Pennsylvania Loop Piping Leak

Considering our options regarding a recently discovered leak in loop piping. Loop has interior manifold set up, and leak is between through wall hdpe piping from vertical well and pvc schedule 40 (glued fittings) ball valve. Thus unable to shut off, isolate and repair....easily. (All interior piping is schedule 40 pvc with glued joints....thus adding degree of repair difficulty)
It is a pressurized closed loop system, with make up water connection to potable water supply. The glycol water mixture has not been tested since it was put into service, 13 years ago.

Looking for suggestions as to the best way to proceed. So far I have come up with 3 options:

1. Do nothing. Allow leak to continue to drip, with make up water continuing to be added. (Not really a viable option...but it is an option)

2. Pick a spot to cut out glued manifold and valves, replumb, have system flushed, purged and pressurized and put back into service. (Current pump set up seems poorly designed with push/pull loop pumping arrangement )

3. Replumb all interior piping from hdpe loop pipes to heat pump, adding a non pressurized flow center.


Having scratched my head on this for a week or so, curious to see if there are any other potential options not yet considered, and others opinions on presented options.

 

Thank You

 

Change to a non-pressurized flow center, the leak may not continue to be a problem.

 

Just for clarification - is the leak in the interior?

Then it is a pretty standard fix. Just some work involved of course.

 

Yes the leak is inside. But please explain more as a pretty standard fix?

 

How is the transition from HDPE pipe to PVC pipe made? Barb fittings with stainless worm gear hose clamps or thermally fused threaded adapters on the HDPE pipe that thread into PVC fittings?

 

a picture would help

 

We do HDPE all the way to the heat pump, with non pressurized flow centers. We have seen SCH40 leak, especially in pressurized systems.

 

Pictures....and I keep reading that non-pressurized systems piping is neater?

 

Yes. I would rebuild that with HDPE (or even copper). Piping needs to be supported as well.

I'm a fan of non-pressurized but you don't have to switch over if your pumps are still working fine. We have done close to 30 fixes with converting using the geo-flo geoprime tank.

 

That appears to be thermally fused threaded adapters on the HDPE pipe. Your leak is most likely in the threaded male adapter where it threads into the female threaded PVC adapter. Thermal expansion/contraction of this threaded female PVC adapter can lead to leaks. This is the weak point in your PVC piping. The glued joints are unlikely to ever have a problem if properly installed. To be able to tighten that threaded joint, you will have to cut off the PVC female adapter. If you have ~1" of PVC pipe between the female adapter and the PVC tee, you won't have to rebuild the entire piping arrangement. You can buy reinforced female threaded PVC adapters with a stainless ring around the outside to limit the expansion contraction of the PVC. Also, I prefer to use automotive grade Loctite High Performance Grey or Permatex Ultra Grey RTV sealant on these threaded joints rather your typical teflon pipe tape or dope.

If you determine conclusively that the leak is where a metal male threaded adapter is threaded into a female PVC adapter, one simple thing you might try is a stainless steel worm drive hose clamp over the female PVC adapter right at the point where the metal threads into the adapter. Use a clamp with a combination hex/screw driver head, and use a hex socket to crank down on the clamp. This will tend to shrink the PVC adapter and might fix your leak. I have used this method in the past to stop similar leaks.

 

The dreaded female pvc adapter, the root of all plumbing evil. They are junk. To make a correct transition a brass coupling should be threaded onto the male fusion transition and then a male pvc adapter could be screwed into the coupling, carefully using Teflon tape and pipe dope.
Eric

 

The leak is from the glued joint on the female adapter, there is not enough pipe between the female adapter glued joint and the next fitting a 90 bend glued joint to cut pipe, remove and replace adapter and coupler together.

Curious what others think of push/pull set up and the current piping set up shown in pictures. (This was not a DYI project!)

 

So is it leaking where it is glued to the pipe or is it leaking from the opposite end where the metal male adapter is threaded into it? If it is leaking from the threaded end (most likely), you can try the trick I posted above using a worm drive hose clamp over the female adapter to shrink and tighten it around the male adapter.

 

the glued side.....definitely not the threaded side

 

Well, you might still try the hose clamp trick on that side and see if you can shrink the fitting down on the pipe and stop the leak.

If it is leaking from the glued side, then that is just poor workmanship - somebody didn't evenly apply the primer and glue or there was an obvious defect in the pipe or fitting.

Are you absolutely sure the leak is originating at the glued joint? Is it possible that the leak is originating in the threaded joint and running underneath and then dripping off the glued end due to the slope of the piping? Can you put some dry talcum powder or flour on your finger, reach under and touch just the middle of the female adapter? If it comes back wet, that indicates moisture is traveling along the underneath side of the fitting and the origin of the leak is on the opposite side of the drip.

 

What size is your heat pump, and what is the model number on your circulation pumps?

Do you have an idea how much flow you are getting when the system is running?

 

The heat pump is a HydroHeat, 46,000 Btu

Pumps are Grundfos 26-99 f

I do not have flow rate, working on getting pressures at p/t ports at supply and return connection to heat pump. I did get pressure from hose bib connections on supply and return lines of 24 psi and 17.5 psi on supply, but there is 22" in hieght difference between the two hose bibs and a pressure tank.

 

6.5 PSI delta P indicates that you are over pumping slightly, and could consider removing one pump, maybe even more justifying a new (non-pressurized) flow center.

Is you heat pump a 4 or a 5 ton?

 

Thanks Doc, I have felt for some time that the system may be slightly over pumping, but finding the leak has prompted many questions on the entire system.

To answer the ton question, I don't know. The best I can do to answer the question is the attached photo.

At this time I am leaning to switching to a non pressurized system and the pumping question has me debating which pumps to choose to power the flow center.

What information do I need, to correctly size the pump (s) for a flow center?