Ground loop purging

[GJ-HVAC/R]

On a geo call and found a bad compressor. Saw this on the flow center and this note written on the wall above it from this past january. Someone tried to purge it with a garden hose

[kdean1]

DIY flush cart.

[GJ-HVAC/R]

DIY flush cart.

Yep. There was almost no pressure and i could hear the air in the lines

[cehs]

As captain jack sparrow once said "apparently there's a leak".
.

[Oldsolarguy]

Well if the person trying to purge the lines with a garden hose didnt get the air out of the hose then they injected more air into the system, thus creating false pressure readings because air compresses and water doesn't. Also the loop conditioner for loops works pretty good in stopping small leaks that otherwise would be costly to repair.

[mattt787]

OK i have never done ground loop system before, How would purge out the system?

[Oldsolarguy]

To purge the air out of a ground loop, you need a pump that can circulate the water. A bucket to pump the water from. Draw the water from your bucket thru the pump into the system, the outlet side would dump into the bucket. That way your air is forced out and replaced with the water. We have what's called a flush cart that has a 2 hp pump installed and a holding tank open to thr air(approx. 10 gal cap.) that way you can see the air coming out. Plus you know all the air is removed with the flush cart because you can shut the pump off and see if there is a rise in the water column(air in system will force the water up) but in your case a 5 gal bucket a 1/2 hp inline pump and some washer machine hoses will do the trick. Just make sure that you turn the 3-way valves on the flow center to isolate the ground loop from the unit. That make sure your water flow isn't short cycling thru the unit instead of the ground loop

[mattt787]

so it is just like how i purge out a boiler system with a pump for antifreeze.