Add copper baseboards to iron baseboards

[Ricardo Umbro]

We currently have iron baseboards in our house, they are tall and big, but they are nowhere near enough.
Please refer to following picture.
RED lines are existing baseboards.
Blue lines are proposed baseboards.

As you can see existing baseboards do not provide nowhere near enough heat for these big rooms (especially living room). Windows are on top of existing bb's and windows run wall to wall.



Please let me know if it will be OK for our plumber to do this job? He said he already bought the new baseboards that are copper based and shorter (not as tall).
I think this is the existing baseboards that is not enough: Multi/Pak 80 Light Commercial Baseboard

Thanks.

EDIT: I just called the contractor, he said what he bought is also Slant/Fin, does that mean he is talking about the piping when he says iron vs copper?

Hmm...

[Mike Speed 30]

Slant/Fin is a reputable manufacturer of fin-tube baseboard units.

If your question is whether copper fin-tube units can be added to a system with taller cast iron baseboards and steel pipe, the answer is Yes.

But, if you're asking about the adequacy of the proposed additional units, it's impossible to say based on the info you provided. Fin-tube units won't hold as much retained heat as cast iron, but that probably isn't a big issue.

Ideally, a heat-loss calculation should be performed. Then, there are other questions: are the existing boiler and piping system adequate? What type and size of piping loop configuration do you now have, and how will the plumber tie in the new units? You should be sure that the plumber is experienced in hot-water heating and has thought through the additions.

If you gave the plumber the go-ahead to procure the fin-tube units, it's a little late to be having second thoughts.

[xiphias]

In general, it is frowned upon to mix cast iron and copper fin-tube on the same zone, due to the vastly different heating/cooling properties that Mike mentioned.

However, if what you are describing as cast iron is in fact MP-80, then that's copper, too. Slant/Fin does make a cast iron baseboard product (Rhino-cast, IIRC).

As Mike said, what you really need to start with is a room-by-room heat loss calculation so that you know how much baseboard you actually need. Simply throwing baseboard along the walls is no way to go about this.

You could end up with highly unbalanced rooms that heat and cool very differently, which you don't want. You could end up over- or under-radiating the room with the thermostat; you don't want that either. You could also cause the rooms to heat fast and cool fast if you have not also addressed the probable root cause of the problem, which is poor insulation or air sealing (high infiltration -- drafts). Adding insulation and sealing around doors and windows is the best bang for the energy-saving and comfort-improving buck, by far. You could also cause some undesirable short-cycling of the boiler depending on how all this stuff adds up.

You should also make sure the boiler is performing properly.

First, check the boiler. Second, do or have done a heat loss to see whether under-radiation is the problem. It only takes an hour or two. Third, do some insulation and air sealing. Fourth and finally, if that doesn't address the problem, consider adding radiation.

[Ricardo Umbro]

Thanks both for the answers.
The boiler is brand new, pipes are all new, the original problem was that zones were mixed, it was in a very strange order. Zone 1: would supply only 2nd Fl Living Room, and return to boiler, -- Zone Two: Supplies 2nd Fl Rear Bedroom 1, Jumps over to Bedroom 2, Goes down to basement boiler room as return but only to go back up in the front end of the house to supply 1st Flr Front Living Room, returns to basement to once again go back up the rear of the house to supply 1st floor rear bedroom 1, then to bedroom 2, and then finally goes back to boiler as return.

As you can imagine, this was one messy setup. Luckily, I figured out the pipe circulation order, the plumber will be cutting the pipe that returns from 2nd flr rear bedrooms, and patching it to the pipe that supplies 2nd flr front living room, hence completing that as Zone 2. Meanwhile he will take the other pipe which was the sole supply of the 2nd flr front, instead supplying it to 1st flr front.. I know it is a mess, but I hope I was able to draw a clear picture.

The thermostat is in that big room where we are not adding too many baseboards.

As for the drafts, don't even ask me about that. I believe I have no insulation on my walls that is facing north-west, although the walls were built on top of old walls, but the drafts are coming from the roof. I don't believe there is any insulation on my ceiling between roof and ceiling, therefore drafts fill the walls. I will open another topic on how to open the walls with minimal effect and fill them with insulation and seal. I am hoping 5' high opening between each stud should be enough to fill them. Last resort, opening bunch of holes and actually sealing the walls with another layer of sheetrock.

For sure, these radiators are nowhere near enough even with proper insulation, so the best way is to just add these. Room on the left of the picture, where I am adding bb's on both sides is my bedroom. My bedroom can never be hot enough!

Boiler surely is performing properly, but it's preset is too high, it keeps the boiler at 120* or so, even when thermostat does not trigger it, so I will also ask the electrician to lower this so it doesn't keep turning on all the time even if thermostat doesn't call for it.

[Mike Speed 30]

Originally Posted by Ricardo Umbro

Boiler surely is performing properly, but it's preset is too high, it keeps the boiler at 120* or so, even when thermostat does not trigger it, so I will also ask the electrician to lower this so it doesn't keep turning on all the time even if thermostat doesn't call for it.

Is the boiler kept hot continuously? If so, 120 deg is very, very low, not high - possibly related to your lack of heat. At 120 deg, it would be very difficult to heat most spaces - and heaven help your flue due to condensation.

What is the boiler temp when the thermostat is calling for heat?

I think there may be some serious misunderstandings here.

[Ricardo Umbro]

I am sorry, it is in centigrates. It is actually 110-120C or about 220F on the gauge, when it goes down -even when thmst doesn't call for heat- it kicks back in to 100's (200F's).
This is why I had to shut down the boiler when it was a little warm outside... I already had a topic on this under boiler section.

[xiphias]

Well that's not right. Hot water boilers should be no higher than about 180-190F. Sounds like there are some issues with this system that should be addressed. If you can post some pictures (via links to a hosting site like photobucket.com) that might help us understand some things.

[Ricardo Umbro]

I will check exact temp, in fact if you can click on my profile and check recently posted messages, you can see pictures of my gauge.
I remember it being aroun 100C, but that's not the issue. Issue is boiler kicking in without a call.
I am on my phone now, but I will put the links to pix when I get home.
If

[rbeck]

They may have it up that high trying to get more heat. A cast iron boiler can do that although not over 210º as long as the pressure is good. It is better to keep it under 200º for efficiency purposes.

[Mike Speed 30]

That is a very possible theory that rbeck has offered.

At his reported 220 deg F, if the relief lifts, the water will flash to steam, possibly filling the boiler room area with steam.

It's a remote concern, I guess, but might be careful bleeding radiators too

He said this was a brand new boiler, too

If the controls are set up to keep the boiler warm at all times, and the aquastat is adjusted for 200+ deg, I could understand the burner coming on periodically without the thermostat calling for heat. At 200+ deg, I can imagine significant jacket loss and perhaps standby loss up the flue.

[Mike Speed 30]

Originally Posted by Ricardo Umbro

I will check exact temp, in fact if you can click on my profile and check recently posted messages, you can see pictures of my gauge.
I remember it being aroun 100C, but that's

I went to your profile with your past posts, but didn't find the photos.

But, I did notice from browsing your profile that you've been having boiler, aquastat, and various other heating problems since at least January 2005, presumably in the same house? I'm wondering if your most recent problems are a continuation of the others? Or new?

I'm thinking that we might need to go back to Square One here. Evidently, replacing the boiler and "all" the piping hasn't solved your problems. Can you call back the boiler and piping installer for help under warranty?

[Ricardo Umbro]

No, I did not post anything back in 2005.
Yes, this is a 1,5 yr old boiler.
Is there any way to just lower the aquastat setting so it keeps the boiler warm at a lower temperature. I understand it may have higher gas consumption when the thermostat calls for heat to bring it back up to higher temp, but the boiler does not even have to run between 9am and 6pm. Nobody needs that kind of heat during daytime (noone is home), and with the way it is set up now, my meter is spinning senseless as the boiler keeps turning on and off, and of course pumps are off.. So actually when the thermostat is calling for heat, the boiler doesn't run any more than it runs when it is idle (keeping core temp).

Here is a picture:

As you can see it keeps it at 100C/210F all day long when thermostat's are at 72 (or Off) and outside is 78.

Here is a picture of my cousin's boiler:

His gauge is at 80C/150F all day, with the temp at same condition as mine (His house is much MUCH bigger than mine, but I think his grills (he has cast iron stading radiators) might be steam, not water like mine.. Does that make any difference?

[NJ Trooper]

Ricardo, in this thread:

Peerless Heating not heating - pump and pilot are on

from one year ago, Grady and I tried to help you... we could see that your wiring was incorrect. That you have an 8148 aquastat and there is no reason for the boiler to stay hot. You did not return... now, you ask the same thing again...

[OldGrouchy]

Your cousin has hot water, not steam.

[Ricardo Umbro]

Trooper,
I actually did not want to go back to that thread but it was asked, and I did mention that there was a topic about this already. Thanks for posting the link to it.
I opened this topic seperately to discuss the baseboard issue and addition of new piping.

After checking everything I think the only thing I need to find out is if my boiler can handle additional baseboards. Is there a BTU to Feet-of-Piping relationship listed somewhere?

[NJ Trooper]

OK then, if you want to keep wasting fuel by keeping that boiler hot 24/7, then I guess there's no point in going back and revisiting the old thread. It's your money! Good Luck!

[Ricardo Umbro]

No no, I am sorry, I think you misunderstood. The plumber will be bringing an electrician along, who will review the aquastat settings, wiring, etc. I am sorry If I did not mention it.
This is the reason why I did not go back to that topic.

The only worry I have now is, would my boiler be strong enough to handle additional 45' of plumbing & baseboard additions.

If I posted a picture of my boiler along with model no, BTU info etc would there be a way to tell what is too many baseboards or if boiler can still handle it.

[furd]

Forty-five feet of baseboard convector is approximately 27,000 BTUs (mabe a bit more) worth if fed by 180 degree F. water. Unless the existing boiler was carefully sized it more than likely has sufficient headroom for the additional baseboards.

[Ricardo Umbro]

I just wanted to thank everyone who chimed in. Plumber is at my location doing the installation right now. I was expecting him to haul large amount of piping, but all he brought was a flexible orange tube.. I thought it was a hose at first, but a close inspection and a follow up to manufacturer's website revealed it is Dura-Pex (B), which claims to be better than copper piping on areas where flexibility is required. Hopefully he can get it done today so I can post some pictures of the end result and share with you guys.

Furd, I don't think the boiler was carefully sized to match the house, it seems to be much bigger than what I saw elsewhere. The boiler info is Peerles MI Series Boiler, 175,000 BTU input per hour, DOE HTG Capacity (I can't clearly read it from the pic I took) 14.3000. (I can't seem to find any "BTU Output" info on the boilerplate) My current baseboard outline seems to be 120 ft of baseboards in two zones, plus pipes leading to 1st and 2nd floor baseboards.

[furd]

I sure hope that Dura-Pex (B) has an oxygen barrier or you will have oxygen corrosion problems down the road.

You should be fine with the additional baseboards with that boiler.

[Ricardo Umbro]

Thanks furd, how do we check that? It probably is already too late for that, but here is the pic I snapped this am:

http://img21.imageshack.us/img21/9263/img00193d.jpg
http://img121.imageshack.us/img121/2865/img00195.jpg
http://img21.imageshack.us/img21/1254/img00194m.jpg

[furd]

From a quick Google it appears that tubing does have the required oxygen barrier. You should be good to go.

[OldBoiler]

Originally Posted by Ricardo Umbro

Thanks furd, how do we check that? It probably is already too late for that, but here is the pic I snapped this am:

Should be OK with the Dura-B:

NIBCO.com - DURA-PEX® Radiant Tubing

It is sold as barrier PEX for radiant systems.

Al.

[Ricardo Umbro]

Thank you both! Will keep you posted.

[xiphias]

Yes, the boiler is oversized. So are 99% of all boilers in the U.S.

120 ft of finned element with a nominal output of 550 BTU/hr per foot is 66,000 BTU/hr. In other words, any boiler with an output > ~70k BTU/hr is oversized, assuming that the installed radiation meets the heat loss. (In actuality, the heat loss of the building is probably less.)

In your case, the 175k BTU/hr input boiler probably has a DOE output of ~140k BTU/hr, or about double the amount of heat that can be put out by the finned element.

I see that the PEX is 1/2". I hope that someone is keeping track of how this diameter is interfaced to the rest of the piping, which is probably 3/4".

And someone needs to keep track of how many feet of piping are being added. the flow resistance (head) of 1/2" piping is pretty high.

You don't want a situation where you've added so much 1/2" piping that you don't get sufficient flow through the zones.

[Ricardo Umbro]

As far as I can see, pipe diameter is consistent from supply all the way back to return, which is 1/2". In otherwords, the places where PEX is clamped to copper, the size is same. (I will take a look at it again and confirm back).

[xiphias]

So it occurs to me that 1/2" pipe can only move about 18,000-20,000 BTU/hr. Just your new baseboard is around 22,500 BTU/hr. That's cutting it pretty fine.

If all this stuff is on one zone, two things to consider:
1) you are trying to move about 32,000 BTU/hr through piping that can only do 18-20 thousand.
2) you will probably have a very high-head system, and it won't flow right or require a moose of a circulator, which is an energy hog and noisy, and you could have velocity issues in the piping.

What is the zoning for this system?

[Ricardo Umbro]

There are two zones.
Here is the boilerplate:


Here is REALLY ROUGH estimate of piping distance, based on what I think the piping needs to travel to reach each one of the destination and return back to basement for a 2nd loop up through front of the house.

Zone 1, 1st Fl. Only three baseboards, 12+6+6=24' of baseboards.
Routing: Boiler supplies -> 20ft to the wall, 10ft up, loop through 6x2=12ft baseboard, 10ft down, 50ft back, 10ft up, loop through two set of baseboards (total about 12ft) loop back down about total of 30 ft back to return pump. Approx 155ft of piping.

Zone 2, 2nd Fl. As drawn above, total 64' of baseboards. Piping in these rooms are either loops or returns moving on top or underneath the baseboards.
Routing: Boiler supplies -> approx 30ft across, 20ft up piping, loop through 34ft of baseboard+add'l piping all near baseboards+20ft back down, 50ft across, 20ft up, through 30ft of baseboards, 20ft down, 25ft across back to return pump, total of approx 250ft of piping+baseboards.

Total, both zones approx 400ft of piping/baseboards/travel incl return back down.

I will post about the electrical issue under the other topic.