2 Rads bridge cold side to hot side of boiler?

Reply

  #1  
Old 06-12-12, 05:25 AM
Member
Thread Starter
Join Date: Jan 2012
Location: Canada
Posts: 2,739
Received 16 Votes on 15 Posts
2 Rads bridge cold side to hot side of boiler?

I was downstairs last night tracing out the pipe work for my domestic water in the house when I noticed something odd.
One the main floor zone, just before the boiler on the cold side, I have a tee that sends a 1" pipe to the rad in my dinning room and the rad in the back hallway. This branch returns to the main 2" loop on the hot side of the boiler.

This definately doesn't appear to be correct and now expains why the dinning room and back hall are so cool compared to the rest of the house.

Has anyone seen this before?

Am I correct in thinking that the 1" pipe size is having more of a negative impact on the rad temp then the fact it's bridging from the cold to hot side?

With the price of copper, this is going the be a bit of an expensive fix.
 
Sponsored Links
  #2  
Old 06-12-12, 02:36 PM
Member
Join Date: Aug 2009
Location: USA
Posts: 4,947
Received 0 Votes on 0 Posts
What makes you think that the water travels from the the return piping to the supply piping and not the reverse? I doubt the pipe size is causing the problem with your rad temperature. You could be right about the way it is piped is causing the problem. How is the rest of the loop piped?
Is it in series?
 
  #3  
Old 06-13-12, 05:19 AM
Member
Thread Starter
Join Date: Jan 2012
Location: Canada
Posts: 2,739
Received 16 Votes on 15 Posts
My zones are setup with the rads in parallel to the loop. Below is a really quick and dirty sketch of how the boiler is setup (only showing the one loop with the bridged rads. The line in red shows the bridge which is 1" pipe instead of the 2" pipe the main loops are using. It's proximity to the boiler in the sketch is about where it is in the basement.

Name:  boiler2bridge.jpg
Views: 445
Size:  15.2 KB
 
  #4  
Old 06-13-12, 10:56 AM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,493
Received 33 Votes on 25 Posts
Redo the drawing showing the circulation pump. As I recall from previous threads your pump is on the discharge of the boiler. If it is between the boiler and the branch pipe then you have the flow arrows on that branch backwards.
 
  #5  
Old 06-13-12, 11:04 AM
Member
Thread Starter
Join Date: Jan 2012
Location: Canada
Posts: 2,739
Received 16 Votes on 15 Posts
Here is a quick update sketch with the circulation pump and pressure tank shown. I put a simple envelop to where they are located in the sketch. The tank is located between the boiler and the circulation pump.
Name:  boiler2bridge2.jpg
Views: 427
Size:  19.6 KB
 
  #6  
Old 06-13-12, 11:41 AM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,493
Received 33 Votes on 25 Posts
The pump discharge is the point of highest pressure so your flow arrows on the branch loop are definitely backwards. Nothing wrong in the way this is piped (according to the sketch) but it IS possible there is some unknown obstruction in the piping.

Do you have only a single pipe system as shown in your sketch? These require special tees in either the supply or return (sometimes both) to the heating elements. They are also sometimes difficult to purge of air.
 
  #7  
Old 06-13-12, 11:45 AM
Member
Thread Starter
Join Date: Jan 2012
Location: Canada
Posts: 2,739
Received 16 Votes on 15 Posts
Looking at it more, you are right Furd.

I'll look closer tonight and see if it is using only standards tees. If so, it would be missing out due to the pressure difference between the 2" main and the 1" bridge.
 
  #8  
Old 06-13-12, 12:14 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,493
Received 33 Votes on 25 Posts
The tees at the main would be standard tees; it is the tees that supply the heaters that need to be special.
 
  #9  
Old 06-13-12, 12:23 PM
Member
Thread Starter
Join Date: Jan 2012
Location: Canada
Posts: 2,739
Received 16 Votes on 15 Posts
I would have thought that the principles that require the diverter tee at the rads would be the same principles that would require it going from the 2" main loop to the 1" branch loop
 
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
 
Ask a Question
Question Title:
Description:
Your question will be posted in: