Runnning out of hot water. Help please.

Discussion in 'Water Heater Forum, Tanks' started by Dogwell, Sep 21, 2017.

  1. Dogwell

    Dogwell Member

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    Maryland
    Hi. We bought a house last year that needs updating and I need some advice on our hot water issue. We're a multi generational family with 4 adults and 2 children. The house has 3 bathrooms. We currently have a 50 gallon electric water heater (ES652DORT) and run out of hot water if two people try to take showers back to back or simultaneously so we are forced to take really short showers and stagger them. Our contractor said changing the heating element could make a difference since the water softener wasn't working and could have caused damage to the element. I'm not sure whether that'll fix the problem or if we should update the heater / add another. Can anyone help? We have a propane tank for cooking and heating the house so gas heating is not feasible. We are on a well. All the water equipment is under the stairs leading to the basement. Access is through the garage. The pressure tank is also not working and we plan to replace with a CVS. We have a water softener, nitrate remover, UV lamp and a big blue filter. Not sure if any of this other info is relevant, but thought I'd share in case it is. Many thanks.
     
    Last edited: Sep 22, 2017
  2. Reach4

    Reach4 Well-Known Member

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    Last edited by a moderator: Dec 1, 2017
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  4. Dana

    Dana In the trades

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    The contractors' "...could have caused damage..." statement feels a bit off- he probably didn't bother to test them. Heating elements are pretty dumb things that also fairly easy to test with an ohm-meter (only with the power off.) Depending on it's power rating it should measure a resistance between 11-16 ohms. Even if/when a heating element is encrusted in scale & lime, if the power is still going in, it'll still be heating the water at the same rate. Only if the thing has been damaged to where contact is intermittent or the resistance has gone much higher than spec would it make sense to swap it out. Instructions on how test them yourself start on page 8 of the manual.

    An eroded/corroded dip tube at the cold input port that is no longer going all the way to the bottom of the tank can also shorten the shower time, since it's injecting cold water at mid-tank rather than at the bottom. It's hard to diagnose that problem until the dip tube is VERY short, when it seems as if the hot water runs out very quickly, but the recovery time is pretty short.

    Easy DIY band-aids would be installing low-flow shower heads (or an in-line shower volume control valves by the shower heads), since lowering the gallons per minute extends the amount of time it takes for the hottest water to be depleted. A lot of old-school gusher shower heads run 4 gpm or more @ 80psi, and are still over 3 gpm @ 30 psi. There are some pretty good 1.5-2 gpm shower heads out there, if simply throttling back the flow with a volume control valve isn't satisfactory. It may be worth bucket-testing the flow rate of the existing shower heads as a sanity check before making a showerhead swap, but a control valve can reduce the flow at any shower head.

    If there is a thermostatic mixing valve or tempering valve between the water heater and hot water distribution plumbing (now required by code in new construction, and whenever a water heater is replaced), you can crank the storage temperature of the tank higher, which will give it a higher heat storage capacity but also higher standby losses-which is still probably going to be OK for most electric water heaters, which have fairly low standby losses. If the hot water distribution plumbing isn't already insulated, insulating it with R3 or higher foam pipe insulation everywhere, including the first 5 feet or so of cold-water connected pipe, and the temperature & pressure relief outflow pipe for good measure.

    If there isn't a thermostatic mixing valve or tempering valve in place, raising the temperature of the hot water is a hazard. Installing a thermostatic mixing valve is do-able as a DIY for handy people, but if your space is really cramped it could be a real PITA project to take on.
     
  5. Brian E Sasser

    Brian E Sasser New Member

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    Most likely water heater (especially if you have good consistent hot water pressure and flow regardless of temp), if it's an old model and you have that many people in the house, good time to upgrade. I would definitely check all those up stream pressure drops. Hopefully bypass valves are installed so you can isolate the main line from them. First place to start is an isolated boiler with direct fill from main line, ensuring the mechanism (in your case electricity) delivering the heat to the system is working and sized correctly.
     
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    If it is an allowed change, you might be able to use higher wattage elements in the WH. THis would require both the WH's internal wiring, the supply cable, and possibly the circuit breaker to be updated. As mentioned, you can make the WH appear larger if you raise the temperature, but that requires you install a tempering valve to protect from scalding. If you already have a tempering valve, it's possible that it is defective. Where I live, a tempering valve is required on any new install or upgrade, if it doesn't already have one, to pass an inspection.
     
  7. MASTERPLUMB777

    MASTERPLUMB777 In the Trades

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    Retired Master Plumber
    Location:
    Texas
    #1 according to the model number that is a 50 gal state wtr/htr which you can get 40 gals of hot water out of before starts to cool off
    #2 get State SANDHOG elements they are longer you get the same wattage but because they are longer more heating surface to heat water,
    #3 have a plumber size and install a tankless propane gas heater and never run out of hot water again,
    most plumbers will tell you to stay away from tankless but in your house conditions that is the best possible solution
     
  8. Dogwell

    Dogwell Member

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    Thank you, Reach4 / Dana. Is my understanding correct that the drain water heat recovery exchange goes in the pipe for just one shower? Does this mean that it only helps keep shower hot for that one bathroom? I looked up pricing and it looked to cost at the least $600 going up to about $1500 depending on the brand and size. We have two bathrooms side by side. I know very little about plumbing so excuse my ignorance, but can the exchange be position in a way that both bathrooms benefit?
     
  9. Dogwell

    Dogwell Member

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    Sep 21, 2017
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    Thank you, Dana! You are right. He hasn't tested the element. This was his suggestion based on talking to us. He is not an electrician or plumber, but a one man band who does everything and is currently working on our deck. I will ask him to test the element. If it is working fine, do you think our consumption is just higher than what the tank allows? The tank is 7 years old. All 3 showers have 2.5gpm rated heads. We can definitely do the other band aids you mentioned, but will they truly fix our problem?
     
  10. Dogwell

    Dogwell Member

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    Thank you, Brian. I'm not sure I understand your suggestion. I have no experience with any of this. Just trying to do things the right way and make our $ go as far as it can. The heater was built in 2010. Can you please explain what you mean by checking the upstream pressure drops? There are bypass valves.
     
  11. Dogwell

    Dogwell Member

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    Thank you, Jadnashua. Do you know approximately what all of that would cost? I will have to weigh that up vs the cost of a new heater. I'm fairly sure we don't have the tempering / thermostatic valve.
     
  12. Dogwell

    Dogwell Member

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    Thank you, Masterplumb777. I don't think it's possible to have a tankless propane system with our setup. The propane stove upstairs is located more or less directly above the furnace and the water equipment is all under the stairs leading to the basement, right next to the garage. I was under the impression that the cost for adding gas lines is extremely high.
     
  13. Dana

    Dana In the trades

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    Before you do anything, test the elements and bucket test the showers. If the elements seem to be up to snuff and the shower heads are running <2 gpm there may be other control issues on the water heater. If it's only 7 years old it probably has quite a bit of tank-life left, and at least worth a closer diagnosis rather than outright replacement.

    If the 2.5gpm shower heads test > 2.5gpm it's likely that someone modified them for higher flow, but a shower flow control valve can still throttle it back at low cost, and replacing the shower head with 1.5 gpm shower heads won't break the bank either.

    You might try raising the temperature of the water heater, but test it's temperature at hot-only flow at the sinks with a thermometer. Anything over 115F has a scald hazard, and that hazard rises fast at temps above 120F. If lower shower flow and higher tank temps up to 115F don't provide sufficient showering capacity, the next step is a thermostatic mixing valve (to control the scald hazard) and a MUCH higher tank temp.

    In most (but not all) places heating water with condensing tankless propane is a bit more expensive than a plain old electric tank. The installation & equipment cost is QUITE a bit more expensive. Depending on model it'll support two simultaneous 2.5gpm showers in mid winter at MD incoming water temps but 3 is often a stretch. What are your electric rates and propane costs like? (I could use the statewide averages, but there is a lot of variance on both propane and electricity pricing.)

    A drainwater heat exchanger isn't a cheap fix either, but if you want to investigate that approach it's often a DIYable project. It has to be downstream of the shower(s) on the drain plumbing, but doesn't need to be close to the shower (or the water heater, for that matter). The heat exchanger also needs to be a perfectly vertical as possible, and as long and fat as possible for maximum benefit. They can't be installed horizontally, which rules out first floor showers for houses build on short crawlspace (or slab on grade) foundations. For maximum benefit the tepid output of the heat exchanger has to feed both the cold side of the shower(s) and the cold input to the water heater, but if the plumbing layout dictates only one or the other, feed the tepid water to the water heater.

    If replacing the water heater seems inevitable there may be other options. How is the house heated? Is the garage insulated &/or heated, and is there enough room for a water heater in the garage?
     
  14. Reach4

    Reach4 Well-Known Member

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    I have never seen one, but I would think that the drain water from more showers combined would be better if it was practical.
     
  15. Dogwell

    Dogwell Member

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    Thanks, Dana. We actually replaced the shower heads when we bought this place last year and none were modified for higher flow. I will do the bucket test anyway to double check. Do I need to do all 3 bathrooms or will one suffice? Will switching to 1.5gpm heads disrupt the pressure? The current pressure isn't high by any means and I don't think we'd enjoy any less pressure. I will check the temp of hit water only and will get back to you.

    The current prebuy rate for propane is $1.69 / gallon. The weighted average price of SOS electricity will be 6.694 cents/kWh through May 31, 2018.

    The house is heated by propane. The garage is neither insulated nor heated. We live on a raised ranch with two stories so the garage is at the basement level. The hot water tank currently sits underneath the stairs, which are directly next to the garage. Access to the space under the stairs is through a mini door at the back garage wall.

    I tried looking at the drain exchange pricing on the website you mentioned on another thread that gives wholesale prices to customers, but it doesn't look like they carry it anymore.
     
  16. Dana

    Dana In the trades

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    With sub-7 cent electricity (that's the full delivered price? Divide the bill by the kwh...) and $1.69 doing the math isn't even necessary (the operating costs are really close) but I'll do it anyway:

    Electricity delivers 3412 BTU/kwh, but the standby losses of the water heater have to be accounted for as well. A legal-minimum efficiency electric water heater now tests EF0.92, or 92% net efficiency so each kwh of electric used by the water only 0.92 x 3412 BTU= 3139 BTU ends up in your hot water distribution pluming. Normalizing to MMBTU (=million BTU) it takes 1,000,000/3139= 319 kwh /MMBTU, which at 7 cents/kwh costs $22.33.

    Propane has 91,600 BTU of energy (source fuel heat) per gallon. Burned at 95% in a condensing propane tankless it's delivering 0.95 x 91,600 BTU = 87,020 BTU into the hot water plumbing. Normalizing to MMBTU that's 1,000,000/87,020 = 11.5 gallons/MMTU, which at $1.69/gallon costs $19.44/MMBTU.

    But that isn't counting the electricity used for the burner & controls.

    So in your case it's pretty much a wash, until you also start adding up the maintenance cost of a tankless (unless you do it all yourself.)

    With the garage at basement level it's going to stay above freezing even if it isn't heated, which means a heat pump water heater is an option. It's not cheap, but may be subsidized. A 300 liter (~80 gallon) Stiebel Eltron Accelera 300 E would use half the electricity of a plain-old tank and would deliver longer showering time than a 60 gallon electric. It would also dehumidify the garage. It needs access to a large volume of air, and can't be stuffed in a closet under the stairs, but they do the trick. There are others, some with worse reliablity track records, so reasearch it carefully before plunking down hard cash.

    If the showerheads are all new and all the same model, testing one would be good enough.
     
  17. Dogwell

    Dogwell Member

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    I apologize. I made a mistake with the electricity cost. I just provided the kwh price without taking into consideration all the other charges. The delivered cost should be 9.5 cents so normalizing the cost will be $30.31/MMBTU. I don't think even with the lower propane costs, the maintenance and install of tankless propane will be justifiable for us.

    We have currently have a $550 rebate on heat pump heaters. Ouch! The garage is too small for us to keep ours cars, so we could keep the pump just outside the closet with no issue. Even with the rebate, the Stiebel will cost over $2k. Ouch!
     
  18. Reach4

    Reach4 Well-Known Member

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    Dividing the whole bill by the number of kWh is going to give too high of a number. You are taking the better method of only taking into account the amount that is not a fixed cost. On my bill, there are 8 line items that have kWh on them. If I add those 8 numbers, I still need to add in a portion of the state tax, which will be based on both variable and fixed items.
     
  19. Dana

    Dana In the trades

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    Propane costs are highly volatile, and not regulated the way electric utilities are. They're often lowest at this time of year, and peak by late winter. The sub-$2 pricing may only be good for another month or so, if history is any guide.

    Assuming you have at least 5 vertical feet to work with on a main drain, how many of the showers would/could be up-stream of a drainwater heat exchanger? Installing one yourself usually doesn't install rocket science math or high plumbing skills. Renewability usually puts up a "loss leader" PowerPipe unit on Amazon priced below their standard list prices (didn't see one up today, but there might be one on Monday...) Eco-Inovation used to sell direct at competitive pricing, but it seems to be all through distributors at this point. Whichever vendor, you'll want at least a 4" x 48" (or taller) or a 3" x 60" (or taller) to hit 50% return efficiency.

    What equipment is used for space heating in this house- a hot air furnace, a propane fired hydronic boiler? If it's a boiler, what boiler, and how many heating zones are there? An indirect fired water heater operated as a zone off the boiler will in most cases improve the overall efficiency of heating + hot water as a system, and is much lower maintenance than a tankless (at a cheaper installed price.) The recovery time on an indirect is fast compared to most standalone gas heaters, and lighting-fast compared to electric water heaters.

    If it's a hot air furnace more than 15 years old and the ducts are all inside the building envelope there are good reasons to consider a right-sized heat pump solution at some point in the future, not that it fixes your immediate hot water situation. Most hot air furnaces are ridiculously oversized for the actual heat loads, and tend to cycle on/off with temperature overshoots/undershoots, and have higher than needed air handlers generating a wind chill. (Unfortunately most people consider this "normal", since that's what they've become used to.) Right-sizing the equipment means the cycle times are longer, but at lower air flow & noise. A right-sized heat pump would have less than half the operating cost of a propane furnace at your local electricity & propane rates. If you still have records of the fill-up dates and quantities for propane from last winter it's possible to get a good handle on the sizing by running a fuel-use heat load calculation. Even if replacing it with a propane furnace, sizing it to no more than 1.4x what you come up with for a heat load would provide better comfort than the typical 2-4x oversizing factor. With a heat pump you'd want to size it pretty close to the 99% heat load, and use the backup heat strips to make up the difference for when it's colder than the 99% temperature bin. Even with the auxilliary heat strips engaged, most of the heat would still be delivered by the heat pump (assuming you don't oversize the heat strips by some ridiculous amount.)
     
  20. Dana

    Dana In the trades

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    That's a good point, but there are also utilities with tiered rate structures that increase or decrease the per kwh energy &/or transmission costs with increased monthly use. (It's not always possible to even figure that out from the billing!)

    Without sufficient information to dissect the marginal cost of an estimated amount of power used by the water heater, dividing the bill by the kwh is as good as you're going to get for estimating the cost of heating water with electricity. Switching to propane won't make the fixed costs go away, but the marginal cost of the energy part of the bill could be higher, lower, or exactly the same if the electric water heater went away.
     
  21. MASTERPLUMB777

    MASTERPLUMB777 In the Trades

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    If you want to solve your hot water problem you are going to have to bite the bullet and spend some money or get used to cold water, you can't have both
     
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