PDA

View Full Version : Chilled water binder test point



Thermatech
11-11-2008, 05:09 PM
One for the UK chiller technicians.

Can anyone recomend a manufacturer / supplier in the uk for binder type pressure gauge.

I want to measure water pressure drop across a heat exchanger & there are some binder type access points installed in the flow & return pipework.

I have not done much chilled water work for a good many years now so I am at bit rusty.But as water cooled VRF is becoming more popular I am finding that it would be usfull to have this type of kit again.

Argus
11-11-2008, 05:23 PM
.

I haven't seen binder gauges for many years.

I would suggest that you look at suppliers of boiler gauge equipment in the UK.

Good luck - all my old gauges were calibrated in psi and I went SI 20 years ago.

.

Grizzly
11-11-2008, 05:36 PM
One for the UK chiller technicians.

Can anyone recomend a manufacturer / supplier in the uk for binder type pressure gauge.

I want to measure water pressure drop across a heat exchanger & there are some binder type access points installed in the flow & return pipework.

I have not done much chilled water work for a good many years now so I am at bit rusty.But as water cooled VRF is becoming more popular I am finding that it would be usfull to have this type of kit again.
Thermatech
We use them all the time, they are still available from BSS or Plumbcenter (sorry Climatecenter.)
I will try and look up the reference/ part numbers and get back to you
Argus.
We still use psi and multiply by 7 (when not having a calculator) to convert to kpa.
Grizzly

Argus
11-11-2008, 06:35 PM
.


Glad you can still get them.

It always beats me how people commission chillers without them as it's impossible to check the flow rate without measuring the PD.

How many chillers get still installed with-out the test points?


.

US Iceman
11-11-2008, 06:40 PM
Argus, what is a binder gauge? It sounds like differential pressure gauge?

Brian_UK
11-11-2008, 06:46 PM
The older type differential gauge is almost obsolete, it's all digital now ;)

See here...
http://www.cranefs.co.uk/index.asp?FrameSet=fsProdCat&SubMenu=4&UID=11%2F11%2F2008+18%3A44%3A546393

Flow 2006 software here...
http://www.cranefs.co.uk/index.asp?FrameSet=fsDownloads&UID=11%2F11%2F2008+18%3A46%3A195464

US Iceman
11-11-2008, 07:04 PM
OK Brian. Thanks. I guess I'm showing my age now, huh? My old gauge was just that, old. However, it worked well and I have to agree you cannot accurately commission a chiller without one of these (or your newer fancy digital model that comes in a box :D)

Argus
11-11-2008, 07:07 PM
Argus, what is a binder gauge? It sounds like differential pressure gauge?

.

It was a trade name that became synonymous with the product.... bit like ‘Hoover’ for a vacuum cleaner.

Here's a link that describe it, but Brian may have already covered it.
http://www.test-plugs.com/

In essence it consisted of a small brass connection point that was installed in the immediate flow and return lines on chillers, boilers etc.

The whole thing consisted of a small brass fitting, with a screwed cap that was removable to reveal a pierced rubber insert that could take a pointed tube attached to a gauge or thermometer. When pushed through the rubber seal it could then directly sample the water pressure or temperature at source. Gauges are open to inaccuracies, but if you had a calibrated manometer with binder points it was possible to check the exact PD through a chiller.
A double-reading thermocouple would also give the TD.

When removed the rubber insert closed up to seal the pipe and the seal cap was replaced.

They were VERY useful.... but prone to leaks when the rubber perished and the cap was lost.

I don’t know about you, but I have seldom seen a chiller that had the PD that the commissioning engineer said it should have had when I checked it with a gauge.


.

US Iceman
11-11-2008, 07:16 PM
Thanks Argus. The test plugs referred to are similar to what we call Pete's Plugs.

The PD gauge I had was a NIST-certified gauge and measured in.H2O to achieve improved accuracy instead of psi.

I think this entire process is a bit like a game of darts. If you get in the bulls-eye, it's close enough. Even if you were lucky enough to have a chart for chiller/condenser flow vs. pressure loss it was still a crap shoot sometimes.

You can use a pump curve and head to help verify the PD data, but it is all within some tolerance as far as I was able to decipher.

Brian_UK
11-11-2008, 07:40 PM
The age old problem of course is fouling of the heat exchanger, hot or cold, which always screws up your readings.

A commissioning valve with built-in orifice is the best thing but whether they get fitted is another matter.

chris96
11-11-2008, 08:59 PM
Hi guy's

I commission chiller's and i have to check the pressure drop's using the binder gauges ( when the nipples are installed!) If there's no point's installed we refuse to sign off the commissioning of the unit until there fitted. The Delta T gives us a idea of the flow across but you can't beat physically seeing it!

Our maintenances also require us to check the pressure drop.

Not to sure where they obtain the gauges tho, my company gave me 3 with different measurements of readings. If you can't find them still let me know and i'll ask our office.

Thermatech
11-11-2008, 11:12 PM
Many thanks for your replies chaps.

I offen tend to commission with the system running flatout then I know within a few kw the system performance duty. I accuratly measure the Td flow & return. Then I can calculate the water flow L/s or M3/hr ect.
The regulating valve can be adjusted to provide the Td & water volume required.
As the tolerance for VRF flow temperature is +10 deg C to +50 deg C this method is normally ok.

But for trouble shooting it would be helpfull to have another method of measurment to prove volume flow arround the water circuit.

I did hear tell of ultra sonic flow test meters but would assume they would be very expensive.

Did anyone have any experiance with this type of kit ?

Brian_UK
11-11-2008, 11:17 PM
I used an ultrasonic many, many years ago.

It did the job that I wanted but you are dependent on having dirty water flowing. I know that sound silly but it is the dirt particles, or bubbles, that are being sensed.

If you can get a proper orifice in then so much the better.

US Iceman
12-11-2008, 12:54 AM
My experience with ultrasonic flow meters is that you need to be careful where you place them on the piping, you need something in the water to measure the flow, and that their sensitivity is dependent on the quality and calibration.

Some models are not very expensive, others are.

The MG Pony
12-11-2008, 06:30 PM
Dwyer has manomitors of difriential types!

I got a Minihelic 5000 series for doing low pressure PD tests calibrated to "H2O