bleeding radiators

Supply House Rick

Did not post this

ED_45

BLEEDING C.I. RADIATORS

THE DRAW OFF ON MY CI GAS BOILER WAS DRIPPING FOR A WHILE, SO WHEN IT CALLED FOR WATER FROM THE STREET AIR MUST HAVE WORKED IT'S WAY INTO THE SYSTEM. I AM GETTING PRETTY GOOD BANGING SOUNDS, OF COURSE MOST NOTABLY IN THE MIDDLE OF THE NIGHT. TRIED BLEEDING THE RADIATORS WITH COIN VENTS BUT PROBLEM PERSIST. SHOULD I JUST KEEP AT IT OR COULD IT BE A DIFFERENT PROBLEM?

Mike T., Swampeast MO

You should not be hearing "banging" from a hot water system! Could easily be the sound of water boiler which is NOT a good thing in a water system.

If you do not already know how to fill and purge the system properly, I'd suggest calling a pro immediately.

Eric Johnson

What are the consequences of boiling water in a hot water boiler, Mike?

Mike T., Swampeast MO

The T&P [should] open before that occurs, but sometimes they malfunction and sometimes people remove or plug them. Aquastat [should] prevent such as well, but they too can malfunction or even be disabled. If the system is low on water and not circulating properly, thermostat can keep calling and the boiler continues to fire--BOOM! Something in a closed system eventually gives way with LOTS of boiling hot water flashing to steam--not to mention the real possibility of metal shrapnel...

If an old gravity system that's still open to the atmosphere, there's a safety pipe to relieve pressure (usually heading out the roof) but eventually the system will run dry and the boiler will be utterly ruined in short order.

ED_45

BLEED

SORRY, WHEN I SAY "BANGING", IT IS NOT FROM THE BOILER BUT FROM THE SUPPLY/RETURN PIES TO THE RADIATORS.

Mike T., Swampeast MO

Again, hot water systems are generally virtually silent. About the only "normal" noises are ticking as fin baseboard heats/cools and perhaps an occasional bang if piping is run though a hole that's too tight. This usually only occurs with baseboard systems as they have a low water volume and the entire system can heat/cool quite rapidly.

If this is an older system with iron/steel pipes and iron radiators you should not be hearing banging! The system could be seriously low on water with safeties disabled, removed or malfunctioning. The pressure gauge on the boiler should read 12 psi. If you get nothing (neither air nor water) from a bleeder when you open it, then the system is not properly filled. And, please, let the system cool BEFORE you add water!

Again, I believe you should call a pro as it sounds as if you may have some serious issues.

Eric Johnson

I don't mean to be contrary or disrespectful of your knowlege and experience, Mike, but I had an old gravity-feed system in a house built in 1910 and the pipes and radiators banged all the time. I also had the water boiling on a regular basis. They didn't make nearly as much noise as a steam system does, but they would make noise when the thing was firing hard on a cold night. And I always kept it full of water.

It was a wood-fired boiler that replaced an old coal-to-oil conversion. It worked great for the nine years that I owned the house. I just left it as a gravity-feed arrangement when I hooked up the wood boiler. It was pressurized and the pressure generally ranged between 15 and 20 psi, even when the water was boiling and the pipes and ci rads were banging. For expansion it had a huge, riveted iron tank that hung right over the boiler.

Maybe there's something about this set-up that makes it different from what you describe, but it worked well for me.

Mike T., Swampeast MO

Not trying to be contrary or disrespectful myself. An uncle of mine was famous for saying, "If it works, it's perfect". Perhaps this applies in your case but allowing water to actually boiler in a hot water heating system is what nearly every safety mechanism is designed to prevent!

Some old gravity systems did operate at temps significantly higher than the boiling point (by keeping the water under pressure) but a failsafe safety mechanism was inherent to their design. Some really old British systems operated at extreme temperature and pressure with really small pipes, but still didn't boil the water--unfortunately they lacked sufficiently failsafe safeties and were prone to spectacular failures--actually explosions.

Eric Johnson

I had two PRVs and pressure gauges all over it, and neither of the PRVs ever lifted from pressure, but I agree that the boiling doesn't sound right. Maybe something to do with that big expansion tank. I always assumed that the noise was the normal expansion and contraction of all that iron in the pipes and rads.

BTW, the firebox burned out after 12 years, but the guy I sold the house to replaced with an identical unit. As far as I know, he hasn't changed anything else.

Dave_4

PLEASE FORGIVE STUPID TYPO!

"water boiler" UGGGH!

Obviously I meant "water boiling"!!!

Vermonter_3

banging and clicking baseboard heat

> You should not be hearing "banging" from a hot

> water system! Could easily be the sound of water

> boiler which is NOT a good thing in a water

> system.

>

> If you do not already know how to fill

> and purge the system properly, I'd suggest

> calling a pro immediately.



Would you please tell me why this is happening, it is very disruptive of my sleep. What is purging and how do you do it?
Thanks
Donna