Replacing my boiler and baseboard heat w/ Panel radiators?


  #1  
Old 02-06-11, 08:22 PM
B
Member
Thread Starter
Join Date: Feb 2011
Location: USA
Posts: 22
Upvotes: 0
Received 0 Upvotes on 0 Posts
Replacing my boiler and baseboard heat w/ Panel radiators?

I am getting myself prepaired to replace my aged boiler this coming spring/summer. I am also going to replace the baseboard heat with wall mounted panel radiators at the same time and have a few questions. My current baseboard system is a continuous loop thru my entire house. 6 rooms that are heated. From what I can tell the system was installed to make the plumbing work easy while not thinking about what rooms should have been heated a little better.

The panel radiators I plan on purchasing have flow control valves mounted in them that allow a percentage of the water to flow thru the unit while the rest bypasses it. I am not really concerned with zoning the system, not much point w/ only 900sqft of living space. My downstairs consists of living, dining, and kitchen. The living and dining room are pretty much open to each other, and the kitchen will be getting a kickspace unit that will blow thru the kitchen and into the dining area. Upstairs is bathroom, small BR, and master BR. my primary heating concern for the upstairs is the bathroom, we don't like the bedrooms very warm. The reason for the panel radiators is with such a small house, it is so hard not to block off the baseboard.

What I would like to know is can I still use a continuous loop since I can control how much water goes thru the units installed in each room? I am only really concerned with heat in the downstairs, and my upstairs bathroom, The bedrooms will most likely have the units set to bypass most of the water. I have already figured out the order of the flow of the system from start to finish. Just trying to get ideas from other that know more than me, which is to say I am comfortable doing pretty much all of my own work, but I don't have a great deal of knowledge about the flow of home heating systems, but enough to know the way my house is plumbed now makes no sense to me at all, and my kitchen is always cold.

Thanks in advance for your input!
 
  #2  
Old 02-06-11, 09:02 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 15,993
Received 85 Upvotes on 77 Posts
There is alot if info here but you need to do a heat loss calculation first. Your current heat source may be under or oversized. How efficient do you want? I Dont understand the bypass thing in the bedroom that you explain so maybe elaborate on that.

Mike NJ
 

Last edited by lawrosa; 02-06-11 at 09:18 PM.
  #3  
Old 02-06-11, 09:43 PM
B
Member
Thread Starter
Join Date: Feb 2011
Location: USA
Posts: 22
Upvotes: 0
Received 0 Upvotes on 0 Posts
The units have an adjustable valve on them that allow near full flow thru the heating coil, or near no flow thru the coil. The install manual states the valves still allow flow to help eliminate air. The manual flow control valves can be replaced with thermostatic valves that self adjust the flow at each unit without affecting the flow of water thru the system. at least thats the way I understand it. I tried asking about the units I am interested in locally, but had no luck.

I can't really do a heat loss calculation now because I am doing a kitchen remodel in 2 months, and blowing in insulation in my walls, and also replacing the last of my old leaky windows this year. I have done the basic calc using the volume of each room and estimated insulation value that I should have when done with my projects. But with a 900sqft house, btu requirements are going to be pretty low as it is. I do know I have a 1500w electric fireplace that does heat my livingroom and dining area to 68* when it is 20 outside.

I don't want to install a small boiler and then install a water heater, so that leaves me with a bit of an oversized boiler that has domestic hotwater. Space is a consideration in my basement, so the boiler I am looking at is a wall mounted combination unit. Everything in one unit, circulator, expansion tank, and all electrics. I have 4 water connections, 120v line in, and thermostat wire. My pap has been heating his house with the same unit for the past 3 years, and it works very good.
 
  #4  
Old 02-06-11, 10:01 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 15,993
Received 85 Upvotes on 77 Posts
No offense but your talking jibberish. See notes under quotes....

The units have an adjustable valve on them that allow near full flow thru the heating coil, or near no flow thru the coil. The install manual states the valves still allow flow to help eliminate air. The manual flow control valves can be replaced with thermostatic valves that self adjust the flow at each unit without affecting the flow of water thru the system. at least thats the way I understand it. I tried asking about the units I am interested in locally, but had no luck.
Sounds like for DHW... I could be wrong.....

I can't really do a heat loss calculation now because I am doing a kitchen remodel in 2 months, and blowing in insulation in my walls, and also replacing the last of my old leaky windows this year. I have done the basic calc using the volume of each room and estimated insulation value that I should have when done with my projects. But with a 900sqft house, btu requirements are going to be pretty low as it is. I do know I have a 1500w electric fireplace that does heat my livingroom and dining area to 68* when it is 20 outside.
If you know what your getting(insulation) and what you have yes you can do a caclulation....

don't want to install a small boiler and then install a water heater, so that leaves me with a bit of an oversized boiler that has domestic hotwater. Space is a consideration in my basement, so the boiler I am looking at is a wall mounted combination unit. Everything in one unit, circulator, expansion tank, and all electrics. I have 4 water connections, 120v line in, and thermostat wire. My pap has been heating his house with the same unit for the past 3 years, and it works very good.
Sir you are going about it all wrong...

Mike NJ
 
  #5  
Old 02-06-11, 10:27 PM
B
Member
Thread Starter
Join Date: Feb 2011
Location: USA
Posts: 22
Upvotes: 0
Received 0 Upvotes on 0 Posts
3-41224 - Buderus 3-41224 - Model 21, 12" x 24" Hydronic Panel Radiator

125012525 - Embassy 125012525 - BMS 10/20, 73,000 BTU Output Wall Hung Boiler w/ Hot Water Supply (Propane)

It all very well could be gibberish, but hopefully the links above will give you an idea. The radiator in the link is just first selection on the site, but operation of it is the same for all.
 
  #6  
Old 02-06-11, 10:44 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 15,993
Received 85 Upvotes on 77 Posts
Others will chime in but without a heat loss calc its just a guess., What are you removing btu wise and what heat emmiters are you replacing???

Mike NJ
 
  #7  
Old 02-07-11, 04:48 AM
B
Member
Thread Starter
Join Date: Feb 2011
Location: USA
Posts: 22
Upvotes: 0
Received 0 Upvotes on 0 Posts
The oil boiler I am replacing is a 100k btu. The baseboard that I am replacing is all beat up and poorly installed. The total linear ft of baseboard is 92ft. It is installed the entire length of every extirior wall of the house. I have a guy that I worked for years ago that does this kind of thing coming over to point in the right direction.
 
  #8  
Old 02-07-11, 03:11 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 19,710
Upvotes: 0
Received 8 Upvotes on 6 Posts
Improvements to the building envelope FIRST. Then a Heat Loss calc. THEN size the boiler.

You need to do the HL in order to know how much output you need on the heat emitters in each room.

The radiators you are looking at should do the job just fine. They do have 'flow diverters' that will still allow flow through a series loop. I would most definitely go with the THERMOSTATIC valves though... that way you can adjust the bedrooms cooler, and the bath warmer, etc, without having to resort to 'micro zones'. Trying to balance heat in rooms by using 'flow control' is a losing battle.
 
  #9  
Old 02-07-11, 03:23 PM
X
Member
Join Date: Nov 2005
Location: USA
Posts: 2,338
Upvotes: 0
Received 0 Upvotes on 0 Posts
Do a heat loss calculation. You can do that at any time, and include or exclude whatever building envelope changes you are planning.

Panel radiators with TRVs is a nice way to go. But if you have access to repipe, consider doing a home-run piping system from a manifold near the boiler. The diverter approach, while doable, seems like a bandaid.

Keep in mind that a kickspace heater will typically have rather different water temperature and flow requirements than the panel radiators (kicker needs higher water temperature and higher flow rate).

Some numbers for reference.

92 ft of finned element puts out about 51k BTU/hr of heat. So your 100k boiler is at least twice what's needed, assuming the house heats ok.

But 51k BTU/hr of heat is probably more than you need anyway. 51,000 / 900 = 57 BTU/hr/sf. Which is basically a house with one side open. A reasonable, post-1970s structure is often a third of that or less.

So you may have a pretty low-load structure. Plan accordingly.
 
  #10  
Old 02-07-11, 03:48 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 19,710
Upvotes: 0
Received 8 Upvotes on 6 Posts
The diverter approach, while doable, seems like a bandaid.
I imagine that you have looked at the product... there is a factory option diverter valve available, made for the purpose.

I would most definitely urge a home run on the kicker.

[edit: I just read through the install PDF and agree that the diverter valve setup is kinda lame. It's not a pressure sensitive valve as I thought... you have to manually set the diverter... and the range is small... between 50/50 and 65/35... I don't like it. I'm going with home runs too...]

Be sure and read and understand what this paragraph from the install manual means before committing:

2. one-pipe system with diverter valves.

This arrangement is similar to using monoflow tees
except that now each radiator is equipped with a diverter
valve. Secondly, the total loop flow can NOT exceed 2
GPM
because of possible noise at greater fl ow rates.
 

Last edited by NJT; 02-07-11 at 04:09 PM.
  #11  
Old 02-07-11, 04:13 PM
B
Member
Thread Starter
Join Date: Feb 2011
Location: USA
Posts: 22
Upvotes: 0
Received 0 Upvotes on 0 Posts
The kicker I have already so while my dad is making my kitchen cabinets he could fit the unit to the cabinet, and allow access for cleaning and service. The radiators have fittings for 1/2" pex or copper, the kickspace unit is 1/2" copper, and the boiler uses 3/4" sized fittings for the heat side. Since 3/4" pipe has about twice the inside area of 2 1/2" pipes, a 3/4" main line should feed 2 1/2" loops correct? Going any bigger than what the boiler can flow doesn't seem like I would gain anything from that, or am I thinking too much into it. Anyway, it looks like the diverter valves will make my install much easier for a loop system, and doing a seperate run for the kicker isn't a real big deal for me, and would installing a diverter valve for the kicker allow me to regulate the output better? I had plenty of time to sit down while at work today and think about my impending project.
 
  #12  
Old 02-07-11, 04:41 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 19,710
Upvotes: 0
Received 8 Upvotes on 6 Posts
boiler uses 3/4" sized fittings for the heat side
That's what the web page says, but if you look at the manual I think you will see that they are 1" ... you can't move 73K BTU through 3/4" pipe without exceeding the max flow rate for the pipe. I would plan on 1" to/from the boiler.

Since 3/4" pipe has about twice the inside area of 2 1/2" pipes, a 3/4" main line should feed 2 1/2" loops correct?
A general plumbing 'rule of thumb' is that to feed two smaller pipes, you need to use one of the next size up... so yes, two 1/2" into one 3/4" is fine.

it looks like the diverter valves will make my install much easier for a loop system,
Be careful... read and understand what the install manual is saying! If the diverter valve option is LIMITING YOU TO 2 GPM in the loop, that means that the loop can only carry approximately 20K BTU! Depending on the size of the individual rads, this means that you can only hook up maybe TOPS three rads on a loop.

And smaller pipe presents more friction (HEAD) to the pump, so if you pipe the whole thing up with 1/2" you will need a honkin' pump...

If you want to use the diverter valves, then plan on only using 2-3 rads per loop... you will most likely need SEVERAL loops.

would installing a diverter valve for the kicker allow me to regulate the output better?
No, not recommended. You will want the full flow of water through the kicker. The heat output could be regulated by the fan speed, or possibly a remote mounted TRV.

Again, attempting to regulate heat output by varying the flow is a LOSING BATTLE.
 
  #13  
Old 02-07-11, 05:16 PM
B
Member
Thread Starter
Join Date: Feb 2011
Location: USA
Posts: 22
Upvotes: 0
Received 0 Upvotes on 0 Posts
So it looks like the home run system will be a better way to do this system. The radiators only flow 2.5gpm which is 1gpm more than 1/2" pex or copper, so it looks like I need to see what the pump and piping in the boiler flow and figure out what i can do here. It also looks like I could use a 2 pipe system with a common supply and return for numerous units. I can't figure out how to post the picture from the manual, but it is on page 24 fig 4 or 5. Could I do a home run type layout, but install say the three units for the 3 rooms upstairs in a parrallel circuit, and then my dining/living room parrallel, then kitchen on its own?

My old scout master has his own plumbing and heating business, he is too far away to come and do the work for me, but he is going to stop by next time he is coming thru the area and give me some ideas. I worked for him during summers while I was in school, but never really got into the theory of a home heating system, just did things the way he told me. I am capable of performing the work, it is the layout I am unsure of.
 
  #14  
Old 02-07-11, 06:04 PM
B
Member
Thread Starter
Join Date: Feb 2011
Location: USA
Posts: 22
Upvotes: 0
Received 0 Upvotes on 0 Posts
Looking at the chart in the manual for the boiler I am considering I need to know the water pressure in ft water. When it asks for ft/H2O, is that vertical ft? And if so do I figure that from the lowest point in the sytem to the highest? If so, it looks like the pump that is built into the boiler will supply a flow of about 7 to 8gpm.
 
  #15  
Old 02-07-11, 07:03 PM
X
Member
Join Date: Nov 2005
Location: USA
Posts: 2,338
Upvotes: 0
Received 0 Upvotes on 0 Posts
ft/H20 is head, i.e., resistance to flow. You will have to do your layout and come up with a resistance curve for your target flow rates and see if the internal circulator has enough oomph left to supply the distribution system under your range of load conditions, at the proper flow rate.

Looking quickly at some of their suggested piping diagrams, it seems that they often specify hydraulic separation of some sort. Maintaining proper flow through this copper tube boiler is probably why.

Make sure you do your heat loss calc. The smallest of these boilers is still probably more than twice the size you need.

And yes, Trooper, I did read about the diverters before calling them bandaids. Much as I like Buderus, it seems like more of a kludge than I would expect of them.
 
  #16  
Old 02-07-11, 07:19 PM
B
Member
Thread Starter
Join Date: Feb 2011
Location: USA
Posts: 22
Upvotes: 0
Received 0 Upvotes on 0 Posts
My other question that pertains to the hydraulic pressure of the system is sinse it is essentially a closed loop, i would think that the actual vertical lift would have less of an effect on flow than the numerous connections and bends in the pipe correct? I would think that any pump would have no trouble moving water thru a 20ft high loop as long as it was 100% filled with water since the same amount of water going up one side is also coming down the other side.
 
  #17  
Old 02-07-11, 07:45 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 19,710
Upvotes: 0
Received 8 Upvotes on 6 Posts
i would think that the actual vertical lift would have less of an effect on flow than the numerous connections and bends in the pipe correct? I would think that any pump would have no trouble moving water thru a 20ft high loop as long as it was 100% filled with water since the same amount of water going up one side is also coming down the other side.
Exactly correct. Think of it as a big Ferris Wheel of Water. The only energy that the pump needs to impart on the water is that which is needed to overcome the friction of the piping. That friction is what is termed 'Feet of Head'. There is NO vertical lift involved at all. The building could be 100' tall. As long as the pump had enough 'oomph' to overcome the friction losses, it would pump.

What gets the water to the top of the system is the STATIC pressure, which is the minimum pressure that the system is filled to, generally 12 PSI for up to a 2 story home. Then progressively higher for taller homes. ( 0.432 PSI per FOOT of height, PLUS 4 PSI 'headroom')
 
  #18  
Old 02-07-11, 07:53 PM
B
Member
Thread Starter
Join Date: Feb 2011
Location: USA
Posts: 22
Upvotes: 0
Received 0 Upvotes on 0 Posts
Awesome! And I thought this ws going to be complicated. Now I need to get some more ink for my rpinter and study the manuals for the boiler and the radiators real good so I know I am making the best choice. Thanks for the help.

Looks like I need to work on my typing also!
 
  #19  
Old 02-10-11, 05:07 PM
B
Member
Thread Starter
Join Date: Feb 2011
Location: USA
Posts: 22
Upvotes: 0
Received 0 Upvotes on 0 Posts
One more question for plumbing my system. Would manifolds work ok for me to hook each individual unit up to them using 1/2" pex. I am going to be using the thermostatic heads on the radiators. I am using 6 panel radiators, and 1 kickspace heater.


Never mind, that would be a home run layout!!
 

Last edited by bustedmp; 02-10-11 at 05:43 PM.
  #20  
Old 02-10-11, 06:46 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 19,710
Upvotes: 0
Received 8 Upvotes on 6 Posts
If you keep it all one zone, I wouldn't use a thermostatic head on the rads the heat the area where the thermostat is. Or if you DO use them, set them above the temp that the thermostat is set to. You want those rads to control the thermostat. You wouldn't want those TRVs closing before the thermostat was satisfied. Remember that since the TRVs don't actually call the boiler, they can really only REDUCE the temp in other rooms... you should probably install slightly oversize rads in areas that you wanted more heat, for example in the bathroom.

Also, don't overlook the fact that you can probably pipe at least 2 rads, and maybe even 3 on one loop. If the diverter valves allow a flow of 2 GPM, that's good for 20K BTU, so if you had say 3 rads at 4K each, they could be piped in series with the diverters, and then run back to the boiler. A good example of this would be if you had say two rads in one bedroom, they could easily both go on one home run.

Manifold is a great idea. Plan on oversizing that ... example: say you had four 1/2" take offs on the manifold. The 'rule of thumb' would more or less dictate a 1" manifold... go one size larger. Doing this will insure that one zone would not 'rob' flow from another by minimizing the pressure drops between the take-offs.

Also, you probably want to use a "Differential Bypass Valve" between the manifolds. This will allow the TRVs to open and close without allowing the pump to see varying pressure drops... as valves close, the diff bypass valve will open and keep the pressure across the pump relatively constant.
 
  #21  
Old 02-10-11, 07:00 PM
B
Member
Thread Starter
Join Date: Feb 2011
Location: USA
Posts: 22
Upvotes: 0
Received 0 Upvotes on 0 Posts
The manifolds are 1" copper with ball valved 1/2" pex outlets. My living room has the t-stat on the wall, and the smallest kickspace heater I found for my kitchen is at least twice what it requires, but I can install a t-stat to control the fan in it. I wasn't really planning on using the diverter valves on the rads. Where the kickspace heater will be located in my kitchen, it will be blowing the air thru the kitchen and into my dining and living room area. Using the manifolds and feeding each unit individually will use more tubing, but I think it will be an easier installation, and the pump shouldn't be overworked. I also want to use a few sections of the old baseboard finned pipe in my basement on the returns. My basement currently has finned pipe on both the supply and return lines, and it stays nice and warm, but I don't want to use up any of the heat coming from the furnace to heat the basement and ther should be enough heat left in the returns to provide heat for it.
 
  #22  
Old 02-11-11, 04:13 AM
X
Member
Join Date: Nov 2005
Location: USA
Posts: 2,338
Upvotes: 0
Received 0 Upvotes on 0 Posts
This is a perfect application for an ECM smart pump like a Grundfos Alpha or Wilo ECO. Costs more up front but will use 50-80% electricity and you don't need any differential bypass.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: