Radiator Banging - forced hot water system


  #1  
Old 10-21-05, 07:19 AM
bluewind101
Visiting Guest
Posts: n/a
Radiator Banging - forced hot water system

My home is two stories and has four zones. Two zones have cast iron radiators. Two have baseboard heaters. The boiler is a weil-mclean, and there is one circulator pump for all four zones.

The problem is with the cast iron radiators in only one of the zones (both are on second floor). They bang very loudly every now and then. I bled them and both bled water right away. There didn't seem to be any air in them.

I looked at the pressure gauge on the boiler reads 5 psi. If that is too low, how do I increase it?

Since the two cast iron radiators on the first floor, do not bang, does that reveal what the problem might be?? Any help would be much appreciated.
 
  #2  
Old 10-21-05, 07:27 AM
Ed Imeduc's Avatar
Member
Join Date: Aug 2002
Location: Mountain Williams Missouri
Posts: 17,505
Upvotes: 0
Received 1 Upvote on 1 Post
Wink

Yes 5 psi is to low for 2 floors should be about 18psi.
But is it the gauge?????? Do you get water out of the top R/D with the pump off?????

Is expansion tank ok??????


To kick up the psi that nut and screw on top of the auto fill is where you do it. Turn it down a little. BUT DONT till you check all the other thing here.

ED
 
  #3  
Old 10-21-05, 09:42 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 12,682
Received 41 Upvotes on 39 Posts
Noise

If you get water out of the rads on the second floor, your pressure gauge is not telling you the truth. If you have zone valves with electric motors (Honeywell or Erie), the noise probably happens when the valve closes. Yes?
 
  #4  
Old 10-25-05, 08:32 AM
phatmax
Visiting Guest
Posts: n/a
Originally Posted by bluewind101
My home is two stories and has four zones. Two zones have cast iron radiators. Two have baseboard heaters. The boiler is a weil-mclean, and there is one circulator pump for all four zones.

The problem is with the cast iron radiators in only one of the zones (both are on second floor). They bang very loudly every now and then. I bled them and both bled water right away. There didn't seem to be any air in them.

I looked at the pressure gauge on the boiler reads 5 psi. If that is too low, how do I increase it?

Since the two cast iron radiators on the first floor, do not bang, does that reveal what the problem might be?? Any help would be much appreciated.
Hey..sorry i dont have ans to your question but i have a question for you. Which one you like better since you have both in your house? do you like cast iron radiators better then baseboard or other way around? thanks!
 
  #5  
Old 10-26-05, 10:04 AM
bluewind101
Visiting Guest
Posts: n/a
Banging - Forced hot water system

Ed, thanks for the quick reply. It takes me a little while to try your suggestions as I am learning about this system plus I need to wait for results. I am still getting the banging. Here is what I tried:

1) Do you get water out of the top R/D with the pump off????? - I turned off the power to the boiler then loosened the bleed valves on each radiator. Both bleed water without any air.

2) Is expansion tank ok?????? - I am not sure how to tell if the expansion tank is ok. It is a 4 gallon Atrol of the diaphragm variety. There is a valve on top of the pipe joint that the expansion tank it hooked to. From what I read this is suppose to automatically take air out of the system. The cap is loose. Should it be tight?

3) PSI too low, but gauge may be bad?..? - I added water to the system until the PSI was 13. The radiators still bang, but I can't tell if they are banging differently... (louder or softer). I just checked the pressure gauge and it now reads 10. I'm not sure why that is, or if it is related to the problem. Should I increase it further to 18? Also, since the pressure gauge changed as I added water, does that mean that it works?

Thanks
 
  #6  
Old 10-26-05, 10:11 AM
bluewind101
Visiting Guest
Posts: n/a
Noise

Grady,
I like your quote, and thanks for the reply. I think the pressure gauge is working because when I added water, it rose. Now, ofcourse, it could be inaccurate.... Is there any way to tell?

The zone valves are Taco and there are four of them. The circulator pump is also Taco.

I turn the heat all the way up to open the valve. Then after 5 minutes or so, I turned all the way down. I waited about ten minutes and received no banging. Though there was a bang after I turned the heat up.(about 3 minutes later).

Thanks
 
  #7  
Old 10-26-05, 10:16 AM
bluewind101
Visiting Guest
Posts: n/a
preference

Phatmax,
I like the cast iron one better than the base board. My wife likes the baseboard better than the cast iron ones..

Anyway you cut it, we both like radiators better than hot air. We live in a small house and I like that the cast iron ones isolate the space taken. Wheras, the baseboard take 3 inches off the perimeter of the room..

On the other hand, the cast iron ones are a bit of a child hazzard..
 
  #8  
Old 10-26-05, 07:06 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 12,682
Received 41 Upvotes on 39 Posts
Bluewind

You can check the accuracy of your boiler gauge by use of a low pressure tire gauge on the expansion tank. Both pressures should read the same. BTW, the cap on the expansion tank should be kept tight. That air valve is only used for adjusting the pressure in the tank, not removing air from the system.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: