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Help for complete amateur

HelpInAKHelpInAK Posts: 33Member
Completely new homeowner with almost no knowledge of home heating systems. My combi boiler is short cycling, with a new ignition cycle starting every minute. I wake up, Adjust the thermostat from 55-63 (its -35 outside if that matters). It seems to run smoothly at 10-20% for about 30 minutes. But eventually it starts to short cycle (prepurge/ignition/flame up to about 70%/postpurge/setpointmet/anticycling) every minute. There are seemingly random periods where it will settle into another smooth 10-20% burn for a few minutes before another period of short cycling. The call for heat isn’t being satisfied - thermostat temp is currently showing 59 when set for 63. I don’t even know where to start. There is a Honeywell 3 speed circulating pump currently on setting 3. Could adjusting it to 2 make a difference? Please help. This boiler has gone through over 450 gallons of propane, nearly $1600 in just over 2 months of us owning the house.
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Comments

  • Can you give us the make and model number of your boiler (sounds like a Lochinvar)? And how large is your house?

    Some pictures of the piping would help, too. Show us the piping where it comes out of the boiler, pump locations, piping further way from the boiler, etc.

    I don't think changing the speed of the circulator will make any difference. There could be some air in the pipes. What does the pressure gauge show?
    Often wrong, never in doubt.
  • Jamie HallJamie Hall Posts: 10,024Member
    Does it have an outdoor reset? Parameters for the reset curve? Any error messages?
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • HelpInAKHelpInAK Posts: 33Member
    It is a lochinvar noble. 1400 sq ft house with additional 750 sq ft garage zone. One potential thing of note is the radiant floor heating doesn’t seem to be operational under the dining room. I went into the crawl space this morning and the two pex tubes leading into the dining room are cold while the rest of the house is heating. It’s a new construction house and we discovered only 2 weeks ago the insulators completely skipped over the ceiling insulation over the dining room. With large bay windows, the area was pretty cold (negative outside temps since nov). If there was some freezing in those pex pipes could that be a cause of the short cycling? Thank you for the help!
  • HelpInAKHelpInAK Posts: 33Member
    Regarding pressure gauge, it is currently reading about 20 with no call for any heat. As I was observing it running earlier it was around 24
  • HelpInAKHelpInAK Posts: 33Member
    Regarding the outdoor reset and the parameters, I’m just not knowledgeable enough to know.. I would imagine no outdoor reset because the screen has displayed “outdoor sensor missing” since we bought the house (I was told by our inspector that the outdoor sensor was not necessary). No other error messages displayed.
  • ratioratio Posts: 1,883Member
    Eliminate the nighttime setback until the problem is found. Also note that an 8° setback is HUGE, and setbacks of any kind must be carefully evaluated as they perform poorly with mod/cons and poorly with radiant.

    You might be on to something with the freezeup idea. Pics will help…

  • IronmanIronman Posts: 4,900Member
    ODR may not be necessary to meet code (actually, it is to meet the federal energy code), but there's no use having a mod/con without it. You're wasting a lot of energy.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • Email "Rick in Alaska" at [email protected]
    Often wrong, never in doubt.
  • HelpInAKHelpInAK Posts: 33Member
    Thanks for the replies, everyone. I didn’t think 8 degree setback was huge considering the garage can easily lose 8-10 degrees in the minute or 2 of moving the cars in (we’ve since stopped parking in the garage just to avoid having to reheat it). I have no idea what the function of the ODR or outdoor sensor is, but more for me to research..

    I wish I knew exactly what I should be showing pics of, but here’s a shot looking up at the pipe system from the crawl space. The two pipes on the far right go into the dining room. They are not warm to the touch while all others are.
  • ratioratio Posts: 1,883Member
    ODR stands for Outdoor Reset. It's part of a control scheme that reduces the circulated water temp based on the outdoor temperature. It aims to put exactly the same amount of heat into the building that the building is loosing to the outdoors, hence no change in indoor temp. With the heat input exactly balanced (in theory) with the heat loss, there's no way for the system to catch up after the setback ends. However, we know that the ODR is currently not functional, so ignore it for now.

    Can you follow the path of the cold pipes, maybe there's a place where cold air is infiltrating. It could be air in the system as well.

    More pics, of the boiler & the piping around it. Is this a new build, remodel, ??? Has it ever worked right? Can you take a temperature reading of the pipes going in to & out of the boiler? Can you tell us the various setpoints?

  • Jamie HallJamie Hall Posts: 10,024Member
    The purpose of ODR -- Outdoor Reset -- is to modify the temperature which the boiler is aiming for. The idea is to run at as low a temperature at the boiler which will satisfy the heating demand of the house, since the cooler the boiler can run the more efficient it can be and so that the heating system circulation is always on -- always circulating. It does this by sensing the outdoor temperature and adjusting via a neat little program the target temperature of the boiler; that neat little relationship has to be adjusted -- usually by the installer -- for best results.

    Clearly the insulation over the dining room wasn't the only thing skimped by the builders...

    On the dining room circulation. Can you find those two cold pipes again (they shouldn't be cold!) and trace them back to where they connect to the other piping and eventually to some pumps or valves? Is there, by any chance, a valve closed in there somewhere? Wouldn't be the first time.

    And if you have even some radiant -- as has been said, an 8 degree setback is impossible. In fact, the system will work best and most efficiently with no setbacks at all, unless you were going to close the house for a couple of weeks or something.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • DZoroDZoro Posts: 719Member
    Use no set backs.
    What water temp are you running?
    What max heat limit set at?
    Are you sure you have ALL the air out of the system?
    The design for air removal ,and over all usage of pex is not a good idea. Concerned you have air in the system, was each individual run fully flushed out , one at a time?
    Has a combustion test been done?
    What size Noble?
    How many BTU's is the flexible gas line good for?
    Absolutely need the outdoor reset and supply system probes used for best operation and efficiency.
    The garage air temp may fall but your cement temp should stay constant, slab sensing thermostats are a good choice for your system.

    D

  • IronmanIronman Posts: 4,900Member
    edited January 6
    PEX'd to death?
    I've never seen so many pex fittings in a radiant system. Since they're not expansion fittings, but crimp/cinch style, they add a great deal of head (resistance to flow) to the system.

    Had the installer used manufactured manifolds (Caleffi, Rehau, Viega, Uponor, etc.) the installation would have been a lot neater, more functional and little or no increased head. You would also have been able to purge air from each loop individually and that may be where your problem lies. You may be air-bound in some of the loops.

    This is what a proper manifold looks like:



    With tubing connected:



    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • nibsnibs Posts: 187Member
    Am a newbie much like you and I built my own system. I did use store bought manifolds but when we first fired up the system I used the ball valves, red handles to begin balancing the system.
    (was & am still learning)
    You might try this first of all make sure that all the ball valve handles are parallel with their pipes, and firmly against the stops.
    It may just be parallax, but a couple of yours look like they may be only part way open. next if you have one on a pex pipe that seems to be warmer than the others, tweek it closed just a little (no more than 1/8th of a turn at a time) then wait and see if it matches the others. Try to get all the pipes to the same temp by touch. This is a very amaturistic approach, but one that you can spend the week end doing. Most of the loops should be open wide, but you can tweek some of the ball valves to try and balance things.
    You need a pro unless you are prepared to learn very quickly, and some of the best in the biz are right here on the wall.
    Best of luck.
  • EBEBRATT-EdEBEBRATT-Ed Posts: 5,280Member
    air bound, possibly frozen could be a flow issue

    you mentioned a "new construction house" and "the inspector said"

    is this a new house?

    Can you talk to the builder and at least get the original install to get this operational until you can get someone that know what they are doing to straighten this out?

    Is there any warranty
  • VoyagerVoyager Posts: 196Member
    Ironman said:

    ODR may not be necessary to meet code (actually, it is to meet the federal energy code), but there's no use having a mod/con without it. You're wasting a lot of energy.

    He’s not wasting any energy at -35. He will in the spring though.
  • VoyagerVoyager Posts: 196Member
    HelpInAK said:

    Thanks for the replies, everyone. I didn’t think 8 degree setback was huge considering the garage can easily lose 8-10 degrees in the minute or 2 of moving the cars in (we’ve since stopped parking in the garage just to avoid having to reheat it). I have no idea what the function of the ODR or outdoor sensor is, but more for me to research.

    If you have a hydronically heated slab in your garage, you aren’t losing 8-10 degrees moving your car in and out. Yes, the air temp may dip that much when you let in a slug of -35 air, but most of the heat in the garage is in the slab and that is not going to cool 8-10 degrees in a couple of minutes. Once you close the door, the temp inside will recover pretty quickly. It does in my workshop that is hydronically heated and has a 12’x12’ overhead door that lets in a lot of cold air when opened, but the thermostat recovers quickly once the door is closed.

    ODR is very simple. You provide 4 numbers that specify two coordinates on a graph and the computer draws a straight line between them. You tell the system that you want the boiler to run at say 120 degrees when it is 0 outside or colder. You then tell the system that you want to boiler to run at say 70 degrees when it is say 60 outside. The boiler control will interpolate the boiler temperature as the outside temperature varies between 0 and 60. If it is say 30 outside, that is halfway between 0 and 60. This means the boiler temp will be halfway between the two set points you provided. So, halfway between 120 and 70 is 95 so your boiler will run at 95 when it is 30 outside.
  • HelpInAKHelpInAK Posts: 33Member
    So I tried to follow the piping as it goes into and above the crawlspace insulation. Picture attached of the small dining space, the piping goes into insulation and across to the left. The insulation ends at the upper left seam, however the dining room has bay windows that actually extend a couple feet past the foundation. I stuck my hand into that space of the upper left-hand seem and the air is ice cold. I threw a thermometer in there and it came back -13 degrees. This is about 6-8 inches away from where the pex piping routes.

    No closed valves, but funny that someone would mention that it happens - the installers left a valve closed in the garage zone that froze half the slab. The boiler was short cycling because of this as well and we thought that that was our only problem. 3 days after having it thawed I realize the boiler short cycles when the house calls for heat as well.
  • HelpInAKHelpInAK Posts: 33Member
    It is a new construction house under warranty, however the builder and most of the contractors are a 5 hour drive from here. Responsiveness is an issue and a lot of troubleshooting is done over the phone, so I’m trying to educate myself on what’s going on so I can explain better. That, and I think they’re getting tired of hearing from us.
  • nibsnibs Posts: 187Member
    @Voyager your description/explanation of ODR above is one of the simplest and most elegant I have seen, thank you.
    @HelpInAK Should have said above that if any of the pro's here disagree with what I wrote, above, believe them.
  • HelpInAKHelpInAK Posts: 33Member
    Ratio, here are a couple more pics along with the set points - DHW 120, space heat setpoint 166, auto reset hi limit 200, manual reset hi limit 210. I honestly am not 100% sure if it’s ever worked right. I never paid much attention the first few weeks we lived here. I don’t remember when it started to occur to me that maybe the constant powering on and off the boiler was not normal. Had the builder come out and we realized half of the garage slab was frozen. Had that thawed out for a week now, and I’m only now noticing the short cycling is occurring when the house calls for heat as well
  • HelpInAKHelpInAK Posts: 33Member
    edited January 6
    Dzoro, unfortunately I don’t know the answer to those questions but I’ll definitely write them down for when I can get the builder back out here. The space heat set point is set to 166 degrees. I don’t know the size of the boiler by just looking at it, no instruction manual either. I’ll also inquire as to why no installation of outdoor sensor.
  • HelpInAKHelpInAK Posts: 33Member
    Voyager, thanks for educating me on that garage slab maintaining heat. My wife will surely apreciate being able to park in that garage again!
  • IronmanIronman Posts: 4,900Member
    edited January 6
    Did they install heat transfer plates with the tubing or is it just stapled to the bottom of the floor?
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • HelpInAKHelpInAK Posts: 33Member
    @Ironman they are just stapled to the bottom of the floor
  • IronmanIronman Posts: 4,900Member
    edited January 6
    No wonder it's short cycling and won't properly heat your house: you're getting very little heat transfer between the tubing and the floor. About 7 btus per sq. foot without plates. About 20 btus per square foot if you had good plates.


    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • IronmanIronman Posts: 4,900Member
    Whoever did this is clueless about radiant floor heat.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • DZoroDZoro Posts: 719Member
    OHH my, are there 2 tubes per joist pocket?
    Like someone mentioned earlier, don't turn your thermostat down. There is some more work to be done if you ever want heat.
    D
  • VoyagerVoyager Posts: 196Member
    edited January 6
    HelpInAK said:

    It is a new construction house under warranty, however the builder and most of the contractors are a 5 hour drive from here. Responsiveness is an issue and a lot of troubleshooting is done over the phone, so I’m trying to educate myself on what’s going on so I can explain better. That, and I think they’re getting tired of hearing from us.

    Being 5 hours away is their problem. That should have caused them to take even more care to avoid callbacks. I am not one to want to involved lawyers unless I absolutely have to, but if they remain unresponsive, sometimes a letter from an attorney can go a lot farther than 10 more phone calls from you.
  • VoyagerVoyager Posts: 196Member
    Ironman said:

    Whoever did this is clueless about radiant floor heat.

    And that is an understatement. :#
  • GordyGordy Posts: 9,250Member
    edited January 6
    This is turning into a radiant design error......

    166 supply temps.
  • VoyagerVoyager Posts: 196Member
    Well, with such inefficient “radiators”, he may need supply temps that high to get enough BTUs into the house.
  • HelpInAKHelpInAK Posts: 33Member
    Thank you for the replies everyone. So I take it 166 is higher than it should have to be, and lack of heat transfer plates could be one of the reasons? Just trying to arm myself with ammunition for when I can get the builder back out here
  • GordyGordy Posts: 9,250Member
    Yes. Sounds like a suspended tube, or plateless stapleup detail.

    Neither of which could carry that load. Which is obvious by the water temps used, and the results you are getting.
  • VoyagerVoyager Posts: 196Member
    HelpInAK said:

    Thank you for the replies everyone. So I take it 166 is higher than it should have to be, and lack of heat transfer plates could be one of the reasons? Just trying to arm myself with ammunition for when I can get the builder back out here

    Yes, probably at least 40 degrees too high with well-installed aluminum plates and probably 60 degrees too hot for in-slab hydronic. For comparison, and we have had a mild winter so only a few nights down to 10 degrees (a long way from your -35), in my workshop, which is 32’x48’x14’ with a 12x12 overhead sectional door, two man doors, and 8 large double hung windows, I run SWT of 78 to keep it 55 in the shop. I was holding it at 60 for a while and that was with only 80-82 SWT. My delta T is about 15 degrees most of the time with RWT in the 60-65 range.

    I can’t remember with certainty as I have been experimenting for the last few weeks, but I think my current ODR settings are 100 @ 0 F and 61 @ 65 F. Even though the manual lists 60 as the minimum boiler temp, as I recall the display would not go below 61.

    There is a lot here to sort through, but I found this document very useful when designing my system.
    https://www.zurn.com/media-library/web_documents/pdfs/zpm02101-pdf.aspx
  • IronmanIronman Posts: 4,900Member
    Another issue that happens with water temps above 120* is the PEX begins to sag and act like a wet noddle causing even less thermal contact with the floor and giving less heat output even though the water temp is elevated.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • IronmanIronman Posts: 4,900Member
    HelpInAK said:

    Thank you for the replies everyone. So I take it 166 is higher than it should have to be, and lack of heat transfer plates could be one of the reasons? Just trying to arm myself with ammunition for when I can get the builder back out here

    Yes, 166* is way higher than it should be and is causing the boiler to run below 90% efficiency because it's not condensing.

    A properly designed radiant floor should not need a SWT above 120* on the coldest night of the year. If it does, a supplemental heat source should be installed, but not cranking the SWT higher. Using higher temps may damage your floor and is defeating the purpose of a mod/con.

    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • GordyGordy Posts: 9,250Member
    edited January 6
    There are several types of radiant panel designs/details. Each one when properly installed will have a maximum btu per square foot output. Floors are limited to 85 degree surface temps for comfort. 82 if there is wood flooring involved in the detail. Your detail is at the bottom end of outputs. Maybe 10 btus a sf or less. An over the top sandwich style assembly, or embed in concrete would be the upper end of output.
  • HelpInAKHelpInAK Posts: 33Member
    I spoke to the installer of the system. Heat transfer plates were not installed because “they were not cost effective,” and would have added several thousand to the cost, and that running the tubes twice per joist pocket was sufficient. He also didn’t have the outdoor sensor installed because he doesn’t trust the electricians to install them in the right place (North-facing side of the home out of direct sunlight).

    I guess step 1 for me right now is to get the pipes thawed under the dining room. The builder’s project manager will be out tomorrow to see if insulation was missed near the bay windows.

    Step 2 is getting that ODR set, but I think I’ll wait til spring and pay a professional to come out and install.

    I also asked the installer about the space heat set point limit (166) reducing boiler efficiency by not allowing to condense. He said I can play around with the setting, maybe lowering it to 140 and see how that works. My question is what exactly happens when I set that to 140 vs 166 and how do I determine whether or not it’s “working” for me? Changing this setpoint reduces the max temp of output water to 140, correct? Does this simply mean the boiler will have to run for a longer period to satisfy a call for heat?

    @voyager thanks for that link, a lot of great information for a beginner like me, but boy is that a long read.
  • IronmanIronman Posts: 4,900Member
    "Not cost effective"??? In other words he didn't use them so he could stuff the $$ in his pocket while leaving you with a system that can't possibly perform correctly! That's like saying I couldn't install the duct work on a forced air system because it wouldn't be "cost effective" for me. The plates are an essential component that should NOT have been left out.

    This guy is either woefully ignorant of radiant or dishonest. Either way, he's a fraud.

    I'd recommend that you tell your builder that this system has to be made right immediately or else he'll be talking to your attorney.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
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