High volume glycol purge pump setup

[Deleted User]

We use to use a small fractional HP utility pump. Then we got serious and got a 2 HP purge cart, like is used for purging geo thermal systems. It kicks some serious flows out, but as you said, can stll be choked so badly as to not do a great job, unless you bump your main circulators while filling the system.

Once you've gotten the lines completely filled, the purge cart does a decent job.

Only problem with a 2 HP purge cart is that you have to have a 25 amp circuit breaker, and nothing else can be on taht line when the pump starts or you pop the breaker.

On our last job, we installed 1-1/2" ball valves for fill-n-purge on either side of a 1-1/2" ball valve in the mains flow.

ME

John McArthur_2

What are you guys using to fill and purge large snow melt systems? I have a pump cart setup but purging through boiler drains and garden hoses is not sufficient for large systems. I have a couple of ideas but am curious to see what everyone else is using.

I'm thinking of using 7/8" ID or larger tubing with a union on each end from a jaccuzzi pump or similar with ball valves and check valve. For my jobs I'll leave a 1" ball valve to connect the union to.

I just finished purging a 1.5 million Btu snowmelt job that I had to do a retro fit on and did not have much fun. I need a system that will purge more and faster. It's hard to purge 2" lines with a garden hose!

John McArthur_2

ME,

Thanks, I have a couple of large snow melt jobs coming up and I plan to install large purge points. The system I just did seems to be working pretty well considering the original contractor on installed 1/2" boiler drains, upside down no less, for purge points. Of course, they also had Taco 007 pumps on the 11/2" mains going out to the slab, serving about 250 MBtu each with 50% glycol.

hr

If you

install shut off on every loop at the manifold, the typica; 1/2 HP transfer pumps have plenty of power to purge 1, 2, maybe 3 loops at a time. I use the Jomar 3/4" ball valves with built in hose connections for the large flow purging.

Any hose supplier csan build large diameter hose with garden hose connectors.

Thick, cold glycol really slows down the process. Keep it warm for faster install.

hot rod
hot rod

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John McArthur_2

Thanks Hot Rod. Unfortunately, I did not build the system I had to work on yesterday, but I'll use your suggestions on my future installs.

I did as ME suggested and used the system circs to get things moving in the large piping. I let the system run all night and all of the loops are now up to temp. The bad part is that it got to about -15* last night, so it didn't melt off too well. I'll pull the manhole covers and check delta T on individual loops today when it warms up a bit. At least the steel manhole covers are melted off.

[Deleted User]

Sounds like a whole lot of hose moving to me...

And I'm usually busy mixing and fixing and pouring. Busier than a one armed paper hanger in the wind...No time for hose movement :-)

ME