Joined on May 31, 2013
Last Post on December 5, 2013
@ December 5, 2013 10:04 PM in 1/2" pex homerun to iron radsShould be 3 sqft per section for 6 tube WM Cameos (picture matches catalog) that are 20" tall. I ran into the same 1" difference in catalog and real life on my Gurneys.
30sections, EDR = 90, 8100 BTUH @ 140 degrees
37sections, EDR = 111 , 9990 BTUH @ 140 degrees
With the BTU someone should be able to help with determining if 1/2 will handle that length.
BTW, Im not a pro, just a homeowner and radiator nut. Im in the process of installing a Modcon with old rads and a radiant ceiling. I oversized my rads to keep the down below 140 on design day.
@ December 5, 2013 1:56 PM in 1/2" pex homerun to iron radsYou say your rads are 7" wide x 6 tubes which seems like a miss-match . For example 4 tube Gurey Copley's are 7" wide and 6 tubes are 10 5/8" wide. (similar to Tinman's pic) That's why I was asking about the manufacturer. Knowing your water temp we just need to determine the EDR per section x number of sections from there BTUH and correct tube size.
I just want to clarify, with the generic tables we can pick 7" or 6 tubes and get two significantly different EDRs per section. If your measurements are correct, your rads fall outside the nominal tube count/width/EDR slope. If we know your manufacturer we can get the right data from their catalogs or the "EDR" book.
@ December 5, 2013 8:25 AM in 1/2" pex homerun to iron radsWho is the manufacturer of those rads?
@ December 2, 2013 3:01 PM in Vitodens Low Loss Header or TeesI’ve been reading through Primary Secondary Pumping Made Easy and many posts about P/S pumping. I was originally double checking configuration but have become side tracked with concerns that with the mixing that occurs with P/S the advantages of a condensating boiler might be defeated.
I was originally thinking to run with Closely spaced Ts (CSTs) and the boiler as the primary loop with the recommended fixed speed pump and a system header on the secondary loop with a Bumblebee on Delta T. As I read in other posts I was going to put a full port ball valve in the middle of the CSTs so I can isolate the Ts if required.
Reading in the Technical Data Manual for the boiler regarding the LLH it states (among other things):
“The temperature sensor connection [TS] typically located
at the top of the low-loss header ensures low return
temperatures to the Vitodens 200-W boiler at all times,
increasing operational efficiency.”
If this is accurate I should just fork of for the Veissmann LLH and call it a day. But, does it really work…
How does the boiler influence the return temperature that occurs at the output of the LLH. I can only think it would be by varying the supply temperature. But, if I understand correctly, the supply temp should be based on the demand imposed by the secondary circuit.
So how does this work?
Or Does it work?
Does anyone have any direct experience with this?
What would you do?
I hope this isn’t too confusing of a question but as I get close to boiler install time every little question puts my sweat pumps to fast speed.
And in case it matter the system basics are:
Cast Rads with one small radiant ceiling
Pri/Sec with DeltaT pump on system loop
@ December 2, 2013 1:34 PM in Residual heat from boiler and radiator pipingThanks Jamie, that makes good sense.
@ December 2, 2013 9:39 AM in Residual heat from boiler and radiator pipingWith the new system I was planning to put an old cast rad in the basement to supplement the heat. But in sizing it I was wondering how much the boiler and piping are going to contribute to the warmth of the basement. This might be a stupid question but, Could I leave the radiator out and the system would respond to the heat loss through the PEX. As we have always heated with wood in this house I have no feel for how much residual heat a boiler/piping put out. The basement is just for storage and I have a workshop down there.
1st floor 19k
2nd floor 9.7k
The first floor radiators are all piped through the basement (home run) with 1/2inch fostapex. About 220 ft total.
The boiler is a Vitodens 200 B2HA-19 running continuous on ODR. Radiators are on TRVs.
Is it worth considering or is it negligible?
I assume it could be calculated but am not sure where to start.
@ November 28, 2013 9:00 PM in New system monitoring, guages, etcI want to make sure I have the sensors necessary to do any system troubleshooting if there is a failure. Also if the design needs any tweaks, we can get the information from the system.
a system preasure guage sound like a good idea.
@ November 27, 2013 10:37 AM in New system monitoring, guages, etcWhat do you like us see installed in a systems plumbing for monitoring; temp sensors pressure gauges etc.?
The system is a Mod con feeding mostly cast rads with one radiant ceiling.
Pri/Sec with as system manifold on the secondary loop that feeds each rad (home run) and also feeds the ceiling manifold.
The Ceiling manifold has supply and return temp gauges and flow meters.
The sec circulator is Bumble Bee and it can monitor GPM
@ November 26, 2013 10:57 AM in best temperature for Cast Iron RadiatorsI'm currently installing so old cast iron rads in my house with a modcon boiler. I purposely oversize the rads meet design day heat loss at 140 supply temp. I built a spreadsheet that given the EDR of the rads provides a table of BTUH vs supply temp. I plan to some day offer it to the community for putting up with my questions for the last 8 months.
Its not ready for the public yet but If you can tell me the manufacturer, number of sections and column/tube count, of your radiators, Ill would be happy to run the numbers and send you the table.
You will still need to do a heat loss estimate on your spaces to help you dial the right heat in.
@ November 25, 2013 1:00 PM in PEX suport requimentsNice trick SWEI But I already cant stand up in most of my basement. I don't know why they couldn't run a couple more courses of stone as there is plenty of it lying around the property!
@ November 25, 2013 9:11 AM in PEX suport requimentsTwo questions:
1. I have 4 tubes of PEX (ROTH PEX-Pert) running up a wall cavity to a radiant ceiling (7' height). To fix an infiltration problem I had to open the wall all the way up I have access to the pex. Since I’m in the wall should I secure the pex or just leave it free?
2. In general when running radiant pex around my basement to heat loads what is the minimum support spacing?
@ November 14, 2013 8:26 AM in Manifold head loss, sketchy info, does it mater?Viega does provide the Cv data for the flowmeters and the balancing valves on the Technical Data Sheets. I'm not sure how I overlooked that yesterday. My apologies for asking an unnecessary question.
@ November 13, 2013 10:48 PM in Manifold head loss, sketchy info, does it mater?A new system we are working on has two manifolds. The system manifold is a Viega and the one for the radiant ceiling is a Roth. For head loss calculations I'm looking for the Cv data. Both have a supply and return bodies with Isolation ball valves on the input, balancing/shut off valves on each return tap and flowmeters/adjusters on the supply taps.
The Viega tech documents provide data for the flow meters and balancing valves. But not data for the ball valves.
The Roth is a new “NP” Manifold System of which there is no online documentation and the documentation I received in the box seemed like it was for a different system. I contacted Tech support and was emailed a copy of the data sheets.
The return side balancing valves list Cv at 2.77 at full open but the Cv values for the Isolation ball valves and the flow meter/adjusters are blank, as if they are still working on that...
Everything I have studied says the head loss for these components is part of the overall circuit head loss, which is critical for proper pump selection.
Are the Ball valves on these manifolds of a flow characteristic that the head loss is negligible?
@ October 25, 2013 8:12 PM in Mixing Cast Iron with radiant panels, matching tempsI had a long discussion with Rob today and we finalized the plans.
Thanks for your help!
@ October 24, 2013 2:55 PM in Mixing Cast Iron with radiant panels, matching tempsAs we are using drywall in the end, and thats fits with Gordy's reply as well.
I should have asked this before but if we go with a mixing valve requiring a supporting pump,
Should it be on continuous circ with the rest of the system?
should it be fixed or variable speed?
@ October 24, 2013 12:09 PM in Mixing Cast Iron with radiant panels, matching temps"Matching Temps Would be simplest. Ceilings and walls can tolerate higher temp than floors."
What would you use as the highest temp for a ceiling? the reason Im asking is that we talked about running the the ceiling on a TRV (no mixing) and using an aqua-stat to shut off the supply if the supply temp got to high.
"The B2HA can control a motorized mixing valve and run two separate ODR curves if you need to."
Nice, I think that means I could run the boiler on one ODR and then a mixing valve for the ceiling on the other.
@ October 23, 2013 3:47 PM in Mixing Cast Iron with radiant panels, matching tempsAs previously stated I wanted to run a simple circuit with one Delta T circulator on the secondary circuit with the boiler on outdoor reset, TRVs on the Rads and some type of thermostatic valve on the Ceiling Panel Header. Something like in the first diagram.
However the designer at the supply house is concerned about the water going to the radiant ceiling getting too high. Although the rads are oversized to run at 140 degrees at ODT he is concerned that if the boiler puts out higher than 140 degrees it could damage the ceiling. He first suggested using a mixing circuit as in the second diagram.
I didn’t want to run an additional pump. But if it has to be it get over it… He made it clear that his use of radiant is limited and is going to check with the manufacture of the boiler (Viessmann) and Roth on other options. We also agreed that I would check back here.
Based on experiences what’s the best way to handle this?
@ October 4, 2013 9:52 PM in Mixing Cast Iron with radiant panels, matching tempsfor your help Zman
@ October 3, 2013 10:46 AM in Mixing Cast Iron with radiant panels, matching tempsif this makes any difference but we already have a gas tank-less water heater. So the Boiler will not provide DHW.