Filling, purging & bleeding

John_34

My boiler system has what B&G calls a "HYDRO-FLO module" complete with the enhanced air seperator, as pictured here:
http://fhaspapp.ittind.com/homeowners/Lhydroflo.gif

My system also has two zones zoned with pumps (pumping away) mounted on B&G's checktrol isolation flanges with built-in flo-control valves, flo-control valves on the return side piping to prevent gravity circulation, and balancing valves throughout. My question is what is the best way to fill my system and bleed out the air? Is it true that with the power purge isolation valve and drain that there is no need to bleed the radiators? How exactly is this power purging done? I'm used to just filling up a system then bleeding the radiators.

Don_4

Purging

My first question is why is the system empty ?? Any hot water system should not be drained any more than absolutely necessary. On initial fill of the system I would still bleed the radiation. That system will take care of any residual trapped air and keep the system air free.

hr

A lot depends on

your system. Cast iron radiators? Lots of up and down piping runs?

I like to power purge one zone at a time with a short hose in a 5 gallon bucket of water to see the air bubbles. If you have a fast fill boiler fill valve raise the lever and bump the pressure to 20 lbs or so to speed the air removal. Be sure to keep the pressure below the relief valve setting, generally 30psi, although cheep o's will start to seep at 25 psi or less sometimes

Even after a good purge, however you may still get some small air bubbles trapped in remote areas. Bleeders at the radiators or baseboard will help speed the purging of this air. A good air purger will clear the system only IF all the bubbles make it back down to the boiler room.

I take a sponge and small bucket and hit all the bleeders after the system has heated up and circulated for a while.

You system should end up clear of air and virtually noise free.

Good hydronic treatment chemicals will have O2 scavangers added to assure a good corrosion free enviroment inside your system. A good final step for all new equipment, IMO.

hot rod

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Brad White_2

I want to

treat myself to making a "purge cart" which John Siegenthaler promotes. (1 HP pool pump, hoses, filter and a 30-gallom barrel). Five gallons? You are an optimist, HotRod!

The purge cart is to my mind really a set-up for a pro who does this a lot, but for my multi-zone home system it is tempting. (I can't leave it alone, always adding radiators/emitters over time where I can, in order to reduce my required water temperature.)
Have you used the system he describes?

I use Rhomar chemicals and have been pleased with what the HydroSolv removes. The "922" or any final treatment is one of those things where you have no idea what it does unless you drain down and check, which defeats the purpose, I guess. Sort of like trying to prove a negative. The 922 has O2 scavengers as you describe.

And of course a SpiroVent.

hr

Plenty of HP, Brad!

I find that small TEEL 1/2 hp (Graingers) pump to be plenty for residential systems.

The 1 hp pool pump cart is good for guys doing ground source or large radiant that needs a lot of GPM to purge multiple large diameter loops at once.

Here is my complete setup. The whole pump/ hose package fits into a small plastic bucket. Johnstone Supply still carries these 10 foot long wash machine hoses. Handy for connecting to purge valves.

I think this Teel pump is now sold as an aluminum body. Mine is a 10 year old cast iron. Fairly heavy. I added a water proof switch and pressure gauge as well as a ball valve for quick shut down.

If I need to haul water to the job I use a plastic 55 gallon barrel. The small plastic "pump" bucket is just to purge, blend, and add chemicals into the system.

hot rod

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Brad White_2

I am grateful

not just for your response but that a smaller pump would do the trick! Those 1 HP pumps start about $200-225 and the 1/2 HP is manageable at about $125. Siggy was emphatic about the 1 HP minimum, but for 1-inch circuits, I do not need to make fish thirsty!

I have a 42 gallon rainwater reclamation barrel (translucent white) with drain cocks from my local cooperative, and lots of hoses and filters. This one will fly now. Another toy for the engineer...

Thanks again
BEW