Jimbo
Plumber
CA plumbing code 708.3 says " any water system provided with a check valve, backflow preventer, or other normally closed device.......shall be provided with .....an expansion tank........"
An expansion tank - for water heater - California region.
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CA plumbing code 708.3 says " any water system provided with a check valve, backflow preventer, or other normally closed device.......shall be provided with .....an expansion tank........"
Bluebinky
Member
You are correct, as usual. No big deal, just us guys with less knowledge of the subject trying to learn whatever you guys who have a lot more are willing to share.
UPC 608.3 basically says any closed system needs a tank -- implying that an open system doesn't. However, 608.2 says clearly that a pressure regulator (the original topic) requires a tank, period. I did find where I read about the bypass exception -- the spiral-bound "Code Check Plumbing (2nd edition)" in the "water supply section.
I'm curious, any of you experts seen these books, and if so, what do you think? They are pretty clear and have helped me interpret the codes better. At least one of the inspectors here carries this series around so he can show pictures with code references as to how to correct a violation.
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Tom Sawyer
In the Trades
Well Ok but thats California code.
Tom Sawyer
In the Trades
Hackney plumbing
Homeowner
Jimbo
Plumber
Well I misspoke on the section; of course it is 608.3,not 708.3
The CA pluming code IS the UPC, with some mods by the Governator and Governor Moonbeam's boys.
We could argue the semantics all day long. Code books don't usually say what you "don't have to do". They say what you DO have to do, and in this case, ....... = XT
Ballvalve
General Engineering Contractor
finally an honest plumber that confirms that these tanks put their kids thru college - even when such tank is totally unneeded.
As to the guy with the burst water heater, his little tank would have likely burst first. They dont take 150 psi either. But a secondary relief valve set at 100PSI is just too easy for anyone to understand.
Jadnashua
Retired Defense Industry Engineer xxx
I, and others, totally understand that this would take care of the inevitable expansion created when heating water. That is not the point. Your 'solution' would regularly dump a little water somewhere. There is no need to dump that water. Plus, most of those things aren't designed to regular releases - especially if you have unsoftened water. Just like the T&P valve is not designed to be opened regularly to dump pressure from a closed system every time the WH turns on. An expansion tank is designed to take that ebb and flow of pressure variations on a daily, nearly constant basis. Yes, they do wear out, but they work for quite awhile without wetting things and wasting water or putting excess stress on the plumbing, valves, hoses, seals, etc.
If 80psi is considered the max safe pressure in a household, why would you regularly want it to get to your 100psi? A true closed system will rise enough to open a T&P valve at 150psi (or your 100psi with a relief valve), and an expansion tank will keep it at the regulator setting, never wavering.
Nice, even pressure, never getting above the prescribed maximums is what an expansion tank does and is what is called for in the plumbing codes and common sense which you seem to lack.
Now, if you want a secondary safety relief valve, by all means, install your relief valve. In a properly working system, it would never open and not have mineral deposit problems. And let's not get started again on a bypass in a PRV...all it does is limit the house pressure to the street pressure. The goal here is to maintain the desired PRV settin, not let it get to the street pressure ever again, especially not on a regular basis.
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Tom Sawyer
In the Trades
Waaaat mine kids shouldn't go to college Oyyyyyyy such a world
Bluebinky
Member
If you did your own plumbing, you could save enough, ...
Ballvalve
General Engineering Contractor
The watts valves are expressly designed to do so. I have a closed system, and my pressure never rises above 80 psi. Much depends on what sort of pipe you have and how much and how flexible. Mine has a few thousand feet of pex for radiant, so that is my expansion tank. The few drops of water you would get from the relief valve can go into a bucket and water your roses with. Or let the dog drink it.
Tom Sawyer
In the Trades
Here's how bad I've gotten. Tub faucet (Symmons S96-2) in my upstairs shower needed a new cartridge. I had one of the guys that works for me replace it.
Themp
Active Member
For 26 years...
I never had an expansion tank in a closed system. I knew the city had added them to code, but did not believe they did anything because I never had a problem that I could see. I do keep my water pressure low with a PRV at 40PSI. Anyway, from discussion on this message board I decided to purchase a pressure gauge that could keep track of the maximum pressure over time. It showed that the maximum was around 80 PSI. I then decided to watch what went on and sure enough after the water heater starting heating and no one used any water the pressure rose to around 80PSI and then dropped to 40PSI. So, something in the system was relieving that pressure. Not till my son who was visiting and sleeping in the downstairs bedroom and I was discussing the water pressure testing I was doing did he mention that during the night the toilet in the guest bedroom would hiss every so often. It turns out the fill valve was relieving the pressure into the overflow tube. So, for 26 years this had been going on. And I did not have a fill valve in the toilet that relieves pressure, I have seen these before.
Last January I put in the expansion tank, no more hissing at the toilet, and faucets behave better(no pressure to release). I just checked the pressure in the tank that I had set last year to 40PSI to match the house pressure and it was at 38PSI. I added 2PSI and will check again next year....
I never had an expansion tank in a closed system. I knew the city had added them to code, but did not believe they did anything because I never had a problem that I could see. I do keep my water pressure low with a PRV at 40PSI. Anyway, from discussion on this message board I decided to purchase a pressure gauge that could keep track of the maximum pressure over time. It showed that the maximum was around 80 PSI. I then decided to watch what went on and sure enough after the water heater starting heating and no one used any water the pressure rose to around 80PSI and then dropped to 40PSI. So, something in the system was relieving that pressure. Not till my son who was visiting and sleeping in the downstairs bedroom and I was discussing the water pressure testing I was doing did he mention that during the night the toilet in the guest bedroom would hiss every so often. It turns out the fill valve was relieving the pressure into the overflow tube. So, for 26 years this had been going on. And I did not have a fill valve in the toilet that relieves pressure, I have seen these before.
Last January I put in the expansion tank, no more hissing at the toilet, and faucets behave better(no pressure to release). I just checked the pressure in the tank that I had set last year to 40PSI to match the house pressure and it was at 38PSI. I added 2PSI and will check again next year....
Hackney plumbing
Homeowner
You really wanna see it in action......run all the hot water out of your water heater and start with a cold tank of water. The colder the better. For those that do not have a closed system.....turn the cold water off to the water heater and make sure you dont even have the slightest drip on the hot side. Now fire the heater off with a gauge screwed onto the water heater drain valve with it turn to the open position. Dont be surprised if the relief valve doesn't open at 150 psi.
Toolaholic
General Contractor Carpenter
I live in the Bay area of Ca. Expansion tanks are not required by code . I install them when T&P is blowing off. I think they're a good idea. Terry, I was told Wash. state Mandated them!
Is it only some cities ?
Is it only some cities ?
Jadnashua
Retired Defense Industry Engineer xxx
Where I live both an expansion tank and a tempering valve are required to pass any WH installation inspection, regardless of whether it is a closed system or not.
Gary Swart
In the Trades
It must be by city because it is not required in my city. I installed on after I installed my PRV and suddenly the T/P began to open every time the water heater came on. Local HD had them, but the local Lowe's had never heard of them! I check their shelves not too long ago and they still are not stocked.
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