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  1. #1
    Join Date
    Jan 2014
    Posts
    2

    Default Temp differences with hot-water radiators

    My wife and I own a two-story house with a gas-fueled hot-water radiator system and a single-story addition in the back. There's 3 radiators downstairs, 4 upstairs, and a hot-water baseboard system in the addition.

    Unfortunately, there's also a 10-degree difference between the upstairs and the downstairs, and another 5 between the main downstairs and the addition.

    So here's what I want to do:

    Crank up the thermostat (which is downstairs) to bring up the downstairs temperature, then mostly close the valves of the upstairs radiators to keep that from getting too hot.

    Will this strategy work?

  2. #2
    Join Date
    Jul 2009
    Posts
    157

    Default Re: Temp differences with hot-water radiators

    Joel,

    It's almost impossible to predict what the outcome will be by your manipulating the on/off valves of the radiators on the different floors---heat DOES have a tendency to rise to the higher parts of the house---but it's worth a try to PARTIALLY TURN DOWN some of the rad valves WITHOUT COMPLETELY TURNING THEM OFF ALTOGETHER.

    You may also want to check the near-boiler main supply/return piping near the boiler to see if there are any BALANCING VALVES on the mains that can be throttled as a means of sending less hot water to various parts of the house, & thus control the amount of heat different parts of the house get.

    Depending on how the various convectors (rads & baseboard) are piped coming & going from the boiler supply/return mains, you may be able to adjust the temp of the various convectors & make the 3 parts of the house more comfortable.

    If turning down some of the valves on some of the rads doesn't do the trick, another possibility is to construct some sheet metal COVERS that will fit over some of the rads that are producing the most heat & fill them with pink insulation to reduce the amount of heat output from some of the rads.

    Another issue you should check is the amount of INSULATION inside the exterior walls, to make sure that you're not losing heat thru poorly insulated external walls; also check to see that you have non-drafty relatively new double-pane storm windows at all window locations---these 2 factors can make a world of difference in keeping the heat inside the house on cold days---there are insulation contractors that will blow cellulose insulation into walls where needed & window contractors that install double-pane storm windows.

    From the description of your post, it sounds like you have only ONE T-stat on the first floor, or near the boiler, and this controls the distribution of heat for the entire house---if this is the case, it can be difficult to get the amount of heat you want for the 3 sections of the house--in such cases the remedy is often to CREATE 3 ZONES for the 3 parts of the house by using ZONE VALVES (sometimes zone circulators), where a heating technician comes in & installs 3 zone valves & a separate T-stat to each of the 3 parts of the house----the temp in each part of the house is thus separately controlled to maximize comfort & save on fuel bills by not wasting heat in those rooms where it is not needed.

    There are also what are known as THERMOSTATIC RADIATOR VALVES (TRVs) that can sometimes be installed on several of the rads (depending on how the piping arrangement to & from the rads was arranged when they originally installed your supply/return HW pipes to & from the rads/baseboard.)

    Unfortunately, most HW heating supply pipes going to the rads & baseboard are piped in ONE-PIPE SERIES loops (below), which is the least expensive way to install supply piping, but also almost always creates UNEVEN HEAT in the various parts of the building.

    Why not consult the Yellow Pages under "Heating Contractors" and have a technician who is experienced in hydronic (hot water) heating systems come over the house & first see if he can modify the heat by adjusting the system you have now, and if not, give you a quote for how much it would cost to install 3 zone valves to your system, or possibly several TRVs.

    Consulting the Caleffi site below, Fig 3-7 has a diagram of how ZONE VALVES are installed & at the end of the site, what they look like; Fig. 3-17 and Fig. 4-1 illustrate Thermostatic Radiator Valves (TRVs); also, Fig 4-5, 4-6 & 4-7 illustrate TRVs.

    When you consider the comfort you will gain, in addition to the fuel savings you will realize over the coming years by not heating rooms where heat is not needed, it makes a lot of sense to have 3 separate zone valves installed, with a T-stat in each of the 3 sections of your house---they will pay for themselves in a short time in fuel savings & improved comfort.



    http://www.caleffi.us/en_US/caleffi/...onics_5_us.pdf
    http://highperformancehvac.com/boiler-water-loops/
    Last edited by Pelton; 01-31-2014 at 03:35 PM.

  3. #3
    Join Date
    Jan 2014
    Posts
    2

    Default Re: Temp differences with hot-water radiators

    ***, thank you for the great advice.

    I think this weekend we'll try partially closing the upstairs radiator valves and see if that helps. But long term, we really need to investigate this three-zone option. I think that's the true answer to the problem.

    Thanks again.

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