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radiant floor

Mark Custis
Mark Custis Member Posts: 539
pictures and include pictures of the manifold.

Balancing will be better than insulation.

Comments

  • dave m  county
    dave m county Member Posts: 2
    trying to ballance

    40'x60' Office biulding in Northern Iowa new in 2005. r30 insulation in the cieling and r10 in the walls. The offices in the north west corner of the biulding are cold and the southern offices are too warm. The thermal imaging camera showed tubing runs going to other zones in rooms that were already hot. Is there any type of insulation to lay down over those runs? under the carpet?
    Now for the cold areas-
    How much does the chair pads under desks, the filing cabinets and other clutter that covers 50% of the floor affect the out put of the floor heat?

    The contractor was taken to court and we won. -a small settlement. Now its up to the janitor to make it work.
    Thanks
    Dave M County
  • Mike Thomas_2
    Mike Thomas_2 Member Posts: 109
    The janitor

    I guess you felt the janitor was better qualified to figure it out than ask the contractor to get it right? You might consider that solar gain might be contributing to the imbalance. It happens in my home. House is just fine, but as soon as the sun comes up in the east, the east end of the house overheats.
  • hot_rod
    hot_rod Member Posts: 21,835
    It's called heat flux

    when you have cabinets or built in furniture that block the output from the floor. Add the square footage of those and divide it out of the total area to get the heat flux. Now determine if the remaining square footage can cover the heatload of that room.

    What about edge insulation? It's often overlooked or improperly detailed.

    Loops running through overheated areas to supply un-heatable rooms is going to be a tough one to tweak.

    Large shop buildings that later on get partitioned off into smaller living spaces is a challange. Unless you have a detailed drawing of how the space will be divide off, down the road, this can a a tough one.

    Or as you may have found out, even with a good drawing, implementation makes or breaks the system.

    I have seen additional padding installed to limit output in one area, throw rugs can sometimes help "balance" areas like that.

    Or a panel radiator retrofit :)

    hr
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • dave m  county
    dave m county Member Posts: 2
    some pictures

    The thermal camera belongs to the city utilities. I will try to get some of those posted by next week. This is what the local plumber came up with -after we gave up on the contrator. Everything would have frozen solid - it never did work.

  • S Ebels_2
    S Ebels_2 Member Posts: 74
    That's a tough one

    Office areas are always a challenge considering all the extraneous heat sources that are present like copiers, computers, coffee pots etc. Hot Rod brings up a good point about the edge insulation too. I have yet to find a general contractor that even considers it for slab on grade buildings. I mention it and get a blank stare most of the time.

    That being said, general use type offices with small room sizes are not a good choice for in slab radiant in my experience unless care is taken in zoning them. Even then problems can arise down the road when interior wall or partitions are moved. Room by room control that is fairly responsive is a better way to go. I'm curious as to who specified the in slab radiant heating system. Customer, contractor, architect? Inquiring minds want to know :)

    You may find that the best resolution is to run the radiant floor at very low output and make up the balance with some type of heat emitter that can respond more quickly to solar, office machine and warm body input. I have found that many times most of the over heating issues can be addressed by setting the system water temp as low as possible instead of relying on room thermostats to "shut off" the heat when it gets too hot. You can't just shut of a slab of concrete. Once warm, it'll radiate heat for a couple days with no further input. as I said above, think about supplemental heat for the cold areas.
  • Dave M County
    Dave M County Member Posts: 5
    Now I think is the lights

    Thanks for your advice! The T5 lights that were installed run about 125 deg. -thats 8'fixtures in each little room. I suggested putting the lights on thermostats. some laughed some didn't.
  • Dave M County
    Dave M County Member Posts: 5
    The cold areas

    The cold side of the building is better now since I adj. the balance on zone #1. Thanks to the download from Heating help library from wirsbo.
  • is THAT ?

    Is that clear cheap ploy tubings being used for floor heat? Tubings look all discolored due to different water usage. If so, don't even bother working on the radiant system. Start planning other methods such as properly installed cast iron baseboard radiators by the REAL hydronic heating pros.
  • Dave M County
    Dave M County Member Posts: 5
    Yes it is

    Yes it is the cheaper pex. That was the main reason the 1st contractor was taken to court. It's a long story. It all predates my employment. I was told an air seperator and all oxide rezistant parts had to be used. How long will this system last?
  • not very

    Not very long, start planning on other system.


  • well you've got cast iron pumps and black iron in here, so you don't have all non-ferrous materials. Munchkins are not the potable versions either.

    I suggest you look into corrosion inhibitors to add to the system.
  • hot_rod
    hot_rod Member Posts: 21,835
    many of the early

    radiant systems used non barrier tube. Polybutylene, polypropylene, SolarRoll, and Entran were all non barrier tube. Problems were usually seen 3- 5 years down the road, depending on operating temperatures.

    Options include separating the tube from the piping and boiler with a heat exchanger, or maintaining a corrosion inhibitor, or removing all the ferrous components from the system.

    Looks like copper tube on the condensate drains? If so it will eat away and the condensate will attack the concrete slab. It should have a neattralizer on the condensate and be piper with plastic tube.

    hr
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Dave M County
    Dave M County Member Posts: 5
    Inspector

    OKaay. More bad news. The boiler inspector is recomending external low water cutoffs , high temp cutoffs and an emergency switch at the door need to be added. The internal safeties don't meet the States standard on the Munchins.
  • Dave M County
    Dave M County Member Posts: 5
    It was

    The customer's idea.
This discussion has been closed.