How to Flush and Purge a Geothermal Loop

Quickly learn how a flush and purge cart works and the methods used to remove air and debris from a closed loop geothermal system!

[@mrchew1982]

I'm surprised that there isn't a strainer or a sock in the system to catch any dirt or debris... Thanks for this series of videos. Geothermal was just starting to enter residential when I went to school 10 years ago, so I didn't get any training on it apart from the few paragraphs in my text book. I want to install one of these systems on my own house when my outdoor unit stops working!

[@aglmechanicaltips]

There is a metal strainer in the flush and purge carts. When we have an existing system we are flushing and it has dirty water we do add a filter that sits in the strainer. No need for one to remain in the system though because it will just inhibit flow rates. Because it is "closed loop" debris normally aren't an issue

[@couchpotatoprepper3357]

Bad ass knowledge!!! I’m staring at the machine at my new job, thanks I needed a refresher course on using it

[@justindotson-dx2fc]

Great videos. Keep dropping knowledge!

[@nuebien]

Great video. Can I use this in my weekly service meeting to train my service techs?

[@aglmechanicaltips]

Absolutely!

[@fionnan2811happy]

Nice video thanks. Should the pump be removed from the unit to allow for better flow etc?

[@aglmechanicaltips]

No, keeping it sealed tight is much safer. If uninstalled and reinstalled improperly, you might end up causing a leak and / or putting air back into the loop.

[@fionnan2811happy]

@@aglmechanicaltips Thanks for your reply 👍

[@kastenusa]

What is the name of the tool that you used to boost pressure or part number? I like it! Thank you!

[@davidmassmann39]

Can you do a video on hanging insulated trunks?

[@dennisfernandez7019]

Really good information I have a question. Do you made that combo equipment or we can buy somewhere?

[@aglmechanicaltips]

The flush and purge cart? I don't make it but here is a link to a vendor that sells it. You can find cheaper ones but this is the specific one I am using in the video. geohydrosupply.com/geothermal-flush-cart-with-1-1-4-hoses-2-hp-stainless-steel/

[@RangeRov49]

Great video! I have a solar collector and a 7 series geo system that use good grade glycol as the coolant and it appears that they're tied in together, but I'm now realizing they're valved off from each other and that the valves are just a service station for both systems. I have the solar coolant changed out every 3 years due to heat degradation, but since the geo is at a much lower temp, how often is it recommend to change out the fluid (if ever)? I'm always checking the reservoir for visual ques but it always looks clear. I'd imagine there's test strips out there that would tell me more information?

[@aglmechanicaltips]

We only swap coolant during a major repair that requires a flush and purge (pump swap, coax coil failed or compete system changeout). When we complete the flush and purge after the repair we simply let our cart run while flooding the tank (adding water as it is overflowing out of the reservoir). We will flush with new water being added for a few hours. In my region we are rarely using glycol.

[@paulgilliland2992]

A sight class or flow meter might aid in seeing bubbles.

[@LaydenJeff]

Good Video

[@Hassamdin]

Hi could you please explain why a loop needs to pressurised, as there are also non pressurised systems?

[@aglmechanicaltips]

Low pressure systems are just a different way of installing these. The low pressure systems do not require a flush and purge because they have a reservoir. The only issue with these systems is that you have to find a point close to the high point in the loop system to install these reservoirs (air travels up). They take up space and cost a little bit more but there is nothing wrong with them it's just a different application. I prefer the "high" pressure systems only because they fit most applications and I don't have to locate a spot for a reservoir up high (which normally forces the reservoir to be located in the house or attic). Both systems low or high basically use the same pumps and the only real difference is that you have a reservoir on the low pressure system so if there is any air in the system it will eventually migrate upward and vent through the reservoir. You would add water during maintenances but after all the air is out you would no longer need to add any more water. High pressure systems are basically the same thing but we are getting all of the air out when we do the flush and purge procedure.

[@Hassamdin]

@@aglmechanicaltips thank you so much for your response, just one more detail. I noticed in a long loop increasing the pressure increased the flow rate. Any idea on what could be the reasoning behind this

[@woodworkingfan1965]

Where’s a good place to source the inducer pump?

[@aglmechanicaltips]

There's a few out there. Here is one already setup. You can find these cheaper but they might not be made specifically for this and you would have to add a needle. This one is setup specifically for this though; geothermalsupply.com/product/super-dooper-inducer/

[@danmccoy6164]

Do you check the ph balance of the municipal water ? Municipal water can also have biologics that can cause a lot of problems. Municipal water in my area is also very hard will cause problems in a short period. You can not use distilled water either. As it will eat your metal parts. My brother had to replace an $80,000 chiller in a plant that he worked at because the mantainace guys flushed it and then refilled it with distilled water. A friend of mine hvac guy said he kept having problems with a system every 4 or 5 years. He said it kept having black slugde coming out. Biologics can cause this. I keep forgetting to tell him that's probably what's happening there. Im sure he's using the same tap water each time. Of course then you can have work replacing equipment that goes bad every few years.😂

[@carlyleworkman1928]

👍🏿