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  1. #1
    Join Date
    Feb 2014
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    Default Can't get baby's room warm!

    My Wife and I live in a duplex. Our bedroom and main bathroom are on the ground level (IE basement) and on one zone of heat. We have cast iron radiators and use a hot water boiler. There is one manifold for both bathroom and bedroom.

    We recently completed renovations to add a small second bedroom on this floor for our new baby. The room is 7*14ft. Our contractor put in slant-fin baseboard heating to the room (with PEX piping) and connected it to the same single loop zone as the rest of the basement.
    The thermostat for this floor is in the bedroom. We are finding that the baby's bedroom stays ~8-10 degrees cooler then our bedroom. Our contractor has agreed to help fix the problem but we are stuck on the appropriate solution. Three options have been offered up. I'd love some feedback on which one of these might be best or if there's another option we're not thinking of.
    1) Move thermostat: We've had one recommendation to move the thermostat out of our bedroom and into the baby's bedroom or in the small hallway outside of this room. I'm concerned that while this might help the baby's bedroom get to a temperature closer to what is set on the thermostat, that it won't solve the heat disparity between the two rooms...and that if we get the baby's bedroom up to 68...my wife and I will be boiling in our bedroom.
    2) Remove slant-fin baseboard and put in Burnham (or other brand) of cast-iron baseboard. One plumber has recommended doing this. He's indicated that it won't be cheap, but that having all radiators the same material and heat type (cast-iron radiator) will help keep temperature more consistent room-to-room. He's indicated that the problem we're having now has to do with the fact that the cast-iron radiators, once hot, don't need much energy to retain their temperature and that the furnace shuts down for long spells...during these shut downs, the baby's room gets cold as the slant-fin loses all heat once the furnace goes off.
    3) Replace slant-fin with electric baseboard...or add electric baseboard. This recommendation came from the electrical inspector. He said that it wasn't worth trying to get temperature consistencies in multiple rooms off of one zone...just put in electric baseboard on it's own zone. He also thought this would be cheaper.

    What do folks think?

  2. #2
    Join Date
    Jul 2010
    Location
    SoCal
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    6,598

    Default Re: Can't get baby's room warm!

    Just an idea: is the boiler sized correctly for the added space?

  3. #3
    Join Date
    Jul 2009
    Posts
    162

    Default Re: Can't get baby's room warm!

    The most common & obvious way to resolve hot water heating discrepancies in adjoining rooms is to install 2 zone valves with separate thermostats, and I don't think any of the 3 suggestions mentioned have any merit; zone valve installation is also a rather inexpensive, effective way of controlling the heat in separate areas of the duplex so that each of the occupants can feel comfortable by turning the T-stat in their room, or "zone" up or down to suit their comfort.

    Basically, how it works is that two $20 T-stats are installed, one in the baby's room (zone 1), one in the adult's room (zone 2 with the cast iron rads); the near-boiler main supply/return piping is cut near the boiler & a "Y" or "T" fitting is installed in the supply piping manifold (where the hot water is pumped out of the boiler); each "leg" of the "Y" or "T" manifold is fitted with a zone valve, & the hot water supply for the 2 separate parts of the duplex is extended to the 2 different parts of the house; with the T-stat leads connected to the terminals of baby's room (zone 1); when the baby's room "calls for heat" (when the room has cooled down) by closing its T-stat contacts (that has been manually set, say at 70 degrees), an electrical voltage is sent to the Zone 1 zone valve on the "Y" or "T" near the boiler, which internally opens, a 2nd electric signal is then sent by the zone 1 zone valve to the boiler's Aquastat (controls boiler firing) to fire the boiler to produce heat, & also to turn on the boiler circulating pump to pump hot water thru the zone 1 piping (baseboard/baby's room); during all this time, the parent's bedroom zone (zone 2) is not receiving any pumped hot water, since its zone valve & separate zone piping remain closed because its T-stat is not calling for heat; when sufficient heat accumulates in the baby's room from the zone 1 pumped hot water, the baby's bedroom T-stat (zone 1 T-stat) OPENS (T-stat no longer calling for heat), canceling the electric signal to the zone 1 zone valve, & to the boiler aquastat, which shuts down the firing boiler, & shuts off the HW circulator pump.

    The caleffi site below in Fig. 3-7 illustrates how 4 zone valves are piped in a heating system--you would need only 2; the "Y" or "T" mentioned in the text would be at the base of the illustrated zone valves (noted as the "manifold" (supply/return)) in your entry, immediately after the circulator (pump); the room T-stats & their wires leading to the individual zone valves are not shown in this diagram.

    Typical install includes 2 zone valves (Taco 571 illustrated) for approx $100 each, 2 T-stats for approx $20 each; step-down transformer 120V to 24V to drive both ZVs approx $25; re-piping the one-pipe supply/return piping you have now to a 2-pipe supply/return arrangement; unable to estimate any additional supplies & labor costs to re-pipe system piping to 2-pipe system.

    Sometimes the heating contractor uses thermostatic radiator valves (TRVs) (caleffi, Figs 3-13 to 4-7) on each of the convectors (baseboard/rads) @ approx $33 each, and "home run" piping to each of the rads/baseboard to & from the boiler manifold, plus labor & other supplies, but this often costs more due to extensive re-piping of the system.


    http://www.caleffi.us/en_US/caleffi/...onics_5_US.pdf
    http://www.pexsupply.com/Taco-571-2-...eat-Zone-Valve
    http://www.pexsupply.com/pex/control...diator%20valve
    Last edited by Pelton; 02-21-2014 at 10:46 PM.

  4. #4
    Join Date
    Feb 2014
    Posts
    2

    Default Re: Can't get baby's room warm!

    Pelton,

    Thanks for the thorough note. My only question about your recommendation...does this recommendation require re-piping a new supply/return directly to the baby's room? My sense is that would be quite costly, no?

    -Will

  5. #5
    Join Date
    Feb 2010
    Location
    South*East
    Posts
    1,213

    Default Re: Can't get baby's room warm!

    Mixing cast iron and copper fin baseboard on the same zone very rarely works. What happens is when the thermostat is satisfied and shouts down the copper fin cools off much faster then the cast iron, which continues to heat for some time. Making the rooms with the cast iron much warmer for a longer time.
    John

  6. #6
    Join Date
    Dec 2007
    Location
    Tennessee
    Posts
    1,747

    Default Re: Can't get baby's room warm!

    Quote Originally Posted by wdecaneas View Post
    Pelton,

    Thanks for the thorough note. My only question about your recommendation...does this recommendation require re-piping a new supply/return directly to the baby's room? My sense is that would be quite costly, no?

    -Will
    Your statement here implies that the radiator in your bedroom and the radiator in your babies room are hooked up in series. If that is true, the the first radiator cools the water down considerably so there is less heat available for the second radiator.

    You can tee off the first radiator to supply the second one, but it must be done in parallel so both radiators get equally hot water. The pipes from the first radiator to the second one need to be insulated as well or heat is lost from there as well.

    As long as both radiators are in parallel, you can have two separate thermostats. You could also supplement the existing slant fin radiator with an electric unit.

  7. #7
    Join Date
    Jul 2009
    Posts
    162

    Default Re: Can't get baby's room warm!

    Will,

    The repair you need would require two separate piping zones, as stated before, & is indicated in the caleffi Fig 3-7 diagram---if you can imagine caleffi Fig 3-7 as having 2 zones (instead of 4) and that each of the T-stats (2) would be wired separately to each zone valve & each zone valve would be wired to the boiler aquastat (not shown) to individually fire the boiler on each T-stat's call for heat, you would be able to visualize how the rather simple zone valve system works----yes, the piping somewhere near the manifold or elsewhere in the cellar would have to be branched (re-piped), one branch going to the baby's room convectors & the other branch going to the adult's room convectors, which can be either cast iron rads or baseboard.

    How expensive it would cost to re-pipe the baby's room to create 2 separate branches would depend on whether there is easy or difficult access to the existing piping; if there is a cellar area or accessible crawl space where they can get at the heating pipes there should be little problem, and zone valve modifications to existing HW heating systems is very widely done; but the cost estimate for the job would be up to the individual contractor.
    Last edited by Pelton; 02-23-2014 at 01:28 PM.

  8. #8
    Join Date
    Dec 2013
    Location
    Montreal Canada
    Posts
    196

    Default Re: Can't get baby's room warm!

    Quote Originally Posted by johnjh2o View Post
    Mixing cast iron and copper fin baseboard on the same zone very rarely works. What happens is when the thermostat is satisfied and shouts down the copper fin cools off much faster then the cast iron, which continues to heat for some time. Making the rooms with the cast iron much warmer for a longer time.
    I can not agree more. I would hold the the contractor responsible. I agree with your plummer remove the copper finn rad and replace it with a cast iron rad. You might also have to change the piping this is going cost a pretty penny so get the contractor to pay for it. do not take the cheaper solution of electric heater, The contractor screwed up and he should make it right. Question why is the contractor doing heating/plumbing work is he qualified .

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