Quick recap...4 ton geomax 2 with Rehau manifold and Rehau pex closed loop. System is running fine (now) and summer a/c last year and winter heat were great. However, Rehau manifold still drips antifreeze occasionally. The previous manifold also leaked in multiple places, was observed by a Rehau rep to leak, was sent back to the company who tested it and found no leaks. The new manifold, my third in 3 years, (that's another story) still drips occasionally. The loop pressure went from 50 psi to 30 between last summer and now. That might be a cup,s worth of antifreeze that's leaked out. My question really is...should I continue to harass rehau until it's completely leak-free, or is such a small loss over time not too much of a big deal? If my geo guy comes in every two or three years and tops off the antifreeze, maybe it's not worth the hassel of complaining yet again to the company?

Some of the pressure difference could be caused by loop temperature.  With HDPE, loop pressure is higher in the winter, and lower in the summer.  PEX(x?) may be different.

My main concern about the leak is that it may get worse over time.  Since you already have their attention, I'd probably lean on Rehau (not the installer) until they make it right.

I guess I have to agree with asking again for a repair since as long as manifold is leaking you can't identify if you have a leak elsewhere.

well you might also want to make it a simple non pressurized system and follow what a grundfos technician was concerned about regarding the inlet pump positive pressure :::: I saw 3 manufacturers pushing non-pressurized before 1991 a long time before then Mr John Manning (nice to most) 1995 was promoting GT QT (now Phoenix distributing for one, has GV (variable named) . As I mentioned the other manufacturer's pressure-less: What they simply did was coming from the loop, went to a T and a shut-off valving to a little 5 gal reservoir (plastic) tank with a tiny vent pin-hole almost easily fitted into basement ceiling joists, and not having to be a highest point, but would have to be above a leaky manifold (or any leak, I believe)... according to the g-fos tech suggesting that 4-to-5-feet of vertical head pressure will be better than none for better circulation performance by the pumps .

.... all of this is about getting away from ANY variable loop pressure concerns ..... also it is about getting away from GT-Guy calls and expense that a small leak at all can be topped off by your own cup of pure or distilled (just a few cups considered over the life...)

All you would normally have to do is change the air filters and maybe the odd (less-expensive) compressor contactors with a more-cu Minnesota-manufacturer's , better contactor than almost all manufacturers use ---- every 8 to 10 years of cycling (any a/c or ht-pump) of a system.

NPSH of NetPositiveSuctionHead is of enough importance that hip-high (other of those pressure-less) flow centers on floor bases can IMPROVE circulation with that little tank in at the 4-to-5-ft above pumps

I do see yours is of a pressurized type and that REALLY means there will always be some nano-air-bubbles in solution which takes a bit away from performance as the LaValle (sp?) heat exchanger company graphs that just 3% of entrained-air is enough of a problem by itself

I am sorry forgetting if I mention a little maintenance, that of with Hot Water generation, you may find a vinegar flush as like for instant gas and any other HW Units which recommend this are suggesting each year to get any inner wall of the cu pipes heat exchangers cleaned a bit.

Hmmm, wish I could position the tank under the leak! It could drip back into the reservoir!
I'd be ok with a non pressurized system. In fact, the installer suggested that last year when he was out trying to solve the dripping manifold problem. He's feeling screwed because Rehau promised to reimburse him for time/equipment but they have not. He even left me a gallon of mixed antifreeze. I probably can't add it myself, though? Although I've heard of people using garden sprayers and things to inject antifreeze through the PT port to get pressure back up to 50.

If it is " a cup" of leaked-out, then consider if you can you put a check valve (for no back low) on an adapter to that like of a garden hose to a washing machine hose (double female) to just keep above 30psi  ... Or at 50 psi in a winter where you find cold piping has constricted at that time... try to plan to get off that pressurized loop if you can have a practical help from any pipe connecting polyethelene- expert

Safe yourself some trouble,for now and in the future. Throw your non-pressurized flowcenter in, and move on. Otherwise, this will be a continues headache in the future.

Get 'r done as the Dj says!

What do you really have to do if you were to "throw in " another >2-pumps? yours might be new enough to just undo the existing and transpose to another pressure-less set up.

Others have found even non-pressurized flow centers perform better with a reservoir 5 ft above the pump(s) . It is about that 4ft of more NPSH above. More auto-purging effervesced-air out gets those 1% dollars per each 3% lab-efficiency,  for your ROI.

Flowcenters seem to be all over the net:
you may also want to ask if it has a 5/8ths 3-way valve or if it might have the 1.1/8th" threeway valves . you could find on a 4 and 5 pipe system , over 4-tons, only needing ONE GT-Loop circulating pump.

? How much is the throw-in, compared to a $24 little 5 gal carboy, maybe having a GT-guy you have, install for $ 350-550 ?


Add-On reservoirs, every year since 1993 for others calls like your, - all can be T'd-in nicely, and w/ a  T for a drain just under the shut-off valve to a reservoir-tank that works with the existing pump(s).

If you go to a flow center standing- a pressure-less system, you may want to see
 FlowCenterProducts.com 
or call Roy for some more history since the 80's. (Your pumps may be the same, so if you change any of theose, squirt H2O pump oil-conditioner on seal and or bearing under a cap , on some, and spin-in a bit:)

“He can compress more words into a smaller idea than any other man I ever met.”
-- Abe Lincoln

Oh golly, just trying to avoid that truth: little things interesting little minds...
so what is the answer, when someone can be of real help?

Cost to T-in a tank,
or throw in a 1400 dollar standing, less pumping unit...

Maybe there is an easier way to ask this. Please advise.

Stuart,
I stayed out of this thread due to my bias against Rehau. However at some point it is time for them to "fish or cut bait" in regard to your ongoing manifold issues. Step one would be a manifold that does not leak, if a non pressurised system is required for that condition to exist, it should have been stated early on in your project design.

Either Rehau and or their Rep will/can make this right at no expense to you, or you will gut your inside pipeing work and start fresh without a Rehau manifold. At this stage still trying to use that Rehau product is admirable, but appears to be folly on your part from those of us reading your posts.

You have allready demonstrated more patience with that manifold then any normal adult would.
Eric

I agree with Eric

I have no opinion about Rehau but agree that I would be far less tolerant of the runaround described. My patience with that kind of nonsense is measured in hours, not weeks, and my suppliers are made aware of that limit.

I have been known to predict that a particular substandard experience would make ripe fodder for a snarky widely read tale-of-woe on popular forums; the threat of which promptly inspires improved response.

I've riffed a few loud public improv blasts at wholesaler tabletop events and home / patio shows. Honeywell's inflexible zone boards and some local clown's attempt to sell the idea of solar superheating compressor discharge gas in the name of doubled SEER were recent targets. Honeywell, after some initial shortlived bluster assured better product is around the corner and the solar nuts seem to have crawled back under their rock.

I do have some fun in between reduct jobs!

Just to update everyone, Rehau had two reps come by the house last week to examine the ongoing leak problem. They have pledged to get the problem solved and to make sure everyone is happy. The current thinking (and I can believe it) goes back to the original installer (who we know did so many things wrong) and the angles at which the pipes come into the flow center (very sharp with a lot of tension) which is causing undue stress on the compression couplings. The plan is to reroute the loop pipes so they come into the manifold more or less directly with minimal "bend" stress. I hope that's pretty clear...I can post pictures if desired.

I am THRILLED that Rehau had someone come out and we have a resolution planned. (And no, they didn't pay me to write this!)

Stuart,
I am thrilled that someone is going to do something on your behalf! Commpression fittings and tension are definately a "no-no" and I hope the solution is really that simple as "cleaning up the plumbing".
Eric

I was one of the original 4-5 Rehau PEX tubing customers, here in Ontario, before the head office moved to the US. I have always had excellent service from them and unlike some of the tube competitors, they actually develop and know their product. I have seen issues like this before and it is an installer issue.

Mike solar provides the universal truth. It is not brand type, it is allways about the quality of the install/installer. A first year aprentice would have been scolded against trying to make a compression fitting "under tension".
Eric

Then I gotta get a pic posted, so we can all laugh at this install (again!). I'm exaggerating, but some of the pipes are coming into the manifold at a DIAGONAL!

Sooooo- it took how many visits for these guys to figure out tension makes for bad joints?