Replacing slant fin baseboard with cast iron baseboard

STvex

Hi,

The first floor of my house is always colder than the second floor and even the basement. I have three zone (each floor one zone) gas hot water/baseboard system. First floor has patio door, front door and bigger windows, all of which doesn't help with heat retention. The baseboards are slant fin 3/4 copper lines. Would replacing the existing baseboard with cast iron baseboard significantly increase heat output or is it better to extend the existing baseboard run. I tried to vacuum the baseboard but it doesnt really do anything. What cast iron baseboard would be good replacements for slant fin.

Thanks in advance.

Big Ed_4

I prefer cast iron baseboard more for comfort . The output may not be too much higher then you have already.. Why I prefer cast iron is the radiant output of the radiator . The warm exposed mass warms the object in the area . Depends on what is needed in BTU's , Sometime just upgrading to a Series 80 would be enough . I only use Series 80 , heaver grade baseboard for longevity .



All base board , needs to be exposed .furnuture and drapes could be big blockers . Cold room with lack of wall space , I would be looking at panel radiators . You can add lots of BTU's and you get some radiant heat .

Some times with not enough heat of first floor , just leaving the AC defusers (outlets) open would cool the lower floors .

EBEBRATT-Ed

If the baseboard you have is in good shape i would just add more feet of baseboard. Or add some panel radiators.

Cast iron baseboard is top shelf but is expensive and more difficult to install. Most manufacturers want the wall behind the baseboard heavily insulated.

just a note you should not have different types of heat emitters on the same zone as they heat differently

bburd

@STvex there is probably no need to change your baseboard radiators; something else may be wrong that would be quite simple to fix.

Did the system ever work properly?

The dampers at the top of the baseboards should be open to allow free airflow. At least 1 inch of opening must be present at the bottom to allow air to flow in; sometimes this is blocked by carpeting. Floor length draperies and furniture can also block air circulation through the heating elements.

When the first floor thermostat calls for heat, does the entire length of finned element get hot, and at about the same temperature? Does it stay hot until the thermostat is satisfied?

hot_rod

It would nice to have a heat load calc for the home. Not knowing the load, it’s hard to say if you are short on fin tube

What temperature are running the system? Pump or zone valves?

STvex

hot_rod said:

It would nice to have a heat load calc for the home. Not knowing the load, it’s hard to say if you are short on fin tube

What temperature are running the system? Pump or zone valves?

Is there a chart I can use to calculate the heat load? I run the thermostat from 70 to 72 and have three zone valves.

STvex

bburd said:

@STvex there is probably no need to change your baseboard radiators; something else may be wrong that would be quite simple to fix.

Did the system ever work properly?

The dampers at the top of the baseboards should be open to allow free airflow. At least 1 inch of opening must be present at the bottom to allow air to flow in; sometimes this is blocked by carpeting. Floor length draperies and furniture can also block air circulation through the heating elements.

When the first floor thermostat calls for heat, does the entire length of finned element get hot, and at about the same temperature? Does it stay hot until the thermostat is satisfied?

System seems to work, I bleed all three zones in the summer and the baseboards do get hot but not very hot like my old cast iron radiators in my previous house. Most of the baseboard is exposed with no blockage. Is there a slant fin baseboard model that produces more heat in general?

STvex

EBEBRATT-Ed said:

If the baseboard you have is in good shape i would just add more feet of baseboard. Or add some panel radiators.

Cast iron baseboard is top shelf but is expensive and more difficult to install. Most manufacturers want the wall behind the baseboard heavily insulated.

just a note you should not have different types of heat emitters on the same zone as they heat differently

Thank you. My best option is to add more feet of slant fin baseboard? I looked at the prices of cast iron and its extremely expensive to replace the entire first floor run. I was thinking if i can add one or two panels next to the slant fin to get more heat.

STvex

Big Ed_4 said:

I prefer cast iron baseboard more for comfort . The output may not be too much higher then you have already.. Why I prefer cast iron is the radiant output of the radiator . The warm exposed mass warms the object in the area . Depends on what is needed in BTU's , Sometime just upgrading to a Series 80 would be enough . I only use Series 80 , heaver grade baseboard for longevity .



All base board , needs to be exposed .furnuture and drapes could be big blockers . Cold room with lack of wall space , I would be looking at panel radiators . You can add lots of BTU's and you get some radiant heat .

Some times with not enough heat of first floor , just leaving the AC defusers (outlets) open would cool the lower floors .

Thank You!

bburd

@STvex what are the high limit and low limit temperature settings on your boiler? Do the temperature gauge readings track those during a call for heat?

STvex

bburd said:

@STvex what are the high limit and low limit temperature settings on your boiler? Do the temperature gauge readings track those during a call for heat?

How do I check this? I have a weill mcclain cg15 boiler. It has a aquastat that is set to 190. Where's the high and low limit?

bburd

Please take a photo of the aquastat, with the cover removed if there is one, and any temperature/pressure gauge you find on or near the boiler (it may be inside the front panel cover if there is one). Then we can better advise you.

EBEBRATT-Ed

Also check to see if all the baseboard enclosures are full of finned element. Sometimes they run dummy baseboard that just encloses pipe.

Measure the feet of finned element and get the total length of that. Then give us the BTU output of the boiler so we can compare the bts of each

STvex

bburd said:

Please take a photo of the aquastat, with the cover removed if there is one, and any temperature/pressure gauge you find on or near the boiler (it may be inside the front panel cover if there is one). Then we can better advise you.

Attached is picture of aquastat and temp/pressure reader

STvex

EBEBRATT-Ed said:

Also check to see if all the baseboard enclosures are full of finned element. Sometimes they run dummy baseboard that just encloses pipe. Measure the feet of finned element and get the total length of that. Then give us the BTU output of the boiler so we can compare the bts of each

I have 42 feet of series 80 slant fin and 24 feet of slant fin baseline.  Boiler is 115k BTU weil McLain CG 15.  Series 80 is like 800 plus BTU and baseline is 600 BTU max I think. First floor is about 1100 square feet 

bburd

Looks like you have a cold start boiler, there is a high limit aquastat, but no low limit.

Have you carefully watched that first floor zone through a long heating cycle? Turn the other zones all the way down and the first floor thermostat up 5°. On call for heat the burner and circulator should start, and water should circulate through the radiators. Once the water is fully hot there should be no more than a 20°F drop from one end of that loop to the other. You can approximate this by feeling the supply and return pipes carefully – don’t burn yourself.

The burner should continue to operate until the high limit aquastat setting is reached. The burner should then shut down, and the circulator should continue to run. Once the supply temperature drops about 10° the burner should restart, assuming the thermostat is still calling for heat.

If the boiler does not start on a call for heat from the first floor, you may have a bad zone valve end switch that is not turning on the boiler as it should. This would mean the first floor would heat only when another zone was calling at the same time.

You might also have restricted flow, if the water cools off a great deal in that loop. 

If neither is the case and the system operates normally otherwise, try raising the aquastat setting to 200 or 210°. Since the system is pressurized, the water will not boil until it gets a good deal hotter than that.

Let us know how you do. 

STvex

bburd said:

Looks like you have a cold start boiler, there is a high limit aquastat, but no low limit.

Have you carefully watched that first floor zone through a long heating cycle? Turn the other zones all the way down and the first floor thermostat up 5°. On call for heat the burner and circulator should start, and water should circulate through the radiators. Once the water is fully hot there should be no more than a 20°F drop from one end of that loop to the other. You can approximate this by feeling the supply and return pipes carefully – don’t burn yourself.

The burner should continue to operate until the high limit aquastat setting is reached. The burner should then shut down, and the circulator should continue to run. Once the supply temperature drops about 10° the burner should restart, assuming the thermostat is still calling for heat.

If the boiler does not start on a call for heat from the first floor, you may have a bad zone valve end switch that is not turning on the boiler as it should. This would mean the first floor would heat only when another zone was calling at the same time.

You might also have restricted flow, if the water cools off a great deal in that loop. 

If neither is the case and the system operates normally otherwise, try raising the aquastat setting to 200 or 210°. Since the system is pressurized, the water will not boil until it gets a good deal hotter than that.

Let us know how you do. 

Thanks.  I turned off the two other zones and ran the first floor one.  The thermostat called for heat and the circulator started.  I think the zone valve works the baseboards did get warm.  I used a laser gun temp reader, the supply pipe was 120 degrees and the return 113 degrees.  All the baseboards were around 113 degrees also.  Burner cut off at 180.  I adjusted the aquastat to 200 from 190.  Hopefully this helps. 

Is it possible some air might be in there causing resistance to water flow?  I have a taco air eliminator but should I T it and add another one?

Is one taco 007 good enough for three zones?  Should I replace with a stronger pump to push more water through the loop?

EBEBRATT-Ed

@STvex

your baseboard is good for an output of about 45000 btu, You size it at the average water temp. 190 off the boiler and 170 return =180 average water temp.

now that you know the basebard output you should do a heat loss and compare it to the baseboard output

bburd

If there is a 7° difference between the supply and return temps on that zone, there is nothing wrong with the pump.

What puzzles me is why when your boiler is producing 180° water you are reading a heating supply temp of 120°. If that’s true, you have some kind of piping / mixing problem. Was this on bare metal pipe? Infrared thermometers don’t work well on shiny things. Try putting a piece of black tape on the pipe and measuring the temperature of that.

STvex

bburd said:

If there is a 7° difference between the supply and return temps on that zone, there is nothing wrong with the pump.

What puzzles me is why when your boiler is producing 180° water you are reading a heating supply temp of 120°. If that’s true, you have some kind of piping / mixing problem. Was this on bare metal pipe? Infrared thermometers don’t work well on shiny things. Try putting a piece of black tape on the pipe and measuring the temperature of that.

Thanks.  I appreciate your help.  I did hit the laser against the copper pipe but it could be I was too close or my reader isn't accurate.  I attached two pics of the boiler piping.  Is this adequate?

EBEBRATT-Ed

Your piping looks wrong. The
expansion tank should be on the same side of the circulator as the water feed....not sure if it is.

If that is a low water cutoff mounted on that extended black nipple that is not good. It will plug with sludge


need more pictures to see what all the other issues are

bburd

Yes, more pictures of the piping please. Other angles, and from a bit further away, taken vertically. It’s hard to sort out what is connected to where.

STvex

EBEBRATT-Ed said:

Your piping looks wrong. The expansion tank should be on the same side of the circulator as the water feed....not sure if it is. If that is a low water cutoff mounted on that extended black nipple that is not good. It will plug with sludge need more pictures to see what all the other issues are

attached are three more pics.  any fixes I can do after the season?  would a better set up be three circulator pumps for each zone PULLING water into the boiler and on the supply side a Spiro vent with expansion tank before the three zones.  The boiler was like this for 20 plus years.  For the lwco can I take out the probe and clean it?

EBEBRATT-Ed

The expansion tank is connected to the boiler on the supply side of the circulator, and you make up water is connected to the return side of the circulator. The make-up water should be connected to the expansion tank like where the air vent is installed.

You can take the low water cutoff out and clean the probe, but that control needs to be installed directly into the boiler water or into the main supply pipe leaving the boiler with the shortest possible connection