Replies

1. 
   reinvent | Oct 03, 2009 01:50am | #1

   I bet the guys over at

   http://heatinghelp.com/

   would have fun with that Q.

1. 
   GRCourter | Oct 03, 2009 02:17am | #2

   This system was installed by one contractor and when it was not heating properly a second contractor came in and looked at the system.  There have been three state mechanical inspectors inspect the system.  I did re-configure the sunroom, but I put my return line on the down side of the check valve, but to confess I have been on the job site 3 different times.  It was not until I was reading the tubing marks to see the lenghts of the runs that I saw the error.  Pretty amazing that the system worked at all

2. 
   mike585 | Oct 03, 2009 03:09am | #3

   I think it's intentional. Known as primary/secondary pumping. A loop around the boiler and a loop to the zones, coming off the primary loop. I think it keeps the boiler return temps from dropping too low, which is bad for the boiler.

   It works as long as the primary loop stays hot, which it does.

   
   

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   Edited 10/2/2009 8:11 pm ET by mike585

3. 
   Marson | Oct 03, 2009 04:09am | #4

   Right. Mike's got it. Check out page 20: http://www.weil-mclain.com/downloads/literature/cga/cgaboilermanual.pdf.

1. 
   GRCourter | Oct 03, 2009 05:59am | #5

   Ok, I would agree that in the system that you referenced works.  There are not any balancing valves return gauges and/or check valves on the system that the customer has.  I did not read the complete manual yet but this appears to be for a specific boiler.  This system uses a Triangle Tube on demand heater which also has a domestic water storage tank.  There is nothing in any of the information that has been left at the job site that suggests that the primary/secondary system should be used with this boiler.  The Weil-Mclain talks about keeping the return temp at or above 130 degrees and this would mean that my supply temperature would be above 130 and this would mean that the wood floor would excede the recommended 88 degrees.  But thanks for the link for I am sure that I will run into one of these boilers sooner or later

1. 
   Marson | Oct 03, 2009 04:02pm | #7

   I just linked to Weil-McClain because I had recently seen their install instructions (I've got the opportunity to get one free from a job). Obviously, you want to go to the manufacturer whether that's by studying the manual, contacting them, or hiring someone who knows the ins and outs of your specific boiler. I was trying to answer the question "why does this work?" in a general way by pointing to primary/secondary piping. Don't really know enough to comment on your situation.I know a guy who didn't trust his boiler installation, so he took photos of the complete system and sent it to the manufacturer (Munchkin) who told him what was wrong (some bozo had piped the whole thing with 3/4 pipe for one thing). BTW, if the system really needs 88 degree water, wouldn't it have a mixing valve?

1. 
   GRCourter | Oct 03, 2009 04:35pm | #8

   By the way, I love Munchkin boilers.  The installation manuals call for a closed loop system and there is no mention of mixing valves.  I have seen 2 other Triangle Tube boilers in use before and they do not cross over the supply and return.  I am looking for a floor temp not to excede 88.  Last winter the boiler was running at 160 output to get the floors to 78 with a return temp of about 140.  I re-piped and changed the heat transfer plates from galv steel to Joist Trak in the sunroom and was able to drop the supply temp to 130 and raise the floor to 86.

2. 
   mike585 | Oct 03, 2009 04:36pm | #9

   If you use primary/secondary piping and you want to control the temperature of your radiant loop, just use a 3 way mixing valve. Don't use a 3 way valve if you are not using primary/secondary. If you want to know more, get yourself a copy of Hydronic Radiant Heating by Dan Holohan. It's a paperback, easy to understand.

1. 
   GRCourter | Oct 03, 2009 04:45pm | #10

   Thanks for the input Mike.  Just wanted to know if I was incorrect in feeling that this needed to be corrected with either mixing valve or removing the T.

4. 
   rich1 | Oct 03, 2009 09:57am | #6

   Why is the return t'd?

   Cause someone screwed up.   They may have been trying p/s, but that ain't it.  But on the upside, TT doesn't require p/s. 

   And 88 is the max surface temp of the floor.   Depending on the type of system, how it is controled, and the time of year, the water temps could be anywhere from 75 - 80 to 165+.

   
   

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   Edited 10/3/2009 3:00 am ET by rich1

5. 
   dreadlock | Oct 05, 2009 05:57am | #11

   unsure but you need to move paperwork from exaust.