Gravity Air and Water Conversion

Unknown

I'm looking at a job right now that has a multitude of cast iron steam gravity air convectors. You may know the type, the huge CI convectors that pull 100% outside air to feed the first and second floor.

The system has been converted to pull from common returns in the basement. Now I have been asked if I would be willing to convert the rads from Steam to Water.

Anyone had success doing this and still getting convection air movement?

Steamhead

Those are Indirect Radiators

and while they might work on hot-water, all the ducting was set up for steam temperatures, so you'd probably have to get them that hot so the air would circulate. This would also mean that a condensing boiler (if you're planning to use one) wouldn't be condensing that much, and would lose its efficiency advantage.

Add the potential for leaks under the much higher pressure in a hot-water system, and this kind of conversion looks pretty risky to me. It's one thing to replace a standing radiator, but you'd have a real hard time finding replacements for these.

I think you're better off keeping the steam. One Wallster says he cut his fuel bill by 75% by fixing his steam system. I'm sure it would be much more cost-effective and less risky to do the same here.

Unknown

Steam Conversion

Steamhead,

I would normally agree and 100% back you on keeping steam.

One large exception, this is a mansion that was built in 1890, the original steam system I am sure was great. Now, many years later the house has been spit into 5 apartments, 2 of which have there own boiler and the steam rads converted.

Now the owner wants to know about spliting the other units in the house. I have 5 & 6" mains, all unneccesary with what has alreadey been removed.

Personally, since they ducted the air from outside to using basement air for convection they have already killed most of the conductive currents. I was going to put in some small low velocity blowers whre the "new" air inlets are when I changed over to hot water.

Just some thoughts.

BTW - the exiting steam boiler has THREE false water line contraptions, all different ages. VERY COOL!

wheels

John Mills_3

pix

Let's see some pictures Inquiring dryhead minds get into this stuff!

Unknown

pics if...

John,

Just got word that the owner may nix all the ideas and go HOT AIR. Grrrrrrrr.

If steam/water is still a go I will get pics before we begin and post them here ;-)

Matt Undy

Wouldn't fin tube baseboard be an eaiser retrofit than forced air? I guess there's the A/C issue. I guess the reason for retrofit is to get each tennant paying their own fuel bill, otherwise I'd say maybe a good application for a high velocity system with A/C and hot water coils.

Matt

Unknown

the rule of economy

Matt,

It's the old rule of economics.

Owner needs to support the 20K tax bill and 20K fuel bill.

So he divides house into four apartments and the main level for he and his wife. Puts in AC for tenants so he can charge more rent and using separate systems can charge each apartment for their own utility. With AC already going in it's just a simple upgrade to install electric resistance heat.... and now no need for separate flues, the units can be located in each apartments utility closet.

See, all problems solved, no piping, one contractor. Easy.

Long term they will all pay out the wazoo.... but the owner just does not care. Short sighted, short term immediate financial economy solution wins over the rule of fuel economy and comfort every time.

oh well