Radiatec Poly PXC pipe

mikel

Thanks Andrew, That seems like a much simpler set up. I would probably go with another controller with sensors on the floor supply and boiler loop to provide reset for that room? The control on the sentry 2100, (the early version I have) is pretty lame. They didn't think it all the way through. The engineers even had a tough time explaining it to me and the installer whenwe first put it in. It is though they had someone with little grasp of the english language write the manual and software.

mikel

Anyone have problems with this pipe?

I installed my radiant system 16 years ago using a Radiantec package. The 3/4" tubing is in 2" of gycrete so I am committed to it. I am replumbing the system again after my Trinity boiler (which replaced 2 failed Polaris heaters in a row) took a dirt nap and I am replacing the SS heat exchanger. The OEM primary pump they provided was too small, the water was too hard and the system had a few leaks. Not sure which killed it, maybe all 3. I am wondering if I am getting oxygen infiltration into the system from the Pex pipe? I have heard some people on the net grumble about the pipe from Radiantec. Most of my send and returns are this pipe too as they homerun back to the boiler room. Those I can replace.

Just to hedge my bet, should isolate the radiant side with a heat exchanger like I have in drawing? Would it be a efficiency killer? Would it be too much pressure drop? etc. I think the warmest water I can get from this arrangement, according to specs, is 120 degrees using 180 degee boiler loop.

I will be putting a Taco RMB-1 between the the primary and secondary loops to control everything and protect the rebuilt Trinity anyone think that injection with the RMB and plenty of purging, air scoops etc is enough without using the brazed plate exchanger?

Any advise would be appreciated.

ALH_4

Well

You dont really need the RMB. You could just use a tekmar 356 and a UPS15-58. I'm not sure of the price comparison between the two. Do your pumps really pump out of a brass manifold?

What happened to the heat exchanger in the Trinity? How long was it in service?

-Andrew

Weezbo

i hate to tell you this buh...

unless you are way good you will never be able to describe flow and temp through the headder side of that plate exchanger.

why not build an injection loop put a couple temp indicators on it .

does the system side have anti freeze as well as possibly non barrier pipe?....that might throw another wrench in the works. with what you have bringing the returns from the field back to the manifold in reverse order of the supplys would help balance out that side of the equasion to your favor however building your own injection system with crossover s would help you dial the individual zones in with closer to the same supply water temps....

one thing i really like is your RMB stencil*~/:)

mikel

The RMB has an injection pump and a circulator pump plus a pretty comprehensive control which will give me a minimum floor temp. that feature I like. Not sure is the tekmar does that.

The Trinity tanked after 2-1/2 years. They have already redesigned it. The orginal supplier quit dealing with them 3 months after it was installed. The new supplier is pretty upfront about it and very helpful. NYT undersized the pump to begin with and totally redesigned the intake and exhaust, blower and condensation drainage. They reprogrammed the their 2100 controller too. That it why I want to go with the RMB and have that provide boiler control, and protection.

mikel

Do you mean an injector instead of the RMB? Or injecton pumps for each zone? That sounds more complicted than my set up. Wouldn't each injcetion pump need it's own controller and sensors?

You don't think with the balance valves and flow meter as well as temp gauges to and from the manifolds are enough to balance the zones?

I find that the zones in my install are all about equal in load, mass etc. the heat is pretty smooth throughout the house. Not a lot of wide swings, PID control or problems like that. I do have digital thermostats. They learn the PID hysterisis and stick with it. I never set it back.

I also have an IR digital thermo that I use in my work that I can use to measure each loop.

I was thinking of adding the heat exchanger to protect the boiler side from Oxygen. I don't really need freeze protection. The power went out once for 72 hours in near zero weather after the froze heaved the underground wires down the street. The whole house only dropped 10 degrees. Granted the floor was at full temp. There is that much mass in the floor. Lots of tile, granite etc. and the house is super insulated with rigid foil face poly isulation under the blueboard. That is perfect for keeping radiation in. Works very well when the boiler works. I just want to plumb in better control and use the pumps and pex that are still in place with minimal new copper and quick work but still have better boiler protection. I need to get back to my easel soon.

ALH_4

Control

You really want to get the coldest water back to the boiler to maximize condensation. You're protecting a boiler that doesnt need or want protection. Why not pump the boiler loop through the heat exchanger directly and save the close tees and rmb altogether? You can always reset the boiler however you want to help control your floor temps. You could run the room you want the floor warm in all the time directly on reset and turn the others on and off.

-Andrew

Weezbo

The Flat plate is it a FP 5X12-16

.....? check this site out FlatPlate Heat Exchangers they have a program that you can use to see what size psi temp and gpm you have on both sides of the plate exchanger.

plate exchangers are very good to seperate different fluid types. the lower the temps that you run through the system the better and because the RMB has superior control from the manifold to the plate it would "cost ' in efficentcy however not likely the cost of new boilers...you could insulate it on the supply sides, The X block is a fancy taco doo dad however i might need to think it by numbers it has three modes like the RMB you can do things with plate exchangers that just an injection system doesnt or cant do. how many BTU's did you say you needed to meet the heat loss ?

[Deleted User]

Silly questions...

Did you per chance complain to the sales rep (Radiantec)? and if yes, what was their response, and if no why not...

Knowing their system designs, there are a LOT of things that could be wrong with your system, the first of which is that it is a direct water heating space heating combination.

I hope you and everyone reading this understands the health implications/impacts a system that is open like their design promotes has...



ME

mikel

Originally it was an open system. I did complain to Radiantec but they referred me to American Water Heater. They did replace the first heater (over night in the dead of winter when my daughter was 1 month old) after it leaked onto the controls. Why a company would STILL design a system with all the electronics below the water tank is beyond me. I separated the domestic and heating water on the second install. The heating worked fine for years until the hard water chewed up yet another tank. So I switched to the Mod/con Trinity and added a indirect DHW tank.

This was all 16 years ago. We have all learned a bit more since then. The health aspect being the biggest concern.

ALH_4

Temps

Does the boiler just have a "boiler demand" contact that fires to setpoint? If so, can you set that setpoint at your heating design temp and still have the boiler fire to 180F for DHW production using separate contacts? If you can set it up that way, it sounds like a Tekmar 260 might work just fine for that setup, and you can set a minimum supply temperature, though if the floor in that room is warm all the time it might get a little warm in there depending on the heat load.

You might play with the boiler supply temp once you have everything up and running to see how low you can get it and have the radiator(s) still work. If they absolutely need 180F, adding another radiator in parallel, or replacing the one(s) you have with a larger version will let you maximize the efficiency of the boiler by dropping the supply temp. VEHA has some pretty reasonable fairly heavy steel panel radiators.

-Andrew

[Deleted User]

I'm glad you recognized the implications...

and took responsible actions.

As for liming, you can try a magnetic water conditioner. I personally have had excellent luck with them, but there are some who will tell you its a waste of your money. Funny thing, none of them has actually applied it. Just spouting hearsay..

If you have any leaks on the closed loop portion of the system, they must be addressed and completely eliminated.

If you have isolated teh DHW with an indirect, ADN the heat source is rated for use with oxygenated water, then the FPHXer is not necessary. Not being familiar with the appliance you are using, I can not say either way. In the event it is not rated for seeing the highly oxygenated water, then yes, the FPHXer is necessary.

Good luck in your ongoing hydroponic adventure.

ME