I was called today by my cousin to check his WeilMclain G-04 boiler and found out that there was a chattering sound when the temperature reaches about 160deg. First I suspected that the sound was coming from the gate valve on top of the boiler (hot water line supplying to the baseboard heaters). I tried to close & open the valve as I suspect that the disc is loose but still the sound is there. The sound is annoying and can be heard up to the farthest room. The boiler is working alright except for this sound. I also suspect that the coil in the tankless heater fitted might be touching something inside the heat exchanger. Any suggestion on this will help me further diagnose the cause of the problem. Thank you

 

This is difficult because we can't hear it... are you sure it's not coming from the circulator pump? Perhaps a broken coupler? If it's that loud that you can hear it that far away... of course if it only does this when the boiler is above 160, that's probably not it....

What are the readings on the pressure gauge when it is at 160 and above?

 

Thanks NJ, yes I know that I can't describe to you the same sound that I heard but for sure it's not coming from the circulator. I also observed that when the boiler is off and the circulator is running, the sound is gone. The pressure on the boiler is about 20psi. I will visit to the place tomorrow to check once more. I am planning to open the tankless heating coil and check further. I'll post whatever results and work done if the problem is solved. This forum is really of great interest to me as I am encountering a lot of calls from friends around here and also it enhances my knowledge further.

 

Burner related maybe? Possible broken squirrelcage or foreign
object in air intake?

 

Thanks Steve. I don't think it's from the motor. The circulator is running ok also. Just today I went back there to check further and this is what I've done. I switched on the boiler from a cold start(about 130F) and observed the pressure/temperature readings. At about 155F the sound starts again till the burner stopped at 180F. I pressure is almost 30psi and I noticed some small drip of water from the relief valve. I let the boiler cool down, drained and removed the heating coil to check furhter. I didn't find any unusual thing inside to I decided not to install back the coil but rather cover it with a prescribed blank cover and install back the Aquastat L8124A. I switched back on the boiler and the sound still comes back same as the previous observation(like a grinding or boiling water sound). Since I cannot figure out what causes the sound I decided to lower the pressure as I am not sure if the pressure gage is giving me a correct reading and the sound was reduced. Reducing it further to 15psi and the sound furhter reduced. I lowered it 5 psi and the sound can still be heard when temperature is about 175F but not as loud as before and already tolerable. The pressure goes up to about 8 psi & 180F(at this time the burner shuts off).
Next time I will change the temperature/pressure gage and observe further. This boiler was checked by a heating service company but was not able to solve or least what causes the sound. Would appreciate if you have more suggestion. Thank you.

 

Is the system glycolled? If so, a mix too rich in glycol will make
strange noises in a boiler. Does the system have a good in-
hibitor in it? I use "8-WAY". Does the 1/2" port next to the
boiler supply have an autovent plumbed to it? Is it working?
That port is for a vertical riser that the fresh water feed and
expansion tank should be plumbed to. Do you have a diaphram
type tank, or old school stuff? Pictures would be a big help!
Gauges on the early GO series boiler are notoriuos for leaking
or giving false readings. Those old style A-stats aren't quite
up to par either. I always adjust A-stats by the gauge, not
the settings on the adjustment block. When you removed the
coil, how cruddy, mucky, slimey, scaley, etc. was the interior
(wet side) of the boiler?

 

Thanks for your quick reply. This is a replacement boiler from the old one which was installed about July '07. I don't think this was glycolled or a rust inhibitor in it. It has a diaphragm type ET with air vents on both the ET and the supply pipe sides. All of them are working. According to my cousin, the service guy replaced the Aquastat with a new one. The inside of the boiler where I took out the coil is relatively clean so with the coil though it looks light black in color but not slugde/slime. When I drain the water(though not drained it totally)is not that dirty at all. I am planning to return back the heating coil as the owner requested to re-piped the heater and connect it back the domestic hot water system(as it was originally). The service guy removed it per request of the owner thinking that it might be the cause of the noise and everytime someone uses hot water and the boiler starts, the noise is annoying. But before doing so, I will pressure test first the coil and drain totally the boiler and set what happens. BTW is there an easy way to add inhibitor to the system? I have done this before on big systems wherein we install a manual chemical feeder on the return line. If you have some more inputs, appreciate it very much. Thanks again.
Tino

 

One qt. of 8-way treats 30 gal., pour it in the coil hole before
you replace the coil. Another option is to remove relief valve
and pour it in there. Still need to know if you have an auto
vent installed at the 1/2" port on top of the boiler, next to
the boiler Out or Supply. Picture?

 

Thanks for the input. There is an air vent installed just beside the supply pipe on top of the boiler and one on top of the tee joint of the ET. Will try to look first for the 8-way here in Juneau if its available before I install back the coil. Thanks again.
Tino

 

Here's how I plumb most cast iron boilers. I get my 8-way
corrosion inhibitor from Hasco.

 

Thanks Steve, you've got a nice plumbing installation there. The one we are talking is not as big as this pic. It is a regular residentially installed boiler. The circulator is installed on the inlet side of the boiler as most of the installation I have seen here in Juneau. Though the boiler works well except for that sound they noticed lately. I still have to further look into this problem. Thanks for the pics. I got an idea of connecting your heating coil with PEX and perhaps I can use that on later of my work. I am not sure if a copper flexible pipe would be advisable to connect this to the rest of the piping work.(If it is used on water heaters, I think it is applicable too? any comments). I'll check with the local supplier if they carry this product. I'll be out for a week so I'll let you know next time. Thanks.

 

Hi. It's only now that I was able to work again on this boiler after over a month long work in the state ferry. I went back to my cousin's place as he wanted to re-install the tankless heater. The sound is still there though not as loud as I've described before. Before I did the re-installation, I did again a thorough observation where the sound is coming. The sound is similar to a boiling/popping steam just close where the tankless heater is located. I was suspected that it might be coming from the burner/electrode sound so I open the burner, inspect the firebox and I can't find anything strange or unsual. I also changed the pressure-thermometer gage, checked the expansion tank and it is ok. I checked also the inside of the waterside of the boiler before installing the heater(thinking that there might be some foreign object) but it's clear. I used an inspection mirror to check the inside just to be sure. I operate the boiler and observe. From a cold start, the sound comes on when the temperature is about 140F similar to simmering sound to a boiler/popping sound till the boiler stop. Although the intensity of the sound is not so annoying compared earlier, it was not totally eliminated. I tried to observe with the boiler on cycling mode(cut in 160F/cut-off 185F) with the heater being used. The boiler runs for about 3-5 minutes and the sound is tolerable. I adjusted the water pressure to 10psi at it seems that the sound lessen with a lower water pressure. When the boiler is operating, the pressure goes up to 15psi max. I also recharged the ET to about 12-14psi(I'm using a tire gauge and not sure how accurate it is). Though my cousin was happy with the work I've done, I'm not still convinced that the sound was not totally solved. Thank you guys for all you inputs.

 

Steve,
I can't source the 8-away inhibitor you mentioned. I tried the local heating supplier here but they only have the Hercules brand boiler cleaner. I didn't use it as I am not sure of its performance or realibility, any comments is appreciated. Although, when I drained the boiler, the water is relatively clean and not much rust or deposits coming out. Thanks again.
Tino