Adding a zone in basement


  #1  
Old 01-26-07, 07:52 AM
J
Member
Thread Starter
Join Date: Apr 2003
Posts: 101
Upvotes: 0
Received 0 Upvotes on 0 Posts
Adding a zone in basement

Hey all..

I recently finished my basement (~490 sq ft).. Orginally the plan had been to use a small space heater to heat the area.. Unfortunatly I got the electric bill and am now considering alternatives...

We had previously been using a small 1500 watt electric heater to do the heat.. This kept the room at about 65 degrees when left on low during normal tempertures... Not sure what this would calculate to btu's/hr but obviously not much.. The room has gotten a little chilly the last few nights, but it has been -15 (in Vermont)

The house has a hot water baseboard with 3 zones (1 water heater, and 2 seperate zones for 1st and second floors)..

So here is my plan..

Run 3/4 pex behind drywall to a two baseboard radiators one 10 ft, and one 6 foot at seperate areas of the basement (probably about 80 feet in length of the loop). Purchase a new Taco 007 circulator pump, and attach this into the system.. The orginal plumber made a nice iron pipe manifold which appears would be easily expanded. The baseboards would be lower then the furance and circulators. Would this cause any issues...

Finally I think I would need to replace my Taco SR503 controller since I am out of available zones on it (it only supports 3).... Will probably just replace with a 6 port controller, just to make sure I do not run out.. A heated garage always sounded nice...

I keep thinking there would be more to the project, but cant think of any big gotcha's... That of course makes me the most nervous since I am certain there is a lot more to hvac then what I am considering.. Any suggestions or recommendations (except saying just use the electric)..
 
  #2  
Old 01-26-07, 02:42 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
It all sounds good in theory.

I'm assuming since you want to use a circ on the new zone that the other zones are with circs and not valves, correct ?

The "gotchas" would be if the existing boiler isn't oversized enough to handle the extra load.

Let's see, 16 feet of BB at appx 600 BTU/FT ... that's like 10K BTU, might actually be too much for the space in fact. You could always throttle it back or close the dampers on the BB I guess.

What size is the boiler, and what does the rest of the heat load look like BTU-wise ?
 
  #3  
Old 01-26-07, 04:24 PM
J
Member
Thread Starter
Join Date: Apr 2003
Posts: 101
Upvotes: 0
Received 0 Upvotes on 0 Posts
I plan on putting the zone on its on thermostat, so even if the bb are a little oversized I would think it would be regulated by the thermostat.. Really the 16 ft was a guesstimate.. How many btu's or feet would be recommended for a basement of about 500 sqft?


Not exactly sure of the size of the boiler.. It is a 1 year old Weil Mclain Gold GV series 4.. It run on LP.. Not sure where the exact rating in btu's per hour is on the boiler... When we built the house last year we told the builder to make sure to have a boiler with supplimental size for a basement and garage, but to be honest I never pushed the issue.

The rest of the heat load is 1 water heater and 2100 sqft of living space.. In vermont.. I can take a picture if that helps...

Hopefully my goal is that this loop would rarely need to come on.. Especially since this room already requires very little heat.. This will probably be a spring project as I dont think I can work on the heat when its barely above zero.. Might upset the wife more then the bill.
 
  #4  
Old 01-26-07, 06:22 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 12,682
Received 41 Upvotes on 39 Posts
BTU requirements

Your 1500 watt electric heater will give you about 5100 btu/hr. You can use that figure & your experience with that amount of heat to roughly figure what you will need.
 
  #5  
Old 01-26-07, 08:24 PM
Who's Avatar
Who
Who is offline
Member
Join Date: Jan 2006
Location: San Jose
Posts: 2,066
Upvotes: 0
Received 2 Upvotes on 1 Post
Why not do a heatloss calculation first? Without that, you're driving in the dark. 1000 watts is 3413 BTU. How cold was it when you were using the heater? The heatloss will help you calculate what you need.

How is the rest of your system piped? Why not first try and grab some flow from elsewhere? If you could spare flow capacity from elsewhere and use a TRV (pure mechanical wax based controller) to regulate temps, you'd probably be best off from an efficiency viewpoint.
 
  #6  
Old 01-26-07, 09:18 PM
J
Member
Thread Starter
Join Date: Apr 2003
Posts: 101
Upvotes: 0
Received 0 Upvotes on 0 Posts
Yes I probably should do the heatloss calc, but I would think it would be a little skewed since the basement already has the copper pipes for the other zones running which I think provide some inadvertent heating.. Kinda hard to gauge the temp of the room before the heat, since it is -19 out right now and I am not about to turn off the heat...

The thing I do not like about tapping into an existing line is that it would then be Dependant upon the upstairs zone being circulated... Additionally it doesnt seem much more of an expense to add a new circulator pump.

Also how would it be inefficient to add an extra zone... The furnace is always on and up to temperature since the water is heated with it...

Thanks for all the replys so far.. Sorry to ask so many questions..
 
  #7  
Old 01-26-07, 09:42 PM
Who's Avatar
Who
Who is offline
Member
Join Date: Jan 2006
Location: San Jose
Posts: 2,066
Upvotes: 0
Received 2 Upvotes on 1 Post
Do the heatloss... there are tables that can give you BTU ratings for bare copper at different water temps.

The 007 is 0.75 amps. That's a ton of pump to move 5 - 10K BTUs.

Are you familiar with TRVs? Maybe check out the danfoss site. Very nice, pure mechanical...

How is your system piped and zoned now?
 
  #8  
Old 01-27-07, 06:25 AM
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 definitely agree with doing the heatloss calc first.

You don't need to turn off any heat to do a heatloss calc. It's not about _measuring_ how fast the building loses heat, it's about _calculating_ how fast.

The calculation take into consideration things like:

How much of the basement wall is below frost line ?
How well insulated are the walls ?
Is there insulation _above_ this space? (i.e. the floor above)
How many door/windows? what type? how big?

You won't need 3/4" PEX for that heat load, 1/2" will do fine.

Let's say for ha-ha's that you do need 10K BTU for the space (it may not be that far off really).

If that is the case, you only need to move about 1 GPM through that loop to deliver that heat. The 007 is WAY too much pump for that.

Don't dismiss Who's idea of a TRV. Understand and consider all options!

The inefficiency Who mentioned would be in the extra power needed to move that heat into the space by running the extra circulator.
 
  #9  
Old 01-27-07, 07:15 AM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 16,321
Received 39 Upvotes on 31 Posts
I like the idea of a separate circulator pump. No need for a different circulator control panel since the boiler is kept hot for the domestic hot water heater.

Install the additional circulator and control it from a line-voltage thermostat in the space to be heated.

As for the "inefficiency" of the additional circulator...Who stated that the Taco 007 takes 0.75 amperes. That translates to 90 watts assuming the pump runs on 120 volts. If the pump runs fifty percent of the time (unlikely) the electricity usage would be 1.08 kilowatthours per day or about 32.4 kwh per month. Even with electricity costing fifteen cents per kilowatt the cost of running this pump would only be $4.85 a month, hardly an exhorbitant figure.

If you have isolation valves installed such that you can remove a circulator without shutting down the system then you could use swap the pump with one of the others if one died.
 
  #10  
Old 01-27-07, 07:54 AM
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
Originally Posted by furd
Install the additional circulator and control it from a line-voltage thermostat in the space to be heated..
Good point furd! If I understand what you mean, you are saying there's no need to tie the new loop to the boiler controls at all... because the boiler will always be at least say 140* or so ? Assuming a tankless coil is the source of the hot water, right ?

What if the DHW is on an indirect ? Would you then use a relay to fire the boiler ? How would you wire it then ?
 
  #11  
Old 01-27-07, 08:35 AM
J
Member
Thread Starter
Join Date: Apr 2003
Posts: 101
Upvotes: 0
Received 0 Upvotes on 0 Posts
See.. I knew there would be gotcha's...

Love this place...


My understanding (although probably incorrect) of the TRV is that it taps into a preexisting loop and draws heat as needed and circulates it. When it warms up it shuts off the flow.. Wouldnt the orginal zone which was tapped into need to be running at the same time. I was really keen on running this area on a programmable thermostat since the times it needs to be heated seem to be directly related to the time the kids are home since it is mainly there play room...

As far as heat loss. I have tried to find example calculations, but if someone could give me a rough idea I would be grateful...... The basement total is 1150 square feet.. The entire basement is in the ground minus the last 1-2 feet.. There are 4 windows in the basement all measuring 1'x2'... All of the exterior walls are insulated as well.. Not sure of the R value but it is fiberglass batts and fills the 2x4 framing. The finished section which would be heated is about 500 sqft... 2 of the 4 windows are located in the finished section, as well as an insulated door leading up to the unheated garage....

I think I picked the taco 007 pump since that is what i have.. If less is better then that is good for me...
 
  #12  
Old 01-27-07, 08:53 AM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 16,321
Received 39 Upvotes on 31 Posts
NJ, I was basing my suggestion on the assumption that the boiler was kept at a minimum temperature level. Since joka stated that there were three zones, one of them a domestic water heater, that may be an erroneous assumption on my part.

Still, with the limited amount of heat seemingly required, as evidenced by the smallish electric heater doing a reasonable job of heating, along with a programmable thermostat, this may still be the easiest solution.

Yes, I could "add on" an additional relay that would allow the burner to operate from the new circulator, I won't detail just how on this site.


Joka, you are correct about the TRV and an existing loop. It MAY work quite well and then again, it may not. Using PEX it would probably be relatively easy to tap into the discharge of one of your existing circulators and if it didn't work then you could move the PEX to a separate circulator for this loop only. Of course if it DIDN'T work to your satisfaction you would still have the cost of the TRV invested in the system along with also needing another pump.
 
  #13  
Old 01-27-07, 02:53 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 think I like furd's plan.

You wouldn't need to "trash" a perfectly good zone control panel. $$$ saved.

furd, if Joka wanted to do this, would you PM him the wiring scheme? (I know how I would do it, but I am probably wrong! )

I haven't priced smaller circs, but it is possible that they are way more $ than the standard 007 . furd, would there be any problems associated with too much flow from the 7 ? What if a balancing valve were installed that allowed throttling the flow in the new loop ?

[just looked at some pumps... the 003 is a bit more money... what you probably could use is the 007 ZONING circ (built in relay) WITH the internal FLO CHECK valve (you need this if you are zoning with circs). Look at http://www.taco-hvac.com and http://www.patriot-supply.com for info/pricing) that pump goes about $150 or so.]


Joka, you said 80 feet of piping ? Why ? you could loop the return line for the new loop back inside the baseboard cabinet... or is the boiler that far away from the finished portion ?

Make SURE you use oxygen barrier PEX if you do use pex. It's important!

Take a look at "sharkbite" fittings. They might fit your bill.

Are the walls dividing the heated and unheated portion of the basement also insulated ? I'll run your numbers through my software later this evening...
 
  #14  
Old 01-27-07, 04:47 PM
J
Member
Thread Starter
Join Date: Apr 2003
Posts: 101
Upvotes: 0
Received 0 Upvotes on 0 Posts
The wall between the unheated and heated space is uninsulated.... The unheated section is where the boiler is located so unheated is a little bit of an understatement... I can send you a rough floor plan if you would like

It would appear the 03 pump is more expensive since it only comes in bronze.... Is there any problem with running the 05 pump.. It would seem the GPM would be dictated by the flow of the pipe, since there is only so much volume the pipe can handle. I cant imagine it would exceed the rating on the pex .. But I am not the expert..

The 80 feet came from the fact that the boiler is on the one side of the house, and the baseboard would end at the other... Also I was thinking of doing two seperate radiators due to the floor plan.. The length of the house is 42 ft.. This would make for more of a circle run... But it was a rough estimate.
 
  #15  
Old 01-27-07, 07:48 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
From what the heatloss program is telling me, your initial proposal of 16' of baseboard was a pretty darn good guess! (assuming you use the 3/4" baseboard) If you go to 1/2" you may need a bit more, so just stick with the 3/4 and you'll be fine. It's probably easier to find and buy anyhow.

Using some worst case figures, it's close enough to 10K for comfort. Consider adding a storm sash to the basement windows, and perhaps insulating the partition wall.

Yes, flow restriction in the pipe will limit your flow to an extent, but not without cost/tradeoffs. For a heating system, you want to keep the flow VELOCITY between 2 and 4 feet/second. Any slower and you won't be able to purge air, it will get stuck. Faster, you will start to hear the water moving in the piping, and possibly experience pipe erosion over time. 4 GPM is a good ballpark figure for 3/4" pipe. Rule of thumb is appx 10K BTU / 1 GPM .

As long as you don't exceed the max flow VELOCITY , all that it would really mean to have more flow than you need is that the water going back to the boiler will have less than the 20* differential that designers shoot for. Really not a problem on a small auxiliary loop like you are proposing. (Too COLD is a problem...)

If you look at the pump curves in the tech data, you will see that the pumps are rated to flow a certain GPM at a certain HEAD pressure (read FRICTION). A straight piece of pipe has a certain amount of friction, as do any elbows, tees, valves, etc. Designers add all these factors up and come up with a number called TEL (Total Equivalent Length) of pipe. Using this TEL, they can determine the head pressure of the piping, and select a pump that will flow the required GPM.

If you do use a 007, as long as your flow is not more than MAX of 5 GPM, you would probably be OK, but perhaps a better choice of pump would be the Grundfoss 15-58 . It's a three speed model, and you could run it on LOW. I don't think they have a model for zoning though... so you would have to set up a relay to trigger your boiler to fire. The 15-58 does have the IFC, so you wouldn't need a separate flow check valve. They can be had for under $100, and if you shop ebay, you can get a good deal (I did!).
 
  #16  
Old 01-27-07, 10:52 PM
Who's Avatar
Who
Who is offline
Member
Join Date: Jan 2006
Location: San Jose
Posts: 2,066
Upvotes: 0
Received 2 Upvotes on 1 Post
If you could do this section of rad with a monoflo and a TRV, there is only only things to go and TRVs, don't go often... I'm sure there is enough flow in some circuit to drive the who shebang, TRV open or closed.

Sorry for being a simpleton on this guys...
 
  #17  
Old 01-28-07, 10:48 AM
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
Who apologized: Sorry for being a simpleton on this guys...

No problem Who! We're used to it ! HA HA Just kidding of course!
(sorry Mods, I couldn't resist...)
 
  #18  
Old 01-28-07, 11:15 PM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 16,321
Received 39 Upvotes on 31 Posts
Who makes a lot of sense. Rather than use Monoflo tees (two would be required if this new loop was below the main loop) I would instead make the return connection from the new heaters to the return manifold and install tees on the discharge of all three existing circulator pumps.

(I am assuming that this is properly piped with the circulators connected to the boiler discharge and pumping TO the heating loads.)

From the side of each tee install a check valve, vertically is best if you use a swing check. Pipe all three of the check valve discharges together and also to the supply for the new heating loop.

With this set-up whenever any one of the circulators runs it will supply water for the new loop, the mechanical TRV will allow flow when the room needs heat and stop flow when it doesn't need heat. Of course the temperature will swing more with the mechanical TRV located at the baseboard than would a properly installed electronic thermostat and you won't have any programmable features.


If you go the separate circulator route then install a globe valve where the return connects to the return manifold to throttle the flow in the new heating loop. Circulators are single-stage centrifugal pumps and the power they draw is proportional to the flow. By throttling the flow the pump will draw less than the rated current. This will not harm the pump or the motor.

For liability reasons I cannot give exact details on how to wire in a relay that will allow the burner to operate in conjunction with the new circulator but NJ has the right idea in using a relay with a 120 volt coil, wired across the circulator motor (so the relay is actuated whenever the circulator is running) and connecting the normally-open contacts of the relay in such a way as to operate the burner while still retaining the functions of all the limit and safety switches.
 
 

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