non oxygen barrier tubing

hot_rod

most tap water will be in the low sevens. 7 is a very unstable ph as it can be easily effected by conditions in the system. 7.5- 8.5 would be a good range

Gin has a ph of 8.2, add some of that to buffer it :)

You'll find most hydronic conditioners will have the system at 8.0 - 8.6. when added to tap water.

TSP is often used to clean steam boilers and it will leave the system around a ph of 10 or so. With all the cast iron and steel in those systems, and he higher operating temperatures, a bit on the akline side is prefered.

hot rod

digger

non oxygen barrier tubing

The fact that non oxygen barrier tubing is encased in my Maxxon Thermafloor Underlayment is water over the dam.
The problem: Corrosion of impeller shaft on B&G LR15B (bronze) pump. Impeeller rotted off first pump. Shaft rotted at seal on pump no.2. Two heating seasons per pump.Since nothing has been done to prevent a recurrence,pump no.3 is due for failure.
What can be done? Treatment? Another brand of pump? Other advice?
A 50 gal. water heater is the heat source.

kevin coppinger_4

seems to me...

a system seperation is in order. A flat plate heat exchanger and a stainless steel pump on the tube side would do the trick I have done this before after the fact,it is not a "cheap" thing...Is this an open system? edit...what is the ph of the water? Try Taco...

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J.C.A._3

Just a question, but....

Is anything grounded to the heating piping in a place that it shouldn't be? I have seen this before. The only other things that gets bronze and stainless going away is pumping at temps. beyond their ratings, or very aggressive water.

Has the water been tested to see that it is treated properly for heating applications?(local OR well supply both need to be checked!) Inquiring minds would like to know. Chris

digger

info

Thank you for your interest. The system is closed. Grounding: the ground wire at the pump power supply IS connected. System is otherwise isolated. Dilectric union isolates at make up water connection. Ph: approximately 7. I tested it today. Temperature: 130F max. Normally 115F or so.
I don't understand "aggresive".
I am trying to pump 9 GPM through (14) 1/2"OD pex loops @ 200' each.
1" main, (3) 3/4" zones.
For what it's worth: water is always milky white. When a sample sits in a glass, the white settles to the bottom.
If I change the system it will definitly be split using a plate heat exchanger.

kevin coppinger_4

14 loops on...

1" sounds like a lot.I would give the system a good flushing and change brands...some have complained about pooer quality for the new B& G stuff...if nothing else have the new one ready to go, it will of course break on a Sunday...kpc

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hot_rod

Try another brand

of circ? I like the Grundfos brand, it has a 3 year warranty. They have a new series of cast stainless. a bit less $$ then the bronze circs.

I'm not seeing anything wrong with your system.

I'd flush and clean with a hydronic cleaner. fill and cross your fingers

hot rod

Unknown

Ph of 7

That's aggressive to anything steel or cast iron.

digger

system water

The system is filled with softened water. I can easily adjust the Ph upward.
As I composed my original question I wondered if there might be a product that perhaps added alkalinity, lubricated, and or inhibited oxygen.