High water pressure revisited...

I read the other posting and didn’t know whether to continue that posting on an issue we have with high pressure. I posted a pix below (since pixs say a thousand words…)
We bought this house 2 yrs ago, owner replaced hot water heater he bought at HD; GE Smart Water 50 gal model GE50M06AAG a 1 yr before. Found out TPV leaking, installed a Watts DET 5 tank and replaced TPV. Leaked stopped but started back up again about 6 mos ago.
We are suspecting the Pressure Reducing Valve to be the culprit, and looking to replace.We are obtaining spikes of 120-140 with hot water heater – mainly after showers. BTW hot water heater is turned down probably to about 110 or less. Pressure was reduced to ~45.

Questions:
Looking at the components installed from Main Line into house, is that the correct setup? We have the PR valve, meter, than the bf valve…in the Watts brochure we saw bf valve, meter, than the PR valve, since Watts claims if you have a closed system the Watts would “reduce” the pressure spikes. Should our set-up be changed? Our Watts model is a 25AUB (installed when house was built 1989)
Since PA finally got its first cold snap, the cold water lines are “noisy”, hear the clicking of the meter on the first floor meter is in basement) and whinings when the toilets/washer fills. Why are the pipes noisier in the cold weather?
Lastly, The expansion tank is a Watts DET5, why did installing it work for awhile and now the TPV is leaking? Or does this go back to possible PR valve replacement?
I didn’t know if we should try arresters on the washing machine before breaking out the blowtorch project on the cold water inline set-up.
Thanks so much for your replies, Terry I love you website – we’re going to be installing a Toto Ultramax in the kids bath (lousy 3.5 toilets) and your website was wonderful in our research for best toilets – would definitely use your services if we weren’t on the other side of the country!

Make sure that the expansion tank is not shot. It should be filled with mostly air, if it sounds like it is full of water when you knock on it, it's probably shot. If you take the cap off the bottom, you can check the air pressure with an tire gauge. If it sounds like it is full of water, you'll probably get water out of the valve rather than air - a sure sign it i shot. the PRV looks like it's been around for a while, too, so it could be bad, but check the expansion tank first.

What is the normal water pressure on the cold line after you relieve pressure once the water heater is hot?

How are you checking the pressure, what instrument and the details of how?

You may need to check the air pressure in the expansion tank at the water heater. Did you keep the instructions for it.

You have a flow check after the water meter. If the normal pressure on the cold water is 40 to 55 or 60 psi, after the water heater is done and you relieve a bit of pressure then the pressure relief valve at the meter is working. You could be getting some wierd pressure spikes off the main line. A night long pressure reading might be a good idea without the water heater running.

Okay got some data:

Tool: Watts water pressure gauge

Cold Water pressure - ~45 (outdoor spigot)
Hot Water pressure - 84, then hubby took it down to 52. hand washed some dishes - spike to 82
child took shower - pressure went up to 125
Ran kitchen faucet - went down to 55-60
Hubby took shower -pressure went up to 110
It's hovering at ~50 pressure .
(all spikes read by that red needle on the gauge)

Watts DET-5 Expansion Tank: It was installed last March, on a 50 gal water tank, why would it fail within a year? Was trying to find hits on failed expansion tank online - what are some symptoms?
The installation sheet from Watts doesn't help, it just goes over how to install . If air pressure is off, does the unit have to be unscrewed off and pumped back up; any warnings if its filled with water how to release before it shoots all over the place?

Lastly; We are in a house with S-trap plumbing would this drainage create pressure all over? I got a wonderful plumbing book from library by B&D Complete Home Plumbing 3rd edit. mentioning a new product I hadn't seen Air Admittance Valves: http://www.studor.com/mini-vent.htm
Any experience on using these?

At this point we're looking to replace PR valve, we're going to monitor it some more whether it's slipping. The insides look "fine" no real deposits.
The expansion tank is unknown.

I would check the expansion tank first. By the pressure figures you give it looks like the pressure goes up while the reheating is happening. Hence thermal expansion.

Is that a check valve right after the meter? Ditto expansion tank suspicions. 45 psi is a proper reading for that PRV, and if it doesn't creep up with zero hot water usage, then I'd rule it out as a problem.

The expansion tank has failed. Why after only a year? Who knows, we don't live in a perfect world. Maybe the tank was defective out of the box, maybe something else. Fortunately, it's simple enough to replace. You do have to be sure the air charge in the tank equals the pressure setting of the PRV, but if memory serves me correctly they come charged to 45 psi. Just use a regular tire pressure gauge. Use care if you have to add air, it only take a small volume to alter the pressure. Watts recommends using a bicycle hand pump. The old tank just screws off of the fitting, and the new one screws on. The old one is probably filled with water, so it will be fairly heavy.

Thanks for the replies.

I'm concluding the expansion tank bladder is split/damaged, he has been using an air compressor with a 50 psi gauge to pump air into it, w/o taking it off and emptying whatever might be in it.....sigh.
He pumped it up last night and the expansion tank lost its charge from 45 and it went slowly down, the use of showers spiked the hot water tank to 150 forcing the tpv to go off........oh plumbing life is wonderful.....

Expansion Tank 101

Expansion Tank 101

Signs that you NEED an expansion tank: (in most cases)
Public Water
Main Line coming in already has a Pressure Relief Valve and a backflow valve
But your hot water tank has NO expansion tank
Your TPV is leaking esp. with showers/baths
When you turn on a faucet an hour or so after shower/bath – it comes out fast
Squealing pipes
Spike in pressure especially from 80-150 (150 makes the tpv leak!)

Signs of a BAD expansion tank:
Your TPV leaks
And you have all signs above
When you knock on expansion tank it sounds solid
Cold water line into tank is cold, all the tme.

Signs of a Expansion tank that WORKS
Your TPV doesn’t leak
The pressure coming out from faucets is normal
After kids take a shower or bath the cold water line above tank is HOT (until you open a hot line –then its goes bone chilling cold)
When you knock on tank it PINGS below (nice empty metal ping) and maybe about 2” on top is solid
IF you check the pressure it reads way below 100 (mine is hovering between 60-high 30’s). Our cold line pressure is ~45.
I have not noticed squealing pipes anymore!

Hubby came home with a AMTROLST-5 Expansion tank. We both said we do not remembering the Watts working as well at this AMTROL, it might have been defective from the beginning.

If you are interested in purchasing an AMTROL Therm-X-Trol ST-5 Expansion tank you must go through a plumbing supply store, this is not carried at local Lowes/HD. We pd. ~$70 it was $20 over the Watts but worth it.

Warning: prepare yourself when removing a bad expansion tank, it’s heavy and wobbly. Ours was filled with water and we re-tested to see if it would take air, nothing.

Thank you everyone for your quick responses that the culprit was the expansion tank, avoided replacing a guessing object of the PR valve. (avoid that blow-torch project)
It looks like our plumbing woes are over for now….

…does Terry have a “beer fund” on this forum ….?