Milky DHW? Ever Seen?
Last Post 24 Feb 2014 10:11 AM by sailawayrb. 6 Replies.
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ICFHybridUser is Offline
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22 Feb 2014 12:48 PM
Has anyone ever seen milky white water coming out of the DHW system?

I have a Daikin water heater and a Stiebel-Eltron Solar tank inline.  The solar tank's heat exchangers are not in service, or even hooked up.  It's just a big 160 gallon bulge in the cold supply line to the water heater although there is an Alpha circulator pump sharing DHW through both tanks right now.

There is only one faucet (outdoor H/C bibb) plumbed and drawing hot water (temp=119F) from it gives you a half gallon of clear cool water, then a gallon or so of milky white water and then clear warm water.  At first, we thought the milky white water came from drywall dust contamination in the system, but we noticed that the "white" cloudiness slowly made it's way to the surface of a collection bucket and dissipated over 10-20 minutes or so.  It's so fine, it looks like you poured milk in the water.  If you wait a while and draw another bucket, the results are repeated.

I think we have run it enough to clear any contamination that might have been in there.

Has anyone seen this sort of thing?
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22 Feb 2014 02:00 PM
Seems like you are getting air into the system. Small leak with a venturi action as the water rushes past??
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22 Feb 2014 03:28 PM
Been giving this some more thought. It could be air entrained in the water from sources unknown but it could also be naturally occurring gas. As the water enters the tanks, they act as accumulators allowing the gas/air to separate from the water and be held at the top of the tank. Your first half gallon is the pipe between the tank and the h.b. Then you get the air/gas from the top of the tank and then the hot water.

Just for kicks, after it has set for a day, hold a lighter over the hose as you open the h.b. If it flares, it is most likely methane. There are also lots of other ground gases that will entrain with the water.
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23 Feb 2014 10:30 PM
Since the plumber doesn't seem able to come to work since last getting paid, I had to go down there today and take a look in preparation for the process of taking over and doing it myself. Turns out there are a number of check valves in backwards. That's right - backwards.

If an Alpha pump is isolated so it pumps against a check valve, it will cavitate and cavitation produces the white froth. Pretty impressive how finely divided it was, actually. This actually 'splains a number of problems I've been talking to him about since he built the mechanical room a couple weeks ago. Go figger.
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24 Feb 2014 12:44 AM
Set the alpha on auto,
If the check valve is backwards the alpa will sense not being able move water due to blocking (as if you had a system with zone valves) may save your pump.
Alpha on auto sends a pulse, if a valve opens it will come on automatically and as more valves open it will increase water velocity. No valves open or backwards check stopping flow and the pump will not come on.
Methane, interesting thought in these times of fracking...
Dan
Dan <br>BlueRidgeCompany.com
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24 Feb 2014 02:35 AM
Ha Ha. When I noted that the pump was showing "0" flow, the plumber just turned it on manual and stepped it up so he could feel the cavitations. "There, it's running now. Sometimes, you just have to bump these units". Never mind that I bought the Alpha and introduced it to him. When I called him to tell him the check valves were in backwards, he claimed his assistant did them. What's wrong with people nowadays?
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24 Feb 2014 10:11 AM
Just another example of a hired Pro learning on the job at your expense and risk.
Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!
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