Question on baseboard system

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Old 01-05-16, 09:44 AM
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Question on baseboard system

This is not my house, but my son's. The issue in particular is that my grand daughter's room gets cold, and I would like some advice on mitigating the problem.

Some numbers / facts:

The entire apartment is on a single zone, and it is a 2nd floor. The boiler is in the basement. The room in question is the 2nd room in the loop (my son's BR is first). The room is 12x10x8 and has about 10sq ft of windows, which are new.

The gauge on the boiler appears to be accurate. It reads 180 degrees when running, and the cut off kicks in at 190. When running, the pressure is 20 Psi.

Using a meat thermometer, I get 140 degrees at the radiator in the baby's room. If I go to the last length of baseboard in the living room, I get 130 there.

I already know the house is poorly insulated, so I am guessing most of the problem is due to that, plus the room facing north in winter is a problem as well.

My question:

Should I be expecting a 40 degree drop in water temp from the boiler, up to a second floor (pipe is inside outside wall), and then going though one room?. There doesn't seem to be that much of a drop once inside the apartment from where the baseboard enters to where it exits. We are talking 40-50 foot run here in total.
 

Last edited by fxcarden; 01-05-16 at 10:11 AM.
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  #2  
Old 01-05-16, 11:08 AM
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A 40 drop from the boiler to the first emitter sounds pretty excessive. That would mean a lot of heat is getting lost in the wall.
 
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Old 01-05-16, 12:09 PM
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Ugh. I was afraid you would say that.
 
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Old 01-05-16, 02:42 PM
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You state both house and apartment. The first thing I need to know is if this is owned or rental housing? If rental then the landlord is responsible for maintaining the heating system in a manner that meets the applicable landlord-tenant laws of the jurisdiction. ANYONE attempting to "fix" the system in a housing unit they do not own is asking for trouble.

You state that using a meat thermometer you measured the temperature of the piping in various rooms. Go back and measure those temperatures again only this time measure at the beginning and end of each baseboard in each room. Post those figures as well as the length of the baseboards in each room. Also use the meat thermometer on the pipe coming out of the boiler where it goes into the wall. Although it is possible I kind of doubt that you are losing 40 degrees from the boiler outlet to the first baseboard heater.
 
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Old 01-05-16, 06:21 PM
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By "house", I mean dwelling. It is an apartment on the top floor of a two family building. My elderly in-laws own the place, so I am kind of "the acting owner" in a way. Any trouble would be self-inflicted, I can assure you. Anyway...I did just what you said, and I got virtually the same reading in all the spots, so I am thinking either (a) the meat thermometer is consistently broken or (b) the gauge on the boiler is wrong.

I also measured at the pipe just above the boiler, expecting to see close to 180, but only got 140.

I think I need a better measurement tool. Any suggestions ?.


Again, the room in question is 10x12, and it has ~ 22 feet of baseboard on 2 of the 4 walls.

This whole thing started with me attempting to figure out BTU output for that room, but I knew temperature was a factor. There is a huge difference in BTU between 140 degrees and 180 degrees obviously.
 
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Old 01-05-16, 06:55 PM
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Back in an hour or two, nap attack coming on.
 
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Old 01-05-16, 06:56 PM
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Its about 550 btu per ft of baseboard.

A digital thermometer is a good item to use..

BTU per room more or less is sq ft x 25.. So 10x10 room is 100 sq ft. = 2500 btu of radiation needed @ 180F boiler water temp..

2500/ 550 = 4.54 or 5 ft of baseboard...

If room is not well insulated or drafty use 35 in the above calculation...

Oh and what type of emitters? Finned tube or cast iron?
 
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Old 01-06-16, 06:03 AM
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The system uses finned tube radiators.
 
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Old 01-06-16, 02:27 PM
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I suspect that rather than "radiators" you have finned tube baseboard convectors. Do they look like this?

[ATTACH=CONFIG]61183[/ATTACH]
(Image from Google Images)

What kind of meat thermometer are you using? I got a new deep fryer for Christmas and was checking the thermostat action and I got wildly different results when I used my dial-type (bi-metal) meat thermometer versus the instant read digital food thermometer. For kicks I then used my industrial digital thermocouple meter and got results similar to the digital food thermometer. I found that IF I waited long enough (several minutes) the dial-type thermometer would eventually reach close to the same temperature of the other thermometers but if you are holding the probe against the pipe that gets old really quickly.

Since you seem to be getting nearly the same temperature at all measuring points I think the problem is low circulation through the system. It COULD be that the boiler temperature is running low but not likely THAT low.

Now if you have the baseboard convectors you have to make sure they are clean. Just a little dust on the fins will degrade their performance significantly. The damper at the top must be wide open and the opening at the bottom must not be obstructed by a tall carpet or any other objects.

Some pictures of the boiler and nearby piping may help us to help you. Pictures need to be well lit and in focus. Close ups not needed at this time but take them from a far enough distance (or use wide angle lens) to allow us to see how the different parts are connected.

I'll be gone for several hours, getting my eyes checked, which should make some members of this forum happy.
 
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Old 01-07-16, 09:05 AM
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Yeah - I have the baseboard convectors. As for the meat thermometer, I just grabbed the one from my daughter-in-law's kitchen. I am considering buying a digital with a probe. I will report back when I get better readings.

How would I know if I have low circulation? When the boiler starts up, the return pipe gets hot pretty fast. I don't have exact timings, but I would say within 2 minutes, you really can't touch it, so that would be an indicator of the water running the loop pretty quick, no ?. The total length of pipe inside the apartment is around 75 feet, plus the height of 2 floors (may another 30 feet combined?), so basically somewhere between 100 and 120 feet total from the time the water leaves the boiler to the time it returns. (These are rough estimates from memory).

So....if water takes ~ 2 minutes or so to circulate 100-120 feet at ~ 20 PSI, what is the gpm ?
 
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Old 01-08-16, 11:30 AM
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OK, so I borrowed one of these

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The outbound pipe at the boiler registers 150 degrees, the return at the boiler about 115. It was hard to measure the convectors, but I got around 130-140, which is close to the meat thermometer. I guess the gauge on the boiler is probably crap because it reads 180.

I pointed the laser at an interior wall and got 72 degrees just like the house. Pointed it at the outside wall, and got 62 degrees. Today it is 45 degrees outside and sunny with no wind. I suppose with 5 degrees and winds out of the north at 30 mph that wall is probably more like 40 degrees. No wonder the room is cold.

Next step : drill small hole, verify no insulation with snake USB camera, then I guess call blown insulation company.

Still wondering if 140-150 is a reasonable temp for the convector. Oh, the circulator is a Bell and Gossett 106189.
 
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Old 01-09-16, 09:20 AM
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Still wondering if 140-150 is a reasonable temp for the convector.

Hello? Anybody?
 
  #13  
Old 01-09-16, 10:00 AM
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There are various charts and calculators out there to give you an idea as to what is in the wall for insulation. Your readings appear to be off the chart, which would agree with no insulation. If those pipes are passing through the outside walls, ouch, there goes your heat. Here's a link:
https://www.ag.ndsu.edu/pubs/ageng/structu/ae1373.pdf

Bud
 
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Old 01-09-16, 10:31 AM
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Heat emmitters are designed around 180F boiler temps.. Youll get about 600 btus per ft at this temp.

Lower temps will reduce the output...
 
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Old 01-09-16, 10:32 AM
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Thanks man. Useful stuff. Much appreciated. I also gotta climb in the attic and see what insulation is up there.
 
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Old 01-09-16, 10:52 AM
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Just a note, I looked for Milwaukee thermometers and saw 2 that looked like yours, one had a 1 to 10 cone and the other was 1 to 12. That gives you a reading over a 1 ft diameter circle at 10 or 12 feet. The same ration holds as you get closer although I didn't see how close you can actually get. But at 10 or 12" you might be reading a 1" diameter circle. See how close you can get and still get a good reading, but at 6" you would hopefully be reading a 1/2" spot.

You can also add a piece of black tape to see if the emissivity is affecting your readings.

While in the attic, look around and check with the laser thermometer for hot spots, heat of air leaking into the attic.

Bud
 
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Old 01-10-16, 08:01 AM
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Thanks. I used the one that was 12 to 1. I have since bought a General that is 8:1.

Will do some further digging. Of course, today is 60 degrees LOL.
 
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