How To Flush Out Old FHW Radiator

Steve_166

Just purchased a slenderized fhw radiator to replace one that had froze/split in an old funeral home. The used on I bought comes from a fhw system as well. Pulled the bushings and it has a lot of sludge in the base of it. I am going to hit it with a wet vac and try to blow it out with a hose. I was wondering if there is a chemical I should add to it to really get it clean. I don't want to risk damaging this one, I picked it up for $75 and it would run me at least $700 everywhere else I called.

Steve_166

Flushed With Water

Okay, so far I have vac'd out as much as possible and then adapted a garden hose. I blew it out until it runs clear and pressure tested at the same time - no leaks so far. Still wondering if there is something I should treat it with prior to installing it.

Greg Maxwell

Radiator Flush

Try Tri Sodium Phosfate.

Steamhead

If the water is running clear

no more flushing is needed. You should be good to go. 

Jean-David Beyer

TSP

Trisodium phosphate is traditional for this, but if you happen to have any aluminum in your system (e.g., a mod-con with aluminum heat exchanger), you do not want to use TSP because it is difficult ot get it all out. And any residue of TSP will ensure corrosion of the aluminum. Or so the manufacturer of my boiler says.

Steve_166

Thank You

Thanks for the suggestions. I ended up deciding to just flush it good (both ways) until it ran clear. I'll look into the TSP for the future though.