Home>Discussions>PLUMBING>Noisy Hydronic Heating System
4 posts / 0 new
Last post
NBPTYEAT
Noisy Hydronic Heating System
NBPTYEAT

Just moved into a home built in 1952 and the cast iron baseboards are great...but they are noisy. I have 3 zones (basement (zone 1), main living area (zone 2), and bedrooms (zone 3)). I have bled each zone, first at the furnace, and then at each baseboard coin bleeder, so I am fairly confident they system is free of air. Each baseboard is getting warm as well. When the heat kicks on, there is 20 minutes of time where there is a lot of popping and snapping in zone 3. The other two zones are noise free. The system is a monoflow hydronic system, so each radiator has a supply and return teed off of a the main supply line in each zone. The master bedroom has a long run (about 37ft) of radiator along 3 walls. I believe the noise is coming from the expansion and contraction of the radiators+copper pipe. I removed the metal aesthetic covers at each corner and on the end of the runs, and noise was reduced significantly. My question is what are my options for "absorbing" the expansion and contraction in the noisy radiator runs? I have seen copper expansion pipes, but have no idea who makes them or where buy them. Any ideas?

johnjh2o
Re: Noisy Hydronic Heating System
johnjh2o

Open the hole in the flooring were the pipe comes through feeding the baseboard.

brewster
Re: Noisy Hydronic Heating System
brewster

NBPTYEAT,

I agree with John!

Expansion noise from hot water baseboard & hw radiator supply lines & enclosures is a very common problem this time of year---the weather is at its coldest, and you accurately note that there is much heating EXPANSION & CONTRACTION of the hot water supply/return lines that create unacceptable noise---there is also the danger that one or more of these metal lines will open at a joint , spilling hot water all over & shutting down the heating system.

Read up on the other respondents on this topic who are also have this same problem:--- in the Plumbing & Insulation -HVAC sections: "Can 2-zone water heat.." by jeanette19; "Radiant subfloor baseboard expansion" by Josiet; "T-stat setbacks for boilers" by marcqs; ""Knocking noise in Baseboard.." by jsurpless.

This problem is best solved by calling in an EXPERIENCED heating service company, especially one that specializes or has a lot of experience in hot water (hydronic) heating; the other postings list a number of things that can be done (some diy) that may or may not work, according to the specific setup of your particular hot water pipe/baseboard/covers setup & determining what exactly is making the noise in each part of your particular system; with any diy approach you always run the risk of causing additional damage & water leakage, compounding the expenses you'll have to pay to hire a pro.

Hot water baseboard heating has been around for decades, so there are local techs in your area that have many years of experience on this stuff & can cut to the chase, based on exactly what the pipes are doing on your particular system to make noise; you mentioned copper expansion pipes; others mentioned taking a small hand-held jig saw & widening the floor access holes at either side of the baseboard sections; others have mentioned cutting out a 12" section of supply/return piping & inserting a foot of plastic PEX tubing; others have suggested checking the boiler operating temperature & to reduce it slightly to see if it makes any improvement; some of these methods require draining part of the system of its water, then refilling & purging the air out---so it can get involved.

You can try to do some of these things yourself, but you may cause damage & water leakage if you're not careful; I think it's best to call in an experienced heating repair person (the problem is finding a knowledgeable tech) ---they have the tools & equipment to make a quick job of it.

NBPTYEAT
Re: Noisy Hydronic Heating System
NBPTYEAT

Thanks John and Brewster. If I were to open the hole up where the pipe comes up through the sub-floor, do you have any recommendations on doing that while the copper pipe is still in place? Obviously being very careful not to cut the pipe, is there a way to cut out enough wood to at least get a plastic isolator between the pipe and wood floors. Removing the pipe to widen the hole is a much bigger project, but I suppose that would be the best way to get this done...?

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.