Very noisy base boards- no air

lukenurn

I have an older munchkin boiler with baseboard radiators that works really well. I just did a repipe and designed it to pump away, introduced an air separator, bladder expansion, and relocated cold supply all at the PONPC. Definitely fixed the air in the pipes. However didn’t fix noise issues that have existed since before repipe

These pipes are terribly noisy- keeps waking me and my family up all night. As soon as the pumps kick on and push water through system, there is a whole chorus of loud pops and clangs for a few seconds, then doesn’t really resume until the water gets hotter, then you get an occasional tick, pop, and sometimes a bang that can be felt through the bed sheets (not the enjoyable bed sheet bangs). 

We have resorted to leaving the master bedroom door open to give the bedroom zone thermostat warm air from the main house zone so those pipes can bang all night away from our ears and keep the bedrooms from kicking on. I’m getting desperate as these Wisconsin winters are long and noisy. 

Could it be the system pressure, the temperature settings, or any only solutions for this??  Seems to not only be noise from temperature change, but perhaps also from pump pressure change as it happens immediately, unless I’m deceived. 

I can share photos of baseboards if that is helpful. 

Home is a 1500 sq ft ranch, 2 zones both on first floor, boiler in basement. From pumps to highest point in system is only 3-4 feet high. 

I appreciate your perspectives!

EdTheHeaterMan

You may be describing the expansion of copper pipes.   As the copper pipes the baseboards are made of heat up, they grow. If you have a long enough straight run of copper the expansion could be significant.  There is a device or fitting available for this problem. It’s called an expansion joint.  

If the pipes are routed thru the floor and the opening is very tight, there is no room for expansion. That can be very noisy.  

In your minds eye, think of how the pipe is oriented thru your home and if the holes are too constricted.  You may be able to locate the actual place the banging is happening and cut the hole larger, or put a piece of felt or rug around the place where the pipe comes in contact with the structure.

i learned this the hard way when I tried to route soft 3/4” copper thru 1-1/8” floor joist so we could Sheetrock the basement ceiling.   Looked great all summer.  Come the Fall,  we thought the house was haunted with all the creaking in the floors and ceilings.   

They have specifications and special plastic inserts to reduce and/or eliminate the expansion noise

https://www.metraflex.com/compensators/model-hpff2/ 

This is one type that is rarely used anymore. You may need to special order if needed

sometimes just adding a small loop coil of copper or a series of long turn 90 Elbows can take up the additional flex of the copper pipe.   I believe it can happen with PEX and Iron pipe also. 

Dave H_2

Also using outdoor reset can mitigate the problem. You have cold copper pipe and water all of a sudden getting slammed with 180 degree water, lots of expansion going on.

A weather responsive controller will modulate the delivery water temp based upon how cold it is outside.

Dave H.

HomerJSmith

Your Munchkin Boiler should have an outdoor reset which would modulate the water temp, as the outdoor temp drops the water gets hotter. As Dave says.

Pics are always helpful.

JUGHNE

Do you have primary/secondary piping.....2 pumps?
Is the boiler pump pushing water into the boiler?

dopey27177

All of the above statements are very true,

One thing I think that may have been left out is maybe the high end temperature of the water is in the 200 degree range. If so any remaining air in the system may cause steam to occur in the heating elements which will cause banging,

I am assuming that your system pressure is about 15 psig.

Some times all the air in the water heating system even though it is pumping away does not vent all the air out right away. Try this,
run the system with out making heat to circulate the water at a much lower temperature, this may help remove the remaining air from the system.

Jake

HomerJSmith

The hotter the water the more air is driven out of solution.

Pressure in a boiler sys is for 2 reasons. First, to prevent air from entering the sys at the end of a heating circuit where negative pressure may pull in air as the dynamic pressure drops. That is where we want 5 psi above the sys static pressure. Second, increased pressure, like the 15 psi radiator cap on your car's radiator, raises the boiling point of water.

Setting the Munchkin high limit to 200 deg is a waste of energy unless the sys heat emitters demand that higher temperature to keep the house comfortable in the coldest day in winter. The sys should be on outdoor reset with the lowest high limit, necessary.
With an indirect water tank with the boiler setting at 195 or 200 deg for a fast recovery of the tank water is ok. Preferably a Vision 1 setup with the sensors.

I really at this point think that the pump may be to big and what you hear flow noise, but I don't have any information to go on.

I don't even know if the Munchkin is piped as a primary-secondary sys which is essential.

Ya! Pic of the boiler and baseboard would help a LOT.