mixing valve

bob young

what is the preferred mixing valve for potable domestic hot water. 200 families

RobG

I have had good luck with Powers. You should contact their engineering department for sizing. It costs more but you may want a mixing station with low flow capabilities. Lawler is another option as well.

jonny88

Holby

kcopp

what pipe size?

jonny88

no question Holby.Go to any NYC apt building.I have installed a few a fantastic product.

SWEI

How hard is the water?

bob young

4 " DISCHARGE PIPING. EXISTING TOUR- ANDERSON ENGINEERED SOPHISTICATED PRODUCT. WIRING HARNESS BROKEN BEYOND REPAIR & PRODUCT OBSOLETE , MAYBE 15 YEARS OLD. REPLACEMENT PARTS NOT AVAILABLE. LOOKING AT SIMILAR 2 " VALVE BY HEAT-TIMER

SWEI

That was where I was going. The globe valve has much larger passages than any thermostatic I have seen, and the price is actually lower when you compare Cv to Cv.

bob young

HOLBY WAS ALWAYS MY CHOICE SINCE 1962 BUT THESE NEW VALVES SEEM TO OFFER NEW TECHNOLOGY THAT IS MORE UP TO DATE. OPINIONS WELCOMED & WANTED.

RobG

The Heat Timer ETV sure seems like a cool unit. I wish they were around twenty years ago when I had the maintenance contract on a nursing home, although the biggest problem there were cross connections in the ancient shower valves and low flow conditions. It looks like that unit handles low flow well. Have you used them SWEI?

bob young

not personally but my associate has. he is a young super sharp radiant type heating expert., formally an electrician, a perfect mix. me, an old school plumber not opposed to new technology. unless any of our experts gives me pause to not use it,heat-timer is our choice.

RobG

Not to discuss pricing, but about how much more are they than the above mentioned valves? Just ballpark. They definitely look like much less of a headache than dialing in a thermostatic.

bob young

holby 4 " lists at 7k, heat-timer equivalent [2 " ] 3k labor on 4 " piping .....i think you catch on, bro !!!!

gennady

Never size mixing valve to pipe size. Actually pipe size has nothing to do with mixing valve sizing. Size it to the load and pressure drop. I like Holby, they are very good, Tour and Anderson is good as well but requires certain piping set up on domestic hot water return line and constant flow through the valve to be precise in controlling of water temperature. And I love Honeywell MX valves.

bob young

IF YOU GO WITH SUGGESTED PIPING DIAGRAMS AS I " ALWAYS " DO , YOU CAN'T GO WRONG. IF YOU CHOOSE TO COWBOY IT YOU GET WHAT YOU DESERVE, A GARBAGE JOB, VOID WARRANTIES AND LABELED " SAP ". CASE CLOSED.

jonny88

What are you referring to?

bob young

MR. GENNADY'S POST, OF COURSE. REGARDING PIPE SIZING, JONNY

jonny88

I would hesitate to call his methods of cowboying it if that is what you are referring to.What is wrong with his method?

hot_rod

What Gennady is saying is correct, any valve, check, zone, mixing, etc, should be sized as close as possible to the flow rate it will be used at.

This is especially critical with mix and balance valves that depend on the flow rate to accurately and sometimes safely in the case of DHW thermostatic valves, do their job. Valve authority is the term used that shows or allows a valve to do it's job.

Swing check valves are also sensitive to flow rate, if over-sized the check flaps in the breeze, or fluid flow Although swing checks really don't have a place in hydronics. They depend on a delta P to close and seal properly.

True you should follow the manufacturers piping suggestions, again this is critical with mix valves and recirc pumps on DHW.

Sizing the valve correctly really isn't always an installation manual detail, per say. The valve selection should be correct before the installation takes place, spec sheets and submittals should have all the sizing details. Or consult with the factory, or a knowledgeable engineer. In my opinion.

gennady

I would go with hot water fixture list first, (not quantity of apartments), then determine what kind of building it is, get max possible demand, GPM. Then how high is top fixture to determine static pressure drop, what is length of the longest run from mixing valve to the farthest fixture to determine dynamic pressure drop. Knowing pressure drop (Cv) through mixing valve or using diagramm in the valve manual, street water pressure and possible max demand I would choose the valve.

Pipe size around the mixing valve is not a factor here.

I don't see where I was a cowboy here.

And if properly sized and installed any valve would work. If procedure of sizing is not followed, any valve would not perform well.

hot_rod

gennady said:

I would go with hot water fixture list first, (not quantity of apartments), then determine what kind of building it is, get max possible demand, GPM. Then how high is top fixture to determine static pressure drop, what is length of the longest run from mixing valve to the farthest fixture to determine dynamic pressure drop. Knowing pressure drop (Cv) through mixing valve or using diagramm in the valve manual, street water pressure and possible max demand I would choose the valve.

Pipe size around the mixing valve is not a factor here.

I don't see where I was a cowboy here.

And if properly sized and installed any valve would work. If procedure of sizing is not followed, any valve would not perform well.

Well stated.

Now in some cases manufactures state some un-realistic flow numbers, I feel.

I see 3 Cv thermostatic mix valves with max. flow rates of 20 gpm or higher listed in the spec sheet!
Yes, the valve could flow that many gpm, probably with some noise complaints, but the ability to accurately adjust the temperature slips away.
One design engineer I know suggest 1- 1.5 bar (14- 20 psi) working ∆P across the valve. Flowing 20 gpm through a 3 Cv valve would look like this.

Oversizing a thermostatic valve will cause problems at very low flow conditions, look at the minimum flow on the spec. on large, high and low potential flows, a mixing station that couples multiple valves, sometimes called Hi-Low is a better option, or a motorized type valve, perhaps.

SWEI

RobG said:

The Heat Timer ETV sure seems like a cool unit. I wish they were around twenty years ago when I had the maintenance contract on a nursing home, although the biggest problem there were cross connections in the ancient shower valves and low flow conditions. It looks like that unit handles low flow well. Have you used them SWEI?

I have not used the Heat-Timer version, but when I looked into it recently, I found out their 1-1/2" model (Cv = 29) would cost us about $200 more than a Symmons 7-1000 (Cv = 22.3) and probably eliminate 95% of the maintenance -- not to mention the >50% cost for "element" replacements on the thermostatic every few years.

We are installing the first prototype of our own electronic tempering valve based on a similar NSF-listed stainless globe valve this weekend. We've paired it with some serious DDC smarts that also manage the indirect temp, boiler modulation, and respond to demand signals from building occupancy, laundry loads, and incoming cold water temp. I expect it will take about a year to optimize, but we expect to learn a lot in the process.

bob young

JONNY, I WAS TOTALLY IN AGREEMENT WITH MR. GENNADY AND MY MAN HOT ROD IS ALWAYS ON THE MONEY. THATS A FACT. THANX MUCH FOR THE EXPERT ADVICE, GENTS. I APPRECIATE IT VERY MUCH. YOU GUYS ARE THE BEST. BOB NYC

SWEI

Most of the TMV makers publish sizing charts, which make it difficult to compare products. I had to convert a number of them into Cv just to see what was what. Caleffi is one of very few who put the Cv on the front page of the spec sheet.

hot_rod

bob young said:

JONNY, I WAS TOTALLY IN AGREEMENT WITH MR. GENNADY AND MY MAN HOT ROD IS ALWAYS ON THE MONEY. THATS A FACT. THANX MUCH FOR THE EXPERT ADVICE, GENTS. I APPRECIATE IT VERY MUCH. YOU GUYS ARE THE BEST. BOB NYC

Bob, turn your high beams down Your cap lock must be on?

bob young

sorry hot rod, i read ya loud & clear !!!