(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 15 of 35

Thread: Aquastat(?) on Forced Hot Water Weil-McClain(about 25 years old)

Hybrid View

  1. #1
    DIY Junior Member GregoryR's Avatar
    Join Date
    Jul 2011
    Location
    Maine, USA
    Posts
    21

    Default Aquastat(?) on Forced Hot Water Weil-McClain(about 25 years old)

    Hello,

    I am very glad I found these forums, and really hope somebody can help. I recently compiled some data from my heating bills. The single oil furnace does the domestic hot water, and the hot water for the baseboard heat. All laundry is done in cold. The home is about 1300 sq ft with about 1000 of it heated in the winter. We have one bathroom and two of us total living here full time. Between last October and this April, we used 2 gallons of oil per day(~345 gallons). We use a programmable thermostat to set the heat at 68 when we are awake and home, and 64 during the night.

    I thought 345 gallons was pretty good for a winter. However, in the summer, non heating months, we used ~300 gallons. Only 45 less than the winter?! Granted, there are three people living and showering here in the summer, shouldn't it be less than that?

    I took some pictures of the furnace, and an "Enertol" unit. I could not find any documentation on the Enertrol at all online. I did open the Honeywell temp. control(gray) box and set it to 160 Hi/140 Lo, and there was another small dial, VAR, I believe set at 5. (It was at 180/160, 5)

    The Enertrol box has a left, right switch and and temp sum. I've attached photos. If anybody can help with this, that would be wonderful. Without touching the hot water, it takes 3:47 to maintain the water temp(i.e., no hot water is used, when the furnace triggers on, it takes this time to heat back up). I also noticed the water in the line for the baseboard heat(under floor)(but not at the baseboard) stays piping hot even during the summer.

    Thanks!


    png upload


    gif upload
    Last edited by GregoryR; 07-20-2011 at 09:30 PM. Reason: added info about my time of three mins

  2. #2
    In the Trades Tom Sawyer's Avatar
    Join Date
    Nov 2010
    Location
    Maine
    Posts
    2,945

    Default

    The Enertrol is an old style analog modulating control that determines boiler temperature by sensing outside temperature. The dial is set at 220 which pretty much overrides the control however for domestic hot water the control has no function anyway. If you want to save money you need to get rid of the tankless coil in the boiler and either go with a gas water heater or an indirect but the boiler looks to be so old that I don't think I would put that kind of money into it. If you really want to save money, tear the old mess out and go with something more efficient and an indirect like a Buderus BE or Logano series or a System 2000

  3. #3
    DIY Junior Member GregoryR's Avatar
    Join Date
    Jul 2011
    Location
    Maine, USA
    Posts
    21

    Default

    Quote Originally Posted by Tom Sawyer View Post
    The Enertrol is an old style analog modulating control that determines boiler temperature by sensing outside temperature. The dial is set at 220 which pretty much overrides the control however for domestic hot water the control has no function anyway. If you want to save money you need to get rid of the tankless coil in the boiler and either go with a gas water heater or an indirect but the boiler looks to be so old that I don't think I would put that kind of money into it. If you really want to save money, tear the old mess out and go with something more efficient and an indirect like a Buderus BE or Logano series or a System 2000
    Cool to know a little something about that. So is the water actually heating to 220 and being unused in the summer? The water in the line for the baseboard heat is very hot, hotter than we ever get for dom. hot water.

    I think there is some dom. hot water storage in the boiler itself(or maybe that isn't how it works), as if you turn on the shower, you will get hot water for a little bit, before the boiler turns on. Any suggestions on the VAR/DIFF switch in the Honeywell box? Or the left right switch on the Enertrol? I am tempted to set this to 165.

    Thanks again!


    EDIT:Yes, the black pipe coming out of the top of the unit must be >200 degrees. Just the outside is MUCH hotter than anything we get from the faucet. This is the one that goes through the expansion tank and to the baseboard.
    Last edited by GregoryR; 07-21-2011 at 08:45 AM.

  4. #4
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,434

    Default

    You domestic hot water is made by running a coil through a small vat of hot water in the boiler. Cold in, hot out through the coil. So, to keep the system able to produce that hot water, the whole boiler stays pretty warm all year, all the time. If you drop the temp down too much, the water through the coil can't pick up enough heat. As a result, the boiler is running all year, all the time (well, it cycles - more in the winter, though, but you understand what I mean).

    As stated, the choices are: leave it alone; disable the coil and add in an indirect; disable the coil and add a stand-alone self-powered WH (gas, oil, or electric).

    A new boiler would probably suggest an indirect, although that could be added to the existing unit and much of it could be retained when updating the boiler at a later time.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  5. #5
    DIY Junior Member GregoryR's Avatar
    Join Date
    Jul 2011
    Location
    Maine, USA
    Posts
    21

    Default

    Quote Originally Posted by jadnashua View Post
    You domestic hot water is made by running a coil through a small vat of hot water in the boiler. Cold in, hot out through the coil. So, to keep the system able to produce that hot water, the whole boiler stays pretty warm all year, all the time. If you drop the temp down too much, the water through the coil can't pick up enough heat. As a result, the boiler is running all year, all the time (well, it cycles - more in the winter, though, but you understand what I mean).

    As stated, the choices are: leave it alone; disable the coil and add in an indirect; disable the coil and add a stand-alone self-powered WH (gas, oil, or electric).

    A new boiler would probably suggest an indirect, although that could be added to the existing unit and much of it could be retained when updating the boiler at a later time.

    So the coil would be taken out, and the output attached to a separate tank to store hot water? Would this cause the boiler to turn on less often at all in the summer?

    Also, any ideas on the VAR/DIFF setting on the Honeywell box?

    Thanks!

  6. #6
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,434

    Default

    You don't need to take the coil out, just cap off the inlet and outlet. Then, unless you are installing an indirect (which acts like a zone in your heating system), you could turn the boiler off entirely for the summer. With the indirect, you could probably adjust it so it didn't run until the indirect called for heat, and then it wouldn't be constantly hot all the time. If you go with a separate, stand-alone tank (oil, gas, or electric), you could also shut the boiler down for the summer.

    To make hot water with the coil, the aquastat needs to keep the small tank fairly hot. If the min/max are too close together, and the load is low, it will short-cycle and this is very inefficient. The only good thing is that in the summer, the incoming cold water isn't as frigid as it is in the winter, so you may be able to get by by dropping the min (turn-on) temp. Since that imersion tank isn't all that big (generally), regardless, it doesn't take too long for it to recover.

    Someone more in tune with the specifics can probably give you more details on how best to set the thing. But, if you want to save some money, you'd probably want to disable the tankless coil and get another means of heating the domestic hot water supply.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

Similar Threads

  1. Professional Opinions of Weil McClain Ultra UO-3 Oil??
    By Greatwhitewing in forum Boiler Forum
    Replies: 3
    Last Post: 05-02-2011, 02:25 PM
  2. GE/Rheem hot water heater fails after 5 years??
    By fleetwood in forum Water Heater Forum, Tanks
    Replies: 7
    Last Post: 05-06-2009, 07:13 AM
  3. weill mcclain boiler, cast iron baseboard
    By mlbauer in forum Boiler Forum
    Replies: 4
    Last Post: 04-07-2009, 11:23 AM
  4. How much forced hot water baseboard for room
    By billc4 in forum Remodel Forum & Blog
    Replies: 1
    Last Post: 09-12-2008, 12:53 PM
  5. oil heat forced hot water ???
    By surfbug in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 8
    Last Post: 01-17-2007, 12:42 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •