1" down to 3/4" Pressure Reducer

[jryan51]

I have extremely high water pressure - 117# to 120#.

Somehow when the houses were built 7 years ago a pressure reducer wasn't required.

Last night the town flushed my area of town which apparently caused a spike and the relief valve on my hot water tank (and 3 neighbors) let go and flooded the basements.

So…it's time to put in a reducer in.

Hopefully this is a simple question. I already have a Wilkins 3/4 reducer on hand.

The line feeding the house is 1" after the meter. Is it o.k. just to put a reducer in to bring the line down to 3/4" put the Wilkins in and then step back up to the 1" line?

I don't believe it makes a difference over that short run but I just wanted to pass it by the experts as to potential issues.

Here's a link to what I have.

http://www.sprinkler.com/buy/item/pressure_regulators/1114


Thanks,

Jay

 

[Terry]

I would go with the 1" pressure reducer.
You are restricting it with a 3/4"

You will also need to add an expansion tank near the water heater when you add the pressure reducer to help prevent the T&P from releasing prematurely.

 

[Sponsor]

 

[jryan51]

I would go with the 1" pressure reducer.
You are restricting it with a 3/4"

You will also need to add an expansion tank near the water heater when you add the pressure reducer to help prevent the T&P from releasing prematurely.

Terry,

Thank you for the reply. I've seen the expansion tanks at the box stores but find it interesting that no one in our neighbourhood has one.

My plumber actually just put a new water heater into my house a few months ago and I mentioned having seen the expansion tanks but he didn't feel it was necessary. He was pretty strict about code things also. The original line on the T&P was about 6" too short so he put a new pipe in. I originally wanted a tankless but I was always an inch or two from an egress/intake or overhang that didn't allow for it to be installed per code. I'm guessing it wasn't required. I'm in MA. He seemed to be top notch.

As a bit of eduction perhaps you can briefly explain the benefits. The expansion tank almost seems like a 3rd line of defense. I'd have a pressure reducer right after the meter reducing the pressure to the entire house.

Then the actual water tank has the relief mechanism. Is the expansion tank just one more level of insurance. Kinda like getting GPS in a new car. Nice to have but not really necessary?

Always trying to learn a little.


Thanks,

 

[Ian Gills]

You "probably" did not need an expansion tank before because you had an open system. Any water that expanded from the heat of the water heater could flow back past the meter without increasing the pressure of the water in your pipes.

Once you put in a pressure reducing valve this will have a device in it that prevents back flow past it. You will now have a closed system. So after you install the presssure reducing valve you will need an expansion tank, else the heat from the water heater may increase the pressure of the water in your home's pipes which is bad for the plumbing and may cause your TPR valve to open prematurely.

With a closed system, an expansion tank is not a defence or an insurance. It is a strict requirement.

With an open system, you simply do not need one.

 

[jryan51]

ahh...

I'm a pencil pusher by trade...I didn't realize that that the pressure reducer also acted as a backflow thereby closing the system.

The tank is short money. I'll have one put in.

I'll need to take another look at my neighbors. He had a different builder and he has a pressure reducer but I dont' recall seeing an expansion tank. I'll have to give him a heads up.


Not to belabor but this actually kind of interest me.

1) If there is a separate meter running outside water for spigots and irrigation that has a pressure reducer; an expansion tank is NOT required on that service.

2) The need all arises from pressure increasing from the hot water tank heating water?

3) The pressure reducer doesn't allow the increase in pressure to flow back into the city supply because it is now "closed". Pressure can potentially build.


4) Is there a reason these expansion tanks all seem to be rated at 150#'s? Why not 200#'s?

5) The expansion tank just takes on extra pressure as opposed to the T&P releasing? Assuming that the issue is infrequent (one time in 8 years) why not just let the T&P do it's function?

Not arguing ...just learning.

 

[Ian Gills]

I am a pen-pusher as well. I just can't afford plumbers on my $90,000 salary which is why I come here. And if they are silly enough to give away some trade secrets, what the hey? Although I guess they make a bit back on amateur DIYers messing it up. I'm gonna get bashed for saying that.

1) If there is a separate meter running outside water for spigots and irrigation that has a pressure reducer; an expansion tank is NOT required on that service. Correct.

2) The need all arises from pressure increasing from the hot water tank heating water? Yes.

3) The pressure reducer doesn't allow the increase in pressure to flow back into the city supply because it is now "closed". Pressure can potentially build. Correct, although some allow water to flow back when the pressure gets very high.


4) Is there a reason these expansion tanks all seem to be rated at 150#'s? Why not 200#'s? Because the WH is rated at that pressure. I think. Remember the water pressure in your home should be nowhere near that high. It should be around 70 psi. Are you sure that you are not getting your blood pressure confused with your water pressure?

5) The expansion tank just takes on extra pressure as opposed to the T&P releasing? Assuming that the issue is infrequent (one time in 8 years) why not just let the T&P do it's function? Because the pressure might build up every time the water heater comes on (that's when the water expands, with the heat). The expansion tank maintains constant pressure in the system. And it's not good for your pipes having high pressure. Remember, you need quite a lot of pressure for the TPR valve to open. And if it fails then you really are in trouble. Moreover, in my unfinished basement the TPR just releases on the floor. It would get very messy for me. And it is a code requirement.

 

[Jadnashua]

The amount of pressure rise will depend on how cold the incoming water is, the thermostat setting of the WH, the size of the tank, and how much of it is drained. It can easily exceed the T&P high pressure setting. There are things that can expand, but you don't want them to; for example, the hoses of the washing machine (you should shut the supply off but it's probably only the minority that actually do), the supply hoses for the faucets, and maybe the ice maker etc. It would not be nice to blow the hose off the ice maker or a toilet or a faucet. Best to not expose them to high pressure when not needed.

The tanks typically come precharged at 40#...it should be adjusted to the PRV setting by pumping it up like a tire. Because the bladder is small, be careful when doing this, as it doesn't take a lot of air to change the pressure. And, make sure you do that before you connect it to the water, or the setup won't mean anything...it will rise to the water pressure setting.

 

[jryan51]

Awesome replies.

Thanks for the insight.

I have a finished basement. At least I had the plumber but in a drip/overflow pan than drained over to the sump.

When it let go why warning sensor kicked in and I just went down and checked on it.....my neighbor...well....he is still picking up wet boxes .

I don't understand. His last tank let lose a few months ago and he spent a few days cleaning up. He had a new one installed. You'd think he learned his lesson and got stuff off the floor. Maybe 2 times in 3 months will learn him.

 

[Gary Swart]

If the TP valve is working correctly, it will trip when the pressure gets too high and reset when the pressure is normal. That means there shouldn't be a huge flood. In the real world however, the TP sometimes doesn't reset or seal completely so water continues to flow. Of course, it doesn't take 2 feet of water in the basement to cause a problem, so put the expansion tank in.