water heater maintenance?
Posted by: DWallach
water heater maintenance? - 26/01/2006 14:24
No sooner do I fix my TV than something else needs work. Ahh, home ownership.
Anyway, the hot water has lately been running out sooner than it used to. We've got a 40 gallon gas water heater, mounted in the attic, where it's not exactly easy to get to. The heater and the house are both about seven years old.
Poking around the web, it seems like I've got several things that I need to do, including draining the thing from below, hopefully to extract any sediment buildup. Does anybody understand this "dip tube" business? If I read the various web pages right, the cold-water intake is on *top*, but it has a separate pipe, inside the heater, to route the cold water to the bottom. The hot-water output is also on top. When working properly, the cold water pressure, from below, pushes the hot water out the top. Does that sound correct? Apparently, this "dip tube" thing has a habit of breaking, and thus you need to check it as well. Finally, does anyone think I need to check out the thermostat? Electric units apparently have multiple thermostats, but gas units... I'm not sure.
Thoughts? Experiences? Water pouring through the ceiling because you screwed up horror stories?
Posted by: tfabris
Re: water heater maintenance? - 26/01/2006 14:36
I have a good friend who JUST DID the dip tube on his hot water heater. It completely fixed his problem with his hot water. I'll link him to this thread, perhaps put you in touch.
Posted by: lastdan
Re: water heater maintenance? - 26/01/2006 17:25
when I lived in an old apartment building we had this neat looking old water heater that looked like a cross between something you might find in the bottom of a ship and some kind of oven, rather large with a 3x3 foot door on the side.
one day I was doing some laundry (in the same room) and a guy was there with a shovel removing an awful lot of calcium (?). and by a lot I mean enough to fill at least a few 55 gal oil drums.
he said it was a common problem and he was thankful the unit had such a large access door.
he told me you can tell when deposit build up is a problem because water heaters will start making cracking and popping sounds as they try to heat the water.
didn't get to do the wash that day, but I learned something new.
Posted by: tfabris
Re: water heater maintenance? - 26/01/2006 17:32
Yeah, in my old house our water heater made those sounds, and yeah, it was calcium build-up. Since it didn't have an access door, the only way to remove it was to replace the water heater. So we lived with the cracking sounds.
Posted by: larry818
Re: water heater maintenance? - 26/01/2006 19:55
Quote:
Yeah, in my old house our water heater made those sounds, and yeah, it was calcium build-up. Since it didn't have an access door, the only way to remove it was to replace the water heater. So we lived with the cracking sounds.
I used a 25 liter tank and a submersible pump to clean the heater. When the capacity of the heater got low enough to bother me, I would disconnect it, and connect up this tank instead. I would fill it with a bottle of CLR (Calcium Lime Rust remover) and water and let it run through the heater until it looked like milk (I'd even let the heater heat it). Connect it back up and rinse the CLR out with the shower and it's good for another three years.
Of course, these tank style water heaters we use in in the USA are crap. I brought an inline (demand, instant, whatever) water heater back from Taiwan with me and now I never run out of hot water. This is the kind used everywhere else on the planet...
Posted by: adavidw
Re: water heater maintenance? - 27/01/2006 07:42
Quote:
Of course, these tank style water heaters we use in in the USA are crap. I brought an inline (demand, instant, whatever) water heater back from Taiwan with me and now I never run out of hot water. This is the kind used everywhere else on the planet...
At this point I'm pretty much just biding my time waiting for my water heater to break so I can have an excuse to get one of these tankless systems in my own house. I am purposefully not maintaining the existing heater, and if it lasts too much longer, will have to find something I can stick into it to hasten it's demise...
Posted by: larry818
Re: water heater maintenance? - 27/01/2006 14:48
Quote:
At this point I'm pretty much just biding my time waiting for my water heater to break so I can have an excuse to get one of these tankless systems in my own house. I am purposefully not maintaining the existing heater, and if it lasts too much longer, will have to find something I can stick into it to hasten it's demise...
When I started working from home, I could hear the tank heater start up. It would heat its self about 10 times in an 8 hour period, with no one using it. It was also only providing about 10 minutes of hot water by that time. I was happy to see it go.
Posted by: wfaulk
Re: water heater maintenance? - 27/01/2006 16:28
Of course, I have the opposite problem, which is that I have to wait 2 minutes for any hot water to get to my faucet. An instant heater would only exacerbate the problem. I'm thinking about installing a hot water recirc system so that I'm not wasting so much water.
Posted by: JBjorgen
Re: water heater maintenance? - 27/01/2006 16:42
Quote:
An instant heater would only exacerbate the problem.
Huh? How so?
Posted by: Attack
Re: water heater maintenance? - 27/01/2006 18:08
If you in the US you can get a solar powered water heater system and get a tax break.
http://www.post-gazette.com/pg/06007/633483.stm
Posted by: wfaulk
Re: water heater maintenance? - 27/01/2006 19:47
Sorry. I'm thinking ahead of my post. The issue is that the water that sits in the hot water lines gets cold while its sitting there unused. In order to get hot water, you have to pump water through the hot water lines continuously, and this is best done with a tank of hot water that you can just recirculate. When you have a tankless system, that means, at best, turning the burner on every few minutes to get new hot water to keep the lines warm, and since there's no tank to recirculate that water to, it just gets wasted. And that means that it's no better than what's going on now, but you don't get any water savings. At worst, you need a pump to deal with pushing the water through a closed system that can no longer be gravity fed, and installing a pump on a tankless system won't really work, so you can't fix it at all.
Of course, IANA plumber, so I could be wrong, but that's how I understand it.
Posted by: robricc
Re: water heater maintenance? - 27/01/2006 19:59
So, you don't have a tankless system presently?
The natural gas heater in my house is about 15 years old now. It has been dependable the past few years I've owned the house, but I will probably replace it soon anyway. I was thinking of getting a tankless unit since the house is small but the gas bill is $350/month in the winter. Since fixing a leaky faucet, my water bill is about $80/quarter.
I have had fantasies about getting a solar panel install connected to the grid. I'm not made of money, but maybe I will check out a home show in the area before doing anything. The vendors typically know all kinds of incentives available on stuff like that.
Posted by: wfaulk
Re: water heater maintenance? - 27/01/2006 20:12
No. I have an electric tank, but I can't imagine that the water sitting in the pipes would somehow get less cold with a tankless system.
Posted by: robricc
Re: water heater maintenance? - 27/01/2006 21:29
I'm sure it wouldn't help you, but with my tank now it only takes about 10 seconds for hot water to come out of the tap. I'm not sure if a tankless system would be any worse in my case since they're supposed to heat water very quickly. My hot water heater is located in my garage which is the coldest place in the house. That probably lowers its efficiency a bit.
In an attempt to lower my heating bills, so far I've had a new garage door and all new windows installed. The last energy waster in my house is the front door. That's being replaced soon. I'm just waiting for the company to come install it.
This coming bill will be the first one since the windows went in. I hope it will be worth the initial expense. My house was built in the late 1950s and the windows and garage were original and made of wood and a single pane of glass.
Posted by: msaeger
Re: water heater maintenance? - 27/01/2006 21:48
I just built a house and was thinking about getting a tankless but ended up with a traditional tank style unit. I didn't get a tankless after hearing reports from people that the unit wouldn't turn on at all if the flow was too low or it wouldn't turn on right away.
Posted by: JBjorgen
Re: water heater maintenance? - 27/01/2006 22:02
Quote:
No. I have an electric tank, but I can't imagine that the water sitting in the pipes would somehow get less cold with a tankless system.
I thought the whole point is that the heater is right next to the fixture. The one time I have used an instant heat system, the heater was actually built into the shower head. Worked great and really was "instant."
EDIT: Something like this.
Posted by: Robotic
Re: water heater maintenance? - 27/01/2006 22:57
Quote:
EDIT: Something like this.
Now THAT is cool! (ok, maybe it's hot!)
I'll have to do some more research and see if that would be good for my off-grid plans at my remote property. 
Posted by: robricc
Re: water heater maintenance? - 27/01/2006 23:36
The point of a whole house unit
like this is to heat water only when it's called for. Constantly heating a whole tank of water all day long when nobody's home isn't efficient.
Posted by: wfaulk
Re: water heater maintenance? - 27/01/2006 23:44
Yeah, that's not what's generally meant. That's a point-of-use (or something like that) heater. Personally, I don't like the concept of electricity heating the water right at the point I'm using it. Seems too easy for it to ground itself through me.
Anyway, a tankless heater is basically one that replaces a "normal" (in the US) hot water heater and automatically switches on a gas burner when it detects that a hot faucet has been turned on to heat the water in the pipe as it comes from the water supply without storing any of it. People complain that they don't produce enough hot water to feed more than one thing at once, like a shower and the dishwasher, but other people say that they work just fine. There is certainly some benefit to not having to keep a few dozen gallons of water heated in a tub with immersion heaters all the time.
I'm sure that part of my problem is my low water pressure, which means that it takes a good while to get all of that cold water out of the pipes. But a refit recirc system is cheaper than hiring a plumber to fix the water pressure. And its benefits wouldn't go away when I finally do get the pressure fixed.
Posted by: wfaulk
Re: water heater maintenance? - 27/01/2006 23:47
Quote:
My hot water heater is located in my garage which is the coldest place in the house.
My hot water heater is located in the crawlspace, so not actually in the house at all. It's not as cold as if was sitting out in the open, but not by a lot. Then again, I live in the southeast, so it doesn't generally get so cold as it does up there in the northeast corridor.
Posted by: Laura
Re: water heater maintenance? - 28/01/2006 01:24
You might want to check into a water heater blanket, that would help. Also, make sure your attic has insulation, older houses tend to have little or none. Insulation will cut down your bill the most, in my experience.
Posted by: larry818
Re: water heater maintenance? - 28/01/2006 02:56
Quote:
Of course, I have the opposite problem, which is that I have to wait 2 minutes for any hot water to get to my faucet. An instant heater would only exacerbate the problem. I'm thinking about installing a hot water recirc system so that I'm not wasting so much water.
You would be exchanging cheap water waste for much more expensive heat waste.
Water is reclaimed, sooner or later. Wasting electricity also causes pollution...
Posted by: wfaulk
Re: water heater maintenance? - 28/01/2006 16:12
True, but I'm already wasting heat due to having a tank-based hot water heater. Adding the volume of the water pipes into that is probably not terribly significant.
Posted by: tanstaafl.
Re: water heater maintenance? - 29/01/2006 00:35
Constantly heating a whole tank of water all day long when nobody's home isn't efficient.
Depends on how efficient your tank is.
My entire heating system (which includes the hot water) is designed for efficiency: A computer-controlled variable temperature oil-fired boiler (made by Buderas) with six heating zones, a Riello burner, and outside air temperature monitoring to control boiler temperature. See attached photo.
My hot water tank holds 55 gallons, and is so thoroughly insulated (at least 6" of high density foam) that I cannot discern the slightest difference in temperature between the outside of that tank and any other surface in the room -- a room which (in the winter time) is kept at an ambient temperature of around 50 degrees.
However, I know what Bitt is saying -- it takes a long time for the hot water to go from that tank to the rear bathroom, a distance of over 70 feet as the pipes run, and of course when the hot water is not in use, the water in those pipes loses its heat, wasting the energy. In my case, the heat is not wasted for at least seven months out of the year, as it helps to heat the house.
tanstaafl.
Posted by: Robotic
Re: water heater maintenance? - 29/01/2006 00:35
Quote:
Of course, I have the opposite problem, which is that I have to wait 2 minutes for any hot water to get to my faucet. An instant heater would only exacerbate the problem. I'm thinking about installing a hot water recirc system so that I'm not wasting so much water.
The house I grew up in was fairly standard for California- a big tank water heater near the garage, far away from the bedrooms and bathrooms.
We installed a small (3gal) electric-heated tank under the house near the baths.
Voila! No more waiting for minutes while the pipes warmed up.
Also, as the main tank ran cooler the small heater would boost the temperature- near endless showers could be had.
Building a recirculating system seems like a lot of effort to me, what with pumps and new pipes and all.
Posted by: wfaulk
Re: water heater maintenance? - 29/01/2006 04:00
I was actually looking at a system that's pretty much just a pump attached to the hot water heater and a thermostatic valve installed at the most remote faucet in the system. It then just uses the cold water supply at that faucet as the "return".
Posted by: DWallach
Re: water heater maintenance? - 29/01/2006 05:10
If you turn on the cold tap from that faucet, would you get hot water out? That sounds like the awful nightmare of my childhood summer camp's shower system, wherein the cold water supply would often become blindingly hot, even if you had the hot tap completely closed. Since then, I've always wondered how you're supposed to engineer a building's hot/cold water system to avoid this sort of thing. I figure it involves having staggering amounts of positive pressure in your pipes such that you'll never get any sort of backpressure, but what if a clogged faucet effectively shorts the hot pipe to the cold pipe? I've likewise wondered why somebody doesn't make a digital shower controller to maintain constant temperature through transient pressure drops (e.g., toilet flushes). Ahh, the things you think of when you're stuck with inferior plumbing.
Posted by: larry818
Re: water heater maintenance? - 29/01/2006 14:38
Quote:
True, but I'm already wasting heat due to having a tank-based hot water heater. Adding the volume of the water pipes into that is probably not terribly significant.
It's not the volume, it's that you'll be running heated water through several meters of uninsulated piping. This will make a fairly effective radiator.
Typically, in houses built with hot water recirc systems, the hot water loop is well insulated in it's entiety. Still, there will be heat loss one wouldn't get if one didn't recirc the hot water.
Posted by: larry818
Re: water heater maintenance? - 29/01/2006 14:47
Quote:
The point of a whole house unit like this is to heat water only when it's called for. Constantly heating a whole tank of water all day long when nobody's home isn't efficient.
Wow, $989. I got a similarly sized heater in Taiwan from Sakura for less than $200.
I think the us market heaters must have more temp control. My heater only controls the gas flow and beyond that, only shuts down if the outlet temperature gets too high. Since everyone uses these in Taiwan, all the fixtures are designed to flow the same, so the heater doesn't need to have great output temp control. Here in the us, nothing is designed with the same flow, as a tank heater will always deliver the same temp. Probably the US instant heaters have to account for this.
We just go adjust the heater before we use what we're gonna use. 
Posted by: wfaulk
Re: water heater maintenance? - 29/01/2006 16:18
Quote:
If you turn on the cold tap from that faucet, would you get hot water out?
Well, it's not going to push it into the cold water pipe until it's reasonably cool, so while it's possible that there might be some warm water immediately after opening the cold faucet, it's not going to be significant. I supposed that the valve installed could potentially fail open, though.
The way this is normally done when putting in a hot water recirc system at build time is that there is a separate return line for the hot water. The return is apparently also sometimes used in the heating system as radiant heating, which, if a separate system, would be circulated anyway.
Posted by: wfaulk
Re: water heater maintenance? - 29/01/2006 16:21
Quote:
you'll be running heated water through several meters of uninsulated piping
What makes you think my piping is uninsulated?
Sure, it's not as insulated as the tank, and there's obviously a greater surface area to volume ratio in the pipes, but, here in the South, plumbing is traditionally run in unheated areas and has to be insulated to prevent freezing for the few days where that's possible.
Posted by: larry818
Re: water heater maintenance? - 31/01/2006 00:54
Quote:
What makes you think my piping is uninsulated?
Sorry, I've only lived in So. Cal. and Taiwan, we don't know from insulation...