800Sqft home copper repipe job by a semi novice who needs advice

[gica69]

Hello to all, I have taken on the task of helping a friend repipe his new old home. I have some experience with copper soldering from when I did my house. Got that covered.
We have opened the walls to expose all of the pipes and wanted to make sure I am doing everything properly.
First off the main as it stands in the basement is 1 inch and reduced to 3/4" as it enters the house, from there some of the 3/4 turn to 1/2 for the cold and some stays the same at 3/4. Don't know if the 3/4 goes to the boiler as hot supply line or changes to 1/2 as well to the boiler. There are 2 baths each with 1 toilet, 1 bath or shower and 1 sink. In the kitchen, which is on the opposite side of the house, there is a sink and he wants to add a dish washer next to the sink. So need help with the piping on that dishwasher. The kitchen hot water goes across the living room from the boiler, the cold gets split from the main through a T the other goes to the boiler as I think 3/4 supply line as I stated before. Outside next to the boiler there is the washer and drier and he might relocate them don't know yet where. There is also a water source outside for the hose one the back side of the sink from the kitchen. Oh and the furthest bathroom is hot/cold supplied from the outside washer.
I know the boiler has to go because it looks old and hot water is yellowish, better safe than sorry. He was thinking either same type boiler with gas, or tankless. Maybe someone can advise.
Do I keep the pipes at the same sizes as the original design from the 40-50s or is the double reduction1" to 1/2" too much. Do I end up with 1/2 pipe size or should I do 3/4 reduced from the 1 inch main. Can that be more beneficial? Do not know the city water pressure to do the math on this. Thanks in advance and look forward to the coaching.

 

[Jadnashua]

It can generally work better to run 3/4" to an area that is using multiple things, and branch off with 1/2" to them. If they regularly use the tub and want it to fill as fast as possible, a 3/4" line to it along with a 3/4" valve might make sense, otherwise, 1/2" will work. Going from the supply to 1/2" then 3/4" won't give you the same volume since the 1/2" line will be the restriction. Most things in a home are flow restricted with the exception of a tub filler and a hose bib. It's generally not a good idea to feed more than 2 things from a 1/2" line - say a toilet and a bathroom vanity would be okay, but not to include the tub, which should come off the 3/4" line (often with it's own 1/2" line). With a repipe, you might be able to incorporate a passive hot water recirculation to shorten the time it takes to get hot water to a fixture. That requires careful placement and slope of the pipes. It may not be worth the effort in that small of a unit unless water is often in short supply...that would mean less down the drain while you wait for it to get warm.

Regarding replacing the boiler...generally, an indirect WH will be more efficient than a coil in the boiler as, most of the new boilers can handle a cold start, and with a good indirect, may only come on once or twice a day for the WH. On demand tankless, can work for some, but my preference is to avoid them...it may require a larger gas line, costs more upfront, and requires at least annual maintenance or it will start to degrade. And, it may not provide what you want if your incoming water temperatures are very low in the winter-time.

For a house that small, it may be tough finding a boiler small enough so that it is not way oversized (that causes inefficiencies and shortens the life) because it short cycles. If he has some bills on heating, there are ways to do a pretty accurate assessment of how big of a boiler it needs. Most old boilers are 2-3 or more times larger than they should be. You might be able to use a special WH tank as your home's boiler and water supply rather than a boiler and indirect.

 

[Sponsor]

 

[Reach4]

A basement in California? Somewhat rare. Nice.

Copper pipe is good where the water is not acidic.

https://terrylove.com/watersize.htm has some info you may find helpful.

If in doubt, go with the bigger pipes on cold. For hot water, avoid going too big. Bigger means more delay. If you use a hot water recirculation system that is demand or control driven vs continuous or timed, that is also a factor.

I know the boiler has to go because it looks old and hot water is yellowish, better safe than sorry. He was thinking either same type boiler with gas, or tankless. Maybe someone can advise.

I suggest that you post into the boiler forum. https://terrylove.com/forums/index.php?forums/boiler-forum.18/

Include house size, construction info including insulation. Indicate if you have natural gas or what fuel you will use.

 

[gica69]

It can generally work better to run 3/4" to an area that is using multiple things, and branch off with 1/2" to them. If they regularly use the tub and want it to fill as fast as possible, a 3/4" line to it along with a 3/4" valve might make sense, otherwise, 1/2" will work. Going from the supply to 1/2" then 3/4" won't give you the same volume since the 1/2" line will be the restriction. Most things in a home are flow restricted with the exception of a tub filler and a hose bib. It's generally not a good idea to feed more than 2 things from a 1/2" line - say a toilet and a bathroom vanity would be okay, but not to include the tub, which should come off the 3/4" line (often with it's own 1/2" line). With a repipe, you might be able to incorporate a passive hot water recirculation to shorten the time it takes to get hot water to a fixture. That requires careful placement and slope of the pipes. It may not be worth the effort in that small of a unit unless water is often in short supply...that would mean less down the drain while you wait for it to get warm.

Regarding replacing the boiler...generally, an indirect WH will be more efficient than a coil in the boiler as, most of the new boilers can handle a cold start, and with a good indirect, may only come on once or twice a day for the WH. On demand tankless, can work for some, but my preference is to avoid them...it may require a larger gas line, costs more upfront, and requires at least annual maintenance or it will start to degrade. And, it may not provide what you want if your incoming water temperatures are very low in the winter-time.

For a house that small, it may be tough finding a boiler small enough so that it is not way oversized (that causes inefficiencies and shortens the life) because it short cycles. If he has some bills on heating, there are ways to do a pretty accurate assessment of how big of a boiler it needs. Most old boilers are 2-3 or more times larger than they should be. You might be able to use a special WH tank as your home's boiler and water supply rather than a boiler and indirect.

So run 3/4 to the boiler and 3/4 from the boiler to the tub and use a 3/4 to 1/2 reducer at the fixture? Same for the cold water to the tub? And the rest just do 1/2? I will take pictures of the pipes and upload in a bit.
There is no insulation for the pipes. Also you mentioned an indirect water heater can you elaborate on that?
Found this as an alternative to recirculation option, but is it even needed in a small house? http://www.gothotwater.com/plumbing-pipe

 

[Reach4]

Just checking, when you say boiler, you mean a thing that heats the house, right? And does it also provide your hot water?

Or are you calling a standard water heater a boiler?

 

[gica69]

A basement in California? Somewhat rare. Nice.

Copper pipe is good where the water is not acidic.

https://terrylove.com/watersize.htm has some info you may find helpful.

If in doubt, go with the bigger pipes on cold. For hot water, avoid going too big. Bigger means more delay. If you use a hot water recirculation system that is demand or control driven vs continuous or timed, that is also a factor.



I suggest that you post into the boiler forum. https://terrylove.com/forums/index.php?forums/boiler-forum.18/

Include house size, construction info including insulation. Indicate if you have natural gas or what fuel you will use.

Can I double post so I can have it there also?
No insulation to the house or pipes yet but will add it. I believe the house is using natural gas from the city. Will add pics soon and some measurements.

 

[Reach4]

Can I double post so I can have it there also?
No insulation to the house or pipes yet but will add it. I believe the house is using natural gas from the city. Will add pics soon and some measurements.

You would not duplicate your post there. You would put info related to getting a boiler used for house heating.

EDIT: I suggest you edit your post there to put only the boiler-relevant info. Your long post with no paragraphing is challenging enough to read without the unrelated info.

 

[gica69]

Just checking, when you say boiler, you mean a thing that heats the house, right? And does it also provide your hot water?

Or are you calling a standard water heater a boiler?

I do mean the cylindrical boiler didn't know there's a difference, sorry.

 

[Reach4]

I do mean the cylindrical boiler didn't know there's a difference, sorry.

In the Western Hemisphere, a boiler is similar in function to a hot air furnace, except it distributes heat, transferred by water, from radiators or heat pipes.

A cylindrical device used just for heating water for faucets and showers is called a water heater.

 

[gica69]

In the Northern Hemisphere, a boiler is similar in function to a hot air furnace, except it distributes heat, transferred by water, from radiators or heat pipes.

A cylindrical device used just for heating water for faucets and showers is called a water heater.

OK I remember that back in Europe they heated the rooms with hot water running through metal radiators installed in every room, I was a kid back then so don't know if there were boilers in each home but it was a communist country back then and I think the city provided and charged for the hot water.
So water heater it is then. That's what I thought it was called, even though again back in Europe the cylindrical unit was also called a boiler, maybe improperly so

 

[Reach4]

OK I remember that back in Europe they heated the rooms with hot water running through metal radiators installed in every room, I was a kid back then so don't know if there were boilers in each home but it was a communist country back then and I think the city provided and charged for the hot water.
So water heater it is then. That's what I thought it was called, even though again back in Europe the cylindrical unit was also called a boiler, maybe improperly so

Not improper... I will amend my post above from Northern to Western.

 

[gica69]

So I took pictures from the main 1" which converts to 3/4 supply to the heater then 3/4 out that converts to 1/2 hot everywhere. The main1" to 3/4 also converts to 1/2 cold to everywhere but the water heater. I have to upload them to Dropbox though

 

[gica69]

More pics

 

[gica69]

Last set

 

[gica69]

Measurements
Water heater to kitchen hot 39ft
To bath one 8ft
To bath 2 38ft
Main cold to kitchen 45 ft
To bath1 25ft
To bath2 75ft

 

[Jadnashua]

If the WH is at one end, and not in the middle, then I'd run a 3/4" line and branch off into the kitchen with a 1/2" supply line, the same for bath one with two 1/2" branches - one for the tub, and a separate one for the toilet and lav, and the same thing for the second bathroom. You'd only need to extend the 3/4" to the tub if you want to fill it faster, and then, only if you want to spend the extra money to upgrade to a 3/4" valve; otherwise, a 1/2" branch to it off of the 3/4" trunk will work fine. Think a tree with a trunk and branches.

For hot water, the Copper institute calls for a maximum flow of 5fps maximum. ON a 1/2" pipe, that's 4gpm. On a 3/4" pipe, that's 8gpm. Going faster than that can cause the pipe to literally wear out from the inside, and it also can lead to hearing the water flow that can be annoying. Most things in a house are flow restricted to 2.5gpm or less except for tub filling (faster is nicer) and a hose bib for outside, so, a 1/2" line to them works as long as that same line doesn't have to try to feed multiple things at the same time (thus, the reason for having a bigger trunk).

Having a large enough trunk means you won't see the flow peter out if multiple water uses are occuring at the same time. A 1/2" line doesn't provide all that much flow if you keep to the industry guidelines. Yes, it can flow more, but that also causes more friction, which reduces the delivered dynamic pressure. The faster the flow, the less pressure you'll have at the end when using water, so a large pipe allows it to flow the same amount, slower, with less pressure drop. FWIW, with no flow, the pressure would be the same, but like a soda straw verses a fire hose...the fire hose will provide more water with less pressure loss.

 

[gica69]

That's how it was designed years ago the cold has 3/4 that turns into 1/2 to the kitchen bath1 through a T, and to bath 2 but the T starts from the washer and it's already at 1/2. Should I run 3/4 and T 1/2 at the washer continue the 3/4 and branch again for bath 2 inside?
And for the hot the kitchen and bath 2 are 40 ft away so should I use 3/4 all the way close to the rooms and branch out right at the room or close to the bath for the last 5-8 feet?

 

[Jadnashua]

Bath 1 likely contains three fixtures: tub/shower, toilet, sink and the kitchen may have a sink, dishwasher, and maybe an icemaker. Both the dishwasher and ice maker may not care, but if it was running when someone was taking a shower then someone used the sink...the 1/2" line would show a decrease in flow. Essentially, run 3/4" the length of the house, and tap off with 1/2" to the kitchen, each bathroom, and laundry from the 3/4" line. On a single tap from a 1/2" line, you don't really want more than two devices, and depending on the device, being a dedicated tap off of the 3/4" main trunk may be the best way to go. One really annoying and potentially dangerous situations is to be taking a nice shower and someone flushes a toilet or turns on some other water and you get a shot of extra hot water or things turn cold. An antiscald shower valve should help prevent that, but it won't do anything with losing pressure when the lines are too small. You don't want the flow to drop to a dribble when say you're doing a load of laundry and trying to take a shower...give them enough potential volume with a large trunk.

 

[gica69]

OK 3/4 through the house and the tubs get their own 1/2's while sink and toilet go on one separate 1/2. I assume that will be the case for both hot and cold. what is the max length I should have the 1/2 so I know where to split?
Also the scalding valves I found this page https://www.plumbingsupply.com/scald.html and this page https://terrylove.com/forums/index....304-kohler-rite-temp-bath-shower-valve.41581/
Do you know any that are better quality?
I want to install water stops right before the fixtures in case stuff goes bad down the line and I don't have to turn off the whole hose to repair, what do you suggest?
And on the water heater any one particular in mind?
Thanks

 

[Dana]

Modern kitchen sink faucets don't draw more than 2gpm these days, which is fine for 3/8" copper. The bath runs might need to be half-inch if it's shower, toilet & sink only, a "half bath" (sink + toilet ) can be 3/8", but if there's a tub to fill make it 3/4". Modern low-volume toilets have a fairly low gpm too.

Separate topic, but there doesn't appear to be any insulation in those exterior walls- what's the plan there?

The local ZIP code or city name, and the material stackup of the wall assembly from the exterior paint to the interior paint may dictate what the best approach is there. The dark color from the interior side view above looks like maybe it's just an asphalted felt tarpaper on those studs, with no structural sheathing(?) or perhaps asphalted fiberboard sheathing.

The exterior views look like its tongue & groove or perhaps ship-lap siding, but is there an intermediate layer between the siding and the studs other than tarpaper?