High pitch Noise

steve617

New boiler installed and getting a high pitch noise from the baseboard closest to return in both zones. Not sure if it air or normal sound. Old boiler had zone valves and was not moving much water because heat exchanger was clogged. Any ideas?

IMG_0562.jpeg

EdTheHeaterMan

When People tell me that the heater is making a humming noise I tell them that it forgot the words. If you place the sheet music with the lyrics in front of the heater… it will stop humming and just sing along with all the other parts.

Your heater looks like a soprano which explains the higher pitch.

🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣

Unfortunately, your installer likely should have used zone valves instead of multiple circulators.

Based on how the two circulators are programmed, and the fact that they are installed on the return piping pumping toward the expansion tank, the noise you are hearing may be the result of the pumps attempting to move too much water while operating at insufficient inlet pressure.

When the pressure at the pump inlet drops too low, the circulator can begin to cavitate. Cavitation occurs when small vapor bubbles form at the pump inlet and then collapse as they pass through the impeller. This process creates noise and vibration, which can travel through the piping and often becomes noticeable in the last few feet of baseboard radiation. Also installing the circulator pumps on the supply side of the boiler pumping away from the expansion tank would have been a better choice by your installer

You may want to try increasing the system's static pressure to approximately 15–18 PSI when the system is cold.

Before increasing the system water pressure, the expansion tank air pre-charge should be adjusted to match the new system fill pressure. This adjustment must be made before the water pressure is raised, so the air charge is not influenced by the system water pressure.

The expansion tank air adjustment must be completed while the system water pressure is still at or below 12 PSI

SO try this:

1. Measure boiler pressure when cold
2. If below or at 12 PSI, addd air pressure to the expansion tank to 18 PSI
3. Now add water pressure to the boiler to 18 PSI
4. Operate system to see if the noise stops

mattmia2

what kind of boiler did you have that the hx was clogged? that is an unusual thing to happen to a cast iron hot water boiler, at least on the water side.

steve617

Thanks. Isn’t the pressure the same on the supply and the return? Why would zone valves be better? I thought pumping is a common way to control two zones.

steve617

This is picture of old boiler.

IMG_0492.jpeg

IMG_9533.jpeg

mattmia2

my bet if you had insufficient output from that is that the thermopile was getting weak, when it was cold it had enough current to open the gas valve then the burner would come on and heat the "cold" side of it, the output would fall, the burner would go out, the cold side would cool, the burner would come back on. you'd get some heat but not enough.

Jamie Hall

https://forum.heatinghelp.com/discussion/comment/1893684#Comment_1893684

It is — when the pumps aren't running. As soon as a pump starts, it creates a pressure difference across itself; that's why the water moves. That may easily be 10 pounds, lower on the inlet side.

Pumping is a common way to control two zones. So are two zone valves. Both have their advantages — and disadvantages.

steve617

So you always have lower pressure on the pump inlet when running, doesn’t matter if on supply or return?

Jamie Hall

https://forum.heatinghelp.com/discussion/comment/1893691#Comment_1893691

Correct. Now the trick is that the pressure at the expanson tank is held steady by the tank, so depending on where the pump is in relation to the tank, the pressure at the inlet may be less than the pressure at the expansion tank — perhaps quite a bit less. Now apparently the pumps are on the returns in your system, and the expansion tank isi on the supply. This means that the whole pressure loss of the system shows up as a low pressure on your pump inlets — and this can be problematic for a number of reasons.

Noise being one of them…

steve617

would it help to put the expansion tank on the return?

Jamie Hall

https://forum.heatinghelp.com/discussion/comment/1893701#Comment_1893701

If you had a common return, yes — but as I understand it you have two pumps, one on each return from the loops? The tank has to be connected BEFORE the inet to the pump, and with two pumps in parallel…