Redwood
Master Plumber
So the dip**** hasn't come forth with the answers yet?
May I refer you again to posts #127-129
May I refer you again to posts #127-129
So HOW exactly do you supply 2 showers running at the same time??
Actually how do you use ANY 2 devices at the same time?
Let me see now. I have 1 full bath and two half baths. How do I supply two showers running at the same time?
Then the last part of this Q & A post I made Straight Talk About "On-Demand Tankless Water Heaters by A.O. Smith applies to you and to others that fall under this part. I put the part I am taling about in bold.
ProStar should only be considered as a “whole house†water heating option for very small homes or apartments with low hot water demand.[/LIST]
Yes, but according to the plumbing instructor you are ignoring "the code".
By the way, the description of a "very small home" has changed over the years. My modest size home 3 bedroom home has 2,400 sq ft of space including the first floor level garage. The McMansions that they have built in recent years are nice, but one needs a nice income to afford them. I wonder how many of those home "owners" are underwater (or worse)?
Let me see now. I have 1 full bath and two half baths. How do I supply two showers running at the same time?
You can easily take a shower and use all the hot water taps at the fixtures at the same time.
Heck even if I did a hot water wash at "the same time" that I wanted to take a shower, by the time I got into the shower the washer tub would be full of hot water
Ladiesman,
I'm not against tankless heaters (I may go tankless myself next time due to severe space restrictions) but I do have a question on your numbers.
You mentioned that your system is rated at 2.09 GPM output at, I believe, 75 degree temp rise and you have also stated that you can run multiple showers at the same time.
That doesn't seem to add up and I'm wondering how you achieve this? Given that a low flow showerhead is rated at a higher GPM that the unit, how can you run two at once?
The only thing I can think of is that each shower uses some cold and some hot so you might be able to squeak by with two running but it still doesn't seem quite right, particularly for those who might like hot showers.
Also, how do you find it works when you have someone in the shower and a sink calls for hot water on full? (filling sink to do dishes, for example) Is it able to keep up?
This would also be AO Smiths way of saying "we don't want to sell them, go somewhere else".... and I would !
You CAN"T supply 2 showers since according to your own posts
your tankwortless will only supply 2.09gpm flow rate
So you have already posted that your tankworthless will NOT supply more then 1 shower at a time
Getting back to the basic question, the code limit for shower heads in this state is 2.5 GPM. If you use multiple shower heads in one shower stall, the total flow of all the shower heads added together can not exceed 2.5 gpm.
They are not saying they do not want to sell them. They are saying it is a costly install, and in most cases you will need to install more than one unit to handle the demand that most homes have. Which has been my point since day one. Yes some people can get by on a single unit install. I could get by on it in my mother's home if I install the largest unit out there. Thing is my mother's home is a 2 bath that was built in the early 50's but its only my mom and dad living their so they never run both showers at the same time and nor do they run the wash or dishwasher while someone is taking a shower.
The newer homes in the Chicago suburbs are at least 3 or more baths, and they do take showers all at the same time and they do do laundry during showers. These larger homes also have 75 gallon high recovery tanks or some even have two 50 gallon high recovery tanks. These people would most definitely need to run two units to be able to handle their peak demand load.
The others that insisted from all their "research" that a single unit will handle their needs I still installed it for them with a disclaimer that I had informed them of a properly designed system. Sure enough after a week I get a call telling me that they are only getting tempered water. I just tell them to read my disclaimer, and if they want me to come and install it the way I recommended to them in the first place I be more than happy to. Other than that I can not help them any further.
Also do that many people run washing machines with the full hot wash and rinse cycle at any time during the day, let alone while someone is in the shower? Sounds like good grounds for a divorce to me!![]()
So you see no difference between a normal sized home and a McMansion?
Tepid water where? Out of the tankless, or out of the shower head? Gas unit or electric? Public water with adequate water pressure, or well water? Current low flow shower heads, or high flow units? Pressure balanced shower valve or temperature controlled? Was this a McMansion?
I assume that you did more than just install a tankless unit without evaluating the full "system".
If you have more than one shower valve, each valve is allowed per the code to deliver 2.5 gpm to its total connected head. So if you have two shower valves that means that shower can have a total of 5 gpm. Lots of homes around here in their master bath have this arrangement, I have seen up to 4 mixing valves in one shower so if they turn on the overhead rain shower, body sprays set one and set 2 and the handheld shower, you are looking at 10 gpm.
My mom still uses pure hot rinse cycle, but like I said her old plumbing she doesn't do it while someone is in the shower. My father likes to take super hot baths, after he fills the tub, then my mother starts the wash and her tanked unit recovered quick enough to supply the hot water to the washer.
I always evaluate the system and make the proper recommendations, but the final decision lays with the home owner. These where all Gas units with city water 60 to 70 psi 1 to 1 1/2" water service, standard flow shower heads at 2.0 gpm. The valves are pressure and temperature controlled., Reason these people got tempered water was they where exceeding the demand of the single unit. They tried to have 3 showers go at once.
You CAN"T supply 2 showers since according to your own posts
your tankwortless will only supply 2.09gpm flow rate
So you have already posted that your tankworthless will NOT supply more then 1 shower at a time
Getting back to the basic question, the code limit for shower heads in this state is 2.5 GPM. If you use multiple shower heads in one shower stall, the total flow of all the shower heads added together can not exceed 2.5 gpm.
Another prevarication!
Simply put, my gas tankless water heater is specified to provide 2.09 GPM with a 90 degree temperature rise.
The coldest my incoming water has been is 40 degrees F.
The highest temperature of hot water allowed by the Massachusetts Plumbing code is 130 degrees F.
40 degrees incoming water temperature plus a 90 degree F temperature rise equals 130 degrees F.
The above meets the volume of hot water required for the intended use based on the lowest yearly incoming water temperatures provided to this residence (AKA winter season low).
Tank type water heaters are very unsafe. Full of germs and other nasty tidbits.
Since you mentioned something related to the cost of "proper" maintenance of tankless water heaters, here is a discussion about the "proper" maintenance of a tank type water heater.
http://www.nashville.gov/water/splash/h2o_heater.htm
Water heater maintenance
Water heaters, whether gas or electric, have become more complex and expensive. They also do not seem to last as long as they once did. This is one modern appliance that we couldn't live without, but is "out of sight, out of mind" until we have problems with it.
Hot water heater flushing
Maintenance books recommend that the hot water heater be drained (flushed) every six months, but few homeowners bother to do this. Often, it is put in an area that is not as accessible as other appliances. It may or may not be easy to drain, even though all heaters have a hose connection and faucet control at the bottom. This task is not only inconvenient, but often the washer and/or washer seat on the faucet must be replaced after draining. Sometimes the entire faucet assembly will have to be replaced. If this is not done correctly, the unit may leak at the faucet. Furthermore, the unit can be damaged while drained. Unless the customer is fully familiar with servicing these units, one should consult their service representatives at the gas or electric utility before undertaking these tasks.
Odors
A heater which is recycled off/on or left off for a period of non-heating may develop offensive odors from sulfur bacteria. The odor is hydrogen sulfide -- "rotten egg odor." This odorous water may be drawn back through cold water faucets as well as the hot water faucet.
Temperature settings
The heater thermostat should be set at a reasonable temperature. Scalding of infants and the elderly can be a real hazard, even when the temperature setting is within proper limits. Again, the user should consult with their energy supplier to have the unit set at a safe temperature.
DO NOT USE HOT WATER FROM THE TAP FOR DRINKING OR COOKING!
Because warm/hot water is much more corrosive of metals than cold water, one should not use the hot water tap as a source for drinking, cooking or dilution of infant formula. It can be high in metals such as aluminum, iron, lead, copper and zinc. The heater tank also tends to concentrate these metals and precipitate them in layers inside the heater tank. Many tanks have a metal "sacrificial anode." This is designed to wear down and can be an additional source of metals. While it may be a convenient shortcut, water from the heater is not an approved source of drinking water.
White plastic particles
It is not unusual for the white plastic (PVC) filler tube inside the heater to disintegrate and discharge small white particles to the faucet aerator screens. These particles can come through not only the hot water lines but the cold water lines as well. These particles may appear to be soft and crumbly, but a good test is to heat this material with a match. PVC will melt; minerals, such as calcium, will not.
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