Serious Shrinkage

[McKraut]

I came across a problem this morning and I have some concerns about what is going to happen to both my copper piping and my PEX underground.
I apologize to AVC8130 and his "Linear Expansion of Pex, how do you deal with it?" post, but I wanted to start my own post about the same subject, but different problems
I installed my boiler earlier this past Fall and have had it burning regularly. Last night, the boiler could not keep up with the cold temps and the EKO Biomass 60 came up with a "FUEL" display some time early in the morning. I went out this morning at 4AM and the boiler was 160* and the boiler room was 95*. When I looked over at the piping, I noticed that the PEX was starting to shrink in the "cooler" temps. I went back out at 8AM and the boiler temp was still around 160* and the room was 90*. The shrinkage of the PEX was over 1 inch on both the supply and return pipes. I brought the boiler back up to 180*, and the PEX lines have been running 180* water for over 9 hours and the pipes have not expanded to their original length. There has been some movement in the house, on the other end of the PEX run, but it has not be problematic (yet).
Next season I am planning on putting in an expansion "loop" to compensate for the PEX expansion and contraction. For now, what would be the best thing to do? I have to go on a business trip in 3 weeks and I will be gone for a week. At that time the PEX will cool down again and I am concerned that the repeated movement will weaken the PEX connections, the PEX itself, or do something to the copper. Any advice would be appreciated.

Keep warm,

Bob

You can see from the picture how far the piping has been pulled down to the right (where the copper connects to the PEX going underground). The horizontal copper pipe was originally slightly sloped upward to the right. You can also see how the hanger has been distorted.

 

[PassionForFire&Water]

I would remove the "sturdy" support on the left and install a "flexible Bungee" support on the right.

 

[MarkW]

If it shrunk in the cooler temps, I would expect it would have returned to normal once the boiler temp got back up. I presume it doesn't run short when the boiler's not running during the summer? It was long enough when installed?

Is this installed outside the home? Perhaps an underground run? I would suspect heaving as a possible culprit, if that is the case.

 

[McKraut]

I would remove the "sturdy" support on the left and install a "flexible Bungee" support on the right.

Is there an actual commercial product that is available? If you mean a regular bungee cord, I don't think it would provide much support.

Thank you,

Bob

 

[McKraut]

If it shrunk in the cooler temps, I would expect it would have returned to normal once the boiler temp got back up. I presume it doesn't run short when the boiler's not running during the summer? It was long enough when installed?

Is this installed outside the home? Perhaps an underground run? I would suspect heaving as a possible culprit, if that is the case.

The PEX was buried almost 2 years. The boiler and copper were hooked up this past summer. Since the boiler has been fired, there was no noticeable movement in either direction as the boiler heated up and cooled down during normal cycling. There have been several times when the boiler was cooled down to below 130* so I could clean the boiler. I would have expected it to move then, but there was none that I saw.
The PEX is in an underground run about 100 feet long. It is buried 4 to 5 feet below ground and it surrounded by around 14 inches of foam. The temperature drop from the boiler to the house is less than 1*F.

Bob

 

[stefan66]

I'd break that vertical copper and put an extension on it to bring it back to it's original location.
Lots of stresses on that copper the way it is in the pics.
I had the same issues with my setup.
Ended up restraining the pex when cold where it enters and exits the house and garage
Let the stress be underground in the pex where it should be.

 

[Karl_northwind]

Check out www.falconstainless.com for reasonably priced Stainless connectors. I've thought about using them to solve these sorts of problems.

 

[McKraut]

I'd break that vertical copper and put an extension on it to bring it back to it's original location.
Lots of stresses on that copper the way it is in the pics.
I had the same issues with my setup.
Ended up restraining the pex when cold where it enters and exits the house and garage
Let the stress be underground in the pex where it should be.

Ended up restraining the pex when cold where it enters and exits the house and garage

I wanted to put wood under the copper pipe to stop the PEX from pulling the copper down. My concern is that the stress may separate the copper from the PEX, or cause structural stress in the PEX below grade -- where I can't fix it. How did you restrain it? Do you have any pictures?

I'd break that vertical copper and put an extension on it to bring it back to it's original location.

I am planning on doing this over the summer. I did not want to cut the lines while I need heat from the boiler. I have some other improvements that I need to make and I want to hold off if I can.

Thanks for the advice,

Bob

 

[McKraut]

Check out www.falconstainless.com for reasonably priced Stainless connectors. I've thought about using them to solve these sorts of problems.

This looks promising. For one thing, if I make an expansion piece out of PEX, I have to buy 100' minimum. That's pretty pricey when I would use only 10 feet of it. I will contact these folks and see what they can recommend. Thanks for the link. I'll let you know what I find out.

Bob

 

[stefan66]

I wanted to put wood under the copper pipe to stop the PEX from pulling the copper down. My concern is that the stress may separate the copper from the PEX, or cause structural stress in the PEX below grade -- where I can't fix it. How did you restrain it? Do you have any pictures?


I put a bracket OVER the pipe when the pipe was COLD . That way any expansion is forced to go underground to the pex.
Seems to me when your pex shrunk, it broke loose from the foam insulation, and then got "stuck" in it's new position.
I wouldn't put anything under the copper to stop the pex from pulling down. Like you said it will only try to pull apart if it wants to shrink more. BTW I only have about 1 foot of pex exposed in the house and garage then a 90 degree turn. made it easier to put the bracket there. I only needed to do this on the outlet of the boiler as the return runs much cooler. Sorry I'm still stuck in the 20th century as far as pictures go. Gonna have to work on that.

 

[Fred61]

A local plumbing and heating installer would more than likely be glad to sell you a short piece. Do you have a crimper? If so do a length of pex with a service loop as was pictured in a recent post on expansion.

 

[avc8130]

A local plumbing and heating installer would more than likely be glad to sell you a short piece. Do you have a crimper? If so do a length of pex with a service loop as was pictured in a recent post on expansion.

He's probably got 1" pex? So he needs to incorporate a 10" radius loop to account for the expansion?

The more I learn about this expansion/contraction the less I like this stuff.

ac

 

[Clarkbug]

This looks promising. For one thing, if I make an expansion piece out of PEX, I have to buy 100' minimum. That's pretty pricey when I would use only 10 feet of it. I will contact these folks and see what they can recommend. Thanks for the link. I'll let you know what I find out.

Bob

Bob,

Unless you need a very specific brand of Pex (based on your fittings and/or tools), you should be able to pick up a 5' length at most hardware stores. The Big Box near me has one brand, the local hardware store carries Zurn. Its straight lengths, but Im sure something could be done if you wanted a coil for expansion/contraction.

 

[McKraut]

Bob,

Unless you need a very specific brand of Pex (based on your fittings and/or tools), you should be able to pick up a 5' length at most hardware stores. The Big Box near me has one brand, the local hardware store carries Zurn. Its straight lengths, but Im sure something could be done if you wanted a coil for expansion/contraction.

I need 1 & 1/4 inch pipe. Lowe's and HD only had 1 inch. I contacted 2 local plumbing supply houses and they wouldn't sell to me because I was not a contractor. What do you think of the connectors that Karl_northwind suggested at www.falconstainless.com?

A local plumbing and heating installer would more than likely be glad to sell you a short piece. Do you have a crimper? If so do a length of pex with a service loop as was pictured in a recent post on expansion.

Yep, I still have the ProPex expander tool. I will take a look at the service loop and think about that. I would appreciate any insight into the stainless steel flexible connectors from Falcon.

Bob

 

[Vizsla]

I'd call plumbing companies, I've never heard of refusal to sell , here in Michigan that is. Now with actual boilers and furnaces yes.

Shame. I would not anchor the pex at all, let it move, sounds like the earth is pulling on you. I would make an expansion loop or flexible supply. Our lowes does have 1.25" shark bite fittings. Even if you use 1" temporarily or two lines in parallel , till you get what you need. Our Menards also sells the 1.25" oxygen barrier in 5' lengths, nothing longer in stock. Another option is to use tracpipe flexible Gasline, as it uses flare connections, its a temp fix. I've used it as high as 200psi. It's actually very close to those flex connectors in the calefi book less the rubber jacket.

Good luck

 

[Clarkbug]

I need 1 & 1/4 inch pipe. Lowe's and HD only had 1 inch.

Hmmm, I thought about that right after I posted. Some places near me are contractor-centric, but cash on the table seems to always get me stuff if I needed it.

Can you take a pic of where the pex comes into the boiler room? It might help with brainstorming...

 

[Vizsla]

I was just thinking, duh rare,,lol.. Just make a swing joint with shark bites to take the movement on the perpendicular axis to the shark bite connection.

 

[McKraut]

Can you take a pic of where the pex comes into the boiler room? It might help with brainstorming...[/quote]

Hmmm, I thought about that right after I posted. Some places near me are contractor-centric, but cash on the table seems to always get me stuff if I needed it.

I was told that is was Maryland state law that they couldn't sell it to me. I live in PA but I work in MD so I do my shopping there. I posted the best picture I have for the PEX. There is only 6 to 8 inches of PEX coming out of the floor. It is hard to see both PEX pipes, one is directly behind the other.

Bob

 

[Clarkbug]

I think the flex connector will work well for you, if you move the shutoff valve to the horizontal section to give you some room to work. A swing joint as Vizla mentioned might also work if combined with a sharkbite, but I know those arent always the most trusted things.

Are you near Lebanon PA by chance? One of the forum sponsors, Smokeless Heat is there. Dean Zook is the owner, and has always been super helpful in helping me all the way up here in NY. He might be able to help you source some things locally if you needed.

Also, for the valve you have that looks like its closed with a "reminder" of electrical tape, just unscrew the nut that holds on the handle and remove that. No way to accidentally turn it then.

 

[McKraut]

I think the flex connector will work well for you, if you move the shutoff valve to the horizontal section to give you some room to work. A swing joint as Vizla mentioned might also work if combined with a sharkbite, but I know those arent always the most trusted things.

Are you near Lebanon PA by chance? One of the forum sponsors, Smokeless Heat is there. Dean Zook is the owner, and has always been super helpful in helping me all the way up here in NY. He might be able to help you source some things locally if you needed.

Also, for the valve you have that looks like its closed with a "reminder" of electrical tape, just unscrew the nut that holds on the handle and remove that. No way to accidentally turn it then.

Dean is about 2 hours away. I will look him up. I am leaning towards the flexible SS.

The electric tape is there so that other people don't open it. On my list of things to do is to pull the handle off completely. As a matter of fact, I'll pull it tomorrow.

Thanks for you help and advice.

Bob

 

[tom in maine]

This is a good cautionary tale. Anyone who is running long runs of PEX should expect this to occur with temperature
swings. Either a loop of PEX or the SS flex would be fine. I would opt for the SS given the restrictions in this installation.
A Zurn rep suggested a loop to me as a built in expansion joint when running long loops.
This should be on any long PEX loop that ties to fixed metal piping.

 

[McKraut]

This is a good cautionary tale. Anyone who is running long runs of PEX should expect this to occur with temperature
swings. Either a loop of PEX or the SS flex would be fine. I would opt for the SS given the restrictions in this installation.
A Zurn rep suggested a loop to me as a built in expansion joint when running long loops.
This should be on any long PEX loop that ties to fixed metal piping.

Agreed. I hope somebody can learn from this and save themselves some time and money.

 

[BoilerMan]

Tom has a great point, when we bury long underground runs of direct burial wire, Code states we must put in "S" loops to account for the lengthening and shortening of the wire, as it can actually pull out of meter sockets and such.

I still think it has moved in the foam and when contracted it bound a bit more on the house end pulling it from the boiler room. Pex is hard for us anal contractors to install because you just can't make it look as good as copper/black iron.

A nice sweeping 90 into the boiler room would solve the movement problem, but the SS connectors are your best bet now if you can't get any more 1.25" pex and some couplings.

TS

 

[McKraut]

A quick update. I did pull the copper apart and installed the stainless steel connectors. I will say that the SS connector does not feel very sturdy. I guess I was expecting something more along the lines of flexible braided SS lines. Anyway. I have heated up the boiler up and cooled if off for 3 separate cycles. The PEX is moving over an inch and the SS connectors are moving along without any noticeable problems.

As always, thank you for your wisdom, input, and advice.

Bob

 

[BulldogAcres]

I run my boiler at 175*. I use a heat exchanger to transfer the boiler heat two 40 gallon buffer tanks. As the water leaves the buffer tanks, it goes through a temperature mixing valve making the water going to the house 120*. I have a continuous loop that supplies hot water and tap off the loop for heating and DHW. My run of Pex from the boiler room to the house is 100 feet each way. I notice when I start the system up in fall the Pex creeps in length at least 1 inch where it leaves the boiler room and where it enter the house. When the system is shut down the Pex returns to it original length. I think Pex is only rated at maximum 180*. Are you sure you are not over heating the Pex and it now will not return to it original length.