First time home owner - plumbing question.

Have you checked the temp setting on the hot water heater? Oil or electric for the hot water heater? Im no plumber but it tends to take a while for my hot water to heat up as well. i also haev a filtration system for radon, a 2 stage carbon filter.

-- "there aren’t many hand tools as awe-inspiring as the #8 jointer. I mean, it just reeks of cast iron heft and hubris" - Smitty

The water heaters are both natural gas. The temps seem fine as when it gets hot, it’s plenty hot. The filtration system is a reverse osmosis (rain soft). Another thing I forgot to mention is that when I finally get the water nice and hot, and then turn off the faucet for 2 or 3 minutes, and turn the faucet back on hot, the water is ice cold for another 3 minutes until it warms up. And when I say that it takes 3 minutes to get hot out of any faucet, I mean that the water is cold cold cold – not warming up gradually and then very quickly goes from cold to warm to hot.

-- IZZZZZI BoB IZZZZZI

Also, the water pressure is great through the entire house. So while I’m thinking it’s the old galvanized piping, that makes me wonder if it is actually the culprit.

-- IZZZZZI BoB IZZZZZI

Have you tried to insulate the hot water pipes. This may not do much but it couldn’t hurt. Congratulations on your new home.

-- Joe from Western Ma.... Peace to all

I’m no plumber either. But, it sounds like the hot water is flowing back to the tank when the water is shut off. Or, at least, colder water is somehow replacing the hot in the just used piping. My guess is that you have overhead piping. You might consider an anti siphon valve, or two. Placement would depend on the piping layout.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

Being a former licensed plumber this is where I can help. First, you said the pipes were galvanized steel, is that the drains? I hope so, since you can’t use them for supply, your water would be very rusty and a 2” pipe by now would have about 1/2” or less than that for water to travel through. The pipes should be copper and wrapped or insulated. They could also be PVC it all depends on the local codes in your area. I assume with two water heaters ther are 2 zones in the house, make sure they are both water heaters, one might be a holding tank. There are several ways to fix the wait for hot water.
1. The system needs some inline circulating pumps, that we keep the water from being cold for 3 minutes before you get hot. Also I have seen some installs where the pipes were run on the north wall and uninsulated making the water temp drop rapidly.
2. Instant hot water heaters, the price of these have come down so you could put on at every bathroom/kitchen so there would be no wait. Still the circulating pumps are the correct way to go.

Congratulations on the new house. I bought my first house 2.5 years ago, a big fixer upper, took 2 months before we could even inhabit it. Replaced alll the plumbing, electrical and I am doing the kitchen remodel now. If your looking for projects, a house is one of the best sources for that. My house was built in 1952 and no updates until we moved in, original owner passed away and the family wanted to sell it quick, so we got the avocado fridge and wall to wall printed carpet soaked with 58 years of dog urine. That’s the first thing I did, ripped out all the carpets and the subfloor and installed new sub and hardwood floors throughout the house.

One last tip, back years ago people did not know the correct way to fix some problems, and did what they could to correct it. Most of my drains were repaired with plaster & caulk so no matter what drained it never all went to the sewer system. Keep an eye out for weird fixes.

-- Martin ....always count the number of fingers you have before, and after using the saw.

Call a liscensed plumber and have him check the fittings on top of the water heaters for internal build up or blocked fittings(very common in galvanized piping.)

32 years in the plumbing and pipefitting industry.

-- Don't rollerskate in a buffalo herd

If you remove the drain valve from the water heater, replace it with a nipple and tee(brass) so that you can put the drain valve back in the “run” of the tee you will be able to create a recirculating system via “thermal siphon”. You must have the branch of the tee pointing up. Install a full port ball valve at that point. Then you run a 1/2” line to the hot water line the furthest point where you can tee into it. Now, the line you run must have upward pitch all the way to that point. This is how you can get “recirc” hot water without the use if an expensive bronze body or stainless circulator pump. You can do it in PEX if your soldering skills are lacking. You might want to do a layout to see how many feet of PEX it would take to replace all that old galv pipe. You can do the cold in blue and the hot in red. Now they make valve manifolds so that you can start at it and make”home runs” from point”A” to “B” with no elbows or fittings except for a tee that you cut in for a branch line to a usage point. A few screws and straps and you’ll be brandy new. Sadly the skills of the torch are slipping by the wayside. Copper’s to damned expensive anymore. They’re even doing hydronic heating systems in PEX. What’s a poor old fitter to do? When I saw my first fire protection system in orange plastic pipe I knew the “end was near”.

The same number Howie as a journeyman steam fitter/HVAC/R UA Local 13.

-- OK, who's the wise guy that shrunk the plywood?

UA 189 retired
Pex is considered the way to go now a days.
One of the problems I used to run into on older houses (and some new ones) whoever plumbed them did so with all 1/2 mains. Thus it creates problems like you describe getting water to a useage point. Good practice requires 3/4 mains and 1/2 branches to the fixtures.
Galvanized pipe was used in a lot of older homes. It has a tendency to build up on the inside depending on the mineral content of water(and electrolisis) in certain areas. I’ve seen it where you could hardly stick a #2 pencil in the pipe.
Again, get a liscensed plumber to check it out. Not some fly by night.
Here’s another food for thought. I had a guy that lived in a sub division and complained he had never had very good volume. Long story short, his main line shut off was only 1/2 open….that effects everything including your hot water system.

-- Don't rollerskate in a buffalo herd

Galvanized pipe was used in virtually all CA home construction in the ‘60’s and ‘70’s. Copper repiping is one of the most common plumbing company services. You probably need to do a repipe in copper. You’ll be amazed to see how badly those galvy pipes are choked down. – lol

-- Adversity doesn't build character...................it reveals it.

Howdy “brother”! I “hit the silk” in ‘05. Just got my first SS check. Life is GOOD isn’t it? I concur with the 3/4 mains and 1/2 branch lines. PEX will never experience build up. Though they have these new “Shark” fittings for PEX, myself I like the ferrule and the crimper. Once that crimps over the barb, it’s there for the ages.

-- OK, who's the wise guy that shrunk the plywood?

Check with the local AHJ about using PEX. It isn’t code in some jurisdictions.

-- Adversity doesn't build character...................it reveals it.

The problem is the length of pipe between the heater and the faucet. When not flowing, the water in the pipe cools off and stays that way until replaced by fresh HOT water from the heater. The solution , albeit an expensive one, is to install on-demand heaters close to each faucet. Bocsh and several others make them.
The really expensive part is the cost of wiring. The require at least 10 gauge wiring and big breakers.

Steve

-- Steve in KY. 44 years so far with my lovely bride. Think I'll keep her.

Not a plumber exactly, but I am an engineer and have done some pretty substantial plumbing jobs.
I do know that Hot is on the left, Cold is on the right, and Sh.t runs down hill. That’s all you need to know, right?

Seriously, as mentioned above, the run is probably too long from the water heater(s) to the faucet.
You say you have good flow so build-up doesn’t sound like the problem. But galvanized pipe has a lot of mass over a long run that sucks the heat out of the water untill the pipe gets hot. But then that doesn’t explain why it gets cold and has to heat up again in just a few minutes. That mass should retain heat for a while also.

I’d be suspicious of two heaters and how, or if, they are interconnected. You may be getting some kind of back flow through this connection, if it exists. Maybe one heater is not working. Check the hot “Out” pipe on both to make sure they are hot after opening a faucet.

Is that house built on a slab, or is it a crawl space or basement below?

Instant water heaters are the way to go if you do re-plumb. Check your code, but CPVC is accepted in Tennessee and is so easy to install a caveman could do it. PEX is great stuff as well.

I installed two water heaters in my house, but kept the circuits separate. One is directly below the bathrooms and the other is below the kitchen. With no more than 8ft to any faucet I have almost instant hot water. I did provide a crossover pipe with valves so I can shut either heater off if it fails and still have hot water from the other one. If someone opened the crossover valve without shutting off one of the heaters I am not sure how it would act.

-- Michael :-{| Diapers and politicians both need to be changed often; and for the same reason.

Funny that you just posted this. Last week’s episode of Ask this Old House had the exact same problem. Rich T. the plumber solved the issue with a pump installed below a sink that was on the other end of the house from the instant hot water heater. It requires an electric outlet and some changing of the plumbing, but in effect you hit the switch for the pump to come on and it pulls the cold from the hot water line back into the cold water side. When the pump stops (it has a thermostat that senses water temp and it seemed take only several seconds,) he turned on the hot and it was right there. No wasting of cold water running for several minutes to drain the cold form the long hot water line.

Since the pump was installed at the first fixture on the second floor, the adjacent bathroom and shower and tubs all benefitted from it. I’m sure if you go on line to Ask this old house you can actually watch the episode and get the actual name of this pump and see how it was plumbed. Hope this helps.

Ken

-- • "I have noticed that nothing I have never said ever did me any harm."....... Calvin Coolidge