PRV w/fastfill

pardon_my_ignorance

does the fastfill feature, when open, allow street pressure or is still under the limits of the fixed setting?

Paul48

Fast fill

is unregulated....gotta be careful. The only stupid question, is the one not asked.

hot_rod

depends on the brand

some valves have a fast fill feature designed into them that does not require "babysitting" This valve will fill up to 5 gpm or so, depending on the incoming pressure, then stop at the pressure you dial in. No need to lift a lever, or build a ball valve bypass around it.



It also has a unique shut off valve built in for those that like to leave the valve turned off after fill and purging.



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Paul48

correction

Nice!......I guess you need to know which valve you have. If the installer didn't leave the literature. Get the make and model off the valve, and get the info online.

ChasMan

In practice though..

You need to plumb a bypass around it if you want to get anything more than a trickle through it. The valve is highly restrictive. A regular fast fill levered valve eg Watts has a much higher flow rate than the Caleffi for fast filling / power purging. Nice valve though.

Paul48

5 gpm

I'd say that's fast enough.

ChasMan

Hmph..

That 5gpm spec must have been based on incoming 70 PSI pressure or something. 5GPM is not what I get in practice. If you have 40 PSI pressure on the front of that valve it is not enough pressure to purge anything more than a simple loop. With street pressure you can purge just about anything. I'm not dissing the valve, I love it. I like the way it keeps it's setting. Makes adjusting simple. However, it needs a bypass when incoming pressure is low at least.

hot_rod

true

piping a bypass around the valve could provide a little faster. But in fast fill mode, compared to competitors, we do a lot of testing to compare.



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Paul48

Hmmm

Kinda defeats the purpose, doesn't it?

ChasMan

The chart

If you open 40 PSI into a small boiler with just the drain open it will go up to 10 PSI in a second. That's probably why I was seeing such a slow flow rate. So, theory is good but in practice, you get slow flow.

hot_rod

exactly

regardless of how fast the valve allows, if you are trying to bleed air just from just an 1/8 vent, what's the point.



I like the Webstone valves for that purpose, connect a wash machine hose to a ball valve and you can fill faster and blow out any crud in the lines at a good flow rate.



On larger air separators you often see a valve on the side to allow a fast means to purge air and catch any dirt that rises up, before it gets into your air valve.



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ChasMan

Hmmmm

Good point. My boiler manual asks you to fill the boiler slowly from the bottom. I've only done that a couple of times. Too lazy to search for that double hose adapter. It is a nice valve and as a bonus, the gaskets don;t blow out of the backflow preventer either. Love the huge stainless strainer in it as well and the unions are so well made they seal when you have them hand tight.

JK_3

getting to technical?

Why are you asking this question? are you a home owner that needs help or are you a plumber/heating pro looking for something specific

bill_105

and another thing ..

Is there not a presurre differential that these things need? It seems that with a house with a low well switch (20-40) needs some help in getting the water pressure, and flow, up high enough. Lfting the lever on a watts sometimes dosen't do anything. But the Calleffi's dial is like, right now.

hot_rod

flow test

My shop is quite a distance form the well house and this is flowing thru 75' of garden hose also.



With around 26 psi, flowing, I get just at 4.5 gallons in the bucket in one minute. So I suspect the 5 gpm at 30 psi is accurate.



Remember that is 30 psi flowing, the gauge goes to 45 psi (static pressure) when the valve is off.



The test bench at our new factory lab is a bit more "deluxe" We will take you on a webinar tour of the lab and factory May 24 Coffee with Caleffi



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