boiler overheating

Reply

  #1  
Old 04-07-02, 04:00 PM
nguyen1953
Visiting Guest
Posts: n/a
boiler overheating

I replaced the water pressure regulator on my boiler (after having replaced the air expansion tank and the pressure relief valve), but the problem of overheating (hot water leaving the pressure relief valve) seems to continue. The temperature settings for the boiler are as recommended.

What could then be the problem?

Thanks.
HVN
 
Sponsored Links
  #2  
Old 04-08-02, 06:53 AM
TheZman
Visiting Guest
Posts: n/a
Hello HVN,

1) What is the alimeter gauge reading when the boiler is cold ?
It should be 12-15 PSI.

2) What is the altimeter gauge reading when the pressure relief goes off ? It should be 30-35 PSI.

3) What is the pressure of the air in your expansion tank?
To measure this, you need to drain your boiler until the altimeter reads 0 PSI. Then with a tire pressure gauge attached to the refill valve on the expansion tank, you should get a value of 12-15 PSI. If not, refill it with a tire pump and remeasure. Then refill your boiler. I am assuming here, that you have a modern expansion tank (with a rubber membrane) that has one pipe to the boiler and no drain valve.

4) By the way what are your temperature settings on your aquastat(s) ?

Thanks TheZman
 
  #3  
Old 04-08-02, 07:09 AM
nguyen1953
Visiting Guest
Posts: n/a
Boiler Overheating

TheZman,

Again, thanks a lot for your help.

"4) By the way what are your temperature settings on your aquastat(s) ?"

There are two: I believe one is set at around 180 (the one right next to the combustion chamber) and the other at 200 (the upper limit aquastat).

I'll try to test the air expansion tank as you've suggested (I do have a modern one as you described).

"2) What is the altimeter gauge reading when the pressure relief goes off ? It should be 30-35 PSI. "

Yes, it gets up to around 35 PSI.

"1) What is the alimeter gauge reading when the boiler is cold ?
It should be 12-15 PSI."

Yes, it's in the range of 12-15 PSI.


Thanks again.
HVN
 
  #4  
Old 04-08-02, 07:52 AM
TheZman
Visiting Guest
Posts: n/a
Hello HVN,

Your aquastat temperatures seem high.

Typically, the high limit (where the burner is cut off) should be around 180 degrees F. The low limit where the circulator pump turns on is 160 degrees F. This is the scenerio, if you have two aquastats.

If you have a differential dial (one master aquastat), the difference between the two (high and low limits) is 15 degrees.

Regards TheZman
 
  #5  
Old 04-08-02, 08:01 AM
nguyen1953
Visiting Guest
Posts: n/a
Boiler Overheating

TheZman,

Thanks a lot!

HVN
 
  #6  
Old 04-13-02, 07:21 AM
nguyen1953
Visiting Guest
Posts: n/a
Boiler Overheating

TheZman,

"1) What is the altimeter gauge reading when the boiler is cold ?
It should be 12-15 PSI."

I drained the boiler, let it cool, and refilled the expansion tank to 12 PSI. When I turned on the water (but not the boiler), the PSI on the altimeter reads 20. Why not 12-15 PSI? Something else is wrong? What else did I miss? I've already installed a new water pressure regulator.

Thanks for your help.

HVN
 
  #7  
Old 04-13-02, 07:42 AM
TheZman
Visiting Guest
Posts: n/a
Hello HVN,

When you refilled the boiler, do you lift the quick-fill lever on your Watts pressure regulator to speed up the refilling?

If you did, it will overshoot above 12-15 PSI, if you do not back it off towards the end.

You should be able to fix this easily, by pulling the lever on your pressure relief valve and draining the excess water till the pressure is within the 12-15 PSI range.

By the way, what is the status of your aquastat(s) ?

Good Luck The Zman
 
  #8  
Old 04-13-02, 07:54 AM
nguyen1953
Visiting Guest
Posts: n/a
Boiler

TheZman,

Thanks. I've lowered the aquastats to the levels that you suggested.

Have a good weekend!

Thanks again.
HVN
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


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