Glycol reserve

Tinman

I am starting a snow and ice melt job next week and plan to use a glycol feed, maybe the Axiom MF200? I'm also considering using an expansion tank like an Amtrol SX-40V. I've never used the tank before and was curious about pressurizing it...just use a transfer pump? Get it up to 60# and I'm good to go? I did see this thread from a few years ago which helped.
https://forum.heatinghelp.com/discussion/comment/1216585#Comment_1216585
Suggestions welcomed and appreciated.

Matt_67

I’ve never used the expansion tank method - but we have been using the axiom glycol feeders on almost all our boilers with glycol. They have worked really well and it makes service so much easier later. When you deduct the cost of the fill valve and RPZ it isn’t that big of an adder - plus it saves the cost of long term testing on the RPZ.

hot_rod

The tank is rated to 100 psi, so 60- 80 should be okay. I've tested a few different versions with water in the shop before I installed them, that 40 should give you close to 20 gallon reserve. A small transfer pump will do the deed.
Typical small feeders hold 6 gallon, do you need 20gallons?

One issue I have with the tank/ pump feeders is they are open to atmosphere. Glycol needs to be stored in a sealed closed container or you deplete some of the inhibitors with O2 contact, according to Dow and other manufacturers.

A Webstone, to fill and isolate if needed, pressure gauge and Autofill.

Zman

Stephen,
I think Hot Rods trick is something he uses in lieu of a feeder.

If you just want to do a typical feeder setup, just precharge the tank and set the feeder to your desired system pressure. If it is a small system with isolation valves on the loops, you can use the feeder to fill then let the main pump do the purging. If the system is bigger, I would use a purge cart to fill and just let the feeder top it off as the air comes out.

I usually put it in manual mode once everything is purged. It is nice to know how much you are losing when you have a leak.

Carl

Tinman

Thanks guys.

This is actually a boiler, near boiler piping, and Controls upgrade/replacement for an existing SIM system. The existing work is horrible. I don't trust anything they did and that's why I'm going to go with some kind of reserve. I want to cover all possibilities.