Iron pipe for solar water heater?

[jondecker76]

I am about to start building my solar collectors, and was wondering if there is any information on using Iron Pipe as a cheaper alternative instead of copper or PEX - I did some google searching but couldn't find anything. If anyone has some information, good or bad, could you please post it?

thanks,

Jon

[imsmooth]

Iron pipe will rust.  This is not a good idea.

[GaryGary]

Hi,

I guess you could use a closed loop system with antifreeze to prevent rust, but iron pipe seems like it would be unlikely to be cheaper than copper or PEX?  

Compared to a drain back system, it would add the cost of an expansion tank, Pres/Temp relief valve, fill valves and antifreeze.

The cost of the copper pipe to do a 4X8 ft collector is down to about $40 these days -- does not seem like there is much potential for saving?

Gary

[jondecker76]

Thanks guys - you are right, with copper so cheap there probably isn't much of a cost savings. I'll probably stick with copper.

[sbotsford]

I'd be surprised if the iron is any cheaper once you figure the cost of all the connectors, and the rent of the pipe threader.

Add to that:

Iron is a lot thicker.

Heat transfer is poorer.

Inside walls are rougher -- more friction loss.

Heavier.  Need sturdier support.

[huntedheads]

Iron and water do NOT mix well! This is the 1" adapter that went into my water tank. They were out of copper that day and wanting to get it all going I used the black iron adapter with plans to replace it later, this is one year later.

[zap]

Decades ago 2 others and I bought a row house unit built back in the late 1800's as a fixer upper.  First thing we noticed was the 10 or so minutes it took for the toilet to fill after a flush.

We only worked on the unit part time and when we finally got around to fixing up the plumbing and got the supply line replaced, we hooked the air compressor to the supply line we had removed.
The pipe didn't let any air pass till we had the air pressure well past 40 psi and even then it was only a tiny stream of bubbles.

We all just about passed out taking turns trying to blow into the pipe to get air out the other side

[ruddycrazy]

We all just about passed out taking turns trying to blow into the pipe to get air out the other side

Just get a few tins of baked beans and you and ya mates gobble em all up then a simple pipe from each rear end will give enough pressure and stench to clear any blocked pipe.......