Use antifreeze to minimize corrosion?

jeff_51

In other words, they heat and cool at differant rates than the older cast iron rads. It is fine to mix them if they are differant zones from each other, but otherwise you will get uneaven heating in the differant rooms with the mixed units. Hope this helps.

Catherine

Add antifreeze to minimize corrosion while relocating?

We are moving our 7 year old gas furnace, water heater, and galvanized pipes. The system is about 70 years old. It was modernized from a gravity-feed to a two-piped pumped system. The pipes are 1" to 1.25"O.D., radiators big cast-iron ones. Is it a good idea to drain the radiators, then add water and antifreeze to each unit to store until the system can be repiped? We are concerned about air in the units causing corrosion. Also; read your note about NOT flushing the system, is it a good idea to do that now?
Thanks for your help.

hr

Are you

just moving the boiler and not the radiators and piping? If so perhaps you could valve off all the piping and leave the water in the system.

Or drain all the system, including the radiators, down and cap off the piping until it is reconnected. Keep the O2 out to minimize any rusting.

If the system is going to sit through freezing temperatures, without running, then you need to drain ALL the water. Including low spots in the piping.

Antifreeze is messey and expensive for a temporary use. If you have to use it make sure it flushes through the entire system to protect all the components.

You really don't want to use antifreeze if you have any galvanized piping as it reacts with the zinc.

After everything is reconnected flush the system, use a hydronic cleaner, like Rhomar, to remove oils fluxes, etc. then fill and purge the system. You may add a hydronic conditioner after you are sure it is leak free.

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Catherine

moving some, not all...

of the radiators, most of the pipes. We're looking at replacing some of the large units with wall-mounted European style radiators. The pipes will be rerouted; changed to copper. We're going to need help with this design. One person we talked to discouraged us from combining old and new radiators, but acknowleged that they personally had never tried.
The house is a 70 year old bungalow, one-story with attic. We're adding several small additions and AC only forced air.
Thanks for your help.

hr

I agree

that mixing old style cast iron radiators and low mass panel radiators could be a challange. Especially if they are on the same loop or zone.

Be sure the contractor does a room by room heat loss calculation so you don't short change any rooms, btu wise.

if upgrades are being made to the home, especially insulation or windows, quite possibly you heat load will be lower than previous. All this needs to be considered when doing a load calc.

Any way to get radiant or hydronic heat in the new addition? You will miss the quiet, clean comfort of hot water heat, when the December "winds of forced air" blow your way

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Catherine

Cast-iron and low mass radiators

So, what is the concern of mixing the two? Do they require different pressure or temperature or what?

We are using Icynene in attic and crawl, new walls will be 2x6 construction, new windows in additions only. Any walls we open up in the existing structure will be insulated. We will be extending the hot-water system into the new spaces. Can the same system push radient piping under the floors or are radiators our only choice?

We will get a professional to do the load calculation and design the system. We like to be educated consumers. I'm an architect, my partner is doing most of the work, demo, framing, electrical, plumbing, etc. himself.

Thank you for sharing your experience with us.

gerry gill

like the others have said,

you can get away with different radiation heat emitters as long as they are zoned seperate..picture that cast iron radiator as a huge chunk of iron that takes awhile to cool off..how much faster will the panel radiator cool off? you might experiance temperature swings of a undesirable amount if you mix the two types in the same zone.

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