Mixed free-standing cast iron radiators and aluminum baseboard

Denise Ward

Three years ago I had the bright idea to change out my free-standing cast iron radiators with alum baseboard in order to get more space. Since I have a two-story house and had limited funds, I wanted to work with the first floor only (getting rid of those things is no small job!).

No one explained the water temperature difference. Even worse, to keep the job at a minimum price I omitted the first floor bath and bedroom, so those still have the free-standing radiators. The rest of the space is very open with the kitchen and dining room off a very large main living room, all with the aluminum baseboard. I had the thermostat placed in the hallway (to hide it), which complicates the whole situation because it's directly opposite the bathroom with the radiator and the other room with the radiator also faces the hall, so it trips based on the higher output of the two rooms with radiators. At the time I did not understand the difference in water temp, but I did know about the difference in surface area of cast-iron radiators and aluminum baseboard.

Once the job was done I had to call back the technician immediately because the radiators were so hot! You couldn't even touch them and the rooms were unbearable. Turns out that was because of the higher temp to run the alum baseboard. It would have been nice for him to explain first, but as he said, "You got what you wanted." Stupid me, although I do love the additional space!

Since the second floor still has all of the free-standing, cast iron radiators, ithas the same problem. The installer's advise was to manipulate the flow of water to the radiators, but that was impossible since the valves would not budge (house built in 1933). Instead, I've adjusted the main valve to the second floor and the valves to the rooms with radiators, but it really only seems to make the alum baseboard rooms colder (perhaps I've adjusted the wrong valves -- it's very confusing). Plus he gave me instructions over the phone, and I was turning the valve the wrong way, so when it wouldn't budget he said use a hammer and, consequently, the valve is bent.

I'm sure there is air in the pipes, too, since the pipe in one wall vibrates at times, and another pipe in the basement vibrates causing the baseboard to vibrate. The installer gave me instructions on how to bleed the system, but I'm terrified to do it because he kept emphasizing not to let the pressure rise to more than some amount that I cannot remember now. There are so many valves and things had to go in the right order, and I just got plain confused.

I've had to adjust the temp of water leaving the boiler so we don't roast in the rooms with radiators. I called another plumbing company and they suggested a mixer valve for about $900, but then they disappeared. Subsequent calls produced nothing. I called another company that always responds but bids way high. wThey wanted $3,500 to replace the two radiators left on first floor and install mixer valve, but the entire first job cost $4,500 and that was all the new piping, valves, pump and baseboard. $3,500 seems a bit much.

I now have even more limited funds having helped two of my children with house and engagement ring downpayments, and two more left to go to college at the same time.

It's been three years now and we are tired of roasting in some rooms and being cold in the others. Is there a simple fix? Can I change the two radiators left on floor one with smaller free-standing? Will a mixer valve really work? Is it possible to answer all of these questions in email? To top it all off, a new pump was installed for the first floor (he zoned the first and second floors), and it is NOISY and rattles a bit, driving my absolutely bonkers. The one for the second floor, which was present when I bought the house, is not noisy at all.

Larry (from OSHA)

Denise

First of all, congratulations on the kids futures. I am only a homeowner and I'd really suggest that you try the find a professional feature of this site. You really need someone with the expertise to actually help you instead of what you've had. Depending on the way your system is piped, you might be able to use thermostatic radiator valves (TRV's). These attach to your cast iron radiators and adjust the flow of hot water depending on the actual temperature of the room. (Very effective, if you can use them) I am not sure of the cost but I'd suspect that they might be less than some of the options that you were quoted. Best of luck to you.

Larry

don_52

trv's

its hard to say why the folks came to the conclusions
that they did, perhaps some very good reasons.

thermostatic radiator valves (TRV's) on the downstairs
cast iron radiators sounds ( maybe ) like it would be
a interim solution till your budget allows.

like Larry said; "if it can be done".

here's a shot of a maconcontrols ent2;

Plumbob

(a) Pumps should not be noisy. Either it is a bad pump or it has been badly installed.

(b) A mixing valve will work, but nothing is cheap; it is not the price of the valve itself but of all the replumbing required to route the two different water temperatures properly.

(c) TRVs are the easiest solution, and it will also give you the ability to individually adjust the temperatures of the rooms that have TRVs (try doing that with forced air heat!). Plus you will be rid of your bad valves. In our house we had six TRVs put in for about $175 each (you will need to do all your radiators at the same time to lower the per-TRV cost, since the system has to be drained and refilled to do plumbing on it, and that takes time and so costs money). Any plumber should be able to do this job. If they don't understand "TRV" or "thermostatic radiator valve", tell them "Danfoss" (this is the most common brand and they will know what you mean).

Weezbo

TRVs ought to dial it in for you...

there are a coupla formations so you can find one thatwill work. as for the air in the line when you have the plumber by for a cup of coffee:) ask him to bring a spirovent junior with th TRV's itwill eliminate air hassels overtime plus when he purges the line it will be always riding entrained air long after hes gone:)

Bill Nye_2

You can

make it work. How much of the aluminum baseboard did you have installed? First, is it the stuff that is about 5-1/2" tall and about 15/16" wide ?

Or, is actually copper fin tube, 3/4" copper tubing with aluminum fins installed in a metal enclosure?

All of these products emit heat at a different rate measured in BTU pr hr, pr linear foot. The aluminum will give about 240 btu @ 180°, the copper fin tube about 500-550 @ 180° and the cast iron radiators are measured a little differently but will be a little more than the copper fin.

So all that to say if you have the aluminum baseboard you will need to cover most of the rooms walls to have "enough" heat. IF, there is enough of it you could repipe a little to seperate the cast iron and rezone. Continuous circulation and weather responsive reset controls will help you achieve a desirable comfort level.

I guess you shouldn't have messed with the radiators. The TRV's mentioned in other posts may help but it depends on how the system was originally piped. I think the only thing you can do now is, go to Books and More and buy a T- shirt. Save the Radiators!

http://www.heatinghelp.com/shopcart/product.cfm?category=5-122

Bill Nye_2

Denise?

Hello,