Lochinvar - 1910 Home with Rads - Balancing Heat Between Floors

timccarpenter

Now that we're down into the depths of cold weather in northern MN (-15 the other night and highs around zero this week), I'm struggling to get the heat a bit more even between the floors (didn't have as much of an issue with my old WM Ultra).

Here is the run down:
KHB-155
Cast Iron Rads
One Zone - 2 1/2 stories

My initial settings included a ramp delay that had my modulation capped at 75% (thinking maybe the boiler was oversized for our house - and trying to decrease the air intake noise outside). I do a set back of just 3 degrees at night for more comfortable sleeping (measuring the temp in the sleeping areas on the second floor, not the first). In the morning, bedrooms were at 67 and the first floor was 58. The daytime setting is 70. It took several hours to get the main floor to 70 and then the 3rd 1/2 story was up to 76 (too warm).

I'm thinking that in fact it may work better to heat the water faster in the morning so that the main floor rads heat up more quickly and start transferring heat faster. I'm wondering if the slow gradual heat is actually causing more heat transfer upstairs creating more of a heat differential. To do this, I would run the boiler at 100% and drop the ramp delay. Then, of course, I could lose a more even heat throughout the day. I may be able to instead use the boost for the morning catch up.

I know this will always be a challenge with a single zone...but I'm trying to mitigate this as much as possible.

Appreciate any insight.

hot_rod

The laws of thermodynamics basically state, heat travels to cold. The rate of the heat transfer is based on the temperature difference. So the hotter the radiator, the faster it transfers heat to the cold space.
So slow gradual heat input cannot cause more heat transfer.

Lowering the flow rate of the SWT will slow the recovery to the setback areas. Any area really.

If the lower level is open to the upper, you will get some stratification with radiators that are both radiant and convection devices. You are warming the air moving across the sections. That warm air will rise up. Under the same "thermodynamic" principle hot to cold- Faster stratification with hotter temperature air coming across the radiators.
So you may be seeing the effect of hot air rising?

timccarpenter

hot_rod said:

So you may be seeing the effect of hot air rising?

I'm sure the hot air rising is a large part of the problem. Trying to see if there is a way to mitigate that somewhat to avoid the top floor turning into sauna on the coldest days.

Jamie Hall

Do the upstairs radiators have valves? Try closing them part way...

timccarpenter

Jamie Hall said:

Do the upstairs radiators have valves? Try closing them part way...

I have done that but hesitate to mess with them too much. Old valves and can start to leak at the stem if I am adjusting them too much. I had them in the sweet spot for the previous boiler and for most conditions. Something is slightly different in this situation

PC7060

timccarpenter said:

Jamie Hall said:

Do the upstairs radiators have valves? Try closing them part way...

I have done that but hesitate to mess with them too much. Old valves and can start to leak at the stem if I am adjusting them too much. I had them in the sweet spot for the previous boiler and for most conditions. Something is slightly different in this situation

@timccarpenter - I had same issue until we installed Thermostatic radiator valves which allow for temperature adjustment room by room. You don't need in every room just the ones that are overheating.

timccarpenter

@PC7060 What thermostatic valves did you put in? I was thinking of doing that in the bed rooms and our one room on the top 1/2 story. Did you consider doing "smart" valves?

PC7060

I used Honeywell Braukmann (now Honeywell Home)TRV.

https://www.supplyhouse.com/Honeywell-Home-V110E1012-3-4-Angle-Valve-for-High-Capacity-Radiator

I did look into smart valves made by Honeywell for UK market but the units aren’t feasible for US market due to compatibility issues with Wi-Fi and power. 

Once I got the standard ones dialed it the units are set and forget so no real advantage to the interconnected units in my house. 

timccarpenter

@PC7060 Did you do this yourself? Obviously a summer project. My experience with plumbing (although I guess not with old galvanized pipes) is I get it all put back together and there is a drip; Would be a real hassle to refill the whole system and find a drip.

hot_rod

If you can find a double angle version, you can keep the head horizontal and still out of harms way.

PC7060

Yes, I did the work, pretty simple operation. I used a high quality pipe dope and a 18” crescent wrench when tightening. If you want the belt and suspenders approach use couple wraps of Teflon tape then pipe goop does the trick. 

PC7060

I learned by watching an episode on ask this old house. The clips been edited a bit too much, the helpful section was removed whiched show the  radiator being rotated slightly by a second person while the wrench jockey turned the valve. This allows the valve enough room to be removed and the new one installed. 

https://youtu.be/_44vzZvmFLM