

                        new work pictures 12/09
                        http://public.fotki.com/hvachawk/

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                        • #57
                          Re: My boiler is short cycling

                          Originally posted by HVAC HAWK View Post
                          i never seen a air vent at the end of a main there should be a end of the main trap before it changes back to water .
                          not saying there should not be one just never seen one
                          On a most if not all ONE pipe steam systems you will NOT see an F & T trap or any other "crossover" trap. You do need them on 2 pipe systems

                          Comment


                          • #58
                            Re: My boiler is short cycling

                            Originally posted by Masterplumb View Post
                            On a most if not all ONE pipe steam systems you will NOT see an F & T trap or any other "crossover" trap. You do need them on 2 pipe systems
                            ok i dont run into one pipe systems thanks
                            Charlie

                            My seek the peek fundraiser page
                            http://observatory.mountwashington.o...nal&fr_id=1040


                            http://www.mountwashington.org/weather/conditions.php

                            new work pictures 12/09
                            http://public.fotki.com/hvachawk/

                            Comment


                            • #59
                              Re: My boiler is short cycling

                              Originally posted by Masterplumb View Post
                              Coming from the top of your boiler you have either one or two pies coming out. They combine into one common pipe. This pipe will usually run along each side of the basement or directly down the middle, in either scenario at the furthest end of these pipes you will usually see these pipes turn down towards the floor(or just trace the pipes until they go from horizontal to vertical). You will usually see the main air vent(s) before the pipes head toward the floor. I hope I explained myself better!
                              I traced the big pipe to the other end of my house in the basement. Before it curve to the side of the house (U-turn), there are 3 vertical pipes to the first and second floor radiators I guess. Then, it curve again and there is a tip. I can't tell if that is the air vent you are talking about. Otherwise, I don't see anything else that looks like an air vent.



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                              • #60
                                Re: My boiler is short cycling

                                It looks like someone capped off where the main vent should go. Where does that pipe continue to? Does it go back to the boiler?

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