Adding A Radiant Heat Zone -hydronic Experts - HVAC - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 03-12-2009, 11:08 AM   #1
Member
 
Joe F's Avatar
 
Join Date: Jan 2008
Location: Washington, DC
Posts: 273
Rewards Points: 250
Default

Adding a radiant heat zone -hydronic experts


I am in the process of adding a single hydronic radiant zone to my existing hot water baseboard (boiler) system. I've done quite a bit of research, however I am not sure if my design is up to snuff and have had some difficulty in converting my plan to a parts list. Most companies I have contacted have provided minimal "tech support". So, I have a design that I think is workable, but no "shopping list".

I have attached a diagram of my system with some specific questions highlighted in blue. Any help and/or constructive criticism is greatly appreciated.
Attached Thumbnails
Adding a radiant heat zone -hydronic experts-radiant-plan.jpg  

Advertisement

__________________
If you don't stand behind our troops, please feel free to stand in front of them.
Joe F is offline   Reply With Quote
Old 03-12-2009, 12:37 PM   #2
I have gas!
 
Clutchcargo's Avatar
 
Join Date: Mar 2007
Location: Massachusetts
Posts: 1,783
Rewards Points: 1,018
Default

Adding a radiant heat zone -hydronic experts


Check out Taco's library. Under "systems" there's quite a bit on radiant systems.

Advertisement

__________________
I tear things down and build them up.
Clutchcargo is offline   Reply With Quote
Old 03-13-2009, 08:33 AM   #3
Member
 
tk03's Avatar
 
Join Date: Sep 2008
Location: PA
Posts: 167
Rewards Points: 150
Default

Adding a radiant heat zone -hydronic experts


Your basic plan is OK except for the return from the bathrooms need to be between the circulator and the boiler. You do not want the return from the bathrooms to have to push through a non-operating circulator.
To operate the pump and zone valve you will need a floor sensor or thermostat. The floor sensor is for a lightweight gypcrete pour and a thermostat is going to be affected by the humidity.
I would run the radiant pump 24/7 through the winter months and adjust the mixing valve to the proper temperature to keep the bathrooms at the temperature I desired. I did this with my kitchen and it worked well except I need to turn the circulator power switch on in fall and off in spring and also had to close/open a valve also.
There are thermostats designed for high humidity areas. What is the part number of the Taco box? I will guess ZVC504. If you are going to use a thermostat I would change the Taco box big enough for your system (6 zone) and upgrade to an EXP version. Then you can easily add outdoor reset (plug in module) either now or at a later date.
BTW your boiler circulator is way oversized.
tk03 is offline   Reply With Quote
Old 03-13-2009, 09:28 AM   #4
Member
 
Joe F's Avatar
 
Join Date: Jan 2008
Location: Washington, DC
Posts: 273
Rewards Points: 250
Default

Adding a radiant heat zone -hydronic experts


Thanks TK, this is starting to make a little more sense to me. I understand the reason for "bypassing" the main circulator.

If I understand the rest correctly, there are two options 1. Use a floor sensor or thermostat to control the pump and zone valve (do I need a zone valve) OR 2. Run the pump 24/7 and adjust the mixing valve to the desired floor temp (if no other zone is calling for heat, cold water will circulate).

My current Taco control box is the 3 zone version. I would upgrade to a 5 or 6 zone to support the new setup. Are the Taco control boxes capable of controlling multiple pumps in different zones?

Funny you mention my circulator pump being oversized. I got a copy of Taco's pump selection chart and after doing all the math for length, number of elbows and tee's etc... I calculated that I need a 0013. My current pump is actually a 007. The chart also makes me think I need a 0014 for the radiant zone. Do I need to reread the directions and recalculate?
__________________
If you don't stand behind our troops, please feel free to stand in front of them.
Joe F is offline   Reply With Quote
Old 03-13-2009, 09:35 AM   #5
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 26,421
Rewards Points: 4,488
Default

Adding a radiant heat zone -hydronic experts


Quote:
Originally Posted by Joe F View Post

Do I need to reread the directions and recalculate?
I think so.

Not too many residential systems have a zone with 27 foot of head that the circ needs to work against to move 10 GPM.

And your radiant zone should be over 20 foot of head.

Last edited by beenthere; 03-13-2009 at 09:40 AM.
beenthere is online now   Reply With Quote
Old 03-13-2009, 10:33 AM   #6
Member
 
Joe F's Avatar
 
Join Date: Jan 2008
Location: Washington, DC
Posts: 273
Rewards Points: 250
Default

Adding a radiant heat zone -hydronic experts


Bear with me, the light bulb is starting to glow (a little).
In my initial calculation, I used 3/4" for the piping (zone pipe size). When I recalculate using 1 1/4" pipe size (that's the size coming out of the boiler into the pump), I get 7 feet of head rather than 25. If I understand you correctly, the radiant zone will be pulling more head because of the smaller pipe size i.e my 0014 pump calculation might be close, but I'll recompute. How do you plumb this pump? 3/4" copper reduced to 1/2" PEX on the input and output? As a single zone, I assume I calculate based on 1/2" PEX.
__________________
If you don't stand behind our troops, please feel free to stand in front of them.
Joe F is offline   Reply With Quote
Old 03-13-2009, 10:40 AM   #7
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 26,421
Rewards Points: 4,488
Default

Adding a radiant heat zone -hydronic experts


You calculate the resistance of all the pipe the water is traveling through. Plus all fittings, including the zone valves. You calculate it for all the loops, and then size to the the longest loop.
If the shortest loop, has too little resistance, then you use balancing valves to control its flow.


The radiant loop is calculated the same way, and you include the mixing valve in the calc.

You can pipe 3/4 from the circ and mixing valve and then connect your pex.
beenthere is online now   Reply With Quote
Old 03-13-2009, 01:30 PM   #8
Member
 
Joe F's Avatar
 
Join Date: Jan 2008
Location: Washington, DC
Posts: 273
Rewards Points: 250
Default

Adding a radiant heat zone -hydronic experts


Thanks for all the help so far

I did a rough recalculation on the pump size and came up with a 007 for the main system (which is what I have) and a 0011 for the radiant zone (based on an estimated 200' loop). Sounds better, right? I'll take real measurements and double check everything this weekend.

I guess the only piece I don't understand is how to control the radiant zone pump. I know a zone control box will work for the zone valve, but how do I wire in a circulator that will only be supporting the one zone? I don't see that the zone control box has provisions to do that (pump & valve).

Here's a picture of my plan based on the latest updates.
Attached Thumbnails
Adding a radiant heat zone -hydronic experts-radiant-plan-2.jpg  
__________________
If you don't stand behind our troops, please feel free to stand in front of them.
Joe F is offline   Reply With Quote
Old 03-13-2009, 01:56 PM   #9
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 26,421
Rewards Points: 4,488
Default

Adding a radiant heat zone -hydronic experts


The easy way, is to just use a circ relay for the radiant zone, instead of going through the same zone valve control panel as the other zones.
And use a flow check instead of a zone valve on the radiant loop.

Just curious. What head pressure did you come up with for your longest regular loop, and what head pressure for your radiant loop.
How much head pressure did you allow for zone valve.
beenthere is online now   Reply With Quote
Old 03-13-2009, 02:45 PM   #10
Member
 
Joe F's Avatar
 
Join Date: Jan 2008
Location: Washington, DC
Posts: 273
Rewards Points: 250
Default

Adding a radiant heat zone -hydronic experts


The flow check would go before the mixing valve? (same place I have the radiant zone valve shown) and T-stat would wire into the pump relay. How does the boiler get the heat call? Tie in with the same wires from the existing zone controller?

I came up with 6.2 for the regular loop and 23 for the radiant. Those numbers are based on system measurements from memory. I stilll need to do actual measurements and figure out which is my longest loop. I just wanted to make sure that I am doing the calculations correctly.

The chart I have lists a head of 10 for a 1/2 inch zone valve and 20 for a 3/4 zone valve. It doesn't give a number for a mixing valve, so I used the zone valve number. FYI the flow check will add 143. For the fittings and valves, the Taco chart uses effective length in feet vice pressure.
__________________
If you don't stand behind our troops, please feel free to stand in front of them.
Joe F is offline   Reply With Quote
Old 03-13-2009, 03:11 PM   #11
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 26,421
Rewards Points: 4,488
Default

Adding a radiant heat zone -hydronic experts


The flow check would be installed after the mixing valve.
Thats 20 foot at 6 gallons a minute.

You shouldn't have a " loop moving 6 gallons a minute.

What GPM did the flow check list.
beenthere is online now   Reply With Quote
Old 03-13-2009, 03:46 PM   #12
Member
 
Joe F's Avatar
 
Join Date: Jan 2008
Location: Washington, DC
Posts: 273
Rewards Points: 250
Default

Adding a radiant heat zone -hydronic experts


Quote:
Originally Posted by beenthere View Post
The flow check would be installed after the mixing valve.
Thats 20 foot at 6 gallons a minute.

You shouldn't have a " loop moving 6 gallons a minute.

What GPM did the flow check list.
You're starting to go over my head a bit, but the chart only gave a single number for each component. Flow chek was 143. I couldn't find a GPM for the Flow check on Taco's site.

6 gpm is way too much, right.
__________________
If you don't stand behind our troops, please feel free to stand in front of them.
Joe F is offline   Reply With Quote
Old 03-13-2009, 04:41 PM   #13
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 26,421
Rewards Points: 4,488
Default

Adding a radiant heat zone -hydronic experts


Quote:
Originally Posted by Joe F View Post
You're starting to go over my head a bit, but the chart only gave a single number for each component. Flow chek was 143. I couldn't find a GPM for the Flow check on Taco's site.

6 gpm is way too much, right.
For 3/4" it is.

The flow check should have had a Cv listing.
With that, and knowing the GPM of the loop, the PD/foot of head of the flow check can be found.

This is the knowledge, that contracting companies don't provide. Because they don't get paid for their training, and time then.
beenthere is online now   Reply With Quote
Old 03-16-2009, 11:48 AM   #14
Member
 
Joe F's Avatar
 
Join Date: Jan 2008
Location: Washington, DC
Posts: 273
Rewards Points: 250
Default

Adding a radiant heat zone -hydronic experts


Taco lists the Equivalent feet/Cv as:

143/2.5 for part #219 3/4 (bronze)

35.8/5 for part #218 3/4 (cast)

Seems like an awfully big difference.
__________________
If you don't stand behind our troops, please feel free to stand in front of them.
Joe F is offline   Reply With Quote
Old 03-16-2009, 01:05 PM   #15
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 26,421
Rewards Points: 4,488
Default

Adding a radiant heat zone -hydronic experts


The cast iron models have a larger internal opening then the sweat models do.

So they have less resistance.

Advertisement


Last edited by beenthere; 03-16-2009 at 01:32 PM. Reason: Said it backwards first time
beenthere is online now   Reply With Quote
Reply


Thread Tools
Display Modes

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Hydronic Radiant Floor Heat KGP HVAC 22 05-02-2011 09:31 AM
Heat source for hydronic radiant floor heating mattedfred HVAC 1 11-19-2008 06:58 PM
Laminate in Basement over Hydronic Radiant Heat art2670 Flooring 3 10-12-2007 11:17 PM
bamboo over radiant heat montaillou Flooring 7 07-25-2007 02:17 PM
Adding radiant heat to existing slab Seabass HVAC 9 04-27-2007 05:10 PM




Top of Page | View New Posts