HELP! Identifying closed vs Open loop ratiant system

barney_stinson

Hi all. I'm new, first time homeowner. first thing I did was to convert from oil to gas heating. The contractor installed Burnham ES-25 14000btu boiler with (3) heat and (1) indirect hot water zones. He also installed Techtonium H40 indirect water heater.
What I'm trying to do is to connect my radiant heat Uponor manifold (with 7 loops and actuators) to one of the 3 heating zones. The contractor at that time told me that once I had my manifold set up with loops connected, all I would need is to connect to the supply/return lines of the boiler and that would be all, no additional parts required (I still figured I'd need 3-way thermostatic mixing valve which I bought). Now that I have my manifold set up and ready to connect to the boiler, I am struggling to understand if these 3 zones that he installed is closed or open loop system. I've read too many scary things about open loop systems so I'm afraid to hook it up given I have a 3 year old child at home. Any insight would be much appreciated as I went through the boiler manual and it didn't mention anything about it.
Thanks all in advance

barney_stinson

Here's picture of boiler and manifold

Rich_49

Barney ,

What type of tubing is that , barrier or non barrier ? Is it Uponor tubing ?

STEVEusaPA

If the tubing has an oxygen barrier, its a closed system. If not, it's still a closed system, but you will have oxygen infiltration, and component/boiler failure. Doesn't the contractor who installed it know?
Why wont the contractor come back, hook up the tubing, purge the system and make sure its working correctly?

barney_stinson

Rich - it is pex tubing made by Rifeng. To be more precise it is Pex-al-pex which is aluminum layer sandwiched between 2 pex layers. I chose this because I did the installation myself and the aluminum layer makes Pex easier to stay in shape when you bend it as well as supposedly transfers heat better.
STEVEusaPA - I would need to find a new guy then since this guy says he only does oil/gas conversion and won't come just to hook up manifold to the boiler.

In any event, I'm just trying to figure out if I do hook the manifold to one of the 3 heating zones, would it be closed loop or open loop.

barney_stinson

STEVEusaPA said:

If the tubing has an oxygen barrier, its a closed system. If not, it's still a closed system, but you will have oxygen infiltration, and component/boiler failure. Doesn't the contractor who installed it know?
Why wont the contractor come back, hook up the tubing, purge the system and make sure its working correctly?

Steve, I was under impression that closed and open system had to do with whether the water circulated in radiant system comes back to the tap when you open the faucet or it just circulates independently from the tap water. I don't think oxygen infiltration into tubing defines open/closed hydronic systems. But honestly, I'm not experienced in this and only know what I've researched online

Bob Bona_4

If it's pex-al-pex, it's got the 02 barrier. If all the loops are hooked to supply/return manifolds, and nothing else, I would assume it was intended to be a closed loop. Really, it's what you pipe those manifolds to dictate open or closed. If you pipe them to the boiler - closed loop.

barney_stinson

Bob Bona said:

If it's pex-al-pex, it's got the 02 barrier. If all the loops are hooked to supply/return manifolds, and nothing else, I would assume it was intended to be a closed loop. Really, it's what you pipe those manifolds to dictate open or closed. If you pipe them to the boiler - closed loop.

Thanks very much for the reply, Bob. I was suspicious because I wasn't sure if a boiler could support both - indirect water line for the tap water heater and closed system for radiant heating.

Bob Bona_4

The potable water should be separated from the heating water via a backflow preventer. Typical is a combination back flow preventer/ boiler pressure regulator, piped into the boiler at the proper location. Your cold potable water is tapped to go into the backflow device.

RobG

If it is PEX-AL-PEX it is Barrier tubing which should make it a closed system as long as there is no potable water piped in using boiler water directly (hopefully not because that would be waaaay wrong). The tubing in the front of the boiler concerns me a bit as it doesn't look secure. Can you take a few more pics of the boiler and system so that we may get a better look? What type of installation is it, suspended with or without plates? Under slab? Is there insulation? What type of flooring? Was a heatloss done? The more info the better.

barney_stinson

RobG said:

If it is PEX-AL-PEX it is Barrier tubing which should make it a closed system as long as there is no potable water piped in using boiler water directly (hopefully not because that would be waaaay wrong). The tubing in the front of the boiler concerns me a bit as it doesn't look secure. Can you take a few more pics of the boiler and system so that we may get a better look? What type of installation is it, suspended with or without plates? Under slab? Is there insulation? What type of flooring? Was a heatloss done? The more info the better.

Thanks for all the points, Rob. The point you make about it being closed loop "as long as there is no potable water piped in using boiler water directly" is exactly what I'm trying to figure out. I will take more pictures when I get back from work so you could take more detailed look at pipes and perhaps figure out if that is the case.
There are unsecured tubing in front of the boiler because at that time I hadn't connected all the loops into the manifold so I hadn't cut them to a precise size yet. That will not be an issue/problem once the manifold will be connected to the boiler. I laid BarrierXT insulation under pex and poured concrete over it. After that I glued down an engineered hardwood using 3-in-1 glue (glue, sound, moisture sealer in one). I haven't done the heatloss.

RobG

It sounds like you have jumped in the water without testing the temperature first. The first step in any heating application is to do a heatloss. that will determine the pipe size, spacing and water temp required to heat the space as well if any supplemental heat is required. I would suggest going to the Slantfin website and downloading their heatloss calculator. I have never used the insulation that you have so I guess their specs must be taken at face value.

Bob Bona_4

What floor level is slab? Basement?

barney_stinson

Bob Bona said:

What floor level is slab? Basement?

The slab is ground level. It is a ranch style house without basement.

Bob Bona_4

Got it. Like Rob said, you're driving blind without a heat loss, because you have no idea what water temps are needed to do the job, if 7 loops are enough, what the tube spacing should be, if any supplemental heat is needed anywhere if the floor loading is too high in spots.