Gas water heater with remote enable/disable?

RandomJoeRandomJoe Solar Expert Posts: 472 ✭✭✭
Does anyone make such a thing as a gas water heater that has terminals for a remote enable/disable? Also preferably with electronic ignition - I can't believe so many units (including tankless) still use standing pilots! I know I've seen some large commercial units that can do this, but that's massive overkill (not to mention they wouldn't fit) for my house!

I'm contemplating replacement of my water heater, and am torn on what to get. An on-demand would be nice, but I use so little hot water I don't think I could cost-justify one - at least, if I compare against the typical residential tank-style water heater cost. By the time I find one that can be remotely disabled - so it doesn't bother keeping the tank hot during the day and evenings when I'd never use it - the added controls may raise the price sufficiently to make tankless more desirable... It would certainly free up some space in the garage to go tankless!

I know I could easily disable an electric heater, but I prefer gas. It's nice to still have hot water when the power is out! (My solar system could run some electronics on a gas heater if needed, no way I could run an electric heater.) It's also what I already have.

Side note: Can anyone tell me if there are issues with piping a water heater backward? I was in the closet adding some temp sensors for my home automation system and noticed mine is in fact backward! Grr... Wondered why they had put a cutoff valve in the hot water line and not the cold, that just didn't make sense! I'm surprised I haven't noticed problems with water temp, but perhaps that's just because of my low usage.

Comments

  • BB.BB. Super Moderators, Administrators Posts: 31,054 admin
    Re: Gas water heater with remote enable/disable?

    Normally, there is a dip tube that goes from the cold water inlet down to the bottom of the heater. This prevents Hot/Cold water from mixing (hot water tap pulls from the top of the water heater).

    Sometimes the dip tube has a twist on it to swirl the water at the bottom of the tank (to keep sediments from building).

    The dip tube is usually easy to pull up out of the tank and, I guess, one could transfer it to the "hot water" outlet and reverse the function (at least a few decades ago the were easy to pull and even replace with a new dip tube).

    I would have suspected that after a few minutes of showering, that you would notice the hot water temperature falling dramatically if the dip tube was not moved.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 9,015 ✭✭✭✭✭
    Re: Gas water heater with remote enable/disable?

    re: standing pilot

    problems with standing pilot systems = 0

    problems with "smart ignition systems" = well over $400 in 10 years, but the parts shop sure likes them. They stock bins of spare glow bars, and ignitor computers, and only a couple thermopiles.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
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  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Gas water heater with remote enable/disable?
    RandomJoe wrote: »
    I'm contemplating replacement of my water heater, and am torn on what to get. An on-demand would be nice, but I use so little hot water I don't think I could cost-justify one - at least, if I compare against the typical residential tank-style water heater cost.

    That makes you a prime candidate for on-demand water heating. The unit itself may cost more (okay, three times more) in the first place but it doesn't sit there heating and reheating 40 gallons of water all day and night. Obviously that is precisely why you want the control to shut down the tank heater when not needed.

    I've never seen a control system like you describe for (gas fired) home water heating. This is probably due to the lack of demand for such a system. I have seen electric heaters on timers. I've put electric heaters on timers. But electronic controls on gas heaters are, like Mike said, prone to failure. This goes for furnaces too.
  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: Gas water heater with remote enable/disable?

    I'm missing the point. A electronic demand gas water heater I'll draw a tiny bi t of AC power standing by, but burn no gas. You can get a Bosch unit that is self ignition with no standing pilot. A small demand will cover one shower or sink nicely. Personally, I would live with the standing pilot unit, and I believe that only Bosch still makes one (name brand). If you can find a older Paloma PH 6 or PH 12 I would buy one in s heart beat. It is too bad they don't make them any more.

    T


    PS the Small Bosch standing pilot unit can be had for ~$400. I just got one for a client.
  • Joe_BJoe_B Solar Expert Posts: 318 ✭✭✭✭✭✭
    Re: Gas water heater with remote enable/disable?

    I have a 40 gallon propane heater with a standing pilot. As it turns out, the pilot consumes a negligable amount of propane over the year. Its the standby losses that really consume the gas. I searched for one with a remote enable but to no avail. So I made my own. I purchased a duct damper from surplus center for $30 and hooked it to the knob on the gas valve. I control the servo from my X-10 system. Normally the temperature is set to keep the water at about 80 degrees when I want to use hot water, I push a button and in about 45 minutes, I am cooking! I have a timer set up to turn the heater back down after 1 hour. Works great and saves me a bundle. If you are interested, I can email you some pictures.

    Joe
  • RandomJoeRandomJoe Solar Expert Posts: 472 ✭✭✭
    Re: Gas water heater with remote enable/disable?

    I know a tankless seems to make more sense for my application - and I'd rather have one, if only for the extra space. The extra cost is what made me think twice, thus why I was looking around to see if there were standard tank models with a remote disable. I realize that's not a feature most residential users would even think about, so wasn't too hopeful - just wanted to see if anyone had heard of something...

    And I understand the more parts and gizmos involved the likelier failure is, but I didn't think electronic ignition was that big of an issue now. Certainly I've never had any trouble at all from my furnace or clothes dryer, both of which have it. (Dryer now 8 years old, furnace probably around 12 - it was here when I bought the house.)

    I'm leaning toward the tankless right now, will have to spend a bit more time reading up on them so I know what else I'm in for - biggest issue I might see is if I need to upsize the gas line.

    In the mean time I need to dismantle the existing heater and see if they moved the dip tube or were just dumb... :p (I'm voting for dumb - in looking at how best to get it disconnected, I realized they screwed sweat fittings into the top of the tank THEN soldered the pipes into place. I'll have to cut the lines to do anything with it... *sigh*)
  • Ralph DayRalph Day Solar Expert Posts: 926 ✭✭✭✭
    Re: Gas water heater with remote enable/disable?

    RJ,
    I have a Takagi tkjr unit with remote. The unit has a standby tare load, but it is minimal. Between the hours of 11pm and 5am it has no tare load...it is plugged into a digital timer. No problems since instal in 2003. The remote gives you more temperature settings than the dip switches, and you can turn it on or off near the point of use (it displays inlet temp, outlet temp and firing rate). It is coupled with a solar domestic hot water heat system, so sometimes you don't need or want the tk jr to fire when the solar water is already hot enough for use.

    Ralph
  • samuelsamuel Solar Expert Posts: 80 ✭✭✭✭
    Re: Gas water heater with remote enable/disable?

    Perhaps a simple solution could be to use a Remote Controlled Switch Socket

    I have used them with good luck in my family's cabin for TVs and other phantom load appliances. Since it uses RF the range is pretty good. Admittedly, we have the hot water heater plugged into an outlet with a light switch controlling it in the kitchen. Heater has electronic ignition and power vent fan. We usually heat water once a day in the morning for showers and then have "warm" water for dishes and hand washing later in the day.
  • techntrektechntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: Gas water heater with remote enable/disable?

    I think that with your lowered need for hot water that it would definitley not make sense to go with a tankless - you would never make back the cost difference. Plus you can have issues with sediment or minerals clogging the small tubes tankless heaters have. I was almost sold on converting to a tankless until I did some research on the net and Homepower magazine. I have lots of minerals so I decided to stick with my tank heater.

    If your outages are less than 24 hours as long as you add 6 inches of insulation around an electric tank it will keep the water warm enough for a shower even after 24 hours. Mine does. Then you can use a standard 240 volt water heater timer.

    If you want to stick with gas, they run from a 120 volt circuit so its easy to add in a 120 volt timer. Many areas require a wall switch cutoff, often at the top of the basement stairs, you can just use that and make no modifications at all. I've also seen small 120 volt timers that will fit into a single-gang switch box, but that might not technically meet code as an emergency cutoff.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • RandomJoeRandomJoe Solar Expert Posts: 472 ✭✭✭
    Re: Gas water heater with remote enable/disable?

    Hah... I must admit I never even thought about the fact I could kill power to the controls on a heater that uses 120V! :roll: Heaven knows I've done that enough times at work for cheaper equipment without "classier" means of control, should have remembered that. Doh! :p

    Another off-the-wall question: Is anyone here worried about Legionella in the tank? I know I've read at least a few turn theirs down pretty low, but how low? Right now I have mine at about 100 degrees! (I actually know now, as I have temp sensors on the water lines. Wasn't sure before what the "A B C" settings equated to.) That's all I need for a comfortable shower in the summer, in fact I still add a little cold to it. But some sites I've found online say that's prime growing temps for Legionella and I shouldn't go below 122 degrees.

    That just seems like *another* good reason to go tankless - I can (maybe?!) run cooler water.

    But then I've heard so many people over the years say they run their heater very low and haven't heard of any cases of people getting sick from it. Perhaps the concern is overstated? Perhaps I'm flushing all the bugs out of the tank by using more/most of it when I shower? :p

    Guess I'm wandering away from topic here... Thanks for the help! :cool:
  • techntrektechntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: Gas water heater with remote enable/disable?

    I've never heard of that outside of large institutions, but that's nothing to go on. Looking at wiki, it says:
    The most common sources of Legionella and Legionnaires' disease outbreaks are cooling towers (used in industrial cooling water systems), domestic hot water systems,and spas. Additional sources include large central air conditioning systems, fountains, domestic cold water, ....

    Looking further down on that page:
    According to the paper "Legionella and the prevention of legionellosis," [15] found at the World Health Organization website, temperature affects the survival of Legionella as follows:
    -Above 70 °C (158 °F) - Legionella dies almost instantly
    -At 60 °C (140 °F) - 90% die in 2 minutes (Decimal reduction time (D) = 2)
    -At 50 °C (122 °F) - 90% die in 80-124 minutes, depending on strain (Decimal reduction time (D) = 80-124)
    -48 to 50 °C (118 to 122 °F) - Can survive but do not multiply
    -32 to 42 °C (90 to 108 °F) - Ideal growth range
    -25 to 45 °C (77 to 113 °F) - Growth range
    -Below 20 °C (68 °F) - Can survive but are dormant, even below freezing

    So it looks like 77 to 113 F is the critical temperature range, and most domestic water systems are either above that on the hot supply side (at factory settings), or below that on the cold supply side.

    When I installed extra insulation on my tank and added a timer I left the cutoff temperature at its factory setting. I wanted to be sure that it would carry over during the "off" periods and starting out with warmer water plus extra insulation has done the trick. The longest off period is from 8 am to 6 pm and assuming it was at max temperature at 8 am I can still take 2 comfortable showers at 5:45 pm. Useful on a Saturday afternoon when we've been at the pool all day. A secondary reason is it needs to serve a family of 4. We mix the water 50/50 hot/cold so we effectively can get twice as many showers from one tank of hot water. If I started off at something cooler like 95 F we would need to draw 100% from the hot side which effectively cuts the hot water supply in half.

    As long as you slow the heat transfer rate with good insulation I don't see why sticking with 122 F would lead to higher energy useage by any noticable amount. The Alaska pipeline starts off at 140 F and only looses a few degrees of warmth by the time it reaches the other end, even with outside temps way below 0 F. Temperature delta is important, but only if you don't control it.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • BB.BB. Super Moderators, Administrators Posts: 31,054 admin
    Re: Gas water heater with remote enable/disable?

    When I have looked at this problem before--It appeared that there were many more reported problems with Electric Hot Water systems vs other kinds...

    I always wondered if the Legionella grew on the bottom surfaces of a water heater and the gas flame tended to sterilize the growing surface even if the water temperature was "low".

    In any case, it also appeared that there were infections based in the plumbing where the entire line did not come up to temperature (dead stubs, insufficient insulation, too cool of source temperature, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jeffreyd123jeffreyd123 Registered Users Posts: 3
    Re: Gas water heater with remote enable/disable?

    There is a timer for gas water heaters that can also be used with remote control or most commonly, Home Automation. You can control your gas water heater from anywhere in the world. Just Google gaswaterheatertimer.com

    Jeff
  • jeffreyd123jeffreyd123 Registered Users Posts: 3
    Re: Gas water heater with remote enable/disable?

    Legionella can't form in a pressurized water system. The system has to be exposed to air for a long period of time. For example: There are vacation homes throughout the nation who have water heaters turned off for extended periods. Folks don't get sick from this. Legionella is most commonly found in Boiler to domestic hot water cross contamination.

    40 years experience in Hydronic heating.
    Jeff
  • BB.BB. Super Moderators, Administrators Posts: 31,054 admin
    Re: Gas water heater with remote enable/disable?

    Welcome to the forum Jeffery.

    Regarding Legionella, nothing I have read about indicates a pressurized system or lack of exposure to air will prevent system infection (I am not a biologist or infectious control person).

    http://wwwnc.cdc.gov/eid/article/10/3/02-0707_article.htm

    There are lots of variables...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CDN_VTCDN_VT Solar Expert Posts: 492 ✭✭✭
    Re: Gas water heater with remote enable/disable?

    I have a few of these : http://www.youtube.com/watch?v=3Uowv7UHoTI
    Not just for Dog's ..
    We use one for the pool shower , another for the camper .

    VT
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