Welcome to Plbg.com
Thank you to all the plumbing professionals who offer their advice and expertise

Over 600,000 posts related to plumbing

Welcome to Plbg.com (aka: PlumbingForum.com) we are the most popular plumbing information sharing, advice, DIY and educational forum on the Web. Ask any toilet, sink, faucet, pump, water quality, and plumbing related questions. Please refrain from asking where to purchase a product, business, pricing, or legal questions, for contractor referrals, or any questions not related to plumbing. Keep all posts positive and no advertising. This site is free and made possible by:  

Post New
Search
Log In
How to Show Images
Newest Subjects
 HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

Hey guys heres what i would like to do and Im looking for the most cost effective way to achieve this.

(Part 1)I have a single loop HW baseboard system, Williams 105k BTU in a 1920's 1100/sqft house. I believe the furnace is way over sized so I would like to make use of it to also run radiant floor heating below my kitchen and living room/office from the basement ceiling.

(Part 2) I would also like to create a downstairs zone and and upstairs zone on the same.

Part 1 proposal- Use the existing return from the baseboard system a using a mixing valve to step down the heat to the acceptable 85-125 degree input recommended for radiant heat flooring. If that can be done where would I return the RF cooler water to the cold water input for the boiler? Or can I simply use the higher temp PEX piping and use the HW BB return feed without a mixer and return to the cold water input? And use a zone valve ahead of the flooring to be run by a separate thermostat.

Part 2 - I would like to also incorporate a outside reset boiler control to my existing system as well as create the separate zones. Do I simply T off the single loop and create 2 zones with zone valves or add a zone valve between the first floor and second floor run to turn the upstairs heat on and off?

All of you comments will be greatly appreciated and keep in mind im new to HVAC if it isn't obvious already.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: packy (MA)

lets start with the radiant proposal..
you can not pull the return water from an existing zone to use in the radiant. the radiant because of its low temperature runs almost constantly while your existing zone will cycle on and off frequently.
you will have to pull a seperate feed and return from the boiler. the feed will be run thru a mixing valve that will have some of the radiant return water being used to cool the feed to normal radiant heat temperatures.
you will need a set of manifolds (premade or homemade) to connect the circuits to.
i would use a seperate circulator for the radiant.
look at "staple up radiant floor heating" to see what you must do as far as the piping goes.
a plain old sparco mixing valve set at 120 will get you by. remember that radiant heat is not like regular baseboard heat. you don't leave for work in the morning and turn the heat down. it take hours to recover because you are only using 120 deg water. so you set it and forget it. if you are manually adjusting the water temperature then 120 may not be enough in extremely cold weather so you would have to adjust the mixing valve upwards. same for mildly cold weather. 120 may be too much and you would ahve to tweek it down.
as for adding other zones, that is pretty straightforward and can be accomplished with zone valves if you wish..

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

Thanks, any chance you could offer some more details? Like what I should buy etc? As stated Im new to this and wanna do it right the first time.

Michael

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: packy (MA)

michael, i am more than happy to guide you thru a small to medium size job. BUT a radiant heat job takes a lot of experience and even more knowledge. if you are new to this, i feel you shouldn't take on a job this big and this complicated alone. even with help over the internet i fear you are in over your head.
please don't be insulted.
here is a picture of a combo radiant and baseboard loop job i did a few years ago.
as you can see it is not for a newbie to tackle.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: Paul48 (CT)

You really should get design help. That way when it's done, it functions correctly. They can spec tube size, spacing, circulation, insulation......It's a lot more complicated than just feeding hot water under the floor.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

Thanks Guys, but as its only going to be a supplemental heat source I cant see how I can screw it up to bad. Here is the kit I ordered to get started with.

I got a 3 port manifold - Housepex 3 Port Premium PEX Manifold set with 1/2 inch adaptor you can find on the goog

Heres what i envision:
X Hot Water Circ Pump Taco 007-F5 XXX Flange into Manifold
X
X
X
INLET FROM BOILER XXXXXXX 1 Inch Mixing Valve XXXXXX into Manifold

What else would I need to do on the boiler side if anything?

Your help is appreciated.

[s86.photobucket.com]



Edited 2 times.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: North Carolina Plumber (NC)

A picture of your current boiler set up would help. You'll want a 1/4 turn ball valve before your mixing valve, and a ball valve on both sides of your circulator pump. I use the pump flanges that have a ball valve as part of the flange assembly. A valve on the return of each loop of the radiant, the pre-made manifold should have them. How many sg. feet are you planning to heat with the radiant ?

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

My guess is less than 800 sq ft as a secondary heat source. Just to take the chill off the tile floors.

I can send over whatever youd like to see. Do you want to see the existing piping?

Can I add zone valves after the manifolds?

Also if i size everything down to 3/4 before the manifold will that cause an issue?



Edited 2 times.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: packy (MA)

you need a feed from the boiler into the mixing valve.
you need a return from the radiant back to the boiler.
there has to be a tee in the return as well.
part of tee goes back to boiler and part goes to mixing valve.
the circulator goes between the mixer and the supply manifold.
when things are cold the mixer is (in effect) mostly closed so you get hotter water to the circulator that then pumps it thru the floor and back to the boiler return.
when thing start to heat up the mixer closes off the hot side so the circulator is only pumping the water in the floor around in a circle. maybe the mixer lets a little hot in but not much. as things get cooler the mixer lets more hot get to the circulator.
so, the circulator is running all the time and the mixer is opening and closing to keep the water temp where it is set at.
now, the circulator wants to be a 3 speed type. there will be thermometers on each manifold. you set the temperature on the mixer so you get 120 deg at the supply manifold and you set the speed of the circulator so you get `105-110 at the return manifold.
breakfast is ready.. so we can continue later..

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

Thanks Ill be waiting.

[s86.photobucket.com]

Here it the existing setup



Edited 1 times.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: packy (MA)

no zone valves after the manifolds..
any zoning is back at the boiler from manifolds that you make out of tees..
remember the water temperature at the supply manifold will only be 120. that is not enough to produce any heat if piped to baseboard heaters.
and. yes, if your radiant manifolds are 3 outlets at 1/2 inch each, 3/4 pex feeding them is suffucient in size.
so, do some research on "staple up" radiant heat. look carefully at the installation methods, the heat transfer plate, the the heat transfer caulking applied to the grooves in the plates and very important look at the insulation required below new tubing. you need to leave a 2 inch air space between the (preferable to use foil face) insulation and the bottom of the floor. otherwise you will have a radiant ceiling below and not much heat above..
with staple up, you have to make damn sure there are no nails sticking down.
lasty (for now) the runs of 1/2 inch heat pex can be 300 feet long max. they must all be within 10% of eachother.
so if one is 300, one is 270 and one is 285, you'll be fine.
or, if one is 200, one is 210 and one is 220, you'll be fine..
this measurement is total length for manifold to manifold..
also, the circulator and mixer should be close to the boiler. you can run 3/4 from there to the manifolds which can be closer to the heated area (if that makes the circuits shorter but not too short).
well, off to wal-mart to do last minute christmas shopping for the grandkids..
good luck..

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

Ive researched all of the specs on attaching the pex and Im going with floating on standoffs due to nails. I know the efficiency will be lacking but i cannot get a good seal even if i bend the nails over. I plan in using R19 with foil faced radiant bubble attached to the bottom of the joists.

So i must keep the runs all within 10% of each other? Good to know.

The manifold only runs up to 100 degrees will that suffice for heating the floors?

I will attach more photos of the add on plans in a bit.

Thanks!

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: Paul48 (CT)

One hundred degrees is useless with staple-up. And no contact with the floor, means little to no heat. You need 2 men with die grinders to cut the nails below the floor. You need heat transfer plates. Use rigid foil-faced insulation, held up to create the 2" spacing that packy mentioned.



Edited 1 times.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

My bad 100 degrees celsius!



Edited 1 times.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: Paul48 (CT)

Not all radiant is the same. In-slab radiant can get away with lower temperatures, because of the surface contact area. Just to be certain, are you reading that correctly? It doesn't say 100*C,does it?

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

It does sorry. Can you look at this drawing and see if im on the right track?

Why cant i just add thermostatic actuators at the manifolds to act as zone valves?

[s86.photobucket.com]

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: Paul48 (CT)

That will work only the manifold you see on the left, you create with nipples and tees. Instead of a zone valve you use a circulator there for the baseboard zone. The other circ in the picture is pumping out of the "mix" side of a thermostatic valve. The "cold" side is above, and the "hot" to the left. Once you reach the temperature you set it at, it just recirculates the water in the radiant zone. Follow?

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

Having a hard time visualizing can you draw it out?

Wait i do have tees and nipples.

The tess on the bootom to ball shutoffs and another nipple to zone valve

I already have a circ on the return side of the boiler

I should be able to zone like this #6 correct?

[s86.photobucket.com]



Edited 3 times.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: Paul48 (CT)

Print out that picture of the manifold set up. Look at it while reading my description of what to do. Since this is auxiliary heat, you're better off doing sections correctly(money allowing), than to do it all half-a--ed.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

A picture didnt attach?

Did you use [ ] from photobucket?

In the attached photos I am not attempting to zone the HW baseboard at this time, only adding the radiant floor heat.



Edited 1 times.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: Paul48 (CT)

The picture you linked to.....The manifold set up with the red circ.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

Im sorry i feel really dumb right now as I dont understand where the recirc should be.

I need an additional one or two?

One for the suuply side of the radiant flooring one for the return? Also mixing valves on both?

Where do i pull the intake water from the return from the baseboard or the output to the baseboard?



Doesnt the water returning to the boiler need to be at 140 or higher as well? I guess that my stumbling block.

Why cant i just temper the water going into this system with the supplied mixing valve to feed the flooring?

[s86.photobucket.com]



Edited 1 times.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: Paul48 (CT)

Go to the link you just posted. When there, use the left arrow, to move to the picture with the red circulator in it. Let me know when you see that picture.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

OK im there.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: Paul48 (CT)

[www.roth-usa.com]

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

ok

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: Paul48 (CT)

That's exactly what you need. See the manifold on the left with the zone valves? Take the zone valves off. Create another manifold directly below that one, on the supply, and put your circulators for baseboard zones there. The radiant and baseboards operate at different temps.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

So i wont user the manifold I bought?

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: Paul48 (CT)

You need everything in that picture.....stop laughing packy!

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

OK so heres what you are saying:

[s86.photobucket.com]

how does it all attach then?

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: Paul48 (CT)

Those are manifolds, you created. The right side of those attach to the loop with the red circulator, in the other picture. Those feed your baseboards at 170-180*. The loop formed with the red circ, off the thermostatic mixing valve feeds the radiant floor, at whatever temperature you set it at, regardless of the boiler temperature. It will simply stop taking boiler water, and circulate the water in the loop until the temperature cools slightly.Then the spool in the mixing valve will shift and more boiler water will be added.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

So all in i need 1 pump for each baseboard run, and 1 pump for the floor heating.

How do i introduce the return from the flooring into the boiler?

Does it get piped back in with the baseboard return water? I thought the return needed to be atleast 140 degrees? Is that wrong?

Also if i only have one baseboard run do i need the top manifold as it already has a return circ?

I think we are getting close now.

How do I control the temp on the flooring zones without a thermostatic control?

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: Paul48 (CT)

Michael.....We are still miles away. The homework necessary to do this correctly can't be done here. If you don't take the time to learn what you're doing....you might as well stand next to the boiler, and burn $20 bills. I'm a homeowner/ machinist/ DIYer like yourself. Heating is a hobby, of sorts. There is countless resources available online....Taco FloPro University, Caleffi's "iDronics" series are just a couple. You're attempting to do what guys have gone to school for, served an apprenticeship for and have been doing for years. You can do this yourself, and on a budget. Just not tomorrow.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

Thanks,

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: packy (MA)

just in from christmas shopping and other errands.
michael, first let me say thanks to paul for his guidance here. but i think we are both trying (in the nicest way) to tell you that there is more to installing the amount of heating you are asking about than simply getting some advice over the internet and watching a few videos.
to me it is almost second nature when installing both plumbing and heating. i've been working on pipes since 1963.
i'm afraid when you don't even know how to get return piping back to the boiler or when you think you can add zone valves for baseboard heat off of a factory made radiant heat manifold... well. nuff said.
so don't be angry and most important don't give up. we have been here for years and we aren't going anywhere fast.
it is a little overwhelming for us to answer a question that you think might be simple but in reality it is very complicated.
so make some single line drawings of what you propose to do. post them here and ask a SPECIFIC question and help will be on the way...

Post Reply

 Thanks guys :thumb:
Author: abigsteelersfan1970 (PA)

Thanks guys,

Could you answer a simple question, am I correct about the return temp going back into the boiler having to be at 140 or higher or risk damage to the boiler?



Edited 1 times.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: Paul48 (CT)

Yes.....If it's a cast iron boiler, it needs to be 140 or higher to avoid flue gas condensation.What's the make and model of the boiler?

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: packy (MA)

it is impossible to get the return temperature above 140if you have a boiler that is 'cold start'..
if the boiler maintains a minimum temperature (which virtually none do nowadays), you can install a 1/2 inch pipe between the feed and return to blend some of the heated water back into the return water.
this is done if you have a small capacity boiler and large piping with old radiators. it will help with short cycling the boiler.
with a boiler that maintains temperature the circulator control will not run the circulator unless the boiler is hot. but as soon as the cold return water comes back the circulator shut off. so to combat this you blend in some feed into the return.
anyway.. remember your boiler is going to be operating at about 180.. so bringing back water from your radiant floor at 110 -120 will not affect anything. the boiler will drop to 160 and fire back up 'till it hits high limit of 180..
the concern comes with firing the boiler at lower temperatures all the time. as paul said, condensate forms inside and that is not good..

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

Williams GWA-105-N-T-S2

Also I was thinking I have an extra HW heater 40 gal, could i just use that for the radiant floor heat? If it were to stop working I wouldn't really care because its just sitting in the basement taking up space.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

Awesome Packy so the current setup is correct then and if i piped the return into the current return it would not hurt the system, is what I think you are saying?

Should I add l a 1/2 inch pipe between the feed and return to blend some of the heated water back into the return water? Or if I am going to return the radiant heat I can just blend there correct? Should i return the radiant before or after the BB return or doesnt it matter?

Have you guys looked at my current system? I dont think its plumbed right I will attach a mock up of it so you can better see it.

[s86.photobucket.com]

BTW the expansion tank photo is a little screwy it hanging off a blue valve with a pressure relief valve on top and the expansion tank below.



Edited 3 times.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: packy (MA)

i have seen water heaters used for hydronic heating.
wears them out in a hurry but it will work.
kinda shoots holes in your original statement of wanting to get more use from an oversized boiler...hahaha

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: packy (MA)

the return from the radiant can go into the same pipe as the house return.
it doesn't matter as long as the pipe is big enough.
heck, you can even unscrew the drain valve from the bottom of the boiler, put a nipple and a tee, put the drain into the end of the tee and run the radiant return there. as long as it goes back to the bottom...
you don't need a 1/2 inch pipe to blend hot to prevent short cycling..
i don't get much out of your system pictures..

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

Does it seem weird they have cold water mixing with the hot water coming out of the boiler? The output is coming from the top correct?

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

Ok that being said. I can pipe back in with no issues, I need the 2 manifolds that i drew up and the one i purchased. Keeping only a single loop for the BB heat I would need just one more circ pump for that.

I would then plumb that into the hot water side of my premade manifold with circ pump and mixer to feed and return BB heat, the return would plumb into existing return or tie into drain as you said.

Am i getting closer now? And with the specs of my heater dont you agree it could handle the extra piping?

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

the return pex is 3/4 going into circ pump and back into boiler at 1"

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

Whats you definition of a hurry 4-5 years, etc. It would only be used 4 month a year.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: packy (MA)

it is the other way around.. the hot is mixing with the cold to temper it..

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: packy (MA)

there is no mixer for baseboard heat. the radiant has the mixer..

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

NO if you look at my existing system they have cold water mixing into the Hot water coming out of the boiler going to the baseboards.

And shouldnt I have concerns about short cycling with the existing system as its is? I think the water entering on the return side is far less than 140 degrees.



Edited 1 times.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: packy (MA)

that is make up water to initially fill the system. it has a pressure reducing valve on it so if the system pressure drops below a certain set point some cold water will be added automatically.
other wise the valve does nothing but sit there.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone
Author: abigsteelersfan1970 (PA)

ok cool one question down finally I can remove that whole mess from the equation.

Post Reply

 Thanks so much for your guidance and patience :clap:
Author: abigsteelersfan1970 (PA)

Guys, Thanks so much for your guidance and patience. I have what I think is now the correct setup. Keeping in mind that I will have only the one zone for BB now. If I choose to add another I will have to add another T and circ pump.

If this indeed correct and I wanted to add themostats to the floor zones how would I do it? Add TZV to the manifold on the hot side?

[s86.photobucket.com]



Edited 1 times.

Post Reply

 Re: HW boiler and radiant flooring and adding a zone ONE MORE LOOK?
Author: packy (MA)

that's OK.. just make sure the circulators have built in flow check. example would be Taco 007IFC..

Post Reply

 Re: HW boiler and radiant flooring and adding a zone ONE MORE LOOK?
Author: Paul48 (CT)

[tekmarcontrols.com]

Post Reply

 Thanks Packy :grin:
Author: abigsteelersfan1970 (PA)

Thanks Packy So you agree I am good to go? Ill make sure i get a flow check pump.



Edited 1 times.

Post Reply





Please note:
  • Inappropriate messages or blatant advertising will be deleted. We cannot be held responsible for bad or inadequate advice.
  • Plbg.com has no control over external content that may be linked to from messages posted here. Please follow external links with caution.
  • Plbg.com is strictly for the exchange of plumbing related advice and NOT to ask about pricing/costs, nor where to find a product (try Google), nor how to operate or promote a business, nor for ethics (law) and the like questions.
  • Plbg.com is also not a place to ask radiant heating (try HeatingHelp.com), electrical or even general construction type questions. We are exclusively for plumbing questions.

Search for plumbing parts on our sponsor's site:




Special thanks to our sponsor:
PlumbingSupply.com


Copyright© 2017 Plbg.com. All Rights Reserved.