Heating basement

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Old 01-14-21, 09:30 AM
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Heating basement

My lower New York zone 6a well insulated basement is 2800sqft. There are 4 well-insulated windows and two wide insulated doors, Most of the basement is underground. The temperature ranges from 60 to 65 degrees during the winter. Even during the rare -15 spell the temperature never dropped below 50 degrees, and quickly returned to 60 degrees afterwards.

I have been using the basement for storage, gym and work area and never really had an issue with the temperature. Plus the basement is dry and comfortable.

Lately I have been thinking of making a space for the kids to be safe and hangout on those rainy/windy/snowy days. I think I should put in a two zones of baseboard hot water heat to take the chill out of the air. This should be easy because the furnace is right there, and for the most part I only have to pipe the returns. My math is probably wrong but my idea would be to put in 20' of baseboard on either side of the basement. Is this enough to raise the temperature 5 to 10 degrees?

Thank you for any suggestions and/or advice.

 
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Old 01-14-21, 12:17 PM
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Welcome to the forums.

I'm not the boiler pro but to have 2) twenty foot pieces of baseboard would be well more than ample to heat that area.

I'm not following on piping just the returns.
If this is a multizone hydronic system.... the basement would need to be treated as a new zone. You couldn't just add the basement into an existing loop or the basement would overheat with no way to shut just the basement off.
 
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Old 01-14-21, 05:15 PM
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As PJ said you cannot just cut into a return. If you are going to put the basement on its own zone it must have its own supply and return that will go into the main boiler return. 20 FT. of baseboard @ about 600 btu's per ft. = 24,000 btu's of heat which should be in my opinion more than enough for a room that is mostly underground and stays at roughly 60 by itself.

Something else to consider is the size of your boiler and the main pipe size that will be supplying the added zone. Pipes have btu limit they carry. You can google the info facts you need for your design or post some pics of your system and piping if possible.

Just my opinion but a zone valve off the main supply if possible would save you some work and material depending how your system is piped now.

Hope this helps a little.
 
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Old 01-15-21, 09:11 AM
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Basement heat loss is often lower than upper levels.

mbarone approach should work nicely by adding piping and zone valve to feed baseboard into existing return line after other elements.

In similar NY home, DH installed 30 foot of baseboard in basement. Found 12 foot was unnecessary and removed it. Then saw way to have cozy kitchen and reduce first floor heat load by making it a second zone on same piping.

The modern solution is to use circulator that automatically adjusts to changing loads as zone valves open and close. Just leave Grundfos Alpha2 powered on with no zone valve end switch wiring.

Old way was heat load calculations, sizing, pump curve charts and whatever. DH years ago designed systems that way. For existing systems, new modern way is “plug and play”.

Most USA boilers are oversized because of reductions in original heat load do to insulation, new windows, etc. so the BTUs are available.

https://www.supplyhouse.com/Grundfos-99163932-ALPHA2-15-55FR-Cast-Iron-Circulator-Pump-115V-1-16-HP-GF-15-26-Rotated-Flange
 

Last edited by doughess; 01-15-21 at 10:54 AM.
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Old 01-15-21, 12:55 PM
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A couple of pictures of the boiler & nearby piping would be helpful as would a sketch of where you intend to put the baseboard in relation to the boiler.
 
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Old 01-19-21, 07:42 PM
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First. Thank you Pete, Spott, Doughess, and Grady for your help.

I see I left out that the house has seven zones with 1" and 1 1/2" feeds running the full length of the house that supply the baseboards. Of course, all the baseboards in a zone are connected to each other before the last baseboard connects back the the furnace. That is why for the most part, I only have to run one side. Splicing into the supply lines that run close to where I want the baseboards should be easy. Everyone was right to warn me that I could not just jump a zone. Thank you for your concern! That would have been a BIG mistake.

I believe the furnace has capacity because, one, the house is very well insulated. Two, the furnace cycles between 180 and 200. When the furnace turns off the temp runs up to ~209. The furnace is more off than on even on the coldest nights.

Separate 20' baseboards, separate zones, and separate thermostats sounds like a nice project. I will have to wait till we have a warm week that the furnace is not needed before I drain and make the final connections.

I thank you for your time and advise. It is nice having knowledgeable friends willing to help. You have given me the confidence to move forward. The kids are looking forward to having a space to play and they say they would be fine with current temperature. It will take me a couple of months to finish. And it definitely will be heated.

Mark
 
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Old 01-20-21, 08:26 AM
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Nice to read that mbarone is making progress.

mbarone should first determine existing boiler capacity on coldest days. For easy, accurate way to find it see DH posts on this link:

https://www.doityourself.com/forum/b...do-i-have.html

Next, boiler scaling increases above 180F so use it as upper limit. Higher boiler temps reduce service life and create other issues. DH's boiler over shoots 10F so set max at 170F.

Using data from first issue, DH reduced nozzle size to 66 % of rated. On coldest days boiler runs 8 hours out of 24 or 33 % of time. The 70 year old boiler now operates at 86% efficiency.

Finally, on new zone use isolation valves so rest of home can be heated if issues arise.
 
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Last edited by doughess; 01-20-21 at 08:46 AM.
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Old 01-21-21, 09:17 AM
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Thank you Doughess. A lot of good information. I loving learning.

The boiler is a P-688V, BTU 218.000. On the coldest day (-15⁰) the boiler used 15 gallons. So at 1.80 gph the furnace ran 8 hours and 20 minutes that day, or 35% of the time. The pass couple of weeks the oil level meter says the boiler has been using between 7 and 8 gallons a day which means the boiler is running ~17% of the time.

So the boiler has plenty of extra capacity.

I did make a mistake on the high limit. The factory default high limit is 190. The factory default low limit is 180. The maximum temperature does range from 204 to 209 before it starts dropping.

Thank you for the warning on scaling. Originally, the well water was slightly hard (20ppm) and had a slight sulfur smell. After installing a large self-cleaning water filter I had the water tested. All the tests are virtually zero with a PH of 7.0, no harmful contaminants and no sulfur smell. I do have a water softener which is set to 1 to catch any remaining impurities. Hopefully the clean water will prevent scaling.

Thank you for your guidance. Because of you I have a better understanding.
 
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Old 01-21-21, 04:18 PM
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Cheap easy way to increase boiler efficiency is reducing firing rate/gph. That is heat exchanger basics 101.

Reducing through put on heat exchanger raises efficiency. Cut firing rate, reduces stack temperature. Less heat up chimney more dollars in pocket. Duh … Duh.

On several posts in link below outline how to do it without combustion analyzers.

https://www.doityourself.com/forum/b...ml#post2877659
 

Last edited by doughess; 01-21-21 at 04:36 PM.
 

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