Hi cactusfreak, I have electric tankless and I don't know if there is much difference in between those two but my LG does the same thing. But I also use only hot or sanitazing cyles so the washer is taking in mostly hot water from the pipe and our tankless is just behind the machine wall so it helps. I can see it might be problem w/ the on/ off action if you have long way to go. I would try to set wash cycle on HOT water and see how hot ir really is when filled up. You can pause the cycle and open door to see, there isn't lots of water in so it will not leak out. Maybe this just might work. Another little help, perhaps, water plus option would give you more hot water in once it starts filling up.

There's no easy way to solve the problem, which is inherent in how the LG fills in relation to how tankless water heating works.

You could add a recirculation pump (there are retro-fit models that install under a sink and run in a closed loop from hot supply line to cold supply line), but that would be more installation expense and increase your overall hot water costs ... and may not even help much depending on where the washer's line taps into the plumbing.

It'd be better to purge the washer's supply line directly rather than doing it by way of the kitchen sink. Apparently you don't have a sink in your utility room or by the washer? You could add a Y or T adapter to the washer's hot tap with an extra hose, purge the line before starting by running it into a bucket, then let the hose run slow until the machine finishes filling to keep the line primed. Problem is most gas tankless units require a minimum flow rate of at least 1/2 gal/min to activate and stay running ... you'd fill up the bucket pretty quick depending on how long the machines takes to satisfy itself on filling. But maybe if the line to the washer was purged instead of to the sink and the tankless's burner activated and the heat exchanger coils heated, there'd be enough residual heat between cycles to make a difference without running it continuously.

Since any front-load washer uses only about 5 gallons per (portion of) cycle, that's about what's in the pipes between the washer and any type of water heater, unless you use a point-of-use water heater.

If you want hot water at the washer hose inlet, before you start the washer, run the hot water at the utility sink till it's hot.

Even top loaders fill the tub the same way. It's the curse of Automatic Temperature Control. It's a universal problem with modern washing machines, period. You just never noticed it with your old setup. I've had a tankless water heater for 12 years now, and I love it and would never go back. I'm waiting on the old top loader to die for me to upgrade to a LG with an internal water heater. An internal water heater washer is the only way to go. But how I mangage now is if I want a true hot wash in my old toploader with ATC, I simply shut off the cold water supply and it only fills from the hot supply. If I want a truly warm fill, then I use the Hot setting, because that's around 90° by the time the ATC gets through with it's fits and starts. I wish there were a less "interactive" way for my laundry to get done, but it works for now.

The LG 2233 has an on board heater. That should help with your hot water temperatures.

live_wire_oak, my old setup was so old it did not have "automatic temperature control". It would just mix the flow of hot and cold depending the temperature I set it. The valve would open more or less. It was not a pressure control valve.
It did not stop and start the filling cycle. I also did not have the tankless heater then. So hot water was always hot once the cold drained out of the pipes. Which was maybe a quart since the water heater was within 2 ft of the washer.
Turning off the cold water supply would not help my case.
The water coming out of the tankless heater never gets a chance to heat up before the heater cycles off.
It is also wearing out the ignition control on the heater by clicking on and then off before it ever lights. It operates by water pressure and not by temperature. It turns off when the water stops and at low pressure it can take 2 or 3 clicks to light.
I tried sanitary cycle to see if it would heat the water.
I opened the washer after it filled and the water was cold. Not even luke warm, not even body temperature.
LG has responded to my emails and said I need a sevice center to look at my unit.
Good luck with that huh?

...if the machine is programmed to let the heater boost the water temperature, not just maintain it.

Hot water cycle should heat your water up, sanitary goes in mine to 159, if not it is not working properly.

cactusfreak, the machine can't heat the water that fast. Check the temperature at the END of the wash period, not at the beginning.

Turning off the cold water WILL force the machine to use the hot only for fill. It will be a steady fill without starts and stops. It eliminates the cycling between more and less hot water as the ATC "brain" demands it. Try it before you get your service call.

re: "Since any front-load washer uses only about 5 gallons per (portion of) cycle, that's about what's in the pipes between the washer and any type of water heater, unless you use a point-of-use water heater."

I know it sometimes feels that way while your waiting for the water to get hot, but that figure is a huge overstatement of reality. Each foot of 1/2 copper pipe contains 0.0113 gallons of water. It would take over 442 ft of pipe to hold 5 gallons. It's unlikely any homeowner has anywhere close to that between their DHW source and the point of use. In large commercial installations where that might be possible they would either have recirculation and/or have DHW zones closer to the point of use. My guess for the reason it seems this way is because copper is such a great conductor of heat. When you turn on the hot water you actually flush the water through the line pretty fast, but the pipes continues to absorb heat for quite a while.

The cold sandwich problem with instantaneous heaters is an issue. As you've found, just flushing the lines isn't enough. You need to have constant flow to prevent cold sandwiches. All the FLers I've seen fill in relatively short spurts. I doubt it's just an LG issue. You should contact the water heater's tech support line and see what they say. A relatively small insulated buffer tank setup with an aquastat in a loop with the heater might be a solution, but the manufacturer of the heater has an interest in finding a good solution as this could be a show stopper for many folks.

cactusfreak, are the short bursts of water entirely from the hot supply, or is it adding cold water too? I returned an LG earlier this year because of water temperature issues. First problem was that I have a long hot-water lag (measured 3 gallons before water got fully hot), and the LG didn't appear to be using the heater to guarantee a hot wash. Before I bought it, I had checked with LG customer service to verify it would use the heater as necessary, because I knew the lag would be a problem. Their response was unequivocally what I was looking for, but it seems to have been outdated (maybe applied to last year's versions). Second problem was that the washer did indeed fill with a mixture of cold and hot water, on a hot wash...even though it should have known the "hot" water wasn't coming in hot at all. I called Sears about it, and was told that current machines use 75degF for "warm", and 90degF for "hot". I don't really know if those numbers were correct for the LG; the online manual listed temperatures that were hotter than that, but the manual shipped with the machine omitted temperature specifics, except for sanitize (which was a little cooler than in the online manual). I returned the machine before I got the "Kill-A-Watt" box and instant-read thermometer (total cost $30 plus shipping) that would have let me refine my observations on it.

My wife came to the conclusion that "they want us all to do cold washes", and I think she was right. Fortunately there's still Miele; the W4840 seems to have restricted the energy-pinching stuff to its "Normal" cycle; use other cycles, and you can choose between 30degC, 40degC, 50degC, 60degC and 70degC water. In my observations, made mostly on the "Custom" cycle, it does lengthen the cycle as necessary to guarantee a minimum wash time in the desired water temperature. The Miele doesn't fill in such short bursts, and it would use its heater to get the load to the right temperature, so "cold sandwich" would be much less of an issue. It is an expensive machine, though, and the door is hinged on the right, so you pretty much have to swap the washer and dryer positions, if you're side-by-side.

Our W4840 doesn't do short bursts, but it probably fills up to 6 times during the first 6 minutes. I believe it does an initial fill and then watches water level before it lets more water in. As the clothes absorb water, more water comes in until the fabrics are saturated and a very small puddle of water is in the bottom of the drum remains.

The Miele ATC is very good, so even in Normal cycle we can easily have it fill with water close to 110F if you choose a hot wash (and our DHW source is set at 122F). So for warm washes 104F) we just use regular Normal cycle as it would be no different than custom-warm. Early on I did a bunch of data logging to try and figure out what the machine was doing. It was never clear to me that the machine really adds time based on local conditions when the heater is used (non-Normal cycles). It seemed like if we really wanted a 60C or 70C wash I'd have to choose the extended wash option to give the machine more time to heat the water. I'd love to hear if you've had other experiences that would indicate something else.

Personally I'm not fond of the downgrading of the meaning of warm and hot. Ask the customer service person at Sears to take a nice warm bath at 75F and report back how it felt.

My W4840 definitely pauses a non-extended wash at 0:50 to let the water heat if necessary. Similarly for an extended wash, usually at 1:10 but I think I've seen it at 1:20 also. You wouldn't see this, if your hot water comes in hot, and you don't wash at 140F or 158F.

If the heater is entirely disabled on Normal, you'd get some benefit from Custom even in your setup, because the heater will switch on during the wash, as the water cools off.

With "cold" technically being 86F as on the Miele, and the new "hot" being 90F, they really are making everyone do cold washes. What I wonder is, what are the financial incentives that make most manufacturers dumb down the temperatures? It's not just Energy Star: Miele W4840 is Energy Star rated. What's more, LG (among others) was already well exceeding the 2007 Energy Star requirements last year, and I don't know of new standards for 2008. So why did they apparently further reduce their hot water usage for 2008 models? Maybe there's some additional tax credit (beyond the $100(?) Energy Star credit) for exceeding the standard? So they're crippling their machines' performance for maybe a few bucks per machine, because in the aggregate it helps them? And Miele isn't competing on price, so they can forgo those few extra bucks per machine? All question marks there, because I'm just speculating, don't know the truth. I am pretty sure, though, that the manufacturers could use their political clout to push back on standards that hurt the consumer, if they wanted to.

This is getting a little off topic, but your experience is making want to dust off the data logger and try these things out again. Maybe Miele has done a firmware upgrade we should request?

Hi,
We just built a new house, and we are having the same problems. It also takes forever for some of our faucets to get hot water. All of our showers and the sinks near the heater are fine.
Our machine is a Samsung washer, but we are also having the same problem with our KitchenAid dishwashers. You'd think that an energy efficient water heater would be compatable with energy efficient appliances! We are still looking into a solution and I am curious to know what you have done. So far, I think adding a retro-fit recirculating pump or a small buffer tank is what we need. As well as getting new appliances with heaters built-in. It seems ridiculous that the tankless heater company (Rinnai, in our case) does not warn of these issues. Now we have to spend more money, when the point of installing the system was to save.

I open up the faucet at the kitchen sink and let the water run til hot and leave it running til the machine fills.
I try to do it when I actually need a sink of water for dishes so I don't waste it. But not always possible. I feel that I am wasting water. I am trying to get my DH to install a Y-connector to the washer faucet with an extra hose so I can let the water run into a bucket or out the window into our pool or rainbarrels. That still means I would have to stand there and wait til the washer fills so I can turn it off.
I tried just not doing anything but the clicking clicking of the ignitor on the water heater is annoying and I know it will wear out the ignitor faster.
Let me know what you try and if it works.

Sandra, what is the physical distance as the plumbing runs from the water heater to the troublesome taps? Tankless water heaters cannot magically reduce 50', 75', 100' etc. of physical pipe between the heater and the target faucet to an effective 1' of distance.

People often assume that "tankless" means "instant hot water at the faucet" It does not. There's also the issue that gas tankless seems to require a fairly high flow-rate to activate. My electric tankless activates at 0.3 GPM.

You could install a smaller Point Of Use Tankless Water Heater near the washer.

I have the same problem with my Whirlpool front load washer, which has its own dedicated line and is no more than 20 feet away from the gas Navien tankless HWH. I have the Navien temperature set to 140 degrees. I run the hot water adjacent to the washer in the powder room until the water is hot. I then turn on the washer which is set to hot. The hottest temperature I can get is 90 degrees via a thermometer (by all standards that is considered warm). I want to get at least 120 degrees to wash by bed linens and towels because of dust mites and allergies. My husband thinks I'm off the wall. Does anyone have any help or suggestions?

We are having a similar issue. We just got a tankless water heater and we have the recirculation valve on our second level. We have new appliances and are having trouble with the dishwasher now – specifically the air dry and the heat of the water. We are also having trouble with the washing machine not actually spinning anymore unless we put it on an actual spin cycle after the original wash cycle. It is all very strange because all worked perfectly before we had the new tankless water heater installed. The installer came back to double check and couldn't find anything wrong. And was actually dumbfounded at our issues. I'm not really sure where to seek answers.