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    turn down boiler in summer when I only need hot water? (27 Posts)

  • Caleb Caleb @ 5:15 PM
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    turn down boiler in summer when I only need hot water?

    I have a burnhan set at 160 deg / 180 deg and its too hot for DHW. I just bought a Watts mixer to set the max temp at 120deg.. But can I turn down the system in the summer to reduce cycle time? What if I have separate gas DHW heater, or go on vacation for a week.. can I shut the boiler off completely?
  • icesailor icesailor @ 6:48 PM
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    Summer heat:

    Did some "expert" on some Internet Forum or TV How To show tell you that?
    They didn't explain that the control strategies of your boiler have your boiler operating at 160 degrees or lower. The 180 degrees are for your heating load. It only goes to 180 degrees if you turn up the thermostat. You can turn off the boiler when you aren't using hot water, but it is better for the boiler to remain hot. It keeps gaskets and seals from leaking as the metal contracts and expands. If you look really carefully, you might save a buck or two. It won't be worth it after the first time one of the gals in the house get into the shower and it gets cold because they forgot to turn the burner back on. That can be painful. A wet hen with wet soapy hair and going out.
    I'll see you later.
  • Caleb Caleb @ 7:42 AM
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    no expert

    No "expert" told me anything, just my own logic thinking I don't need to maintain 160 deg throughout the summer.. I turned it down to 150/170 and it's working fine for now.. Want to get a monitor installed to see when it's cycling on and off while I'm not there
    This post was edited by an admin on June 17, 2014 7:43 AM.
  • icesailor icesailor @ 10:44 AM
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    Clocks:

    Get an El Cheapo electric clock cut the plug off, and wire it in through the burner motor. Set the clock for 12:00 O' Clock. Whenever the burner runs, the clock will run. Third World Clocking Device.  Just be sure that you keep a log book so you can remember when it runs more than 12 hours.
    You can set the "Low Limit/Operating control to anything you want. The lower you set it, the less hot water you have available.
    When you are done, you will find that your exercise in splitting pennies cost more in Sawzall blades than you saved in pennies.
    This post was edited by an admin on June 17, 2014 10:45 AM.
  • bc3510 bc3510 @ 4:57 PM
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    What if?

    You mentioned "What if I have a separate hot water heater"?

    The answer to this question.............which you posed............determines the answer. Nobody can properly respond without it.

    Either the boiler makes your hot water via a tankless coil or a DHW heater makes it and stores it in a tank.

    Completely different situations.
    B.C.
  • icesailor icesailor @ 5:49 PM
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    Hot Water Tanks:

    No, you can heat water in a hot water storage tank using the tank less heater coil in the boiler.
    Which is the same as using a indirect coil inside a dedicated indirect heater tank. Except that a water heater tank used as a storage tank is a lot cheaper than a dedicated indirect heater tank.
    SS. DD.
    This post was edited by an admin on June 17, 2014 5:50 PM.
  • bc3510 bc3510 @ 6:13 PM
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    Read the OP

    He states that the water temperature is too hot, leading to the conclusion that he does not have a tank. He also is unlikely to have a stand alone DHW heater.

    But, without confirmation, nobody can give proper advice.
    B.C.
  • icesailor icesailor @ 12:40 PM
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    Always too hot:

    Straight Tank less coils without  hot water extenders are always too hot. That's what the mixer is for. If he thinks his water is too hot when it first come out of the faucet, does it stay like that after 5 minutes? If it does, he need the extender replaced. If not, it will get a lot colder when he drops the boiler operating temperature down some more below 160 degrees.

    Want to kill the boiler quickly? Make it a cold start.
    As I understood the discussion, can you turn down the aquastat (that's set now for 180 degree High, 160 degree operating. If it's a tankless only, that's on the cusp. Lower and you get mad women and teenagers in the shower. Even with storage tanks. I set the Operating Control setting to 135 to 140 with a 20 degree differential because if I am going to clean it, I hate Kibbles & Bits with my very being.
    It matters not to me what is done. I'm not doing it and I'm not going to clean it.
  • bc3510 bc3510 @ 1:00 PM
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    always too hot

    I'm going to relate a story that is the one boiler that will disprove that theory (and there is only one).

    It's an American Standard Arcoliner 2BT with a 10 gallon tankless coil. The volume of water in the boiler is estimated to be close to 20 gallons. It is fired at .85 with an estimated efficiency of .75. 82K to the water.

    Aquastat is mounted in well at coil and set to 150F (winter) or 145F (summer). Boiler starts within 15 seconds of demand.

    Temperature of the water at the fixtures is 135F. and it will not drop if the usage is at or below 2 gallons per minute (provided the controls hold off the circulator for heat).

    See if any of those fancy and expensive indirects can match that performance..............!!!
    B.C.
    This post was edited by an admin on June 18, 2014 1:02 PM.
  • icesailor icesailor @ 4:39 PM
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    Choir Director In Chief:

    You're preaching to the choir.
    If you have a boiler with an internal indirect coil (Tank-Less), why on earth would you want to disconnect it and buy an expensive water tank with a coil installed in it that you have to re-pipe the boiler and add a zone?
    I'd have to go looking, but someone used to make a big water boiler that looked like a big oil fired water heater. It ran at 12 PSI. It had this huge coil mounted in the front. No tank unless you installed one. Those suckers made some serious hot water. They were far better than a large Bock oil fired water heater because there was no corrosion on the heater side. The only thing the potable hot water touched was the inside of the coil.
  • bc3510 bc3510 @ 4:46 PM
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    reason to disconnect the tankless

    The reason to get rid of the tankless is legendary..............it cannot keep up with the demand in any boiler manufactured in the last 40 years. The internal tubing is too short and the amount of water in the boiler is insufficient.

    So, as you mentioned, you start with very hot water and watch it fall all the way down as the length of the shower increases.

    Sadly, most of them are useless.

    In my own system (the Arcoliner), I am beyond chagrined to move away from that coil and procure the gas fired tank. But, the cost of oil is too much to bear and the gas fired tank is going to provide DMH and space heating for the entire house. It will be installed in parallel to the Arcoliner and the DMH will be installed in parallel to the coil.

    So, I will have gas heating for the house and a backup of the oil system in case the gas appliance (AO Smith 75 gallon forced draft) decides to puke (which it will, eventually).
    B.C.
  • icesailor icesailor @ 8:27 PM
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    You mean like:

    You mean like this?
    This post was edited by an admin on June 18, 2014 8:41 PM.
  • bc3510 bc3510 @ 8:48 PM
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    similar for DHW

    He's got the coil in series with the hot water heater. I suppose he can shutdown the loop and simply run on the HW heater.

    I will have the capability to run either on the DHW heater or the tankless coil...........not both.

    But, I will also have the capability of sending hot water from the DHW heater to the CI radiation via a huge HX. Or, I can operate the oil boiler.

    He cannot heat the dwelling with the DHW heater.
    B.C.
  • icesailor icesailor @ 10:49 AM
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    Coil In Series?

    Look again Capt. Not in any way like you see it. If you shut off the power to the boiler, the tank will get cold and there is no other way to get it hot without turning it back on. There is no 240 volt power to any tank that I have ever done. Not either of those two, or any one I have ever done.  And although I won't say I've done hundreds of them. it is in a higher group of ten.
    HINT: The water heater isn't a separate heating zone. And it doesn't even have separate 120 volt power to the tank. And no other boiler controls except what it came from the factory with. The standard grade, El Cheapo Honeywell 8182 triple acting control or whatever the number is. I've always been numerically challenged. In my old age. it gets worse.
    I did a lot of electric heat conversions, got rid of the electric heat baseboard. I could sell the job because I would use the old, often new electric water heater as a storage tank. No indirect,  Replace the electric baseboard with #30 baseboard and you didn't need any carpenter work to replace baseboards. HW baseboards have more output than electric baseboards. Do just the first floor because you didn't have to go nuts getting pipes to the second floor. Use existing electric as back up, the first floor was heating the second, never had a complaint, and never have ripped out a tank because it didn't work.
    I've used the same piping scheme on places that needed more supplemental hot water or a place with a high output water heater that needed storage. Like a Bock 73E and a 120 gallon Rudd Commercial Storage Tank. That only needed the extra nuts for 3 hours in the evening. And it stops "stacking" of high output water heaters.
    Got a house with a 50 gallon gas water heater that works fine? Then, they add a jetted tub and they run out of hot water?  Add a 50 gallon electric water heater piped as a storage tank with the new tank as the draw tank and the old tank as the energy source. 100 gallons of stored hot water. Whatever the first hour draw on the gas water heater is, you just added 50+ gallons to it.
    That probably won't work for you. It always did for me.
    This post was edited by an admin on June 19, 2014 11:05 AM.
  • bc3510 bc3510 @ 11:15 AM
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    wire

    I think you meant to say "There is no 115V power to any tank that I have ever done". I would agree.

    However there is a grey wire from the outlet box to the top of the water heater.

    If it isn't supplying power to the water heater..............what's it doing there?

    Could the DHW heater have a 115V heater? I find that unlikely but I cannot explain the wire.

    My conclusion that it was in series with the tankless coil assumed that the DHW heater was powered in some way.
    B.C.
    This post was edited by an admin on June 20, 2014 11:18 AM.
  • Charlie from wmass Charlie from wmass @ 12:01 PM
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    sigh you know Ice is really good and smart right BC?

    The cord goes to the thermostat that controls the circulator pump. when the tank cools the circulator turns on and charges the tank. Please realise other people have good workable ideas that differ from what you think you know.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • bc3510 bc3510 @ 12:16 PM
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    agreed

    I couldn't understand what that cord was doing. If it's just powering the circulator and the "DHW heater" is just a storage tank, I now completely understand what Ice was referring to.

    It certainly appears to have been a true DHW heater at one time in its past..................
    B.C.
    This post was edited by an admin on June 20, 2014 12:20 PM.
  • icesailor icesailor @ 5:42 PM
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    True DHW heaters:

    Those and all the others I have ever installed have been installed as true DHW heaters. They are piped like a prehistoric Brown Bros. Copper tank with a side arm heater in a gas burner or a Florence kerosene stove. The "tank Less" coil is the side arm heater. The only heaters I ever did were electric heat conversions where the electric water heater was already in place. The tanks are piped full size 3/4" nominal size on the hot and cold. There is full pressure in the hot and cold water supply. There is no potable water restriction through the tank less coil.
    I did indirect's. I did anything anyone wanted. I gave everyone lots of choices with prices. I'd have done Indirects if people were willing to pay more. I installed many water heaters like shown for people that didn't have enough hot water with a coil only and a 70A mixer. 40 years ago, they sold 30 gallon indirects (Aqua Boosters) for as much as I could sell the same electric water heater for a nice profit. The Aquabooster was just a standard 30 gallon gas water heater without the burner. The extra hole for the control is where you put the extra line to the coil. The instructions they showed didn't work well. I changed the way to make it a true side arm. It worked far better. With the concept, you can make any water heater a side arm heater for a bigger tank for more storage. Without the increased hourly BTU input. It has never once failed. Not EVER.
  • bc3510 bc3510 @ 6:35 PM
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    interesting stuff

    I never had the pleasure of working with a sidearm heater. Seems like you'd have a long recovery time with them.
    B.C.
  • Charlie from wmass Charlie from wmass @ 12:27 PM
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    Tankless coils work just fine IF

    They are installed and piped properly. Aside from the cost of fuel oil being so high, they should always work. The one in my fathers own house that he installed new in 1971 gives a continuous flow of hot water until the boiler runs out of fuel. I can take an hour long hot shower at his house, get out do, do dishes, wash laundry, and have my kids shower without a cold shower. If your tankless is not providing this kind of hot water it is not working properly. Does it waste fuel, yes it does as you are warming the chimney all day long, but it does also make your boiler stay dry and it to not have the stress related to cold firing. So you burn fuel, not boilers. You need to decide which is more cost effective for you. I prefer a cold fired boiler with an indirect water heater. Ice prefers keeping the block warm. Both have their merits and faults.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • bc3510 bc3510 @ 6:55 PM
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    tankless coils

    When they are brand new, they can certainly do the job well, especially if the extender is utilized.

    But, as they age, I find their performance deteriorates to the point where they're useless.

    I have removed them, and put them in a bath of Muriatic acid for about one hour. All the fins, blackened with a fine soot, are now nearly new. The performance increase is significant.

    I would like to pipe the tankless coil to the electric water heater with a circulation loop and see if I can eliminate the need for the electric elements.
    B.C.
  • icesailor icesailor @ 9:32 PM
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    You're kidding?

    You're kidding?
    What do you think that I have been describing? How do you think I connect what I posted two examples?
    Did you miss the part about where I and someone said that the only electrical connection to the electric water heater might be a lamp cord to act as a switch leg through the bottom thermostat to the small Taco 006ST pump?
    When tank-less coils fail and do not produce hot water, if is ALMOST always from the inside of the coil becoming plaqued up from water hardness coming out of suspension in "hard" or water with high dissolved solids. Many of us who have been faced with this scenario pump a acid solution with a acid resisting pump through the INSIDE of the coil. Some of us even planned when installing a boiler with a tank-less in hard water areas to make provisions to do so for the future need to be de-scaled. Most of us have never taken a coil out of a boiler to clean the inside.
    Some of us have only seen a coil that is coated with calcium on the outside is from indirect coils where the coil is immersed in a tank of potable water high in dissolved solids and the hot high limit boiler water circulates INSIDE the coil. The heated water around the coil precipitates the dissolved solids onto the outside of the coil.
    The water inside a closed heating system becomes devoid of dissolved solids. Which are supposed to fall out of suspension into the bottom of the boiler where they stay for life.
    At least that has been my observation.
    This post was edited by an admin on June 20, 2014 9:35 PM.
  • bc3510 bc3510 @ 10:30 PM
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    the tank

    I understood the use of the tank completely.

    My experiences with the tankless coils do not match with yours. I find that an acid treatment of the inside of the coil doesn't restore performance. It's the fins on the outside of the coil that are clogged with a fine layer of carbon residue. That's what is preventing the heat transfer.

    There are plenty of companies that claim to clean the hard water deposits from the inside of the coil. I've used three or four of them..............none have been successful at restoring the coil to full performance.

    I remove the coil and perform the acid treatment in a separate bucket..............a full dip for an hour in muriatic acid...........truly gives them some new life. I do both the inside tube and the outside fins at the same time.


    Try it .
    B.C.
    This post was edited by an admin on June 20, 2014 10:34 PM.
  • icesailor icesailor @ 9:19 AM
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    Nasty Water:

    You must have some kind of nasty water in your boilers. They must be steam boilers where you can't see the water level in the gauge glass. I have never in my life ever seen a coil in even an old and long running boiler that came close to your description. If you're talking tank less only boilers with no storage tanks, maybe you have a control issue. I think this all started with a controller setting. Maybe you just don't understand how the control strategies work. Maybe you have bad mixers or improperly installed ones. Maybe you were trying to save $$$ and set the limits too low. Either way, your experiences don't come close to what I have seen. If I spent the time to take a coil out of an active boiler, it would have only been to replace the coil because of a leaking red rubber gasket leaking and I was trying to save a boiler for someone that didn't have a lot of money to spring for a new boiler. Either way, I could have cleaned the black iron oxide residue off with some TSP and high water pressure from a hose.
    As far as cleaning coils, you hire someone else to do it? I don't hire anyone else. If they are lazy and don't know what they are doing, they are dangerous.
    I once cleaned a dirty (on the inside) coil that took me over 24 hours to clean. I left the full strength 40% Muriatic acid running overnight. The next morning, it was plugged solid. Nothing would pass. Even trying to run it backwards. So I hooked my air compressor to it and blew it backwards. Great big white chunks of calcium chips came out of the coil. About 2 cups worth. It was fine after that.
    One of the things about storage tanks is that as the coil loses performance, it just takes longer to fill the tank with hot water. The efficiency goes down but they sit idle most of a day so who cares. And they don't use anymore fuel running longer.
    But I guess you are right. You are far more educated than I am. I went to the University of "How does this work". with a Graduate Degree in "How Do I Fix It". A Post Graduate Degree in payment from satisfied customers who didn't wonder if they were being robbed. Like that late heater guy I used to follow. He wasn't a licensed plumber but he represented himself as one. He never saw a case of a lack of hot water that couldn't be resolved with a new boiler. He often sold the old boiler as a "Reconditioned" boiler. He never installed a 70A properly with a heat trap. "You don't need them".

    An "Old Timer" once told me that if they call you on the phone, they want to spend money. I'm going to send them to some fool that cleans coils and the sells them a boiler? Where I worked, I didn't have the luxury of sending them to a coil cleaning expert. Who would sell them a new boiler. I'll do that myself.
    I wonder if that's a reason why so many of us are so possessive about our customers. Especially the good ones who pay their bills and don't crab. I always gave them extra special care. Because they were special. Some still call me about problems that they can't seem to get resolved.
  • RobG RobG @ 1:30 PM
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    Tankless

    I also have had Ice's experiance with tankless coils. Now if you are talking about an indirect water heater the outside of the coil will get crudded up. It's the introduction of fresh water that calcifies. No boiler leaks=no calcification


    JMHO,
    Rob
  • bc3510 bc3510 @ 1:47 PM
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    I might or might not be right

    Firstly, you can stop with the "engineer so you must be smarter than me" crap.

    My work in this field is nowhere near the level of yours and I fully admit it. I try to maintain some rental houses as best as I can and I don't have anywhere near the required equipment to do so. All of my experiences with these hot water boilers have nothing to do with the fact that I have an engineering degree. So, you can just forget about that tidbit that you learned from the other thread.

    These were all hot water boilers.............not steam.

    I need to use an outside service to clean the coil because I don't have the equipment to properly pump the acid through the coil. Maybe you are correct................the idiots that I hired that clean the coil in 30 minutes or less..............have not been doing the proper job. My own results with the Muriatic acid, which cleaned both the external fins and the internal tube were successful. Were they successful strictly because of a good cleaning of the internal tube? Possibly right. The tube remained completely filled with acid for about two hours.

    I'll take your advice on properly cleaning the internal tube thoroughly while the coil remains installed. If you could explain what equipment can be used to do that, I'd appreciate it.
    B.C.
    This post was edited by an admin on June 21, 2014 1:52 PM.
  • Charlie from wmass Charlie from wmass @ 12:05 PM
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    Delta T

    That is the difference in temperature. If the boiler temperature is too close to the target temperature you will not make enough hot water to supply your home. Reducing the standby temp of the boiler can save fuel, yet it reduces the capacity to create hot water. A stand alone water heater may be a sensible answer for you, especially if you have a different fuel source such as natural gas.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
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