Replacing Heating System

WRMcAninch

I'm new to the forum so a little about myself. I'm a accomplished DYI'er with some schooling in the trades (in high school) and swung a hammer with a couple contractors for a brief time. Built my own house (sold it 4 years ago) from my own design and did most of the work myself. I am now in the Buffalo, NY area living in a small ranch built in 1964 and upgrading just about everything.

The heating system is old, hot water baseboard with some add-ons cut in for basement heat. It has one zone, two loops. Loop 1 is short (just the living room), Loop 2 is pretty long; kitchen, bath, bedrooms and the cut-ins for the basement. It's a 960 sq. ft. ranch with a somewhat finished basement. The boiler is a 27 year old Utica, 83,000 btu I believe, fired by natural gas. The only comfortable rooms in the house are the Living and Kitchen, they get the hot water first.

When I started my research I knew very little about hydronic heating so I started reading. After my head stopped spinning with all the info; delta-T, head, flow rate and the acronyms (did I tell you I hate acronyms), I'm starting.. I stress starting to get a handle on things.

Anyway..... here is my plan, hopefully with help from experts from this forum I can make it work.

Replacing the beat up base boards with Myson radiators on a 2 pipe reverse return system. I'll have at least 2 zones, one for the living area the other for the basement, (in the future remodel the finished basement). As I stated it's a small ranch so I didn't know if it makes much sense putting the 2 bedrooms on there own zone. Hopefully do the radiators and piping before next winter and the boiler the following year.

A couple questions to start;

Any thoughts on the Myson radiators good or bad? They seem to be less expensive than others by a fair amount.
Thoughts on 2 pipe reverse return for residential applications?

Looking forward to everyone's thoughts, ideas... good or bad.

Thank you kindly,
Bill

Ironman

The FIRST place to start is with detailed heat loss calculation for each room. This is THE foundation for sizing and designing everything in hydronic systems. SlantFin has a free app that you can download that's easy to use.

Myson is a good product. Are you planning on baseboards or panel rads? I generally would lean toward panel rads with TRVs. That would give individual temp control at each rad.

Reverse return is the best method to insure equal flow, but usually the most costly and it may not be necessary. A homerun system using 1/2' O2 barrier pex with a manifold(s) would probably be easier and less expensive and work just as well. Don't use Chinese manifolds or pipe.

You skill set may be sufficient to pipe in a new boiler, but more is required to set it up properly: a digital combustion analysis, calculating and adjusting ODR, etc. I'd highly recommend that you get a COMPETENT hydronic pro before purchasing a boiler. Also, all manufactures require that the boiler be installed by a properly trained and licensed contractor and they will not warranty products sold over the internet.

Start with the load calc and post its results so we can go from there.

Tinman

The only thing I could add to what Bob said is that my preference for a home run/manifold system would be to use pex-al-pex tubing.

Paul Pollets

I'd size the panel rads for 140 degree design and use a mod-con. I prefer continuous circulation with a "smart pump" and TRV's on the radiators.

MikeG

Stephen, why do you prefer pex-al for this instead of more flexible pex-A? I'm looking at doing something similar. Is it because of the potential for higher, temps, less movement, stays put better? I did a radiant ceiling with pex-al. No noise, works great. It was a bit of a pain to keep in the plates, but it was a lot different than just running tubing. Thanks Mike

Tinman

MikeG - A number of reasons...First of all It has to be pex-al-pex for home run to rads and/or bb to meet City of Chicago code which is where a lot of my work is. I also like the fact that once you bend it, shape it, it will maintain that bend which I like in this particular application. Slightly higher temp./pressure ratings as well.

WRMcAninch

Thanks for the quick reply. I did the load calc with SlantFin. I'll get something written up and posted as soon as I can. What a great resource.

Ironman

Stephen Minnich said:

The only thing I could add to what Bob said is that my preference for a home run/manifold system would be to use pex-al-pex tubing.

Stephen, that's my primary choice, too.

kcopp

I have seen a lot of pex/al/pex delaminate after a few years. I will stick w/ uponor/ Wirsbo.

Ironman

kcopp said:

I have seen a lot of pex/al/pex delaminate after a few years. I will stick w/ uponor/ Wirsbo.

That's interesting. I've only used Kitec and Roth, but I've never seen it happen. I can only guess, but I've probably run 20 + miles of it.

Was it Chinese?

Tinman

I've used Uponor MLC and before that Weil McLain's Alumi-Pex without a single problem.

WRMcAninch

Here is what I came up with using the heat load calculator.

Indoor Temp: 70°F
Outdoor Temp: 6°F
Design Water Temp: 180°F

1st Floor 20,020 btu/hr
Living room… 5407 btu/hr
Kitchen/Dining… 5253 btu/hr
Bath… 1378 btu/hr
Guest room… 3178 btu/hr
Master bedroom… 3946 btu/hr
Walk-in closet… 858 btu/hr

Basement 11,962 btu/hr
Family room… 9422 btu/hr
Laundry/Utility… 1270 btu/hr
Bath/Storage… 1270 btu/hr


Heading off to bed, 2:15 comes early, I'll add more info tomorrow.

WRMcAninch

Okay.. I’ll clarify a few things, give some more info and of course ask some more questions.

Ironman;
Glad to hear Myson has a good product. After researching on the net I liked the Myson Rads the best, and yes.. I was planning on using Rads with TRV’s.
I kind of like the 2 pipe reverse return, I see the benefit of the homerun system but not sure if I want the maze of piping.
Yes, I can do most of the labor intensive part of the job, but when it comes to the Boiler I was planning on hiring that out to a reputable contractor. Hopefully I can find one that will work with me and not try to change the plan I (we, this forum) come up with.

Paul Pollets;
I like the idea of a lower temp design and think I understand the reasoning, if you could elaborate a little so I have a better understanding. When sizing for 140 degrees, is it better to be over or undersized on the btu’s per room? When you say “continuous circulation”, what does that mean? “Smart Pump” ?, guess I’m ignorant on that.

My Load calculations are posted above. My plan is to replace the old beat up baseboards on the 1st floor this summer with the Myson rads. I’ll put one or two of the old baseboards in the basement for now until we remodel that area, they will be piped in series. Hoping to use my old boiler for the next heating season with the new distribution system, then replace it the following year. Any problems foreseen using the old boiler?

If I stay with the 2 pipe reverse return piping, is ¾ inch going to be sufficient for the 1st floor (20,020 btu/hr) or will I need to go larger? Also..is Pex with O2 barrier ok to use with the larger diameter pipe in this application?

I thank you all for your input. I have a whole new respect for someone that understands hydronic heating systems.

Bill

Paul S_3

I personally like the homerun manifold setup, everything is in a centralized locations. You should not size your heat emitters to a lower supply temp unles you are going to use a modulating condensing boiler or have some sort of boiler protection on your existing boiler for example injection mixing because your existing cast iron boiler cannot handle water temp lower than 140f and water will start to condense in the boiler destroying the iron....your using panel rads with trvs you will use a ecm delta P circulator pump....constant circulation would run the pump continous throughout the heating season only adjusting supply water temp through outdoor reset...for example on a 0f day you will use 180f 40f day use 120f...you can use 3/4 pipe for your first floor distribution system....do not undersize your heat emitters...if it was me i would do the homerun trv rad setup....with new modcon boiler. ...you will purchase the smallest possible boiler with a heat load of 32k....i would use a buffer tank to minimize short cycling

Ironman

Panel rads have 1/2 connections and in many cases 3/8" tubing could supply enough flow. But stick with 1/2". I say that to show that 3/4" reverse return would be the more difficult approach with no benefit. Manifolds provide several benefits right out of the box that are not easily accomplished in the field: individual circuit isolation, individual circuit flow control, purging, testing, etc.

You'll have a better system with less labor involved if you use the manifold homerun method.

SWEI

Big fan of both manifolds and reverse return here. Which (sometimes we employ both) depends a lot on the size and layout of the building and the accessibility (or lack thereof) of space below the floor.

Paul Pollets

I like the idea of a lower temp design and think I understand the reasoning, if you could elaborate a little so I have a better understanding. When sizing for 140 degrees, is it better to be over or undersized on the btu’s per room? When you say “continuous circulation”, what does that mean? “Smart Pump” ?, guess I’m ignorant on that.

Sizing the radiators for 140 rather than 180 means the room temps are satisfied at design temps with 140 degree water, rather than 180. The radiators will be slightly larger, but the boiler will be in condensing mode 90% of the time. There are correction factors for boiler temperature on most of the manufacturer's sites. A "smart pump" like the Grundfos Alpha, will adjust its output to the required flowrate. When TRV's are closed, the pump slows down, and vice versa. If a smart pump is not used, a pressure bypass differential valve needs to be installed.

WRMcAninch

Paul and Paul... When I was talking about over or undersized for the rads, I wasn't very clear. When I go to purchase the rads for example, my Living room calls for 5407 btu/hr. One model rad puts out 2562 btu's at 140 degrees, times 2 = 5124. The next model up puts out 2968 x 2= 5936. What side of the 5407 target is best?

After reading the comments here and other articles I'm starting to rethink my project. Maybe I'm putting the cart before the horse. Rather than doing the rads and piping first, then the boiler the next year or year after. Maybe I should do the Boiler first then the rads and piping, or better yet everything all at once. Any opinions which way would be better?

Money is tight with other things that need done. Maybe try and re-pipe what I have so it's more comfortable and save up and do it all at once?

Ironman...
You'll have a better system with less labor involved if you use the manifold homerun method.

I now see the other benefits of the manifold system but must be missing something on the labor part. I will end up with ten or eleven rads, that means 22 pipes run through out my basement just for the first floor, drilling holes etc. Reverse return would have two pipes running around the perimeter with laterals coming off them to the rads. Seems like Reverse return would be easier to install but this is not my expertise. Thoughts?

SWEI

WRMcAninch said:

I now see the other benefits of the manifold system but must be missing something on the labor part. I will end up with ten or eleven rads, that means 22 pipes run through out my basement just for the first floor, drilling holes etc. Reverse return would have two pipes running around the perimeter with laterals coming off them to the rads. Seems like Reverse return would be easier to install but this is not my expertise. Thoughts?

Which is easier really does depend on the layout. With all the rads installed on outside walls and good access underneath, reverse return can sometimes require less pipe and less work. Remember, you don't need (or want) to run 3/4" all the way around both loops. Somewhere in the run, the flows will reduce to the point where 1/2" trunking will handle it. On small systems, 3/4" may only run to the first or second rad in the loop.

Ironman

22 lines of pex-all-pex with no joints vs reverse return with 3/4" copper that has to be Tee'd to 1/2" at each runout. Unless you have a ProPress, all of that will have to be sweated and will have no flexibility. You tell me which is easier. It's very easy to bundle and secure the pex-al-pex lines. They only require securing at 6' intervals. Bend it by hand and it stays put.

I've run copper for 45+ years and pex-al-pex for about 15 years. Like I stated earlier, I have done a few feet of it.

I've got a new home we're doing the second floor on next week. The bottom floor is in-slab radiant; the second will have 8 panel rads and it didn't even cross my mind to do a RR system with copper. Pex-al-pex with manifolds is all I ever considered. And all I would consider. We do these regularly.

kcopp

Ironman said:

kcopp said:

I have seen a lot of pex/al/pex delaminate after a few years. I will stick w/ uponor/ Wirsbo.

That's interesting. I've only used Kitec and Roth, but I've never seen it happen. I can only guess, but I've probably run 20 + miles of it.

Was it Chinese?

Viega..... 3 or 4 separate occasions.

Paul S_3

Like ironman said ....homerun with pex al pex....best way to do this ....i use fostapex by viega

SWEI

Who said copper? ProPEX supply/return loop, ProPEX risers, some in MLC if needed.

Ironman

Kurt, remember, he's a DYIer. He probably doesn't have all tools that we would.

WRMcAninch

Kurt, remember, he's a DYIer. He probably doesn't have all tools that we would.

I'm sure I don't... just the basics and Pex crimp ring tools. With that being said, can you use the crimp ring connection when you're installing a heating system? It seems the Uponor pex expander system is more popular now.

SWEI

F1807 crimp PEX will work just fine.

The F1960 (cold expansion PEX) fittings have larger passages and the tubing is a bit higher grade, but at the flows you'll be using the difference would be infinitesimal.

If you're OK with PEX to the radiators (works better from behind than from below IME) then you can pipe away.