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We have an oil HW baseboad system with 2 zones. The burner is cleaned every fall prior to the heating system. During the winter the temp is kept at 70 (zone 1-first floor) and 64 on zone 2-2nd floor. The walls throughout the house are painted off white.
The problem is that the walls above the baseboard heat becomes blackened to the height of 18 to 20 inches and in corners it discolors the ceiling. Does not happen on walls without the baseboard heat.
I questioned our heating rep about the cause of the the dirty walls and his response was that the temp. of the water running through the copper piping was to hot and it was burning any dust on the piping and heating fins. He decreased the temp and said that would correct the problem. He also stated that it was not necessary to vacuum the heating fins.
We will be painting the walls shortly and want to be sure that the problem does not occur again. Your comments will be appreciated and any suggestions concerning products to wash the walls.

Re: Heating

Soot or staining on the walls above hot water baseboard has been blamed on a score of things---it is often hard to pin down for a specific house.

If you had a house that has forced hot air heat, or burn a lot of candles, or have a wood burning stove, then one could say you have a source of soot in the air---but you have FHW baseboard heat---how can any stains accumulate on the walls from that???

One favorite theory is that in these cases the "stains" are caused usually on the inner part of exterior walls by "ghosting" or "thermal tracking", which is caused by ionization (electrical charging) of the heated air coming off the finned baseboard, and being attracted to the cold parts of the wall immediately above the baseboard due to lack of wall insulation at these points.

"Ghosting" has also been often noticed on uninsulated walls in winter where the 2 X 4 or 2 X 6 studs inside the exterior walls reflect their spacing pattern of 16" or 24" spacing and display dark vertical stripes along the interior parts of exterior walls or on ceilings---supposedly, what is happening is that the cold 2 X 4 members are bridging the exterior cold exterior siding to the interior sheetrock or plaster.

You'll have to do some detective work to determine exactly what is causing the problem in your particilar house---check the wall insulation above the baseboards by temporarily removing any electrical outlets after temporarily shutting off the electrical service, unwinding a length of steel hanger and waving it inside the walls to see if there is any insulation in there---if you hear the wire rattling, you have little or no insulation; if there is none, have some blown in (for only a few hundred $$$).

I have my doubts that turning down the water temp as your oil dealer suggested will help very much, but who knows...

The site below describes the issue of wall "staining" from several viewpoints.

Also Google "How to recognize & diagnose Thermal Tracking" to get the excellent inspectapedia article.

Also Google such terms as Thermal tracking, ghosting stains, thermal bridging, electrostatic deposition, Thermophoresis, Roger Hankey, Joe Lstiburek


Water Temp

I'd like to begin by stating that how can one determine that the water is too hot without doing a heat loss and determining that the water temp being delivered to the board will overcome it. If the room requires 180 degree water to overcome the heat loss of the room then you need the 180 degree water. Not only did he change the output of the board to that room he changed the output to the entire zone.

Turning down the water temp should be done with the use of an outdoor reset control which will automatically change the water temp in the boiler dependent on outdoor temperature. The colder the out door temp the higher the boiler water the warmer the outdoor temp the warmer the boiler temp. Some like the Beckett Aquasmart will also allow for good cycle burner run times to help in fuel savings. Basically giving you cruise control for your boiler similar to the cruise control in your car.

If we are talking about a single piece of board and it's filthy dirty, fins are bent etc it probably would be much better to just replace that section. Fin-Tube board is not that expensive and it will also eliminate the board as the cause if it continues.

Re: Heating

This problem happens in every room on the first floor. More so the closer it is to the heating unit in the basemant.

Re: Heating

Cold air is drawn in at the bottom of the BB units is warmed and exits the top of the BB units and flows up the walls. The warm moist air hits the cooler wall and condenses on the wall leaving air born particles as a stain. Most BB heater covers have a thin adjustable deflector the can dirt the air flow. If they are fully open the warm air goes directly up the wall if they are closed some it will direct the air out away from the wall a little. Try closing the deflectors a little and see if that helps.

The BB heaters should be kept clean and if the water temp were high enough to burn the dust chances are your boiler would have gone through the roof by now. JMHO

Re: Heating

i can say i had that proplem too what seams to work for me i don't burn candle's any more I REPAINTED WITH SEMI GLOSS AND VACUME BASE BOARDS BEFORE HEATING SEASON. i have not had the problem back in three years so far. boiler temp at 175 if that makes a difference

Re: Heating

I believe you can fix the problem with a good quality satin paint, as it is a reaction with the warm air, humidity, and particles in the air, with the paint. You may need one coat of Kilz to keep the color from bleeding through.

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