# Copper and Cast Iron Rads



## OldSchool (Jan 30, 2010)

I search this forum and it seems that this has never been addressed.

Tonight I was watching MIKE HOMLES on tv.....One of my favourite shows. 

In the episode they were adding a rad to a hot water heating system.... the home was cast iron rad through out the home...somebody prior took out one of the rads and looped it together ( which is fine ) . But Mikes plumber suggested putting in a copper rad to replace it.

Big mistake.... even before he did it I said to the wife watch he will put in a copper rad. 

I see this mistake done by so many plumbing and heating companies that we are constantly being hired to fix the problem caused by other contractors.

You should not mix the two types of radiators. Cast Iron rads start to emit the proper BTU at 140 degs F and copper rad at 160 deg F.

You will not be able to maintain the system at a comfortable level. Jacking up the system temp to satisfy the copper will make the other rooms with cast unbearable.... Not only that depending where the Stat is it will either make the sytem shut off or remain on leaving the system unbalanced. :furious:


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## Don The Plumber (Feb 14, 2010)

What about installing copper piping to steam radiators? I do alot of bath remodels, & they always want me to move or add a radiator. I always pipe them in, in black pipe, with black, or cast iron ftgs, but can't remember why I was told not to use copper, on steam lines.


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## Miguel (Aug 10, 2009)

The copper lines will wear away fairly quickly. If you use copper then use L minimum, but try to avoid it if you can. 

Oldschool: good catch! One's a radiator and the other's a convector and you're absolutely right. The only way to do it for comfort is to way oversize the tube and fin, almost doubling the length and stacking 2 runs in one baseboard cab. Can be done but ther are still CI and even cast aluminum rads made for this type of alteration.


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## OldSchool (Jan 30, 2010)

As far as I know copper would be fine with steam....the only thing that I think would affect the copper big time would be the expansion of the copper under those extreme temperatures...... we did a lot of steam back in the day but it was all with black...... This is for piping of coarse..... In regards to radiators you would have to stick to cast iron rad.


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## Miguel (Aug 10, 2009)

OldSchool said:


> As far as I know copper would be fine with steam....the only thing that I think would affect the copper big time would be the expansion of the copper under those extreme temperatures...... we did a lot of steam back in the day but it was all with black...... This is for piping of coarse..... In regards to radiators you would have to stick to cast iron rad.


Yeah, for the rads you're into different supply temp requirements (you were talking HW rads, were you not?)

As for the piping? Not sure why the steam eats it so quickly. Impurities and the velocity is my guess since copper piping on vapor systems seem to last just fine. But I've replaced alot of copper steam lines with BI simply because they'd "split" in half!


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## OldSchool (Jan 30, 2010)

Miguel said:


> Yeah, for the rads you're into different supply temp requirements (you were talking HW rads, were you not?)
> 
> As for the piping? Not sure why the steam eats it so quickly. Impurities and the velocity is my guess since copper piping on vapor systems seem to last just fine. But I've replaced alot of copper steam lines with BI simply because they'd "split" in half!


Yes I was talking about HW rads, but the question was brought up about steam. You may be right about the impurties in the steam system.


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## RealLivePlumber (Jun 22, 2008)

I watch that tard once in a while. 

I think that guy gets a kick out of hearing himself talk.

He sure does like to make a big project out of some stuff.

Whats he always say, tear it all down?

I find it interesting that his original plumber, who was a hack, was a carpenter for a while, later on in the series. (I guess he liked being an actor more than a plumber.) Now, he's got rooter for a plumber.

And why don't they hire a real freaking tile man, for God sakes. carpenter/helper hack wanna be tile man.


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## 1703 (Jul 21, 2009)

I saw that show and made me raise my eyebrows.

Out of curiousity (I have limited experience in this area) what would the best solution for that situation be?


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## OldSchool (Jan 30, 2010)

He should have put in a cast iron rad plan and simple.. there is many sizes and design to choice from......this guys lack of knowlegde will eventually come back to haunt him


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## pauliplumber (Feb 9, 2009)

I watch the show at times and like it too. I agree with RLP though, he does make a project out of some jobs that are only practical because of the TV show budget. I don't know what kind of discount they give people that agreee to be on his show, but it's gotta be substantial. He will take a 10,000 remodel and make it into a 100,000 project. Mike Holmes comes across as a total douche alot, seems to be full of himself. 

All in all a pretty good show, they do some good work for the most part and I've picked up some good tips from the other trades.

Maybe a mod could move this to the new Mike Holmes thread.


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## PLUMBER_BILL (Oct 23, 2009)

OldSchool said:


> I search this forum and it seems that this has never been addressed.
> 
> Proper way to mix cast iron & copper radiation (in this case the copper radiation would be in the form of a toe space heater) Becon/Morris or equal in a bath or kitchen remodel where the design person has decided the cast iron should be removed to make way for cabinets etc: ...
> 
> You as the plumber/heating man will have a very unhappy customer unless you zone the copper with its own thermostat. IMHO!


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## PLUMBER_BILL (Oct 23, 2009)

DELETE double to # 11


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## Protech (Sep 22, 2008)

Pardon my ignorance, but what is the defining difference between a radiator and a convector? It seems like they are both very similar. I'm just starting to learn about hydronic heating (mainly for my own enjoyment as there is almost zero demand for it in Florida)



Miguel said:


> The copper lines will wear away fairly quickly. If you use copper then use L minimum, but try to avoid it if you can.
> 
> Oldschool: good catch! One's a radiator and the other's a convector and you're absolutely right. The only way to do it for comfort is to way oversize the tube and fin, almost doubling the length and stacking 2 runs in one baseboard cab. Can be done but ther are still CI and even cast aluminum rads made for this type of alteration.


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## RealLivePlumber (Jun 22, 2008)

A cast iron rad has a heavy mass, and requires a lower water temp to warm the area. It radiates heat from the mass.

A convector is a sheet metal cabinet, with fin and tube radiation inside. It relys on convection (cool air being drawn in from the bottom, and exiting the top) and requires a higher water temp to warm the space.


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## Protech (Sep 22, 2008)

So most radiators are cast iron and most convectors are copper?


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## RealLivePlumber (Jun 22, 2008)

I think it depends on who you ask. 

Around here (NJ), a "radiator" is cast iron. A convector is like I described in the previous post. Tube and fin baseboard is just that, "tube and fin baseboard." (Although, technically, it is a convector, also.)

(A convector with a sheet metal cabinet is shaped and is similar in size to a cast iron radiator )


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## gladerunner (Jan 24, 2009)

Cast-iron radiator will hold heat and continue to "RADIATE" heat after boiler shutts down. convection relies on thermo dynamics of continuously btu to draw air through exchanger. essentially stops convecting heat when the boiler heat source shuuts down.
When you try to mix the two on the same loop one will remain hot and one will not. If the ci radiator is satisfying the termastat any area served by the convection will remain cold.


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## RealLivePlumber (Jun 22, 2008)

Protech said:


> So most radiators are cast iron and most convectors are copper?


 Convectors traditionally have copper tubing inside, with aluminum heat transfer plates, like tube and fin baseboard.


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## nhmaster3015 (Aug 5, 2008)

Boy, talk about a whole lot of confusing information :thumbsup:

Cast iron radiators will heat just fine at almost any water temperature you want to run through them. Copper fin tube baseboard will also. The imbalance occurs because cast iron radiators put out a crap load more heat. The solution to the problem is to install balancing valves or thermostatic valves on the radiators.


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## futz (Sep 17, 2009)

RealLivePlumber said:


> A convector is a sheet metal cabinet, with fin and tube radiation inside. It relys on convection (cool air being drawn in from the bottom, and exiting the top) and requires a higher water temp to warm the space.


Trouble with baseboard convectors is that probably 90% of them end up being radiators after all. They fill up with spider webs and pet dander and stuff until virtually no air is convecting through the cabinet. HO's never clean them.

They stay clear in clean-freak's houses, but not in normal people's. :laughing: Anyway they radiate pretty good.


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