Very uneven hydronic heating

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Old 01-11-17, 06:56 AM
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Very uneven hydronic heating

Hi. First, here is my info:

1. In which area you live and ambient temperatures you usually experience. CT (very cold in the winter)
2. House style and construction details. 2 story colonial
3. Make, model and age of equipment related to the problem. Not sure, about 10 or 15 years old maybe? Maybe more, but I've been told it's in good condition, no problems, many years left
4. Fuel type. Oil
5. Water temperature and pressures of boiler systems. not sure
6. What type of zoning do you have with your boiler system. two zones, one for upstairs and one for down
7. Thermostat type. Nest
7. Anything else that would be useful. No detail is to small. The more information you provide the easier

My issue is that I have very uneven heating, both upstairs and downstairs. I believe the heat travels through the baseboards counterclockwise, and the rooms it hits first (both upstairs and downstairs) are the rooms that get the hottest (almost unbearably/quickly) while the rest of the rooms get lukewarm at best.

As an example, I keep the heat at 64 upstairs (where the bedrooms are) at night, as we like it cold and prefer to bundle up. When the temp drops to whatever level (62/63?) the heat comes on. The master bedroom (the first one in the loop) gets really hot/really fast (66/67), but the far bedrooms, where the kids are, barely get to 64 (which is perfect).

Is this just the way it works or should it be more even? In the master bedroom you can really feel the heat if you are in the room. The other bedrooms you can really only feel it if you go over near the heater and put your hand near it.

Same situation downstairs. Family room (first in loop) gets ridiculously hot really fast, while the rest of the downstairs barely warms up.

Thanks for any thoughts!
 
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Old 01-11-17, 04:29 PM
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You're in the furnace forum and have a baseboard hot water system with a boiler. Perhaps one of the mods will move the thread.

I'm not a boiler pro (I can hear the pros laughing now) but what temperature is the boiler set at? Sounds like it is way too high, maybe 180 or 190. I'm sure there are other issues but a short fix might be cranking that temp down. There may also be dampers on the front of those baseboard radiators that can be partially closed to limit the heat in the first sections so it can reach the more distant areas.

I'll follow along.

Bud
 
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Old 01-11-17, 07:36 PM
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Thread moved to the boiler section.

Bud is right. There is a damper inside the baseboard heaters. When the damper is all the way open.... you get maximum heating. When the damper is closed you get minimum heating.

That damper controls the air flow thru the baseboards.

#2 in the diagram is the part that moves.

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Old 01-11-17, 07:49 PM
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Thanks PJ,
Years ago I had an apartment with a similar problem. Even with the damper closed it was still too hot for this New England boy. I took a blanket and folded it so I could cover the entire length of that baseboard. Perfect.

Your long term solution might be a little more involved but could also incorporate some energy saving improvements. Always nice when the savings pay for the improvements with the added benefit of improved comfort.

Bud
 
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Old 01-12-17, 07:49 AM
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Thanks. Yeah, I've tried closing the 'flap' as we call it (i.e. the damper)

Doesn't help The rooms in question are still hotter than the farther rooms.
 
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Old 01-12-17, 08:51 AM
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Did you check the temperature reading on the boiler? There should be a gauge visible somewhere on the front. There are also shutoff valves on each zone so make sure they are full open.

Short of changes in the zone configuration, reducing the boiler temperature (which also improves efficiency) or moving the heated water past the overheated room (circulating faster) so it can get more heat to the distant rooms before it overheats your bedroom, I'm out of options.

Covering the problem radiators with a blanket would at least give you some temporary relief.

Bud
 
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Old 01-12-17, 09:18 AM
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Thanks so much. I'll check the temperature and see what it says. Next time by boiler guy is here (hopefully not for a while!) I'll ask him to look into the issue as well, and see if it's circulating properly.

Thank you again!
 
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Old 01-16-17, 07:50 AM
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Here are the readings on my boiler.

It was not running at the time. Should the pressure be higher, or is it ok given that it wasn't running?

And is the temp ok?

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Old 01-16-17, 08:40 AM
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Something else you can try is covering some of the fin-tube in the too hot rooms with HD aluminum foil. Sounds crazy, but it limits the amount of heat given off in that area more than the damper flaps can, and send the heat along to the next baseboard unit. I had a temporary situation in my house, and used the foil, and was amazed at what a difference it can make. Easy and cheap to try-
Good luck, Steve (to give credit, I think it was NJT on this board that first suggested this idea)
 
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Old 01-16-17, 11:31 AM
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The heavy duty foil works well. There's a bit of trial & error determining how much fin tube to cover.
 
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Old 01-16-17, 01:20 PM
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My initial thought was to just lower that boiler temp now that we see where it is, as a lower temp will allow the circulator to run longer and reach the other rooms. That thought leads to an ODR (outdoor reset control) but I'm not a pro on hvac so can't say for sure you can add that to your system. ODR monitors the outside temperature and reduces the boiler temperature accordingly, it is an energy saving measure. I'll add a link and wait to see what Rick or others have to say.
Outdoor reset has arrived

Bud
 
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Old 01-16-17, 02:00 PM
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Outdoor resets are good as they reduce boiler temperature based on outside temperature.
They monitor how long the boiler runs and how long it takes to reheat the water and then adjust accordingly.

However, even with lower water temps..... the baseboard closest to the boiler will always be the hottest.
 
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Old 01-16-17, 02:28 PM
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Pj, I agree, but with 160 water it might be able to make a couple of trips around the loop. Certainly easy to test. Not sure how low is safe, other factors like return water temperature.

Bud
 
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Old 01-16-17, 05:59 PM
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You probably have too much baseboard in the hotter rooms. Usually last rooms on the loop get slightly longer baseboard because of the temp drop of the boiler water. usually 20 degrees..

How big are the rooms in question and how many feet of baseboard element only are in said rooms..?
 
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Old 01-17-17, 07:59 AM
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Thanks everyone for your input/advice.

Part of the problem (at least downstairs) could be the large amount of baseboard in the first (hottest) room. 3 walls have baseboards and the room itself is not open, there are just 2 normal doorways.

The cooler rooms are bigger, more open, and only have 2 walls of baseboards.

Upstairs it doesn't make as much sense, as the first (hottest) room is big and only has 2 baseboards. When the heat comes on it very quickly gets very hot. The next room is a smaller bedroom that has one baseboard but also gets pretty warm pretty quickly. The next two bedrooms are same size as that second room, but have 2 walls of baseboards, yet never ever feel hot (mildly warm at best, while that first room and, to an extent, second room, feel so much hotter).

I'll maybe give the foil a try and see what happens.

Also, I've used an infrared thermometer on the baseboards and they basically all get to the same temperature. But I guess there just seems to be more heat coming off/rising up out of the first baseboards than the last. So even though the temp of the baseboard is the same, the first rooms get hot, but in the farther rooms you have to put your hand near the baseboard to feel it.

If baseboards had fans, it would be as if the first rooms had the fan on high, and the last rooms were on low or not at all (so you only feel the heat, which is hot, if you put your hand right near the baseboard).
 
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Old 01-17-17, 08:22 AM
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newbie, you said "So even though the temp of the baseboard is the same, the first rooms get hot, but in the farther rooms you have to put your hand near the baseboard to feel it."
That doesn't seem right. Depending upon your brand of infrared thermometer they will read different spot sizes at different distances, so your reading may be averaging a 6" or 12" diameter circle of heat. Also, being infrared sensitive it may have difficulty with metal surfaces. I use an infrared camera and must compensate for the emissivity of the surface.

Intuitively the baseboards in the hotter rooms must be hotter or be hot longer, or both, for those rooms to be getting very noticeably warmer.

Note, if your circulation was moving the water 10x faster than it is, the hot water would be getting to all rooms before the first baseboards could give off much heat. Make sure there are no shut off valves that are partially closed. Also, air in the loops can slow circulation. I'm not an hvac pro so my comments may be useless.

May have been mentioned but didn't see it in the initial history, how long has this problem existed? Did the house ever heat evenly?

Bud
 
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Old 01-17-17, 03:28 PM
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Post the type of heat emitters you have and how its piped. You may have a mono flow tee system ..

We need to see or know specifically what you have..
 
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