Hi Guys

Just wondering about the Delta T on my ground loop, on first stage I have a delta of 2 degrees and on second stage 3 degrees. EWT is 33 and LWT is 31 on first stage,EWT is 33 and LWT is 30 on second stage.

Delta T on duct air is at 20 degrees for first stage and around 22 on second stage.

Just wondering, have heard of people with much higher delta numbers, mine seems low. What would that mean?

Thanks

John

low delta T could suggest a higher than required flow rate. Not bad or good.  What is the PSI in/out on water loop of HP?

I do not know how to test the PSI, I do have P/T ports on EWT and LWT.

Thanks

John

An athletic ball needle inflator mated to a good 60 psig pressure gauge works with the ports

Thanks Engineer will try to find one of those.

Do you think my Delta T on the loop is OK? Delta T on air seems OK. Will higher GPM lower performance, higher electic bill?

Thanks

John

High GPM won't lower performance. It will slightly increase electric bill since you may be operating pumping capacity you don't need.

If your flow center has two pumps, consider shutting one off and remeasuring.

Ok Engineer

I disconnected 1 pump and have a delta T on second stage of about 5.3 degrees and on first 3.5 degrees.

Don't know if that tells us anything, still need to find pressure gauge to measure PSI.

Thanks

John

You can get a gauge for less, but for about $170, you can get a digital gauge originally spec'd by our friend Looby. Let me know if you are interested and I'll post a link here with info on the parts and where to buy them.

Geome, Please do.

Thanks

John

Posted By johncomyn on 19 Jan 2011 08:09 PM
Ok Engineer

I disconnected 1 pump and have a delta T on second stage of about 5.3 degrees and on first 3.5 degrees.

These Deltas are much nicer plus you are spending less to pump

Posted By johncomyn on 20 Jan 2011 08:21 AM
Geome, Please do.

Here is the link:
http://forum.geoexchange.org/maintenance-and-troubleshooting/4056-checking-pressures-and-temperatures-3.html#post32656

You may not need the pressure snubber (evens out pressure fluctuations.)  Looby and Stuart can give you more information on this.  Also, I don't know if the 1/8" gauge adapter will universally go into all PT ports, or if 1/16" gauge adapters are needed for some PT ports.  You can always pick up 1 of each since they only cost about $12 and there may not be an incremental shipping cost since the part is small.  If bought separately, you might incurr $12 more for shipping.  Let us know if you have any questions.  The black gauge is correct.  The red one is not correct.

For most people, an analog gauge may work just fine (and at a lower cost too), but no one has assembled a list to this point (that I have seen) of necessary parts.  If interested, someone at Flow Center Products can probably tell you what you need.  A bigger gauge will be easier to read than a small one.  I like the idea of a gauge that goes to 100psi since our loop pressure can be considered normal at 70psi (off the scale of a 60psi gauge.)

I did get a snubber, but never bothered putting it on the gauge.  Works fine without it.  I did get both the 1/16 and 1/8 needles.  The 1/8 looks so much bigger to jam into the port, so I ended up using the 1/16 exclusively.  It slips it pretty easily.  My installer told me to make sure the p/t caps were TIGHTLY put back on after the measurement is taken. 

Re the snubber, I found that without the snubber, the pressure would vary .1 to .2 psi for the first few seconds of the reading, then "settle down" to a steady number, typically between 35 and 70 (I know the 70 is pretty high, but we're had some antifreeze problems here).

Highly recommend getting the one on the posted thread above ("Looby's Gauge").  The digital is great.

Interesting - I've been using the 1/8" since it seems sturdier than the 1/16".

I've been making the caps just snug, at least until I find a source for the rubber liners inside the PT port caps.  I'd like to keep some extra on hand.  Please let me know if anyone knows where to find these.

20 Jan 2011 12:21 PM Quote Reply Alert
Posted By johncomyn on 19 Jan 2011 08:09 PM
Ok Engineer

I disconnected 1 pump and have a delta T on second stage of about 5.3 degrees and on first 3.5 degrees.


These Deltas are much nicer plus you are spending less to pump

I reconnected the one side after testing, do you think that it is fine to leave disconnected? I have a 4ton Climate Master and a horizontal loop which I beleive is 2400'.

Or is there a way to reduce the speed of each pump?

Thanks

John

I considered disconnecting one of my 2 pumps in the flo-center.  I contacted the manufacturer and asked if this would be a problem.  (Geo-Flo).  They wrote back right away saying "not  a problem to leave one pump running, the other electrically disconnected."  They even said that if you only need the one, use it and if it ever stops working, you can just switch to the other.

There's a user on here somewhere who posted he has some sort of electrical flip-flop switch and when the system runs, it alternates automatically which pump it uses, thus reducing the wear on each pump by 50%.  And someone else (I think) had it do 1 pump on first stage, and both pumps on 2nd.

Yesterday I cleaned my Air Filter, did not seems particulary dirty.(Have a elctrostatic cleanable filter). Tested my EWT and LWT, still have both pumps running. Delta T on first stage was 3 degrees up 1 and second stage was 4 degrees up 1. Delta T on air was down a little, first stage was 18 degrees and second stage 21 degrees.

Does this make any sense? Will a dirty filter reduce the heat extracted from the loop? Lower air temps I pressume would be from increased air flow.

Will make sure to clean the filter more often. Once a month instead of every 2 months.

John

The real question is "can an airflow restriction across the fan coil interfere with amount of heat transferred?"

of course

j

Ok I did a quick test on first stage, pressure drop is aprox. 4psi. Will test tonight again.

Delta T on first stage is between 2.5 and 2.6 after running for hours. 33 EWT 30.5 LWT.

Delta T on air is 18.5 degrees. EAT is 66.5 LAT is 85.

All measurements are on first stage for now.

So can I calculate if from these measurements if my system is running to spec?

I have a Climate Master Tranquilty TT049 4ton, with 2400' horizontal loop(Clay Soil).

Thanks

John

CM book gives you values at full load heating (2nd stage).
Same measurements in second stage will do.
Joe

Ok taken some more measurements in Stage 2.

PSI 39 and 44
EWT 33 LWT 29
EAT 63.5 LWT 85.5

In the Climate Master manual for the 4ton 4.5psi is the max that they show, which is 12gpm.

Thanks for any input.

John