Installed new thermal expansion tank & pressure gauge: how did I do?

Users who are viewing this thread

Temp945

Member
Messages
106
Reaction score
18
Points
18
Location
Florida
Hi all,

I installed a new thermal expansion tank today as well as a pressure gauge.

Does the way I've hooked everything up appear correct to you? Feel free to offer any criticisms which would help me make this install right.

A couple things:
1. I intend to replace the galvanized pipe in the wall ASAP. The rest of the system is now Uponor PEX.
2. The length of pipe going from the cold supply to the expansion tank is 3/4" PEX and I have covered it up so that it does not get exposed to UV light.
3. I have new copper water heater hoses to replace the braided lines but am waiting to install them because I found a problem with my water heater today and may be able to have it replaced under warranty (I only want to install them once to avoid re-bending the copper and compressing the washers).
4. I intend to add a brass elbow and nipple on the hot side by the wall to relieve strain in the hose.
5. The pressure gauge was installed so I can see at a glance if there is a problem with my water pressure / pressure reducing valve. But as I posted previously today, the city seems to have removed my PRV. In other words, the gauge is of limited use now. I actually wonder if I should remove it in order to have one less potential leak point.
 

Attachments

  • IMG_2703_(Medium).jpeg
    IMG_2703_(Medium).jpeg
    68.6 KB · Views: 370

Reach4

Well-Known Member
Messages
38,798
Reaction score
4,412
Points
113
Location
IL
The pressure gauge was installed so I can see at a glance if there is a problem with my water pressure / pressure reducing valve. But as I posted previously today, the city seems to have removed my PRV. In other words, the gauge is of limited use now. I actually wonder if I should remove it in order to have one less potential leak point.
The gauge can be useful in seeing if the thermal expansion tank fails later. Right now, assuming the new meter has a check valve, I expect some pressure increase after you use much hot water, and stop using water. If the thermal expansion tank fails the pressure will rise a lot more.

What does the gauge say -- around 55 psi? Nice.
 

Temp945

Member
Messages
106
Reaction score
18
Points
18
Location
Florida
The gauge measures right about 50 PSI. I got the same measurement at the hose bib at the location where the water main enters the home.

You make a good point about the pressure gauge being useful for monitoring the thermal expansion tank.

You mentioned that the pressure should rise after I use hot water (presumably because the water heater is working and causing expansion). I thought that the point of the expansion tank was to eliminate any pressure rise - does it actually only reduce pressure rise?
 

Reach4

Well-Known Member
Messages
38,798
Reaction score
4,412
Points
113
Location
IL
You mentioned that the pressure should rise after I use hot water (presumably because the water heater is working and causing expansion). I thought that the point of the expansion tank was to eliminate any pressure rise - does it actually only reduce pressure rise?
Yes, it only reduces the rise. So maybe it will rise from 50 to 80, for example. Or even 120, depending on things, such as the amount of water used, water heater size, incoming water temperature, the size of the expansion tank. But not 15o.

So I would set the air precharge to maybe 52, to take into account that the incoming city water pressure will probably rise higher at times.
 

Jeff H Young

In the Trades
Messages
8,766
Reaction score
2,168
Points
113
Location
92346
that looks good. I'm a little surprised to hear Reach 4 say pressure could still go to 120 psi from 50 I wouldn't expect that but never have checked to see how much thermal increase there would be I would have guessed 20 or 30 psi.
I know recommended air pressure in tank is only 2 or 5 lbs more than normal pressure but dont get why putting 10 or even 20 pounds over would be wrong if it rises from 50 psi all the way to 120 it would seem a little more precharge might insure that tank doesn't completely expand and allow it to get too high. but have never heard this recommended so wouldn't experiment
pressure should be the same at w/h as it is 50 feet away so I wouldn't worry about the extra potential for leak but on other hand how many gauges you want is your choice
Temp945 why would the city mess with a home owners property and remove your prv? My PRV belongs to me they really got no business touching it
 

Temp945

Member
Messages
106
Reaction score
18
Points
18
Location
Florida
The instructions from Amtrol state to set the precharge to the same as the incoming water supply, so that's what I did (50 PSI).

Jeff: I really don't know why the city would "steal" my PRV - but it appears that they did so! My only guess is that there was not enough room in the water meter box for the new wireless meter they installed and so they removed the PRV to make room. I'm going to contact the city tomorrow to inquire.
 

Jeff H Young

In the Trades
Messages
8,766
Reaction score
2,168
Points
113
Location
92346
The instructions from Amtrol state to set the precharge to the same as the incoming water supply, so that's what I did (50 PSI).

Jeff: I really don't know why the city would "steal" my PRV - but it appears that they did so! My only guess is that there was not enough room in the water meter box for the new wireless meter they installed and so they removed the PRV to make room. I'm going to contact the city tomorrow to inquire.

Yes I follow instructions dont think a few pounds maters as your pressure tomorrow could change or even differant times of day it can fluxuate with demand. but been wondering why it couldnt be set higher .
As you may or may not know water companys operate differantly all over country us that live in warm weather have meter out next to street in the cold north they are often in basements . Ive never seen the prv in the meter box we have them on side of house or inside garage. Id call city and ask maybe it was thier prv?
Id say you look pretty on track here, dont know why the expansion tank perhaps city put a check valve? or if youve repiped the the whole house but heater looks good
 

Temp945

Member
Messages
106
Reaction score
18
Points
18
Location
Florida
Thanks again, Jeff.

The reason that I think it was my PRV is because it was on "my" side of the shutoff inside the meter box. I'll have to ask the city and see what they say.

I put the expansion tank in because I replaced all the galvanized steel lines in the house with PEX and noticed that the lines were getting pressurized when the water heater would come on; after I opened a faucet, the water would come out with high pressure for a few seconds. I read that the high pressure may cause problems with appliances (ice maker, dishwasher, etc) as well as potentially even cause a PEX fitting to fail. Also, I read that my PRV (that I used to have!) operated as a check valve and this was the reason that the pressure was building up. So I installed the expansion tank. I had read that these were a code requirement in my area as well. Are these expansion tanks actually not very common to install?
 

Sarg

Enjoy Learning
Messages
227
Reaction score
51
Points
28
Location
Upstate New York

Temp945

Member
Messages
106
Reaction score
18
Points
18
Location
Florida
Sarg: yes - the braided hoses are total junk! I posted another thread here tonight about the horrible black flakes they were causing.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks