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    Radiant floor heat not heating properly (20 Posts)

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    Radiant floor heat not heating properly

    I am the home owner not a plumber I hired one to install this.

    Picture and floor plan PDF attached

    Ok here is what I have
    2200 sq foot 1 story slab on grade

    Triangle tube 110 boiler with smart tank for DHW

    All zones are controled by zone valves

    Zone 1- 5 LOOP Uponor true flow jr. manifold in the closet of bedroom 2 fed 60 feet by a 1" pex from boiler room

    Zone 2- 2 LOOP Uponor true flow jr. manifold in the boiler room

    Zone 3- 2 LOOP Uponor true flow jr. manifold in the garage fed from boiler room


    1. Bedrooms 2 and 3 are 8 degrees colder than other rooms in same zone
    2. Used twice as much LP as a friend with same system and a bigger house
    3. Systems has run one heating season and show over 14,000 CH ignitions


    Looking at the pictures is this system hooked up correct why am I having these issues

    Please help
    Thanks Challenger
  • Ironman Ironman @ 8:23 PM
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    Hooked Up Right?

    Obviously not with the issues you're describing.

    A lot more info is needed. Particularly more detailed pics of the near boiler piping and controls. Manifold piping too, please. Can't tell much from the lone, fuzzy pic.

    A piping diagram would also be very helpful.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
  • N/A @ 8:26 PM


    Only one pump for all all three zone and boiler piping??? Looks like you should have one pump for low loss header and other
    pump for each zone.. sorry to say this.. the plumber you hire was not a hydronic heating expert.
  • Paul Pollets Paul Pollets @ 8:48 PM
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    Near Boiler Piping

    The TT boiler needs an 11/4" primary loop using (1) circulator; any additional secondary zones are taken off the primary loop with closely spaced tees. The primary loop will be set for the highest temp required; zone temps are controlled by mixing valves for RFH zones. Each "takeoff" with closely spaced tees requires a separate pump. Use a variable speed pump for best results, especially if the zone uses zone valves.

    See page 21:
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  • Rich Rich @ 10:03 PM
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    Bedroom 2 & 3

    What manifold are they on ?  You only have 9 loops in a 2200 square foot house , is this correct ? That home would require app. 3300' of tubing at 8" on center and 2750' at 12" on center . At 12 your average loop length is 305' and at 8 the average loop length is 366' .  You my friend are in trouble .  You will  need an in depth analysis of what loops are on what manifolds , what rooms are zoned together , and how much pump you will need to push fluid through those long lengths to salvage some of your sanity .  I would venture a guess that your boiler is oversized also . 50 BTUh per sq. ft is a bit heavy handed even in the coldest of climates . Where are you located ?  You will certainly need someone to hydraulically separate your system from the boiler . Sorry to say you have a lot on your plate .  Is this installer avoiding you now or can you persuade him to remedy the situation or at least hold him responsible so you can be reimbursed for whatever the cost is to have another make it at least work acceptably and keep you warm ?  Did this slab get insulated below the tubing ?     Where the hell did you find this guy ?
    You didn't get what you didn't pay for and it will never be what you thought it would
    This post was edited by an admin on November 11, 2013 10:10 PM.
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    On my floor plan pdf I posted shows the different zones.
    The bedrooms in question are on a 5 loop manifold on zone 1
    The loop from what I remember in the building process is 8" around the outside walls 12" everywhere else.
    The bedroom 2 loop would be just that room and half the bathroom
    The bedroom 3 loop would be just that room and other half of bathroom
    Yes I have 2" of blue foam under floor loops and up the footing walls and my above grade walls have 3.5 inches of spray foam. Don't think I'm losing much heat that way.
    Live in MN
    300 foot loops sound correct think I remember him saying that
    I hired the local plumber that has been in business 30 years to install this system. I've had him back a couple times added the check valve on the DHW supply last time and now wants to install a variable speed pump to fix the cold rooms.
    Not much I can do now as far as loops go unless I rebuild a 11 month old house. I hope this can be fixed above the cement level.
  • Rich Rich @ 12:08 AM
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    0013 VDT

    if you are willing to allow him to just replace the existing pump . That should get you through .  I would most definitely advise you to find out more , maybe hire someone to do a proper room by room heat loss .  I would say get rid of the zone valves , employ some thermal actuators for rooms 2 & 3 and the others on the 5 loop and add required thermostats . Find out the actual head losses for each loop and fix this thing up top as best you can . Too big boiler for your house my friend for sure , gonna keep on short cycling and wear that thing out quick , a real shame .  I noticed Uponor manifolds , zone control modules . Is the pex Uponor also , is this man recognized by Uponor as an HCT ?  Where are you in Minnesota , anywhere near Prior Lake ?  Maybe you could contact someone around there ?  I know at least 4 guys from the Minneapolis / St Paul area that could quite probably help you make this system the best it will get at this point .  Remember though , accept nothing but the Taco 0013 VDT at this point and dial it in to a 10 - 15 degree Delta T , the extra 5 degrees will help slightly with your cycling issue . And for Christ's sake move that thermostat out of the lowest heat loss , warmest area and put it on the angled wall at foyer , great room junction or in the coldest bedroom . If your family likes a little chill while sleeping put it out in the foyer or the angled wall , at least that way the zone will stay on  a little longer and let some BTUs into those bedrooms .
    You didn't get what you didn't pay for and it will never be what you thought it would
    This post was edited by an admin on November 12, 2013 12:17 AM.
  • Zman Zman @ 1:01 AM
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    There are some problems with your system
    Your boiler is piped mostly correctly.
    The boiler has an internal primary heating circulator. There should be a check valve on the primary heating loop. I don't see one. One inch is fine for the primary on the 110.
    On the secondary, I am not sure which circ you have. 1/30 HP is way too small for radiant loops. I have not heard anything about the outdoor reset curve?
    The insulation is adequate. The tubing is a little light but should be workable.
    I would make sure you have a check valve on the primary loop.
    I would try to determine the loop lengths and size the radiant circulator correctly.
    Once you have proper circulation, I would adjust the heating curve on the boiler until the heat is comfortable.
    Sure the boiler is oversized and there are some install and design errors.This certainly not a horrible system and I believe it can be easily corrected
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  • RobG RobG @ 2:25 PM
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    Make sure all the pipe has an oxygen barrier. I count three different types of piping not counting the copper. If the pipe does not have an oxygen barrier let us know, hopefully all the under slab piping is He-pex at least.
  • Mark Eatherton Mark Eatherton @ 9:10 PM
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    I hate to be the first to say it, but I think you got what you paid for. It is never a good idea to mix sleeping rooms with common living spaces (kitchen). It's also not that much more expensive to provide individual zone controls for additional spaces. You want sleeping areas cooler than bathing areas, etc etc etc.

    First things first, First thing to do is to make certain that you do in fact have good and proper flow through all circuits in the 5 circuit manifold. Could be something as simple as closed valves on the manifold causing the problem. If you confirm good and proper flow, then you need to start looking at the possibility of zone addition.segregation. The TF Jr manifold is conducive to this by adding small telestat operators to each port. You will have to determine what circuits does what rooms, and then you can control these zones by purchasing and installing Honeywell wireless thermostats in the individual rooms that you could have/should have controlled separately anyway, You may have to mount the receiver in the basement/crawl space, and run the low voltage wiring up to the individual telestat operators.

    After you've verified good and proper flow, you will then need to run each circuit on the manifold individually to determine the physical areas served by a given circuit. Hopefully, the tubing layout is conducive to your true zoning needs, but you won't know until you do a thorough investigation, and it IS going to take a LOT of footwork/time on your part to get to that point. Once you've figured that part out, you can contract with a qualified hydronic radiant contractor to get the work done. I have no idea where in Minnesota you are, but if you are any where near Eric Aune, Aune Plumbing and Heating, he can get it figured out and fixed.

    As for fuel consumption, if the original installer did a poor job of purging, the boiler will run forever, trying to satisfy calls for heat, and WILL waste a ton of fuel in the process.

    There is also a remote possibility that your "issues" are not even related to the hydronic system, but in fact may be a construction defect issue. Too much infiltration is one of those deTAILS that can and will wag the dog...

    You do have some homework to do, and once done, should realize excellent comfort and reasonable fuel bills. Radiant heating, when done RIGHT is unbeatable comfort. Done wrong, or improperly commissioned, it causes a lot of desperation and waste time and money.

    Bear with us and we will get you there.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • Weezbo Weezbo @ 3:00 AM
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    Mark ,

    i cannot see the foundation detail clearly . however , what it looks like is there is no foundation wall insulation no perimiter insulation and there looks like a tremendous amount of edge loss around the entire slab , .
    the exterior shows no sign of sheet insulation , would you mind speaking to the amount of edge loss for a moment ?
    i think that you hinted at it in your post.
    i cannot quite even make out the numbers along the drawing , i see some numbers and at the same time i dont .
    Thanks Weezbo.
    *~//: )
  • Gordy Gordy @ 10:39 PM
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    I'm wondering

    If a heatloss calculation was done? No mention of it.

    Was slab insulated?
    This post was edited by an admin on November 12, 2013 10:42 PM.
  • wrxz24 wrxz24 @ 6:01 AM
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    I have the same boiler

    But each of my radiant zones have circulators. Like Mark said, check the flow at the manifolds. I had sort of the same problems as you. Some parts of my floor were not getting heat. It turned out that the flow in a few of the loops were too slow. I adjusted each loop so I was getting a good 10 degree delta t and I was able to get heat to the parts of the house that was cooler.
    Also, you said you were short cycling. For me, when just one my radiant zones are calling, I short cycle because of the mixing valves, ( i also,have baseboard zones) due to primary secondary and my radiant zone not requiring a lot of boiler water, most of the boiler water returns back to the boiler and the set point is reached faster.

    Check your ch post pump times and ch block time setting too. I set mine at about 8 minutes for each, that helps with the next call so there are longer burn times.

    Just something to check.
  • Harvey Ramer Harvey Ramer @ 9:41 PM
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    I concurr with Mark.

    Radiant does not comply with, rules of thumb, shortcuts or the cheapest price. It costs what it costs and that's a rule that can't be broken.

    To start troubleshooting, first you have to do a heatloss or get access to one that may or may not have been done. Trust me on this, you have to do it!

    After you have your room-by-room heatloss, it is time to determine you have adequate flow to all manifolds. An easy way to do this is to purchase a Caleffi flow meter and install it inline to the manifold. Then measure the temperature difference between the supply and return tubing. Those two figures will tell you the BTU's being transported to the manifold, using this formula GPM = BTU/h ÷ (∆ x 500) Look at your heatloss calculation to determine if you have enough BTU's to said manifold. If you do not have enough flow you will need to determine the loop lengths on the manifold and what size and type of tubing it is. You will need to measure the length of the supply and return tubing. Each type of tubing should be measured separately and should include all fittings and devices so a headloss calc can be done. We can do one for you.

    If you have no flow issues, and even if you do; you will probably want to create more zones off of the manifold in question. First you must determine how the tubing is laid out so you know which loops to make your zone. The fastest and easiest way to do this is with a thermal imaging camera. Find somebody who has one and check it out.

    Once you are armed with this new data on your system, get back to us and we can advise you on the appropriate repairs.

  • Chris Chris @ 12:05 PM
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    One Missed Question To Be Asked

    What are the floor coverings in the bedrooms? Carpet? I see no mixing device in the boiler pics so this system is running on one water temp. Where's the heat loss and design to say one water temp is what you need?
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Steamfitter66 Steamfitter66 @ 8:59 AM
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    Start with a proper heat loss calculation

    and then you will find that your plumber with 30 years of experience is just that. Experienced plumber. Not a pipefitter or hydronics designer. There is a big difference.
    A proper design includes input of all walls, floors, ceilings sq ftg and there insulation values as well as sub floor construction and finished floor coverings.
    Did the plumber do or have a design done or was it all off the cuff?
    Most likely your short on tube and have carpet in the bedrooms. High gas consumption is probably a combination of building envelope issues and elevated water temps from being short on tube.
    there are many people with years of experience but still lack knowledge.
    This post was edited by an admin on November 22, 2013 9:07 AM.
  • Jean-David Beyer Jean-David Beyer @ 11:40 AM
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    there are many people with years of experience but still lack knowledge.

    In another field, I had occasion to describe someone who "did not have 12 years of experience: she had the same six month's experience 24 times."
  • Gordy Gordy @ 1:23 PM
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    My reply

    Every time a 30 year experienced knuckle head says he's been doing it like this for 30 years. "Then you have been doing it wrong for 30 years"

    They are out there in EVERY TRADE !!!

    It's hard to believe how many people I have been across that wing it for so long, and still manage to hold a career in their field.
    This post was edited by an admin on November 22, 2013 1:28 PM.
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