Discussion in 'Maintenance and Troubleshooting' started by mldncx, Feb 25, 2014.
Can anyone recommend a backflush pump?
Are you referring to a flush/purge cart?
I have purchased the B&D manufacturing flush cart and have flushed 10 tons at a time with no problem.
They are easy to make your own if you have simple plumbing skills and can source the parts easily.
What I'm looking for is a pump capable of pumping whatever chemical is needed to backflush a geothermal heat pump water coil. I suspect it's plugged with rust. The unit is a Waterfurnace 5 ton. What makes me think it needs to be backflushed is that the temp drop across the water coil has dropped from 11 degrees to 6 degrees. The water flow has stayed the same at 8 GPM.
We have a junky little pump from our local Princess Auto that we can plug in to 110V. Use it for backflushing and emptying 55gal drums of glycol.
What do you want to flush? Just the unit? Unit and loops?
How old is the system?
Just the unit. The system is seven years old.
Google "Descaling tankless water heater" and a lot of info will come up. The procedure is the same for the Coaxial Heat Exchanger in your Geo...
I think we own 8 of these, yes 8, very handy!
Yes a simple transfer pump is all it will take.
I was thinking more along the lines of loopfield purging.Sorry for the mistake.
Thanks for the link, Bergy. That's exactly what I was looking for.
ok, why do you want to flush the system?
Because the temp drop across the water coil has gone from 11 degrees last winter to 6 degrees this winter. I'm guessing that the coil might be plugged.
Has the GPM remained constant?
If you are going to back wash your coil on a regular basis, use the LEAST aggressive solution posible...
We don't do open loop so I'm not sure what to use. Vinegar perhaps? Maybe someone who knows will let us know.
Yes, the GPM has remained the same. I've rigged the system with valves so that I can physically measure the output.
What is it that you suspect may be obstructing the coil? Do you use a sediment filter?
We have had open loop systems in my AO run for decades without flushing. Our worst problem is iron fouling of the drains downstream of solenoid. Flushing is not required half as often as the open loop fear mongers suggest.
Update on the backflush: I flushed the system last Saturday. Whatever I removed turned the flush water black. Anyway, the process increased the temp drop across the air coil from a marginal 15 degrees to 20 degrees, which is spot-on spec.
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