Water takes 30-40 secs for bathroom showers to get hot after new Hot Water heater

[hj]

Water is lazy, and it will flow the direction of least resistance. Without a check valve the direct line to its connection point, usually the furthest shower or tub, is MUCH more direct than the normal hot water path, so when you turn on THAT faucet the lazy water decides to flow through the recirculation line to get there. The initial water is hot, but soon the replacement cold water starts to flow through that same line. When you open MORE faucets at the end , the greater demand overwhelms the smaller circulation line and hot water starts flowing the right way. This ALWAYS happens, unless there is a check valve to prevent water from flowing through the circulation line, which is why I said, "it MUST have a check valve".

 

[lesjanes]

Water is lazy, and it will flow the direction of least resistance. Without a check valve the direct line to its connection point, usually the furthest shower or tub, is MUCH more direct than the normal hot water path, so when you turn on THAT faucet the lazy water decides to flow through the recirculation line to get there. The initial water is hot, but soon the replacement cold water starts to flow through that same line. When you open MORE faucets at the end , the greater demand overwhelms the smaller circulation line and hot water starts flowing the right way. This ALWAYS happens, unless there is a check valve to prevent water from flowing through the circulation line, which is why I said, "it MUST have a check valve".

Thanks HJ. everything you say makes sense to me and seems to explain why I only get warm water at the kitchen faucet until others faucets are open.

The only reason I can think of why the previous set up got away without check valve was the size of the tank and temperature set at highest level. I.e. a lot of very hot water at top of tank rising above and through the pipes.

 

[Sponsor]

 

[hj]

The size of the water heater has absolutely nothing to do with it. The size of the pipes, and their routing, is the only factor as to whether it works or not.

 

[Reach4]

Everybody agrees that you need to get rid of the hot side heat trap. I would do that before anything else. I wonder if that would be a simple DIY thing. It looks like you have a union-looking fitting at the top of the nipple.

 

[hj]

I would not say "every one agrees" about the heat trap, although it removing it COULD ease the problem, since it is another point of restriction that can make backflowing through the circulation line more desirable to the "lazy water" that is trying to get to the faucet the easiest way possible. BUT, it does not eliminate the need for a check valve. NOTHING will do that.

 

[lesjanes]

Everybody agrees that you need to get rid of the hot side heat trap. I would do that before anything else. I wonder if that would be a simple DIY thing. It looks like you have a union-looking fitting at the top of the nipple.

Reach, plumber coming today to remove heat trap. And that is all at this point. It will be a decent experiment to see if that helps or if I will also need to put in a check valve later.

The previous set up did not have a check valve. But now there are a couple of extra elbows on the return side. Not sure if that will be enough to affect the flow. I will keep you posted on results....

 

[Jadnashua]

According to the copper tubing institute, on 1/2" copper pipe, each 90-degree elbow is the equivalent of an extra foot of pipe, and if when they re-routed things, if any of the sections have a reverse or flat section opposing the desired flow direction, it can disrupt your convection loop. But, that extra friction is quite small...it doesn't take much in aggregate to disrupt it, though.

 

[lesjanes]

According to the copper tubing institute, on 1/2" copper pipe, each 90-degree elbow is the equivalent of an extra foot of pipe, and if when they re-routed things, if any of the sections have a reverse or flat section opposing the desired flow direction, it can disrupt your convection loop. But, that extra friction is quite small...it doesn't take much in aggregate to disrupt it, though.

Ok, Here are the results of the "experiment".... Heat Trap removed....nearly instant heat through out the house for 1st morning shower! It appears the convection loop is working without a check valve.

I am a bit surprised that the convection flow has apparently returned to the way it was. The new tank, extra turns, etc.. put a little doubt in mind that merely removing the heat trap was all that was needed.

Thanks for all the advice, tips, opinions on this board. I am not a plumber, but can understand/fix most typical home plumbing issues. All the advice here helped make me an educated consumer. Thank you!

 

[hj]

If it works, it will be "in spite" of not having a check valve. It will not be working "properly" but might be good enough that you do not know the difference. But, since it is not my system, or my problem to get it working, do whatever you wish to.

 

[Runs with Bison]

Out of curiosity, what is your baseline natural gas usage per month (in therms, CCF or however you are billed for quantity, not $.) I expect this natural convection to come at a substantial annual cost. Keeping lines continuously hot, especially if uninsulated requires energy. For perspective, family of 4 with nat. gas water heater in Midwest we used 10 CCF/month in summer and ~15 CCF/month in midwinter. Of that, 3 CCF/month was due to standby losses of the tank (determined by readings before and after extended vacations--consistent on multiple checks.)

 

[lesjanes]

Out of curiosity, what is your baseline natural gas usage per month (in therms, CCF or however you are billed for quantity, not $.) I expect this natural convection to come at a substantial annual cost. Keeping lines continuously hot, especially if uninsulated requires energy. For perspective, family of 4 with nat. gas water heater in Midwest we used 10 CCF/month in summer and ~15 CCF/month in midwinter. Of that, 3 CCF/month was due to standby losses of the tank (determined by readings before and after extended vacations--consistent on multiple checks.)

Well, it is kind of an apples to oranges comparison. I now have a new energy efficient water heater that replaced a 28 year old one. So to compare last years therms would not be totally fair. Though I think your therm usage appears quite a bit lower than ours. (though all lines are insulated)

My main preference for instant hot water is more in line of wasted water and wear and tear. We are on well and septic with a water softener. Running water 35-45 seconds for each shower 1) makes my well pump run a little more, 2) consumes more salt in softener, 3) adds more water to a septic field (and we are in a low area where sump runs frequently)

So overall, I consider it an energy and resource trade off. Undoubtedly I consume a bit more natural gas. But I save a little on the electric side since my pump and water softener run slightly less often. And I hate wasting water, a pet peeve of mine. With natural gas prices relatively low the last few years and it being one of the cleanest forms of energy, I am ok with using a little more nat gas and sparing the other aspects mentioned.

 

[Runs with Bison]

Well, it is kind of an apples to oranges comparison. I now have a new energy efficient water heater that replaced a 28 year old one. So to compare last years therms would not be totally fair. Though I think your therm usage appears quite a bit lower than ours. (though all lines are insulated)

My main preference for instant hot water is more in line of wasted water and wear and tear. We are on well and septic with a water softener. Running water 35-45 seconds for each shower 1) makes my well pump run a little more, 2) consumes more salt in softener, 3) adds more water to a septic field (and we are in a low area where sump runs frequently)

So overall, I consider it an energy and resource trade off. Undoubtedly I consume a bit more natural gas. But I save a little on the electric side since my pump and water softener run slightly less often. And I hate wasting water, a pet peeve of mine. With natural gas prices relatively low the last few years and it being one of the cleanest forms of energy, I am ok with using a little more nat gas and sparing the other aspects mentioned.

Can't speak to a water softener as I've never used one, even when our water was incredibly hard well water coming from Ozark limestone...as a teen/early twenties I changed a lot of water heater elements at the barn and in the house.

Short run times to warm don't waste much water, and our use is typically about 33 gal/day per person. With a water heater tank and insulated lines it wasn't much of an issue. It is more of a concern with tankless and these infernal "home run" manifold systems that waste several times as much water for the same task. I'm going to eliminate some of the wasteful dedicated lines to improve preheating for long runs to the dishwasher, etc. The system designers didn't know squat about how to use a system efficiently or effectively.

Well water demand is a bigger issue than municipal water pulled primary from a river drainage pump field (former home.) However, at 33 gal/day per person (there) I doubt many do/did better.

While I prefer natural gas to other fossil fuels, I also recognize that unlike water it is non-renewable.

 

[David M 20817]

I'd like to just confirm in my case that removing the hot and cold heat traps fixed an issue where new water heater 'broke' the gravity hot water re-circulation loop. After the plumber installed a new hot water heater, we were getting very odd behavior. Long story short....the heat traps were creating enough impedance in the line that when a hot tap was opened in the house, the cold water was back flowing through the recirc loop to the faucet, mixing with the hot water to create luke warm water. The heat traps (both hot and cold) changed the path of least resistance when a hot water tap was opened, allowing the cold water to backtrack the recirc loop. Removing the heat traps fixed the issue. The plumber had also added a 90 degree turn in some of the cold water intake between the recirc loop and the water heater and that MIGHT have added to the problem. The plumber removed the heat traps and the 90 degree turn so can never be 100% sure which was the root cause but I'm convinced it was the heat traps.

 

[hj]

Blunt reply. It could NOT have worked "properly" without a check valve. Fluid dynamics CANNOT be altered, or turned off.