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  • #16
    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.
    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.

    Comment


    • #17
      Re: My boiler is short cycling

      Originally posted by HVAC HAWK View Post
      the valve with the yellow handle next to the glass tube ,put a bucket under it and open it if nothing comes out wait untill the boiler heats up then open it . this is a skimmer valve and if the water gets oil or a lot of stuff in it it will not make steam , so you need to skim this stuff off .
      Should I still do this now that the boiler stop firing? Steam is coming up in all radiators.

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      • #18
        Re: My boiler is short cycling

        OK, I open the valve with the yellow handle. About 6-8oz of dark brown water/dirt came out.

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        • #19
          Re: My boiler is short cycling

          Since I have turn the thermostat to 69 @ 8:55pm, the boiler was firing till 9:10pm. It stayed off until 9:37pm. It went on for about 3 minutes.

          So should I keep the cph to 3 or change it back to the default 6? Seem like 3 cph is working better, less short cycling so far.

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          • #20
            Re: My boiler is short cycling

            Last comment before I head to bed. I took the Honeywell pressuretrol off. I see that the pig tail is filled with water. Is that normal? I tried to take the pig tail off but can't. I will let a pro replace it if needed.

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            • #21
              Re: My boiler is short cycling

              Originally posted by zuffy View Post
              Since I have turn the thermostat to 69 @ 8:55pm, the boiler was firing till 9:10pm. It stayed off until 9:37pm. It went on for about 3 minutes.

              So should I keep the cph to 3 or change it back to the default 6? Seem like 3 cph is working better, less short cycling so far.

              OK, think it's sorted out now. Change the thermostat. Get hold of one of the new mercury free, solid state ones. Honeywell, Robertshaw, ect. Make sure when you install it you read the instructions and set the heat anticipator where the directions say too.
              sigpic

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              • #22
                Re: My boiler is short cycling

                Honeywell T8775A-1009 would be a good choice $ 50 - $75 bucks
                sigpic

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                • #23
                  Re: My boiler is short cycling

                  You're saying the thermostat is bad? The one you recommended is non-programmable. If I am replacing it, I would like somthing similiar to what I have now, which is the Honeywell T8600D.

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                  • #24
                    Re: My boiler is short cycling

                    A very simple test to be sure it really is the thermostat.

                    Open a window in the room where the thermostat is located and close the door so the rest of the house doesn't get cold. Set the thermostat to 80 and leave it. After about 1/2 to 1 hour are you getting loads of heat in the house? If yes, that would mean that your thermostat either has a bad temperature sensor or an over acting anticipator. Be sure to set it back to a more normal setting and close the window.

                    I would go for a simple non programmable manual thermostat for a replacement. Think about Murphy's law and that keeping things simple help fight off Murphy. This is if the thermostat does need to be replaced.

                    Bottom line: For your safety and that of others, please call in a good licensed professional HVAC tech to check over everything and help flush the crud out of the bottom of your boiler. He needs to check and be sure all safety devices are working properly and any that aren't must be fixed or replaced ASAP.

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                    • #25
                      Re: My boiler is short cycling

                      This isn't so much of a DIY but more of me wanting to find out more info before the pro comes in. I just like to be well informed of the situation.

                      Woussko, I hope understanded your test right. You want me to open the windows in my living room where the thermostat is located and then close all the doors to the other rooms. If I set the thermostat to 80, wouldn't the boiler stay on because now the living room is cold regardless if the other part of the house is warm? Isn't that how a thermostat works? Am I missing something? Sorry to sound so stupid.

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                      • #26
                        Re: My boiler is short cycling

                        Zuffy

                        You really don't need to open the window. The idea is to set the thermostat well above the room temp and be sure the boiler fires up and keeps fired for some time. My idea is to try to be sure one of your safety devices isn't what's shutting the boiler off.

                        Normally a thermostat will sense the need for heat, close contact(s) and keep them closed for a good 5 minutes if not longer. When the fire starts, the anticipator (intermal part of thermostat) heats up the bi-metal coil or other temp sensor and when heated up some then the circuit opens.

                        My idea is to rule out that anything but the thermostat is the cause for short cycling there. You could just short out the wires, but I recommend not doing that for now and just set the thermostat high. You could just open a window in the same room it's in. The test is to be sure there is a call for heat for a good 1/2 hour and see how the boiler behaves.

                        Please note that not all thermostats have anticipators. Some of the new electronic ones don't need them.
                        ---------------------------------------------------------------------------------------------------------------------------------
                        To help save you confusion, maybe this is how I should post this little test.

                        Just open a window near your thermostat (if you can do so) and also set it up high for the test. Don't worry about closing doors at this time. I was thinking of a way to help hold in heat. Forget that for now.

                        After about 1/2 hour, close the window and reset the thermostat. Then please let us know what happened. Did your boiler fire and stay fired long enough so the radiators got good and hot or did the boiler fire, shut off soon, fire again and such.

                        Please go sit near the boiler and observe it, and make notes of what happens. If anything seems to be going wrong, shut it off. Do not chance safety. If your gut tells you something bad is happening, shut off the boiler.
                        ---------------------------------------------------------------------------------------------------------------------------------------
                        I would also call a good HVAC tech to come and check things over. There's no reason to put this off. It's great that you want to learn things, but don't risk safety or having a cold house. Call now if you haven't done so. Ask friends and neighbors for recommendations or horror stories about who not to call.
                        Last edited by Woussko; 03-12-2008, 11:45 AM.

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                        • #27
                          Re: My boiler is short cycling

                          OK, got it. I will post the result tonight. Thanks Woussko.

                          I have asked my in-laws to call the HVAC tech they know and used to help them installed 2 boilers and 2 WHs in their house. He is kind of busy so in the meantime, I was just trying to find out as much as possible of my problem.

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                          • #28
                            Re: My boiler is short cycling

                            OK, here is a log of my testing. I did not open any windows.

                            7:39pm - manually override the thermostat from 68 to 80 degree. water is clear at the glass tube. psi gauge needle is at the bottom

                            7:52pm - thermostat is still showing 68 degree. boiler is still firing. glass tube is water is light brown

                            7:59pm - boiler stop firing. thermostat still calling for heat with the flame icon. psi is close to the third mark so I will assume it's 2.5 - 3 psi

                            8:00pm - boiler is back on. thermostat is now showing 69 degree. psi gauge is back to the bottom

                            8:02pm - psi needle is at the second mark, assuming 2 psi

                            8:03pm - boiler stop firing. thermostat still calling for heat with the flame icon. thermostat showing 69 degree. psi is at the third mark, assuming 3 psi

                            8:04pm - boiler is back on. psi gauge needle is at the bottom

                            8:05pm - psi needle is at the second mark, assuming 2 psi

                            8:07pm - boiler stop firing. thermostat still calling for heat with the flame icon. thermostat showing 69 degree. psi is at the third mark, assuming 3 psi

                            8:08pm - I lowered the thermostat back to 68 degree to stop the testing

                            Looking at the gauge, is the second mark consider 2 psi?

                            Comment


                            • #29
                              Re: My boiler is short cycling

                              This is the third time, but I'm gonna say it again. Change the thermostat. Refer back to my original post if you want. Be sure to read the very beginning. Change the thermostat.
                              sigpic

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                              • #30
                                Re: My boiler is short cycling

                                i dont do service work i install boilers so i'm not up on all the trouble shooting .i think you have a good idea about things now and i'd say call some one to look at it ,it will be safer that way .
                                it is hard to help when we dont have hands on but people here try and some times it works and some times it does not .

                                sorry i cant come up with some more ideas .
                                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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