Noisy Baseboards

NBPTYEAT

I am hoping someone can help solve my noise issue in our new home. Let me start with describing the system. We have a Lochinvar Knight gas fired boiler, with Squire hot water tank. The heating system is a monoflo hydronic, with three zones (main, family, basement). All baseboards are cast iron and have there own supply and return with a coin bleeder valve on the return side of the baseboard. The three bedrooms are on the same zone (main), along with the kitchen and office. I have no noise issues with the family or basement zone, only the main zone. When the thermostat calls for heat, there is a 10-20 min period of noise (snapping and popping) locally at the baseboards. Its so loud that it will wake you up from a dead sleep! It also happens when the hot water is no longer supplied and the baseboards begin to cool. I have tried a few things:

1. Bled the whole zone for air at both the boiler and each baseboard. No noticeable change.
   
2. Opened the hole in the floor/subfloor around the copper supply and return. Some minor improvement.
   
3. Replaced the supply side section of piping to the master bedroom. I had suspected that the pipe was rubbing on the sill plate, and it was. I had to drain the whole zone to do this. When filling the zone back up, we ran the heat for a few hours and the noise seemed to be gone, but it wasn't. The next morning all the popping and snapping started again.
   
4. I reduced the water temperature out of the boiler from 180F to 125F, thinking this would reduce the amount of expansion/contraction. Still not much improvement.
   

There are three sections of baseboard in the master bedroom, each on a different wall and connected by a section of piping at the corners. This is the longest run on the first floor, around 35ft from the main supply loop. I'm out of ideas and would kill for a good night sleep! Any help would be really appreciated!

Gordy

Obviously you understand this noise is expansion when heating, and contraction when cooling.

When you bled the system did you get air? If not it's not an air problem, and an entirely differentt noise.

As you have found friction of piping rubbing on structural components is probably your biggest issue. Coupled with high supply temps.

Constant circulation can curb the noise of expansion do to a slower expansion contraction process. A long with lower average water temperature if possible. Did anyone do a heat loss, and determine if the baseboards are oversized enough to run lower water temps?

Also are you utilizing outdoor reset? This will help improve noise, and efficiency of the boilers performance.

Aaron_in_Maine

Popping is usually pipe touching wood somewhere usually where the pipe comes through the floor. The wood does not like the temperature change when a call for heat changes the water temp so fast. You can either make the holes bigger or if there is enough room put a ring of rubber gasket material around the pipe.

NBPTYEAT

No air when I bled the system. Nobody has done a heat loss analysis. How would I get this done? I am aware of outdoor reset, but when I cycled through the menu options on the Lochinvar, I didn't see this feature, although it is talked about in the manual. Would it be hidden under the INSTALLER code (can anyone share this for Lochinvar?).

As an aside, the DHW is set to output 140F. Does this seem correct?

Gordy

Is the outdoor reset sensor installed? Let's get som pics of the boiler, and associated piping posted. Also if you can get some with the monoflo baseboards from below.

What is the Lochinvar boiler model? KHN? High efficiency?

NBPTYEAT

Not sure how to tell. The display will read the outdoor air temperature, but it also shows SYS:Open and OUTDOOR: 46F

Gordy

For the DHW if you mean supply to fixtures is 140 then you should be using a mixing valve.

Are you running out of hot water?

NBPTYEAT

I believe DHW is the supply temperature to the hot water tank from the boiler. We don't have any issues with running out of hot water. There appears to be a mixing valve installed, and its set to 125F, which works fine. My feeling is a 140 set point is ok.

Gordy

NBPTYEAT said:

Not sure how to tell. The display will read the outdoor air temperature, but it also shows SYS:Open and OUTDOOR: 46F

If it is displaying outdoor temp the sensor is installed. Should see it outside hopefully on the north side of the house, and where heat sources will not effect it's reading.

Was the manual with the boiler?

Gordy

NBPTYEAT said:

I believe DHW is the supply temperature to the hot water tank from the boiler. We don't have any issues with running out of hot water. There appears to be a mixing valve installed, and its set to 125F, which works fine. My feeling is a 140 set point is ok.

That's fine.

For simplicity there is a free heatloss calculator offered by slant fin online. Once you do a room by room calculation . Then you can see output charts at different water temps for your particular baseboards.

Understand you do not need 180* water everyday of the heating season. Maybe only at design day.

NBPTYEAT

Yes I have both the operation and installation manual. The previous owners left behind a sensor KIT40022, but I don't what it is for.

Gordy

That's a sensor and bulb well.

Gordy

Need to know the model of your boiler, size etc.

Gordy

That kit is the system supply sensor for the boiler. Either it was not installed, or it was replaced. I suspect it was not installed.

NBPTYEAT

Model# KBN150
Heating Capacity 136,000 BTU/Hr

Gordy

Can you take some pics of the boiler, and associated piping?

I know your inquiry is about the noise. But fine tuning the boiler has effect to this.

If you can do your own heat loss will help also. Pretty big boiler unless you have a really big house, or poorly insulated envelope.

NBPTYEAT

I did the heat loss calculation for the master bedroom, which is probably one of the worst cases. There wasn't an option to include a fireplace in the calculation, and there is one in the bedroom that has a damper, but is not airtight. Without the fireplace, I came up with 5754 BTU/hr.

There is 30ft of 7in tall cast iron baseboard in the master bedroom. It looks original so it may be from the 1950s.

NBPTYEAT

I figured out how to set the Night Setback time and temp. It's now programmed at 120F from 7am to 10pm. Although I was still hearing noise with a 125F set point that I tried earlier....
I am only guessing if the 120F night setback temp is correct, please advise otherwise.

Gordy

I don't see the supply sensor installed.

Your ODR sensor must be installed. It's giving outdoor temp readings.

So your setting back at night? How much? That adds to noise issues also.

NBPTYEAT

Night set back was disabled until now.

Gordy

If you want optimum system ,and boiler performance for efficiency. And hands off operation you need the ODR setup properly.

The near boiler piping seems per the manual. All though no supply sensor installed. Need that.

Gordy

Do you understand what outdoor reset is, and it's advantages?

Gordy

Another thing is there a condensate tube running off the boiler? Is that it in the pic black, and gray pipe running along the wall?

Is there a neutralizer in the piping?

NBPTYEAT

ODR reduces the circulating water temperature between predefined nighttime hours. Correct? I could set ODR to 60F, then program the boiler to raise temperature 10deg every 10min until the zone thermostat temperature is met. This would allow things to warm up slowly, and maybe help with the noise? I'm guessing this won't help noise due to contraction during cool down.

Should I have the supply sensor installed?

Gordy

No.
Outdoor reset adjusts the systems water temps based on the outdoor temperature automatically. At design day (coldest day) you may need 160*. On a mild day you may need 120*.

I think you should get a competent installer that is fluent with the Lochinvar boilers controls. Yes the sensor needs to be installed, and the ODR programmed.

That boiler will never get it's advertised efficiency with out the ODR installed and programmed properly. Right now it may be running mid 80's efficiency.

Go to find a contractor on the main page of this site see if someone is close to you.

If you have the ambition to read the I/O manual so you can more fluently understand the appliance I would also do that.

NBPTYEAT

Sorry, I mixed up ODR with Night time set back and the boost temperature functionality. I believe the ODR is programmed. Today the temperature outside is 50deg, and the system is running 120deg water temps. The maximum water temp setting (SH set point) is 150deg. Recently, I had a heating technician come in, clean and service the system. He plugged in to the boiler and printed a measurement of efficiency and told me the parameters were within manufacturer recommendations. I should have read the manual before I had them come in

There is a condensate tube that is piped down through the foundation. Not recommended nowadays from what I've learned.

Gordy

Okay. Did not know all this.

Back to your issue. Do what you are doing with piping rubbing on structural components where ever you can.