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rust inside radiators?

Arlynda Member Posts: 2
You know the story: young couple in love, no money, old fixer-upper, cheap price, lots of high ideals about restoring its former glory. Well, we got the pigeons out of the attic, the roof closed up, and the porches stabilized. Now let's do something about this $1,000-a-month heating bill, shall we?

Hot water radiators, natural gas boiler. The radiators don't get very hot at all (the cats sleep on them). Boiler's been tuned, it's mediocre but working. My father-in-law says, "Those radiators are full of rust! Blast them out with high pressure!" I say, "Yeah, and say hello to Swiss-cheese radiators? No thanks." Is he right? Is that our problem? The heat seems even from top to bottom, though weak. We don't drain the system in the summer, just shut off the pilot. Should we drain it? Is there something to inhibit the rust or eat away what's in there? The house belonged to an 80-year-old widow. She never had money, and the radiators have likely had no real maintenance since the day they were built. The cost is so bad we keep the thermostat set at, yes, 55 all winter long and just wear jackets indoors and have blankets on every chair. ANY advice will be gratefully welcomed and thanked profusely.


  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    It's EXCEPTIONALLY unlikely that cast iron radiators are clogged with rust! The internal passages are HUGE and in a properly functioning system little (if any) additional water is ever added to the system. With little or no water being added, no additional air is being added--no additional air means no additional rust. That's why you SHOULDN'T drain the system on a regular basis--only when absolutely necessary for service.

    Unless your climate is extremely cold and/or your house extremely large and/or your house exceptionally leaky, $1,000 per month should not be considered "normal"!

    Your radiators are not hot because they don't need to be hot to keep place at only 55°!

    I'd highly suggest getting a good hot water heating man in to carefully review the system. (Check "Find A Contractor" here at this site.) If this is a gravity system it may be WAY past time to be converted to forced flow. If it's a gravity system that's already been converted, it's a real possibility that your circulator is not functioning.

    If the problem is an extremely leaky house--INSULATE AND WEATHERIZE!!! If your heat loss is out of control, your heat bills will be out of control as well! NOTHING you do will help much until you control the heat loss!

    While I HIGHLY suggest calling in a pro for evaluation, here's a simple test you can make:

    Turn up the thermostat considerably. Observe the boiler. If the burner cycles (the flame starts and stops more than once) BEFORE the thermostat is satisfied, you can HIGHLY suspect a flow problem (inadequate gravity flow/malfunctioning circulator). Your cast iron radiator system should be able to absorb and liberate heat more rapidly than can be produced by even a grossly oversized boiler.
  • Arlynda
    Arlynda Member Posts: 2
    Here's the profuse thanks!

    You're a life-saver! That advice all makes perfect sense, and we'll get a boiler guy in immediately to check out the circulation of the system. It is a big, drafty house, but we're working on the insulation as we go. It's better now than it's ever been, but considering that its previous "insulation" was four to six inches of pigeon poop, that's not saying much. Thank you so much for the advice, though--we had almost convinced ourselves that rust was our problem, and we'd have spent countless hours chasing a problem we didn't have, and probably making more for ourselves in the process. You saved us!
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