recessed radiator

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by pachai, Dec 17, 2005.

  1. pachai

    pachai New Member

    Jul 25, 2005
    Greetings, working on phase 1 of a "bath" project I mentioned before,
    and I have some questions I would "love" to bounce off you...
    I demolished a couple closets, now I am getting ready to move the
    radiator that was between them.

    I traced the pipe. Appears to be 1.25". Big old Cast-iron radiator
    is midway on outside wall. Pipe runs 6' under the floor
    between the joists to the center load bearing wall, there is an
    elbow in the wall to go down to the boiler, accessible from the stairs.

    Plan is to install a recessed radiator between the studs in that wall.
    Looks like I'll need two elbows and two 6" nipples to feed the radiator.
    (I bought the 6-section, 13.5" radiator and valve and vent already).
    My hope is that this 6-section radiator will provide the heat needed.
    (Suffice it to say, this is a serious factor in a marriage :)
    By putting this small radiator at the head of my bed, even if the
    room is cold, at least I'll be warm. And if my wife finds it is not cold
    enough, she can still open a window 12' away on her side (Canadians! :).

    Notes: the old radiator is a thick cast iron 8-section. Also, a second
    8-section on the other side of the room has been turned off for two
    years, wife's orders...that one will be replaced by another recessed
    one when the bathroom is built. (The room will shrink a bit for the bath,
    from 12 x 21 less 38" for closets = 12 x 18....down to
    12 x 21 less 66 for bath = 12 x 15.5)

    However, I am thinking - IN CASE 13x20" is not enough heat,
    perhaps I should be prepared to install a second 6-section radiator
    between the studs near the foot of my bed. This leads us
    finally to my question: To be ready for this possibility, I could use a T
    instead of an that I won't have many hours of work to put
    in a T later if I decide to add the second radiator....
    Thus, I plan to have: pipe from boiler comes up, elbow, Tee
    to go up to first radiator, and a plug.....Later, if I am cold, I can
    replace the plug with 6' pipe (running through the joists, below the floor)
    and its elbow and new radiator...This would avoid the risk of needing to
    redo everything if the second rad is desired (since pipes thread one way :)

    (BTW, I am planning to use metallic Radiant Barrier left over from the attic
    to line the wall behind the new radiator).

    Second question...Radiator came with no instructions...
    This radiator will be set into a load bearing wall. a few options
    come to mind...sitting the radiator right on the bottom plate...
    or installing something harder for it to sit on, so that over
    time I don't need to worry about whether it is level, or sinking in.
    ...or, I didn't yet cut the baseboard...should I install it above
    the baseboard? I'm pretty sure that's not beneficial. instructions...I know about levelling (or not quite)
    a big cast iron radiator (my plumber used nickels, I guess cheaper
    than washers..)....Do I level recessed radiator in a similar way?
    I have some pieces of oak floor (cut from under old radiator :)
    or I have some 1/4" scrap steel plates in my shop.

    Fourth/last...when and how should I paint the recessed radiator?
    I heard that you could even paint with latex in off-season,
    but if you paint in season, the latex won't cure right, and will
    smell bad forever (and that's probably very unhealthy).

    Many thanks to all..
    PS will post to a blog around Jan 2.
  2. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    From your description I assume this is a one pipe steam system. If so your plan will work fairly well as long as the pipes are going upwards continuously, no turns down or backpitch.
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  4. pachai

    pachai New Member

    Jul 25, 2005
    Radiators, joists, and studs, oh my!

    Thanks. Now I have the next issue...or two

    I bought the radiator, 13" x 20" recessed...and I
    got a valve, vent, plug, tee, cap, and a "run" of nipples
    (A plumber friend told me about this....All the nipples
    available from 2" to 6" in 1/2" increments).

    I cut away some of the wall where the new radiator
    will be recessed, and drilled down into the cavity where the
    current elbow is, about 9" off center. Of course, exactly
    where I was going to run the last leg (a 6" nipple up
    into the radiator valve, which lies on its side for recessed)....
    Of course, there's a joist there.

    I preceive a few options, I think in preferred order...
    1) feed the radiator from the right, so the pipe would pass
    under the radiator and come up into the far side.
    The only drawback here is running the pipe through the joist
    (within the cavity where it rests on the bearing wall)
    In trying to drill the hopeful opening, I effectively notched the joist
    about 3/4". (12-inch stud). May need to install a short sister joist.
    Q: how much rise does a single-pipe system need?
    The current elbow is 3" below the top of the joist, and the run is 9"

    2. Install a coupler, let the pipe come up, into wall, then elbow over and
    up to the radiator. Since it is recessed, this will mean the radiator
    will need to be raised a few inches, but then again, I can restore
    the baseboard afterwards. (I have scrap oak 2x4's to hold the
    radiator off that pipe, pack rat :) Advantage is, if
    I decide to add the second radiator, I don't need to go through
    any more joists, just studs.

    3) Cut a stud so the radiator can be closer to the original pipe
    It's been said that cutting one stud is no big deal...and the fact
    is that it's "only" holding up the attic floor, since the ridge roof
    is supported by the outside walls. Perhaps a header would
    be the prudent thing for this approach. (Project getting bigger :)

    Second question, it seems to me that it might be impossible
    to install the valve to the after the pipe is installed (5" thick wall).
    I imagine a union in the 9" run would make this easier.
    Am I mistaken about difficulty installing the valve?

    Thanks much for the advice....
    Last edited: Dec 27, 2005
  5. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    I am not sure what you mean, or why you have to have the valve on its side, unless the radiator is being installed vertically, rather than horizontal. If so, then you will have a problem with venting it and it will not heat properly. Only by seeing it can we determine if there is a way to screw the valve on, or if the union is the best way.
  6. pachai

    pachai New Member

    Jul 25, 2005
    radiator drawings

    Thanks. I had a chance to draw 3 options.
    The vertical pipe with the tapered end is existing,
    all others are proposed. The color scheme might
    not render correctly on all computers.

    All horizontal pipes are level only for simplicity in drawing.
    They really will be on an angle.
    I include the extension, which will be capped
    in case it is needed in the future.

    PS the valve is shown, in the same orientation as all the
    existing recessed radiators in the house, (it is the only way it fits)

    PPS these views are from the stairs, where I can see into the floor
    cavity under the load bearing wall. The radiator will be recessed
    from the other side of the wall in the Bedroom.

    Attached Files:

    Last edited: Dec 27, 2005
  7. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    Your valve, as shown, is in backwards, which is not a problem as long as it does not leak, or have to be serviced under pressure.
  8. pachai

    pachai New Member

    Jul 25, 2005
    It's the plumber, I've come to fix the....radiator!

    I just wanted to share the update,
    thanks for your help...
    On Sunday and Monday, I managed to get
    all my ducks lined up
    (broken away enough wall, bought all the fittings...

    and on Monday at about 9:00pm I turned on the radiator
    for the first time...and got heat!

    Here's what I ended up needing to do...

    I attached a pdf...
    A is what I wanted to do, simply turn the L to the side,
    add a 9" nipple, turn up, into radiator....that didn't work,
    ...I realized the valve used on recessed radiators (per my supplier)
    has the union on the Radiator side, but the rough-in is too close
    to the wall to allow the valve to be done last.

    A1 is what I thought of next....The union would allow
    me to assemble from below. (I actually wanted a Tee
    instead of the second elbow, so I could feed another rad).
    It all couldn't work, because there was a joist in the way.

    C is what I thought of next, preserving the Tee to feed
    a second radiator, but using 45' angles.

    D is what was actually done, I found when measuring
    correctly, there wasn't room for any more fittings.
    BTW, that's a Close elbow, fitting right into a 45' el,
    a 2" nipple, Union, 4" nipple, 45' el, 2" nipple.

    I'm grateful to the person who told me to buy a run of nipples:
    from close (2") to 6 inches in 1/2" increments...worth about
    ten times what it costs.

    The extra Union made it easy to take apart
    when I saw that the first elbow wasn't in tight enough,
    and steam leaked...

    (If I need another radiator, I'll have to cut the original
    pipe shorter...I mean, I'll have to get a plumber for a change :)

    My next step needs to be filling all the gaps left from cutting out
    most of the bottom plate under the radiator.

    BTW, it took me many many tries to break the original elbow...
    I was at the end of my rope and started beating it with the sledge...
    reminds me of when I had to break a brick wall in my old house...
    Note, don't try this at home. For me, the pipe was secured
    by all the wall lumber, so it wouldn't break anything below...
    (Though the plaster is a mess from missing the pipe :)
    I still have to get the old valve out. That elbow won't break.
    But at least I have heat.

    BTW, I plan to pull the radiator and find a way to
    secure it better, and put a radiant barrier behind it,
    so it will throw more heat into the room, since the rad
    is smaller than the original one was...

    Attached Files:

    Last edited: Jan 3, 2006
  9. pachai

    pachai New Member

    Jul 25, 2005
    Painting radiator

    PS, I was debating whether to paint the radiator before
    installing...and a friend convinced me...I googled, and learned,
    basically that oil-based paint is adequate, but that it needs
    time to cure (even beyond drying time).
    If used with steam before curing is done, the
    curing is faster, and the vapors are a problem...but,
    you can just run the steam with the windows open for a while.

    What I did was....

    I painted the radiator over a course of 2 weeks in the attic,
    allowing it to dry between coats, then put a small space heater
    to keep it warm, at the end but not hot.
    I stopped painting 4 days before the install date....then
    I planned to turn the rad on in the am with the windows
    open to air out.

    In practice, the plumber (me) got finished at 9pm,
    ran the radiator for 10 minutes, then shut it for the night....
    (thanked G-d it was the warmest January 2 in history :)
    The smell was not awful. Next morning, turned the radiator on
    for the whole day, with windows open, report from home is OK.

    Plan to pull the radiator out and put aluminium radiant barrier
    behind it.
    Last edited: Jan 5, 2006
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