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Nice BSS.
I seem to recall from the manual that recirc pump plumbing can get a little tricky. My igniter is fired by a water-driven generator (no flow, no fire). The manual said that a recirc pump would require a storage tank and checkvalves to prevent back feeding the tankless. For awhile, i used a 2.5 gallon electric located at the shower for instant hot water. By the time that was empty, the hot water had arrived from the tankless. since the water in the 2.5 was already hot, the 2.5 gallon tank only had to keep it warm, which means it didn't use too much electricity. After a few months, i decided i could live with waiting 15 seconds for the water to heat up and ditched the small tank. I also have a small house/short pipe runs, so YMMV.Quote:
Originally Posted by OSECS
Thought I'd bump this since I'll soon be in the market for a new water heater. The house I just bought has the original water heater (10 years old), so it's overdue to break with the water around here. Looks horrible and doesn't work so hot, so I'm assuming it's chock full of minerals like my other 10 year old heater down the road was. Was a nightmare when that pos broke!
I've always wanted tankless but never had a place that could really justify the higher cost until now. Anyhow, the main reason I'm bumping this thread is because I'm wondering have costs come down much over the last few years? Please tell me they have, so I can convince my wife to get on board with it. Haha.
Has the technology changed much too?
I'm in the same boat. The water heater here is likely on it's way out and I would really like to go tankless. We had tankless when I was a kid and it was fantastic even back then (>25 years ago). But it's hard to look at the expense of plumbing, ducting, and the unit itself without getting a little concerned that I'd be making a big mistake. I can do a fair amount of the work myself, but I could pop a replacement tank unit into the spot that I pull the old one from in a matter of a couple of hours on a Sunday whereas I'd be spending all day trying to sort out retrofitting a tankless unit.
I've been told that the water in my area (eastern, WA) is too cold and that the water will never get really hot, just luke warm in the winter. Does that sound right? I see that a few people have them in areas colder/just as cold as my location. What are your thoughts?
We have one in N.VT, (well) water gets hot, but you need to let it run for a while as in turn the hot water on in the shower and then go brush your teeth or do something else for a few minutes.Quote:
Originally Posted by 1080Rider
Hmm. I might want to rethink it then. My local water can come in pretty dang cold sometimes. Like 45 out of the tap. Makes for awesome drinking water, but sounds like a tankless water heater might have a tough time catching up. Also don't like that it takes so long to deliver it to your faucet initially.
I might just go with a somewhat higher-end tank, then.
It's a minor annoyance that we didn't realize until after we got the house, but the water runs hot and it doesn't run out. Since we are only up there 1-2 weeks a month, I'll take the savings not heating water 24/7. I think its a function of distance from the heater to the faucet/appliance.
That's definitely the case. The faucets near my unit heat up really quickly while the faucets on the other side of the house take a couple of minutes. Tanked houses aren't that much different. A little faster, but not necessarily.Quote:
Originally Posted by Moeghoul
I've been told that the water in my area (eastern, WA) is too cold and that the water will never get really hot, just luke warm in the winter. Does that sound right? I see that a few people have them in areas colder/just as cold as my location. What are your thoughts?
This is not true. We live in Eastern WA and our water comes from a well, and you can set the instant on for whatever temp you like within reason. Incoming temp is a non-factor.
We live in Truckee. We have a 199,000 BTU tankless water heater--a Navien. No problems with getting hot enough water, or enough hot water. The unit is much larger than others I've seen. The wait at fixtures near the tank is no problem. Only the kitchen is a problem--when the new heater was added as part of an addition the hot water pipe went to the old system, doubling the already long run. The furnace was in the way of a direct line--when we replce the furnace we'll run a direct line.
I have a question--we have a house in Sacramento that sits empty most of the time with a 25 year old gas tank water heater we need to replace soon. The house was built in the thirties, with galvanized pipe in the original house and copper (with dielectric fittings) in the upstairs addition. I've been told you can't use a tankless heater with galvanized. I assume the water main in the street and the line from the main to the house are galvanized. We could run a copper line from the main valve to the new heater, but there would still be galvanized coming to the house. Is there any kind of filter that could be used to protect the heater from the crud in the galvanized, which I assume is the problem.
What, like particles of zinc? There are sediment filters you can get, I have one and it works like a champ, but it seems odd that that would be a big problem.
I've had a tankless water heater for 6 or 7 years with galvanized pipes with no problems. I'm pretty sure there is a simple mesh filter on the intake side of the water heater that will catch most particles coming from the pipes.
Have you looked at heat pumps?
nobody cares about heat pumps
Many tankless units are recommended to have a corrosion protection device installed inline to help the longevity. Whole house filters are a good idea also. Navien is the best I have looked at.
Plus the incoming temp of the water makes a big difference, they can only heat the water up so much. More BTU size is of course better fro this.
The small point of use electric water heaters make the most sense for vacation condos or remote locations.
I don't think incoming water temps get too much colder than we have in Truckee--our Navien 199,000 has had no trouble heating to 130 in the winter. These things probably don't pay for themselves unless they're in a house that is unoccupied a lot, but if we all had one maybe the snow level would come down a couple of feet.Quote:
Originally Posted by scottyb
My inlaws are way the fuck up in Northern Maine, and just installed a tankless water heater last fall.
They initially had a bit of a warm up issue as well, but also have a woodstove. They ran a waterline through the woodstove to prime the temps prior to hitting the water heater in the winter and solved that problem.
Now they already had the stove setup in the basement, so it was like 20 bucks and an afternoon of DIY to make that work, but could be an option for you as well.
The question of gas tankless water heaters working without electricity has come up a few times, maybe in the home improvement thread. I was pretty sure mine ran without, but hedged my bet till the power went out to test. My unit for sure heats without electricity, and I don't think it has a battery either. That said, I don't know how that happens. Maybe a mechanical level that moves with water flow and engages a solenoid? There's absolutely no Romex going to my water heater.
With all that in mind, perhaps entirely coincidentally, the power went out last night, and I was using the hot water. And then an hour later it stopped heating. Now the power is back on, and still no heating. The pilot light is on. A little googling mentions a solenoid, but not sure mine would have one considering there's no electricity. Wouldn't be the end of the world to replace it and upgrade, but kinda bad timing for a variety of reasons.
Ours definitely doesn't work without electricity. It plugs into an electrical socket. It has electronic ignition. It's hard for me to understand how one could run without electricity but I'm no expert. If you have a back up battery or generator a gas tankless would certainly use less electricity than an electric WH.
Re the math--our LEED-certified architect friend feels that for a usually-occupied house tankless WHs offer minimal energy savings compared to an up-to-date energy star ranked conventional, with a very long payback period. He feels the money is better off being spent elsewhere. And he is the guy who designed a bathroom addition with tankless water heater for us--at our request.
A friend and former mag clued me in that mine probably has a thermocouple. Still Greek to me but I'll start there..
https://en.m.wikipedia.org/wiki/Thermocouple
Does your WH have a pilot light--if so the thermocouple can generate enough electricity to operate it. I guess some do, although neither of the ones I'm famiiiar with do. This is how a lot of furnaces used to work and tank water heaters still work. Apparently some tankless have a little generator that makes electricity when you open the faucet and water starts flowing through it. News to me. Mine still doesn't work with the power off.
Yup pilot light. I've never looked into how water heaters worked because the one time I had to replace one it was because the tank rusted out, not because the burner stopped working. Guess I will see if I can replace my thermocouple to get another year out of it. Might be out of here soon would be silly to spend a bunch on a new heater.
I missed the pilot light in your first post. Sorry.Quote:
Originally Posted by Rideski
As I understand it the thermocouple is supposed to sense if the pilot light goes out and shut off the flow of gas. I would have thought that if a bad thermocouple wasn't sensing heat the gas to the pilot light would have shut off. But I've already proven I don't know shit about water heaters. Just for giggles, have you tried turning off the gas and then relighting the pilot? I mean, rebooting works for computers. Why not for water heaters.
No worries. I was going to try a reset of some sort.
Working way too much and I've just been showering at the gf's for a couple days.
Bad timing but I'll have some time soon.
I watched some vids of ripping a thermocouple out if a traditional WH. Didn't look easy, but not harder than a car radiator.
What's so bad about showering at the GF's? With the GF of course. (We added a bathroom and a shower with two heads. But way too late in life.)Quote:
Originally Posted by Rideski
How about this? Heat pump water heaters. Seems the math works out pretty darn well:
https://cleantechnica.com/2022/04/08...-panels-costs-
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sounds ok as long as your wife doesnt mindQuote:
Originally Posted by old goat
I'm late to this thread, and didn't read all the previous posts. My WH just shit the bed, I pulled the burner assembly out and buffed the carbon scoring off of the thermocouple and it's good as new. Skip the sand paper and go straight to the dremel. Then make sure you reset the tiny invisible little fuse that is (probably) coming off of the power supply from the controller to the tank. This is a slightly temporary fix, as the thermocoupler will gather carbon scoring faster now that it's been cleaned, but it can get you up and running until you can grab a new burner assembly. I'd replace the whole thing, not just the thermocoupler. Generally you can buy them as one unit.Quote:
Originally Posted by Rideski
Thanks, that is rather encouraging since this is an older discontinued model and I wasn't sure I would be able to buy a new thermocouple even though they are cheap and seems to fit a variety of machines.
Didn't get up there to look at it yet, working my guts out.
I’m launching a kickstarter for a crypto mining server integrated with a tankless water heater. Teenage daughters + long showers = profit.
Anyone replace 2 water heaters with one tankless? I have two 50gal gas tanks that are 22 years old. Working fine but probably just a matter of time before I end up with a shitshow in my basement. One is on a recirculation system, the other one is not. My hunch is that the labor cost alone here will make it not worth it, but curious if anyone has gone down this road.
We replaced 2 50 gallon electric tank heaters with one gas tankless. This is in a house that gets a lot of overnight company, especially in ski season. 2 or 3 people can take showers at the same time and people can take showers one after another after another without running out of hot water. It's a 199K BTU unit, with very cold intake water temp, and showerheads are 2gpm. We set the temp at 130 so we can mix in a fair amount of cold--I've never thought seriously about that; it probably makes no difference what temp you set as far as the number of showers and appliances that can work at once.
Thanks! How many years would you say to break even?Quote:
Originally Posted by old goat
More than I have left.Quote:
Originally Posted by ColMan
I have to admit I haven't done the math--comparing the electric bill before the switch with the gas bill after. And there are so many variables--weather, occupancy, the new tank being farther from the kitchen I'm not sure a comparison in an individual case would be meaningful. I go back to what my architect friend said--about the energy savings being small. We were going to have to replace the two 50 gal electrics soon anyway so the total cost of installing two electrics vs one tankless might have been similar--which would make the tankless more cost effective than if we were comparing to replacing with one tank water heater.
I had to think about this, but I think you could get better performance from a slightly lower output temp if the limiting factor is total watts to the heater. It should run slightly more efficiently (i.e. more total heat transfer to the water at max power) if the hot water has a little higher flow rate (aka a little lower final temp). But there's a limit where pressure drop through the heater takes over as the limiting factor, too, so maybe not.Quote:
Originally Posted by old goat
I had a thermodynamics professor who was adamant about this but explained his position purely based on change in entropy. Suffice to say he reached the same conclusion but didn't really convince me until I was today old. I'd lay out his reasoning, but I kinda doubt anyone else cares, either. RIP, Dr. M.
So…I just figured something out with our Rennai tankless. We did a whole bunch of work on our cistern etc. which messed with the temp at the faucet, so I turned the temperature up, and it actually resulted in colder water because to get it hotter it constricts the flow.
Since we had low flow anyway it kind of screwed things up. I reduced the temperature from 140 to 125 and we actually have hotter showers now.
So Dr. M. has reached a state of entropy.Quote:
Originally Posted by jono
I took thermodynamics. Physical chemistry lite. A couple of my friends had their prospective medical careers torpedoed by P Chem, but then who wants a doctor without the common sense to not take P chem. I don't feel like not taking P chem hurt me in any way--my showers are hot, my jacuzzi is right at the sweet spot, and the water from my bidet toilet seat soothes and relaxes without burning. What more can a man ask for?
Lower utility bills?
I feel like Dr M would argue for that. We had a different name for him, though. Now I'm wondering if our name for him was in any way related to the giant chip on his shoulder about P chem? (It was definitely about the chip, I just don't know if Pchem had anything to do with it.) He would have stamped his feet a few times over that--like everything else, really.
One of the highlights of my college career was watching a friend of mine who had flunked pchem sic his german shepherd on the prof as he biked across campus. The dog didn't bite him or knock him off the bike, just barked as the prof tried to kick it away until my friend called the dog off