Question to the homeowners out there

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vkhosid

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Hey guys,

I've got a bit of a question for you. I just moved into a house a few weeks ago that was constructed less than one year ago. Although the house (overall) is fine, my gripe is with the hot water. In an effort to save a buck, the developer put in a tankless water heater at one end (of a long, skinny floor plan), and didn't put in a hot water return loop for a re-circ system. Now, when turning on the water in the master shower, it takes roughly 5-6 minutes for hot water to reach the fixture. I've settled on installing a re-circ pump with a cross-over at the furthest fixtures, but that's where I've hit a roadblock. Ideally, I'd like a re-circ pump with an aquastat that keeps track of the water temp at the farthest point in the line, and kicks on when the temp falls below a certain temp. However, I've only seen pumps that are demand-controlled, and require you to turn on a (any) fixture for a moment to get the process started. The other option I've found would be a "timer" re-circ pump. But, I haven't seen any that are compatible with tankless water heaters.

To throw a wrench into this, the way the plumbing is layed out, I have two fixtures that could qualify as "the furthest fixture"....the master bath and the kitchen sink. If any of you know of a re-circ pump that would accommodate two senors (one in the master bath, and the other in the kitchen) that would be ideal.

Thanks in advance for the suggestions.
 
Being that it is new, I suggest having the builder resolve the problem to your satisfaction.
 
Or just replace the feed with 1" pipe and insulate it. Run the tub for 10 sec to get the flow at max.
 
mscard88 said:
Being that it is new, I suggest having the builder resolve the problem to your satisfaction.
Click to expand...

The issue is that there isn't a "problem".....there's no requirement for a hot water return line to be built into the design...it's certainly a good idea, but not a requirement. So, the house is built to code...the 5 minute wait time is an "inconvenience". Though I am working with the builder. I'm trying to give some options of possible solutions without having to tear down the walls to add in a return line.

paflyer said:
Or just replace the feed with 1" pipe and insulate it. Run the tub for 10 sec to get the flow at max.
Click to expand...

That wouldn't be a practical solution, as the sheetrock would have to be removed to replace the pipework.
 
Have you considered relocating the tankless water heater closer to the master bathroom?
 
Anthony said:
Have you considered relocating the tankless water heater closer to the master bathroom?
Click to expand...

That wouldn't make much sense either because I'd have to run the gas piping to supply the water heater wherever I put it...which will require tearing down walls.


Zeldman said:
Wow... you have an indoor outhouse..???? You must be a rich pilot......;)
Click to expand...

The outhouse is outside....I prefer to wash my hands indoors, like a gentleman!
 
Tankless wh and recirculating lines do not go together...unless you want $1000 electric bill. Either put a standard 50-80 gal wh and recirculating line on a timer or add another tankless on opposite end. Add additional insulation to tank and 3/4" thick armaflex to all hot water lines The builder should have put two in.
 
I have had for 20 years, a recirc pump running continuously at my 1800sf home.
I would do that again; forget the timer/temp controller.
I would be ready to ditch the on demand water heater too.
 
You are also limited to the volume of water your low flow shower head can run for the hot water to catch up (hence your 5-6 min lag). Although it is a complete waste of water and does not really solve your issue...you can run both the bath which is not throttled and sink both at full hot which will speed up the flow of the hot water to the shower head from the water heater.

I have to do that in hotels all the time.
 
vkhosid said:
Hey guys,

I've got a bit of a question for you. I just moved into a house a few weeks ago that was constructed less than one year ago. Although the house (overall) is fine, my gripe is with the hot water. In an effort to save a buck, the developer put in a tankless water heater at one end (of a long, skinny floor plan), and didn't put in a hot water return loop for a re-circ system. Now, when turning on the water in the master shower, it takes roughly 5-6 minutes for hot water to reach the fixture. I've settled on installing a re-circ pump with a cross-over at the furthest fixtures, but that's where I've hit a roadblock. Ideally, I'd like a re-circ pump with an aquastat that keeps track of the water temp at the farthest point in the line, and kicks on when the temp falls below a certain temp. However, I've only seen pumps that are demand-controlled, and require you to turn on a (any) fixture for a moment to get the process started. The other option I've found would be a "timer" re-circ pump. But, I haven't seen any that are compatible with tankless water heaters.

To throw a wrench into this, the way the plumbing is layed out, I have two fixtures that could qualify as "the furthest fixture"....the master bath and the kitchen sink. If any of you know of a re-circ pump that would accommodate two senors (one in the master bath, and the other in the kitchen) that would be ideal.

Thanks in advance for the suggestions.
Click to expand...
I dont know nuthin about recirc pumps so I cant help you there. Poor design but I guess you're stuck with it. 5-6 minutes seems to long. Are you running it through the shower head? Those things are all pretty low flow. If its a tub also, run it through the tub tap until it warms up. Try the head on its maximum flow rate and then adjust it down when it gets warm. Open the hot water tap on the lavatory sink until it warms up.

Or just get a Kramer
 
What would you circle it into if you use a recirc pump with a tankless water heater ?

Isn't the idea of those things that you don't have a volume of water that has to be maintained at temperature and that they only kick in if they sense demand for hot water ?
 
If you're looking for instant hot water for washing hands, face etc, how about a supplemental electric on-demand under the sink?
 
Do what most people do. Turn on the hot water, go to the bathroom, then wash your hands, shower or wash your hair.
 
RV10flyer said:
Tankless wh and recirculating lines do not go together...unless you want $1000 electric bill. Either put a standard 50-80 gal wh and recirculating line on a timer or add another tankless on opposite end. Add additional insulation to tank and 3/4" thick armaflex to all hot water lines The builder should have put two in.
Click to expand...

They absolutely do. As a matter of fact, many manufacturers (such as Rinnai, Navien, etc) pre-wire/install re-circ pumps in most/all their models. You may be thinking that the re-circ pump runs constantly...that's not the case. There's a switch or timer that triggers the start/stop of the pump.

weilke said:
What would you circle it into if you use a recirc pump with a tankless water heater ?

Isn't the idea of those things that you don't have a volume of water that has to be maintained at temperature and that they only kick in if they sense demand for hot water ?
Click to expand...

Well, ideally with a hot-water return line, you'd push the water through the "return" line into the cold-water "in" connection at the tankless water heater. However, for instances where the re-circ pump is an "after-though", there's a cross-over at the last fixture which pushes the water back through the cold-water supply line back into the tankless water heater as well.
 
Regarding all the comments about the low-flow shower heads....yes, I've thought of that as well, but haven't yet had the chance to take off the shower head and remove the water metering device...(another issue is that the shower feels like a drizzle, instead of an actual shower).
 
If you have the space, I'd consider putting in a small electric water heater under the sink or in a nearby closet. It would give you the short-term hot water until the tankless system reaches the bathroom.
 
Are you absolutely sure that the heater kicks on the moment the water starts flowing?
 
RV10flyer said:
Tankless wh and recirculating lines do not go together...unless you want $1000 electric bill. Either put a standard 50-80 gal wh and recirculating line on a timer or add another tankless on opposite end. Add additional insulation to tank and 3/4" thick armaflex to all hot water lines The builder should have put two in.
Click to expand...
That's kind of what I was thinking, we put a recirculating system in our house when we built it, it's great, but the idea of tank less is they don't have a tank to send the water back to. :) But, I am no plumber!! :rolleyes:
 
I have a new construction home and we too have the tankless wh. Love it, it never runs cold...ever. Mine is by the master so the kitchen and the master bath gets its water pretty fast. However, the vanities in the master bath are slow to get hw. I mean slow and I think its because the flow is low on it. So if I crack the tub faucet and the vanity faucet I get hot water pretty quickly. Its a small price to pay to not have a tank. I love not have a tank that gets cold!

And with that for those that ever followed my contractor thread, we moved in and LOVE our house...okay sorry for the thread drift.
 
I love the tankless heater in my cabin,I never have to worry about running out of hot water... but it's a small cabin so there's never much wait. In my house, I have a large tank heater at one end of the house, and a small electric heater in the master bathroom at the other end, no waiting.
 
Zeldman said:
Wow... you have an indoor outhouse..???? You must be a rich pilot......;)
Click to expand...


Freakin third world problem fer sure. ;) Reminds me of the meme with the little African kid looking at an American woman captioned:

You mean to tell me that you have so much fresh water that you **** in it?
 
vkhosid said:
They absolutely do. As a matter of fact, many manufacturers (such as Rinnai, Navien, etc) pre-wire/install re-circ pumps in most/all their models. You may be thinking that the re-circ pump runs constantly...that's not the case. There's a switch or timer that triggers the start/stop of the pump.



Well, ideally with a hot-water return line, you'd push the water through the "return" line into the cold-water "in" connection at the tankless water heater. However, for instances where the re-circ pump is an "after-though", there's a cross-over at the last fixture which pushes the water back through the cold-water supply line back into the tankless water heater as well.
Click to expand...
Well, if one is trying to maintain 120F water using a thermistor sensor, attached to a circuit board that turns pump on and off as well as heating elements, no thanks on the complexity and power consumption. I would rather just have my 80 gal tank or two 40 gal tanks(one on each end). As far as putting hot water back into cold, hopefully it cycles off before it fills my cold water line. Otherwise, I would have to run cold water to brush my teeth.

I have many hvac customers and family that installed those tankless wh. They switched back due to expensive power bills and numerous breakdowns.
 
Shawn said:
You are also limited to the volume of water your low flow shower head can run for the hot water to catch up (hence your 5-6 min lag). Although it is a complete waste of water and does not really solve your issue...you can run both the bath which is not throttled and sink both at full hot which will speed up the flow of the hot water to the shower head from the water heater.

I have to do that in hotels all the time.
Click to expand...
Yep, that's what I suggested; have to do the same, since master bath is on 2nd floor on opposite side of the house, prob 85' of 3/4" pipe in between. If you run the shower or sink, the EPA-mandated flow control will take forever.
 
RV10flyer said:
Well, if one is trying to maintain 120F water using a thermistor sensor, attached to a circuit board that turns pump on and off as well as heating elements, no thanks on the complexity and power consumption. I would rather just have my 80 gal tank or two 40 gal tanks(one on each end). As far as putting hot water back into cold, hopefully it cycles off before it fills my cold water line. Otherwise, I would have to run cold water to brush my teeth.

I have many hvac customers and family that installed those tankless wh. They switched back due to expensive power bills and numerous breakdowns.
Click to expand...
Standard practice is for gas-powered tankless water heaters for single family residences. At least in california.
 
Ventucky Red said:
Probably has a cement pond too...
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ScreenShot6423_thumb.jpg
 
The tankless ones work well in a non-freezing place like FL where you can stick them on an outside wall right by the bathroom.
I had one 20 years ago. Hated it.
 
85' of 3/4" type m tubing holds about 2.3 gallons of water. Of course you need to heat all of that water line too.
 
We had a tankless gas wh in Germany from 89-91. I bet the plumber worked on it 10 times. High efficiency does not always equal saving money in the end. HVAC systems that I sell are similar. They save electricity while they are working. When they break down out of warranty, they can cost a small fortune to repair.
 
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RV10flyer said:
85' of 3/4" type m tubing holds about 2.3 gallons of water. Of course you need to heat all of that water line too.
Click to expand...
Yep. I bought the house used, hence no say in where the equipment was installed.
 
RV10flyer said:
We had a tankless gas wh in Germany from 89-91. I bet the plumber worked on it 10 times. High efficiency does not always equal saving money in the end. HVAC systems that I sell are similar.
Click to expand...
But it made some people feel good to demand them as standard.
 
RV10flyer said:
We had a tankless gas wh in Germany from 89-91. I bet the plumber worked on it 10 times. High efficiency does not always equal saving money in the end. HVAC systems that I sell are similar.
Click to expand...

paflyer said:
But it made some people feel good to demand them as standard.
Click to expand...

Perhaps...but i'm willing to bet that perhaps one or two things has changed technology-wise in the last THIRTY years? That's like saying, "I'm not buying a Ford this year because of their Pinto fiasco."
 
Good luck with whatever your choice. Let us know. Congrats on the new home.
 
vkhosid said:
Perhaps...but i'm willing to bet that perhaps one or two things has changed technology-wise in the last THIRTY years? That's like saying, "I'm not buying a Ford this year because of their Pinto fiasco."
Click to expand...

Yeah, exactly. Tankless is the greatest thing ever for us long-shower guys. It's funny that way. Tankless is a more efficient design, so should be an energy saver. But a significant portion of the time the only thing that gets me out of the shower is that I'm running out of hot water!
 
Here is a little video I found...

 
If you add a motherboard to something, it must be better. Right?
 
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