should I remove a tankless for a tank?

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We recently moved and our new place has a tankless water heater that appears to be from 2016. This is our first experience with a tankless system, and I'm trying to keep an open mind about it, but I do miss our old tank.

We are a small family that never ran out of hot water with our previous Rheem 40-gallon tank. I had it set between 130-140. With the tankless system (set at 135) now, we have to wait much longer to get hot water. Based on its performance, it feels like a downgrade.

Our previous tanked system had a much longer run of copper pipe, 60' or so. We were used to having to wait for hot water. It was not instant hot water. However, with the tankless system, it has a much shorter run of PEX, about 10-25 feet, which I thought would deliver hot water faster. When you prime the line, you can feel cold water, followed by warmish water, then cold water again, followed by warmish water, and finally hot water. This makes sense if it is not drawing on a tank of hot water, but instead taking a minute to heat up the cold water. But it does take a much longer time to get hot water from a source that is much closer to the faucet.

I'm considering removing the tankless heater and installing a 40-gallon water heater instead. I feel silly doing this so I am not going to do it as it is going against what the trend is now, maybe I need to rethink this and consider my options. I could consider putting in a recirculate pump but it seems like a waste of energy and gas, Can anyone relate to this or have some advice?

From my brief reads, it seemed like a tank and a tankless, delivered hot water at about the same rate, so it is very possible putting in a WH woudl give me the same results as the tankless. And maybe other factors like thermal heat loss or something?

Curious if anyone has removed the tankless due long wait times?
 

Reach4

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Tankless heaters need the lime deposits removed periodically.

You might post the make and model of the tankless, in case somebody has suggestions on how to deal with that.
 

Fitter30

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All tankless wh need yearly service can find that info on you tube. If you don't have the manual can find one on line.
60' of 3/4" copper holds 1.37 gallon
20' of 3/4" pex holds .38 gallon
 

Master Plumber Mark

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Tankless heaters are a pain in the ass and you have to baby them
and when they break down its a miracle to find someone knowlegeble
enough to work on them quickly....

If you are having fits with the tankless,
I would install a 50 gallon gas if I were you instead of a 40
because you will get more bang for the buck

if you know what you are doing it should not be too difficult
as long as you have a metal flu pipe that is compatible with
a tank type heater ..... then you are good to go
 
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OK, that is good to know I am not the only one . I am going to try to descale this thing and see how that goes. Then I might consider a tanked WH if there is not performance uptick. I can check out the 50 and compare price and size. Thanks
 
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I was able to do a thorough descale. I can report that there is not difference with performance. We are use to a tanked water heater and maybe this is just the down side to this Tankless trend? They under perform compared to a Tank?
Here is my presumption:
Both tankless and tank need to clear out the line to prime it with hotwater.
So you wait for both systems.
However, you are pulingl hot water from a tank that has it ready.
Apposed to
You are pulling cold water from a tankless, and there needs to be a certain amount of time for that cold water to run through the system and heat up than to travel to your fixture. So lets say it was a race, between the two. The Tankless would require maybe another min or two to heat the water to temp, before it gets delivered. So rather than waiting for 1 min from the furthers point. You end up waiting 3-4 mins which give the tankless a few minute to get the water up to temp.
It really seems like a way to waste tons of water.
With my Tank, I had the burner on a schedule and it never went on when we were away, so it seemed pretty efficient. Just my two cents.
 

wwhitney

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You are pulling cold water from a tankless, and there needs to be a certain amount of time for that cold water to run through the system and heat up than to travel to your fixture. So lets say it was a race, between the two. The Tankless would require maybe another min or two to heat the water to temp, before it gets delivered.
Your analysis is reasonable, but in my experience the tankless startup delay (after the pipes are emptied) is more like 10 seconds.

One other factor you haven't mentioned is that depending on how the tank's hot water piping is plumbed, you may get a thermosiphon effect. So you may not have to wait for the pipes to empty before you get hot water. That advantage would add to the tankless's startup delay as far as the time difference in the race. [Although it's a disadvantage energy usage wise.]

One option is to install an on-demand (push a button) recirculating pump. E.g. if there is only one distant bathroom where the delay is a problem, an undersink hot to cold pump that will empty the pipes for you. That would save water and reduce wait time compared to either non-recirculating approach.

Cheers, Wayne
 
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I have used an under the sink cir pump at a diff location, and it was helpful. Good suggestion. Maybe I can look into that.
The sad part is that we are experiencing the delay in the kitchen which is about 6-8 feet from the Thankless water heater. Not sure if these lines are all home-runs as well, which would render the circ pump not as helpful to other fixtures. Just casue each run is pilling from the source and not some primed racetrack.
During my next descale process, I will plug it in and run hot water through it and out the other open end and time how long it takes. If it is only 10 secs than a tank may get similar result and it has more to do with how it is all plumbed and insulated. And not so much the source of the heating? 10 sec delay is fine. A diff of minutes is another thing. I will run more tests and see if priming the fixture furthest helps any other fixtures in the house as they might be grabbing water from a main trunk somewhere and it is a win win. But if there is some manifold with home runs all run, or maybe the PEX is not insulated. I have not jumped to any conclusions, just asking around at this time. Thanks for your thoughts.
 

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I have used an under the sink cir pump at a diff location, and it was helpful. Good suggestion. Maybe I can look into that.
The sad part is that we are experiencing the delay in the kitchen which is about 6-8 feet from the Thankless water heater. Not sure if these lines are all home-runs as well, which would render the circ pump not as helpful to other fixtures. Just casue each run is pilling from the source and not some primed racetrack.
During my next descale process, I will plug it in and run hot water through it and out the other open end and time how long it takes. If it is only 10 secs than a tank may get similar result and it has more to do with how it is all plumbed and insulated. And not so much the source of the heating? 10 sec delay is fine. A diff of minutes is another thing. I will run more tests and see if priming the fixture furthest helps any other fixtures in the house as they might be grabbing water from a main trunk somewhere and it is a win win. But if there is some manifold with home runs all run, or maybe the PEX is not insulated. I have not jumped to any conclusions, just asking around at this time. Thanks for your thoughts.


Good luck with the descaling thing....

they really need pampering and attention
 

wwhitney

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If it is only 10 secs than a tank
Because of "cold water sandwich," you can measure these effects. Unless your tankless has an internal buffer tank (in which case misbehavior of the internal buffer tank controls could contribute to your delays). If not:

Start with the system quiescent (no hot water usage for a couple hours). Draw hot water from a fixture until it first gets hot; use a stopwatch to see how long that takes.

Now stop the hot water draw and wait 5 minutes without using any fixtures. Then start a new hot water draw and your stopwatch. You should get hot water immediately (stale in the pipes, maybe slightly cooler) until you get some cold water (that ran through the tankless during startup). The time that takes is 100% due to the pipe length between the water heater and your fixture. Then measure how long until hot water returns. That's your startup time.

The very first time you measure should be very close to the sum of the second two times.

Cheers, Wayne
 
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You got a recirculating pump for the descaling? What descaling solution did you use?
I pumped this solution through for 90 mins. 5 to 1 mix. So not the entire gallon. I have Vinegar to use on the next round.
 

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Reach4

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It's stayed red, for the entire 90 min process, however, it got darker red from what was coming out. Like redish dirty water. I observed no yellow color change,
Do you have a water softener? That would minimize liming up. City water that comes from a river also tends to be less hard that water that comes from wells.
 

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Do you have a water softener? That would minimize liming up. City water that comes from a river also tends to be less hard that water that comes from wells.


Darn, I did not think to ask that question which is sooo obvious.....

You have to have a water softener with a tankless heater or you will be pulling your hair out
deliming that thing twice yearly depending on the hardness of your water
 
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