Radiant Supply Panel Questions

HFC

I am finally ready to move ahead with the supplemental heating system for our master bathroom tile floor. The Joist Trak has been installed in the joist bays below the master bath and the 1/2” Uponor hePEX has been run. I am now ready to work on the radiant supply panel. It will be located in our garage next to the AO Smith 100K BTU Vertex Water Heater. I will utilize the Taco X-Pump Block and will follow their installation recommendations.



<img src="http://www.fototime.com/792C8BBC722CED6/standard.jpg" width="640" height="349" alt="" />



I laid the components out on a piece of plywood to get started.



<img src="http://www.fototime.com/C541B56393C0CD3/standard.jpg" width="640" height="433" alt="" />





Using the height of the Taco X-Pump Block secured directly to the plywood I find the rest of the system components land at the following heights above the plywood:



• Expansion tank is flush with the plywood surface.

• Uponor manifold bracket is 2-1/4” above the plywood surface.

• Air separator body is 3” above the plywood surface.



I have the following questions:

• Is a sheet of plywood the best way to secure these components to a wall?

• All of the components between the Taco X-Pump Block and Uponor manifold are unsupported. What is the best way to support them? I have not been able to find any adjustable standoff supports for copper pipe.

• I would like to add unions to the radiant side of the Taco X-Pump Block for easy

servicing. How reliable are copper sweat unions? Is one brand more reliable than another? I found a manufacturer of copper sweat unions with an o-ring seal, but their cost was prohibitive.



Thanks for taking the time to read my post and consider my questions.

Alan (California Radiant) Forbes

Boiler Boards

You will see a variety of ways to attach your components to your mounting surface.  We use a combination of strut channel, strut clamps and acoustic (cork and rubber) separators.



Your can purchase the strut at a plumbing wholesaler and the acoustic pads at Grainger.  The strut channel is available in different thicknesses.

Jean-David Beyer

It seems strange to me.

It seems strange to me that you would put the air separator and expansion tank on the return part of the plumbing. I would think you would want the air separator on the hottest part of that loop, right after the water exits the bottom of the X-Block.



I was so surprised I looked it up on Taco's web site and they do it pretty much as you did.  I am not a heating professional, and maybe I am too easily surprised.

HFC

Boiler Boards

Alan,



Are you located in Santa Cruz? I am over in Aptos. Do you acquire your strut channel

components through AL Lease, Slakey Brothers or Ferguson?



Thanks,



Howard

HFC

It seems strange to me too

Jean-David,



The system schematic shown in my post above is from the Taco X-Pump Block installation manual. I am just following the instructions from Taco’s design engineers for

the placement of the air separator on the secondary side.



Howard

Gordy

pumping away

 You both are correct in that you will get the best air removal in the hottest part of the system. But with the location Taco specs you are pumping away from the point of no pressure change which trumps.



Gordy

Alan (California Radiant) Forbes

Resources

Hi Howard:



I'm in Berkeley.  Ferguson and Slakey (don't know AL Lease) will stock what you need as well as Cal Steam.

HFC

Pressure Relief Valve Location

Gordy,



Do you know why Taco specifies the pressure relief valve be located on the return side instead of the supply side of the radiant loop?



Howard

HFC

RE: Resources

Alan,



Thanks, I will try Ferguson and Slakey tomorrow when they reopen after the holiday.



BTW, When I searched for California Radiant I came up with this location.



http://www.californiaradiant.us/ContactUs.html



Howard

Jean-David Beyer

Why not eat your cake and have it too?

Why not put the expansion tank as shown by Taco, in the return so it is pumped away, and put the air eliminator in the supply so it is getting the hottest water? That way you could pump away from the PONP and have the air eliminator in the hottest place. You could put the makeup water connection into the bottom of the air eliminator so as to get some use from it. The diagram does not indicate any way to fill the system or make up for leakage.

HFC

I will use a Watts 9-11TM3 for makeup water

Jean-David,



The expansion tank is located in the return as specified by Taco. A Watts 9-11TM3 will be connected to the right hand port of the Watts RBFF below the air eliminator.



http://www.watts.com/pages/_products_details.asp?pid=668



Howard

Jean-David Beyer

The expansion tank is located in the return as specified by Taco.

I agree. Gordy pointed out why that is, and he is right. That does not make you have to put the air eliminator there, though. You could hook it up with a T (with an isolation valve beneath it) where you have it.



You could then put the air eliminator on the bottom right, the supply. You could put the make-up water into the bottom of the air eliminator, or hook it up on the return where the expansion tank goes.



My guess is that when all is said and done, more is said than done, and that it will make little practical difference. But I have mine in a part of the system where water temperature never exceeds 139F, and it will not even do that unless it gets 8 degrees below design temperature around here. I have never seen that happen, but it is theoretically possible.

Gordy

Added pressure of the pump

Having the relief valve on the supply side the pump would be discharging its added pressure differential into the relief valve maybe causing it to relieve itself. When you pump away from the PONPC the pump is adding its pressure differential to the supply, and its suction side is lower pressure.



 This is why it is recommended to pump away on the supply side of the boiler, and not the return. You can do it on the return, but there can be consequences, especially if system pressure approaches 20-25 psi such as in a 4 or 5 story home.



Air removal is recommended to be done at the hottest point in the system with the lowest velocity for the air separator to do its job the best. This is why it tends to be right after the boiler, or at a hydraulic separator which is usually close to boiler. The boiler, or hydraulic separator provides a wide roadway that allows entrained air to come out of solution for removal by the separator





 With all that being said the XBlock is a different animal. Its a HX, pump, and injection mixing all in one. So you have to think about the XBlock as the boiler. The PONPC properly placed so you are pumping away from it, and the relief valve place in that setup so the pump can not wreak havoc on it.



Taco has done all this for you in their schematic. There are reasons they recommend the components locations. In your install it may not make a lot of difference, but they have to cover all the bases where their product may be used in the field.





Gordy

Alan (California Radiant) Forbes

California Radiant

Howard:



I had the California Radiant URL before they did, but dropped it after a few years because my company has another name - Forbes Plumbing.   The only reason I came up with the moniker was to let everyone know where I'm from.

Gordy

JDB

 Yes you could do that JDB, but it is not as neat, and tidy as the expansion module is. To many components in a small area. I doubt it will make that much difference in the air removal.........in this case.



Gordy

NRT_Rob

in any case

the benefit of hotter water in the air eliminator is pretty small. with a good air eliminator you could put it anywhere it will see the air, and it would be fine.

Jean-David Beyer

benefit of hotter water in the air eliminator is pretty small

Do you have any data to support this? The reason I ask is that I have a Taco 49-125 microbubble resorber; see page 2, ratings on page 4:



http://www.taco-hvac.com/en/products/Air%20Separators/track_file.html?file_to_download_id=15268



It is in the secondary piping of my near-boiler plumbing, where the temperature never exceeds 140F, and is usually between 90F and 120F. The flow rate in there is probably slower than normal because the installer used 1 1/4 inch pipe instead of the minimum 1 inch size the boiler manufacturer specified. But it seemed to take a couple of months to get the all air out. It just seemed to me if the water there were hotter, it would have accomplished this sooner.



The zone in question is baseboard, well above the rest of the system and has no bleed valves to get the air out. There is a purge valve for the zone below, where the boiler is. There is about 110 feet of horizontal pipe up there, so any air that gets up there stays there until it dissolves in the water and gets pumped down to the  separator.



The installing contractor says you do not use bleed valves in baseboard heat emitters. Well, maybe he doesn't.

NRT_Rob

not really

just 15 years of low temperature radiant design experience and nearly zero air problems. Don't really care how fast the air leaves, as long as it doesn't restrict flow unduly, but usually we expect air to be gone within a few weeks.



bleed valves are not fun. we don't use any air valves other than the microbubble resorbers. which are very often on the return.

Gordy

I will add

 To Robs comments that the wide spot in the road (boiler, hydraulic separator) where velocity decreases  has more effect on water coming out of solution than the temperature in a radiant type of system. 



 Just saying water temperature in a high temp system where temps could be 180 ish  would do more in assisting air removal than a radiant type system where temps are averaging 90- 100 ish or lower....With the air separator away from the highest temp in the system. 



Air can also be driven into solution by raising system pressure, and out of solution by lowering system pressure.



And then there is Dawn dish soap.



Gordy

HFC

Spoke To Taco

I spoke with a Taco applications engineer and asked him about the placement of the pressure relief vale in the return line as depicted in the first drawing in my post which is from the Taco installation manual. He stated it does not matter where the pressure relief valve is located. I was concerned about the pressure relief valve being on the other side of a possible blockage in the radiant system, but he said the X-Pump Block would not create enough pressure to do any damage. Anyone here have experience with the Taco X-Pump Block and where did you locate your pressure relief valve.

furnacefigher15

Relief valve

The relief valve location in this application is moot, but the base of the valve should be in the horizontal plane, the the vertical plane as is pictured.

HFC

PRV orientation

Are you sure? I checked the Watts installation instructions and it does not specify a specific orientation. I see Alan Forbes in his post above orients his PRV the same as I did.