Radiant heat controls

[minnermp]

Hi all. I built a new shop this summer and i'm in the process of installing the radiant heat. I have a 60' x 30' pole barn style building with 1800' of 1/2" Pex tubing in 6 loops of 300'. I did use 1' foam board insulation underneath the slab and there is the 2" x 6" board around the perimeter of the slab. Right now I just have dbl bubble insulation, may do more later. I have a Munchkin condensing boiler to supply hot water. i'm just not sure where to go from here. I picked up the boiler cheap on CL and found a manual online and it basically shows that you can pipe it with a single loop with single pump on the supply side for a retrofit or the preferred way is with two loops, two pumps and with closely spaced tees. I have most of the parts to start plumbing but not sure which way to go. I have seen a lot of info on here and on the web but sometimes I feel overwhelmed. Any help would be greatly appreciated. There seems to be some experienced people on here. Thanks

 

[Bondo]

Ayuh,.... Do ya plan on a single zone, All of the barn at one temp,..??
Or,...
Are ya gonna zone it off into different temps in different areas,..??

 

[anthony666]

closely spaced tees

primary secondary with closely spaced tees is definitely the way to go

in my experience munchkins are tough on flame sensors and ignitors .. make sure you change them out and have a backup set .. there's two versions original and revision 2, the difference as far as you're concerned is the flame sensor and ignitor .. another common issue is the system pressure sensor clogging

google munchkin problems .. you're gonna be very familiar with 'f09' and 'f02' .. buying a used munchkin is a lot like buying someone else's dog

 

[minnermp]

The whole shop will be open and same temperature single zone. The boiler was cheap so if too much trouble I can do something else, but for now need to get it up and running. So if I go with pri/sec do I then need two pumps and exactly where to locate them? this boiler is the later revision with the 925 control . Thanks for the info

 

[anthony666]

yes, you need two pumps .. google 'simple primary secondary piping', there's tons of diagrams and im almost out of phone battery .. i will try a better explanation later if you want

get a copy of the install manual from munchkin/peerless and have a guy set up the gas valve with a combustion analyzer, that's 99% of the battle right there

 

[minnermp]

OK I got my propane in and piped now is time to start installing this system to boiler. The manual shows, for a system with tees, a differential bypass valve between the manifolds? I don't really see this on any systems i'm looking at online. HELP

 

[minnermp]

Also, I was going to go with a closed system with some anti frz in it so I didn't get a pressure reducing valve or a backflow preventer as used in a open system. Still tossing this around. anyone got any input on this? Thanks

 

[anthony666]

a differential bypass valve

lets see the diagram

Also, I was going to go with a closed system with some anti frz in it so I didn't get a pressure reducing valve or a backflow preventer as used in a open system. Still tossing this around. anyone got any input on this? Thanks

that's not the difference between an open and closed system .. back in the old days, pre expansion tanks, system designers would use a cistern or similar vessel vented to atmosphere to control expansion .. that is an open system, open to the atmosphere .. a system that is not open to the atmosphere at any point is called a closed system

you have a closed system, the pieces you didn't get are for makeup water .. when you add water to the system it is full of dissolved gases, as it sits in the system these gases come out of suspension and vent via your air eliminator .. you have to make up for the loss in volume by adding more water .. if you don't use those pieces you can buy a self contained pump in a reservoir like this

or you can monitor a pressure gauge and add water manually .. i can tell you from experience that gets old VERY fast

 

[DonPowers]

Here is a good site on radiant heat, lots of good stuff by John Slegenthaler the radiant & hydronics guru.

http://www.radiantandhydronics.com/topics/2652-the-glitch-the-fix

 

[Scott r c]

I dunno much, but I thought it was a combi system. They even make water heaters with built in heat excahngers for this. They are called combi heaters.

 

[minnermp]

OK, whatever it is called I was considering a system that is not open to make-up water but and not connected to the potable water system. I have seen those reservoirs that add anti-freeze to the system and that's cool but, the thought was do I need anti-freeze in the system in Oklahoma. It does get below freezing here and occasionally down near zero but not very often and not for long. I do like the idea of not having to worry about adding fluid to the system.

 

[Bondo]

OK, whatever it is called I was considering a system that is not open to make-up water but and not connected to the potable water system. I have seen those reservoirs that add anti-freeze to the system and that's cool but, the thought was do I need anti-freeze in the system in Oklahoma. It does get below freezing here and occasionally down near zero but not very often and not for long. I do like the idea of not having to worry about adding fluid to the system.

Ayuh,.... If there's Any chance, that any part of the system could possibly freeze, Ya, I'd use antifreeze,....

For instance,...
When I put hydronics in my Rental house, I filled the system with antifreeze, even though I also plumbed it with a auto-fill valve, check-valve, 'n ball valve,...
Because,.....
I can't be there all the time, checkin' the system pressure,....
If it don't leak, it'll still be antifreeze,...
If it does, the pressure won't drop,...
So far, I doubt more than a pint or so of water has been added,...

More importantly, because I can't control whether the tenant runs the tank outa oil,...

If the system shuts down, for Any reason, All I gotta do is get the boiler runnin' again, 'n Not have to fix a bunch of frozen busted fittin's, 'n lines in the system,...

So,.... Whether ya use antifreeze or Not,...
I suggest ya plumb it proper, with an auto-fill, 'n check-valve,...

 

[minnermp]

OK so I plumbed everything with the closely spaced tees and two pumps according to the Munchkin manual . sorry I don't know how to post pics yet. I origionally got a taco single zone 501 controller. how can I hook up and run two pumps with this setup?

 

[anthony666]

OK so I plumbed everything with the closely spaced tees and two pumps according to the Munchkin manual . sorry I don't know how to post pics yet. I origionally got a taco single zone 501 controller. how can I hook up and run two pumps with this setup?

run one single bx line out off your 501 into a junction box .. split it off into two inside there

 

[minnermp]

awesome that sounds good ! almost ready to fire this system up. So wiring this way both pumps will come on at the same time when there is a call for heat,correct.

 

[anthony666]

awesome that sounds good ! almost ready to fire this system up. So wiring this way both pumps will come on at the same time when there is a call for heat,correct.

hold on, back pedal a bit .. sorry, this project isn't fresh in my mind anymore

you're wiring the secondary pump to that 501

the primary pump you wire up to the boiler so it can run post purge

there's a end switch in the 501 .. run a t-stat wire over to the TT terminals in the boiler .. the tstat itself wires to the low voltage side of the 501

 

[minnermp]

OK that makes sense. I'll get r done thanks

 

[finn]

Sorry, Anthony, but you are in error here.

 

[minnermp]

Whats the error finn ? and do you know what setpoints to try on the Munchkin to start?

 

[mygarageone]

Beg to differ. Here's just one website from googling "open radiant heat system:



http://www.gwgillplumbingandheating.com/webapp/p/264/open-radiant-versus-closed-radiant

Cheers
Steve

Anthony is correct by what he said.

An open system is exactly that , non pressurized and open to the atmosphere , a closed system is exactly that closed and pressurized .
You can not change the industry terminology to suit a differant system.

 

[anthony666]

Sorry, Anthony, but you are in error here.

k .. this is completely my fault because i got angry at stingry .. im gonna explain this and put the issue to bed

a closed system is a system that is completely sealed off from the atmosphere

an open system is a system that is open to the atmosphere

very very simple

now where you guys are getting confused is when you open a faucet that is connected to a hydronic system you are opening it to the atmosphere .. again, you open the tap, you OPEN THE SYSTEM to the atmosphere

there is no correct name for these systems, they are an incorrect and dangerous blip on the radar in the evolution of hydronic systems

it's not a regional thing .. it's not a nickname .. it's not a error on my part

i hate to say this part; i do radiant and hydronics for a living .. i have done it for a very long time .. i have factory training from dozens and dozens of manufacturers .. please trust me, i know wtf i am talking about

let's please move on from this subject .. happy new year

 

[minnermp]

is there a way to wire the pumps so I can override the controls and just wire in a switch so I can just turn the pumps on for circulation?

 

[anthony666]

turn off the gas .. and jump across the thermostat terminals in the taco box

 

[minnermp]

will that turn on both pumps or just the one controlled by the taco?

 

[anthony666]

you'll still get a signal to the boiler .. it will start the circ pump try to fire three times then lock out on a flame sensor code (f09 iirc).. you'll need to hit 'reset' to get it running again

what are you trying to accomplish ??

 

[dfiler2]

Just have to add this, I work for a manufacturer that produces boilers, we currently make boilers that are open to the atmosphere, we have in the past manufactured boilers that have an "H" stamp and are closed to the atmosphere.

anthony666 is 100% correct in his definition.

There is a book by Dan Holohan called "Pumping Away" that does a great job of explaining it in simple terms.

 

[anthony666]

thanks dfiler

 

[minnermp]

OK got the little Munchkin fired up on tues eve before the cold wave hit and the little sucker actually fired right up after bleeding the gas line. I hooked up the make-up water line and bled the system thru that and much to my surprise it went very smoothly! Seems to be running great but the pressure seems a bit high. It is holding at about 30 psi on the primary side and a bit higher on secondary side.There is about a 30 - 40 degree difference in the supply vs the return temps. I played around with the flow adjustments on the manifold and have it set at the highest flow and still 30-40 degrees difference. Is that correct ? Thanks for all the help on this and if someone can tell me how to post pics I will try

 

[dfiler2]

It could be you have a low flow causing the large differential or it could be a very cold floor. Sometimes it takes a while to warm up a floor this time of year.

Good explanation of how to attach photos with out using a third party site.
http://www.garagejournal.com/forum/showthread.php?t=169618

 

[anthony666]

30 psi is a bit high for a munchkin .. i'm pretty sure they're meant to run in the 20's with the water hot

check the air pressure in the expansion tank and adjust it accordingly .. you might have to turn down the pres regulator as well .. if it's non adjustable close the make up water