Water pressure jumped to 85psi - while out of country

[Anon5656]

Hi, we are out of country and our smart water shut-off system is detecting a high-pressure of >80psi in the pipes. It's showing about >80 psi which is higher than the typical 50 to 60 psi seen in my house.

My house is in Seattle area.

To mitigate the issue, I shutoff the water to inside the house remotely and my friend checked the house and drained all the water in the house as a precaution.

But there is another problem.

The incoming water(from city) to my house forks into 2, one for the house water supply and the other for the fire sprinkler.
My smart water-shut off, that I used to shutoff water at my house, is only for the fork of the pipe, that feeds water to my house, but not to the fork that feeds to fire sprinkler

Therefor the high pressure is still sitting on the water, that feeds to the fork of the pipe to the fire sprinkler.

I've not done any testing for the water pressure to the fire sprinkler in the last 1.5 years.

Any thoughts/suggestions on what I should do next? Any contacts/recommendations would be appreciated. Worried that the fire sprinkler pipes might burst, but the pipes read 175psi.

I don’t know if my 2010’s office has a pressure reducing valve.

See pics, showing normal pressure at my house of 55, but currently reads 85psi.

 

[Reach4]

Did you leave the WH on?

 

[Sponsor]

 

[Anon5656]

Did you leave the WH on?

Yes water heater is ON

 

[Reach4]

Thermal expansion could have caused the elevated pressure if you have a tank water heater. The incoming water supply may have a check valve, and if you don't have a working thermal expansion tank, a little expansion of water could make a significant temperature rise.

Or it could be a change as to what the city provides, as I think you were thinking.

 

[Anon5656]

Should I turn the water heater to pilot mode (ie away mode), while I’m out on vacation? Will that help in maintaining the water pressure?

Yes it is a tank water heater without thermal expansion tank

 

[Jadnashua]

You need to determine if you have a closed or open water supply system. While some places require an expansion tank regardless, it's not a bad idea to have one. If you have a closed system, it is required to account for thermal expansion and to keep the pressure in check, otherwise, thermal expansion just pushes that excess out into the supply which is why utilities are installing check valves, to protect their system from possible contamination from inside of a dwelling where they have no control.

It's not unusual for the water pressure to change in the supply during the day, often peaking late at night as the utility might be trying to refill any water towers, and the usage goes down.

My guess is that your sprinkler system will be fine with the higher pressure.

I'll usually turn my WH off if I'm going to be away for an extended time. It's not a bad idea to turn it up to high, let it sit for a few hours, and flush the lines after it gets hot again and then return it to your normal temperature when you return.

 

[Jeff H Young]

I wouldn't be worried about 85 psi I might be curious or interested as to why , fire sprinklers should be no problem.
pipes do burst poor joints can fail etc it does happen not to all houses but occasional .
If you are on a " Closed system" once pressure rises its difficult to pressure to lower again without bleeding of some water, remember you have a relief valve so pressure shouldn't go that high but good to monitor and have an understanding of your system. enjoy your vacation I would not be alarmed at any of your provided info

 

[Anon5656]

On further investigation, it looks like leaving the water heater ON while away, somehow is correlated to high pressure. As soon as I turned water heater to Pilot/Vacation mode, the pressure is back to normal. Any thoughts on how water heater is related? Maybe a failed pressure relief valve ( I don't have a thermal expansion tank) ?

I'm still out on vacation and plan to investigate once I'm back.
Any suggestions on how I can investigate further before calling a plumber?

 

[Reach4]

Until the pressure rises to 150F, the pressure relief valve does not affect things. You don't want the pressure relief to be used as your normal pressure-limiting thing. You should also test your pressure relief with the lever, maybe annually. The test is to see if water comes out when you operate the lever, and that water flow stops when you release the lever.

For investigation/education, see if you currently have a thermal expansion tank. If yes, it has probably failed. If not, you want to get one. For other investigation, note what happens to the pressure after you take a hot or warm shower, and then stop using water for 10 or 20 minutes. No toilet flushing. No lavatory use. Expectation is that the pressure rises as cold water was brought in to replace the used hot water, and the water gets heated back to the set point. Expect the pressure rise after a shower to be bigger than what you saw while on vacation. The rise to 85 was just due to the water heating from cut-on temperature to the cut-off temperature. Presumably nobody was actually using hot water. So when you test, expect a much higher rise.

If you have a thermal expansion tank, it is still normal for the pressure to rise after a shower, but the expansion tank limits the pressure rise. You don't want the pressure to rise anywhere close to the 150 F level, but 100 or 120 psi is not alarming to better-informed people. As soon as somebody uses a faucet or you flush a toilet, the pressure will drop back down to the supply pressure.

 

[Jeff H Young]

85 psi is not alarming. if the system is open then its not thermal related I'm not 100 percent sure its thermal related . As I said enjoy your vacation don't worry set heater to vacation or pilot and monitor pressure if it never rises for days and then you turn heater on and it spikes you need x tank, but not an emergency at all

 

[Terry]

As water heats, it expands. When cooking on the stove, you might notice that boiling water will cause the lid to rise and let steam out. It's why steam boats had engineers to keep high temps from blowing up the ships.
I've also been reading that if oceans warm, they will expand too. That could be a problem for some coastal cities.
My entire neighbor has 92.5 PSI as it's pressure. I wound up installing a PRV to reduce the pressure and added a ball valve for a good clean shutoff.
Anything over 80 PSI is supposed to have a pressure reducer installed.

I think you're fine. When you're there, the pressure gets reduced as you're using it.

 

[Jeff H Young]

If pressure is lower and the increase in pressure is caused by thermal expansion causing it to spike over 80 psi that's no reason to get a PRV. That would be reason to get an expansion tank . Agree with Terry under a different situation of just high pressure