How far can you run hot water lines?
Is it reasonable to run hot water 70 ft for a washer and basin and can I get by with 3/8″ copper tubing?
Here are the details.
A friend of mine bought a house with an addition(s).
The orginal house has a basement. It is on a hillside. On the side there was what was rummored to have been a garage. However, the drive would have had to rise 8 ft in 40 to get into it.
Anyway you can look at it from the newest addtion and see that it has joist about 4″ over a concrete slab. So all the wiring and plumbing must have been done before the sub-floor was put in.
In this addition is a powder room with a washer and dryer.
In front of this is a 2 story addition with a garage in the lower level. In the garage is a furnace, hot water heater and sub-pannel. The cold water, gas, and sub-pannel feed all run from the old basement into the in accessible part of the addtion and then into the garage.
When she moved in the hot water heater in the garage was not working and it was said to have “exploded”. I think that just the safety went off, but I have no idea what happend. Anyway the hot water heater has been removed and there is currently no hot water for the basin or washer.
The plubmer was out doing some other work and I wanted him to run a line from the hot water heater in the old basement. But we looked at it and thought that it was easiest to just replace the one in the garage.
But I had and electrican out to look at upgrading the serive and runing a new feeder to the sub-pannel (way undersized). That is also unaccessable, but he said that he could punch a new hole through the foundation between the old and new sections and fish it the 5-6 ft needed to get into the garage addtion.
I was wonder if I could do the same thing with copper tubing and if so could I get by with 3/8″ to reduce the time for the hot water to get there. The run will be about 50 ft from the old water heater to where the new one was in garage. And then another 20 ft to the washer and basin. Water usage will be mimimal. Most clothes washing is with warm and even cold water.
I prefer not to replace the WH for two reasons. First it will be used very little so the energy efficency will be poor. Secondly I am not sure about the venting and the gas lines. That can be fixed, but there are many problem areas in this house and I think that the efforts can be better spent fixing other things.
Replies
Code doesn't allow 3/8 tubing to service a washing machine and a powder room. Anyway fill on the WM would be very slow. I would run 1/2 with a 3/8 recirculation line and a small circulator (bronze internals) with the circulator controlled by a timed switch in the laundry room. When you need HW turn on the switch and you will have HW without a lot of wasted water. The timer on the switch will prevent an excessive loss of energy due to the recirculation.
Thanks for the reply.
I am not concerned about code here. Inspections are not required and it is not a safety issue.
But I don't think that a recirculation pump would work in this case. There is no access to anything in that powder room.. To run a return line it would have to be fished across about 20 ft span with a 4" of clearance.
If I go with 1/2" how much extra running of water will there before it get hot. I am not as concerned with the extra cost of the water as I am with gas to keep a new hot water heater runing just to wash hand few time a month.
If I take the 1/2 tubbing and put it through foundation into the "crawlspace" area about 4 ft from where I have access (and parrallel to that access) and push it in a 6-8 ft what is the lifely hood that I bend it out that 4 ft in a nice arch without kinking it? Basically the same thing that I will do to fish in the new feeder for the sub-pannel, but I know that the tubbing is not as forgiving.
Don't know about all that bending and stuff, but...
I have a Buderus boiler/water heater on one end of a full basement - 50 feet away on the first floor is a full bath. Total run of 3/4" copper is 62 feet to tub/sink. By actual measurement, I go through 5 1/4 gallons to get hot water.
Good Luck.
Well let's see, 1/2" tube is pretty close to 1/2" internal diameter so:
V= (3.1416*.25^2)*7.5/144 = 0.0102 gal/ft
(7.5 gal/cf and 144 in^2/ft^2)
so for 50 ft you would have to run a llittle over 0.5 gallons out. There will be some heat loss due to the mass of the tube and heat loss so probably a gallon or less. At 4 gpm it should take about 15 seconds.
Note the above about a measured time for 3/4" which seems a little excessive. Remember 3/4 holds over twice a s much water per foot and has 6 times the surface area for heat loss.
My kitchen sink run is probably about 40 ft and it takes about 15 seconds to get hot water.
Now the flow at this sink is not as strong, but I think that it is worth it from that asspect to at least give it a try. It is worth trying $25 of copper rather than $250 for a WH. And if it does take too long them not much is lost.
I will have to wait until we get the electrican to punch a hole to run the feeder and I have a better idea if I can fish some tubing through there.
There is a reason the code requires this though. A practical and valid reason that will bite you if you ignore it.
I don't disagree with the concept in the least. It it just when you have a building like this one that is so far off the map that that the idea it to end up with the best results based on what you have to work with.
But all that said I have been convinced that 3/8" is too small to be supply the washer, so I will go with 1/2" if it can be fished into place.
Why hasn't anyone mentioned PEX? Seems the ideal way to go. Come in a long, unbroken piece, loses a little less heat than copper. No bad solder joints or joint torqued during installation. 1/2" wouldn't have great flow over that distance, but decent. 3/8" doesn't cut, IMO. And 3/4" would give good flow, but have a long wait time. So I'd go 1/2" PEX.
Wet: I don't think the circ pump would erode the 3/8" line. Unless it is a constant flow rate pump (i.e. positive displacement like a piston pump). But circ pumps are centrifical and, as the pressure increases, the pump curve shows the flow will decrease. Maybe below the minimum flow of some pumps, but most circ pumps are pretty flexible in that regard. Given the max pressure of the small circ pumps used for instant hot loops, I'd expect a flow velocity around 3 or 4 feet per sec over that length. Actually under the 5 feet per second that pipes typically experience during max flow. This is a result of the pump being fairly low pressure and the long length of the run.
David Thomas Overlooking Cook Inlet in Kenai, Alaska
David
PEX would really be a lot easier to fish that the copper tubing.
I only need one connection at each end where I would tie into the hold and new systems. Both ends woulb in unfinished, accesable areas. It there a reliable compression connection that does not need special tooling?
Kitec uses one special tool that costs about 6 bucks.
I know that is what the charts show but out here in the real world I (we) are seeing a lot of it (erosion). Lots of debate going on about it.
What about the small "instant on" electric water heaters? What is the demand on basin and washer? Given the "no code enforcement" I suspect way out in the country, those newer front loading washing machines use about 1/4 of the water (less load on the septic system), and the instant hot water heater also means less septic loading (no need to run the water for a minute to wash up).
Tom
Tom
In general that would be an good idea, but not workable in this case.
The electrical makes the plumbing look like it should have been featured on the cover the Plumbers World as a model of the best practices in plumbing. And those electrical units take LOTS of power.
> I am not as concerned with the extra cost of the water as I am with gas to keep a new hot water heater runing just to wash hand few time a month.
If the sink is only used a few times a month, maybe the thing to do is step back a little farther and consider the overall design of the house. Do you even need this powder room? Could you walk to another bathroom instead, and use that space for something else? Is there a better place -- closer to the water heater -- for the laundry machines? Sometimes things get easier when you look at the big picture.
-- J.S.
Well I lost the battle, but won the war, or it the other way around.
I was over there today changing the locks and she told me that he had another friend get a new hot water heater and he delivered while I was there.
He ask her who was going to install it and she said I was.
I said that I would not. That the gas connections need to be reworked and I am not familar with that. That it needs a stand and that require reworking the vent pipe and the vent pipe "looks strange" as it is and I don't know anything about those.
I had already told here all of those thing last week.
While well over the 50 mark she has "teangage hearing syndrome". She only hears what she want to hear.
NEVER put a recirc pump on a 3/8" line as it will have wayyyy too much velocity which will erode the pipe.
Otherwise a good idea.
1/2nch line would be min . I have a bath and WD about 35 ft , and I have to wait for the hot water to get there on 1/2 line . 70 ft and 3/8? how long does it take? Any way it seems you have made your call it already .
Tim Mooney