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arevely
Thumping in the Radiators

I live in a 100 year old house, and recently noticed a thumping in the radiators. We have radiator heat and the sound usually occurs when the blower comes on. I've tried bleeding the radiators, but to no avail. When I do bleed them, sometimes water and air comes out; sometimes not. The system we have (Weil-McLain, installed 1995) works fine and is serviced twice a year. It works great otherwise, but the thumping is driving me crazy. Does anybody have any advice?

Dobbs
Re: Thumping in the Radiators

arevely:

Could you describe your heating system in a little more detail---it sounds like you have a forced hot water boiler & heating system with radiators that you bleed, but where is the BLOWER located??? A blower is usually associated with a forced hot air system---is the blower blowing thru a fan coil somewhere in the house??? where???

If indeed you have a forced hot water boiler, go down to the boiler room & get the model # & post back; while you're there check the little dial on the front of the boiler--there are 2 needle indicators on these dial gauges---one needle indicates the water temp; the other needle indicates the "altitude" or water pressure---the altitude or WP needle should read at least 10 psi to 12 psi---if it's lower than this there's not enough water in the heating pipes & the rads, especially for any rads that are higher in the system, like the 2nd floor---always concentrate your bleeding attempts on the HIGHEST rads in the system---if you don't get any water out of the high rads, this could be the cause of the thumping---the boiler pump is trying to pump only water thru the piping system (which it always does quietly), but when it tries to pump water and air, you get thumping--are you also getting any noise like a waterfall,or can you hear water running thru the pipes when the heating system is on???

JLMCDANIEL
Re: Thumping in the Radiators

Do you have a steam heat system with a single pipe going to the radiators? I fthe answer is yes, you need to check the radiators with a level, it should be slightly down hill towards the pipe side.

Jack

arevely
Re: Thumping in the Radiators

No, I don't have steam heat. Sorry, I was mistaken before.

arevely
Re: Thumping in the Radiators

I have a hot water boiler with radiators in the house. When I turn up the heat, I hear it kick on, which I previously described as the "blower" turning on. Everything is in the basement though I'm not aware of any fan coil.

The unit is a Weil-McLain, Model # - HE II-6.

There are in fact, two gauges. One says it's at 95 (degrees, I assume based on your comment) and the other says it's at about 12 psi.

We can sometimes hear water flowing when the system is on, but not so much recently.

JLMCDANIEL
Re: Thumping in the Radiators

You can lift the non piped low end an install shims. With a steam radiator, the steam is fed in through the pipe, it condenses and the water runs down and back out through the pipe. If the pipe end is to high the water collects in the bottom of the radiator instead of draining and will eventually create a water dam. The steam forcing through the water is what causes the thumping.

Jack

Pelton
Re: Thumping in the Radiators

arevely,

This boiler is listed by the manufacturer (Weil-McLain, Model HE II-6) as a forced hot water system which has hot water running thru the system, not steam.

McDaniel accurately describes a condition in steam rads where steam condensate backs up in the rads & piping & causes a thumping noise, but in YOUR case, with a system that pumps hot water thru the rads, we'll have to try & look elsewhere for the source of the noise.

Could you provide more info as to are all the rads on a single floor, or do you have some on a 2nd floor???

When you say the boiler is in the basement, I assume you mean that most or all the rads are on the first floor.

Describe more clearly what happened when you tried to bleed some of the rads ("to no avail"); do you mean nothing came out, or only air came out---do you have any rads that are HIGHER than the others (on another floor, etc.)???

What happens when you try to bleed the rad that's higher than the rest of the other rads???

Do you have "hard water" in your area, where water pipes have clogged in the past, laundry stains on washed clothes, etc.??

Have you heard any noises coming from the boiler, or is it just the rads???

JLMCDANIEL
Re: Thumping in the Radiators

I have never heard of a hot water single pipe system.

Jack

Pelton
Re: Thumping in the Radiators

LOL, don't worry Jack, between you, me, the OP & the rest of the crew here, we'll get it all sorted out eventually!

JLMCDANIEL
Re: Thumping in the Radiators

With 12 PSI and if as the OP says when the bleeder is opened "sometimes water and air comes out; sometimes not" may suggest that ther is no auto fill valve.

arevely
Re: Thumping in the Radiators

Thanks for all the support here because there's some confusion on my part.

I have a forced hot water system; not steam, as I previously noted. The system that controls the heat is in the basement and I have radiators on the first, second, and third floors of the home. The radiators on the first two floors work fine. There are three rads on the third floor - one is hot to the touch, one is warm, and the third is cold. When I try to bleed the rads on the third floor, sometimes water and air come out, sometimes just air, sometimes nothing happens.

As far as I can tell we don't have hard water and I haven't heard any other noises coming from any other place other than the radiators. I say, as far as I can tell because we've only lived here for a little over a year so I don't have much experience (hence the confusion before) with the system.

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