small replacement radiators?

jhosef

I have recently become the current caretaker of a steam heated brooklyn house from ~1920. my first steam system.



The previous owner seriously neglected the property (ie left it abandoned no heat) and left me with 3 cracked radiators. I am replacing the nasty oil burner with gas and, after several weeks of considering repair, I am planning on throwing in some replacement radiators.



The plumbing company offers replacements by Governale, which appear to be quality made, but look like toys versions of the original (1/2 the size). Confused about this, I looked at their website and note that they don't make tall radiators anymore.



For example:

the existing American 5 tube type (8"W X 38"H / 9 sections) is suggested to be replaced by a Goverale 4 tube type (4.4"W X 17.5"L X 25"H / 10 sections).



I am in discussion with the plumbing company and the response is that the new ones are more efficient. The problem that I have is that I do not want to undersize the radiators and get knocking. I am concerned as well about insufficient heating, but since I'm insulating the house, the place won't be as drafty as in past so this may be a moot point.



I can't find anything regarding this in Dan's books so far or this website. Am I just worrying too much or is there a way I can compare the new and the old?



What pointed questions should I ask the plumbing company to feel better about this? I plan to be living with this decision for a while.



Thanks.

Brad White

EDR is EDR

So long as EDR matches EDR, different styles of radiator will heat about the same, size for size.



Governale and Burnham make the "Victoria" and "Classic" respectively which are quite beautiful in my opinion. I believe they are identical and are made by one company and sold by both. They are about 30 inches high, I would have thought 38 inches which is a common height. So if they do not make it, I suspect you are going to seek salvaged radiator stock. Ultimate recycling!



But here is something to think about: You said you are insulating and sealing the house, great. (We can have another discussion about this, if the house is brick. But keep that aside for now.)



Your challenge will be: Will you re-evaluate all radiators in place, versus the new heat loss? Or keep them and add others to fill out your needs?



If you are starting from scratch, no radiators but good heat loss calculations, you size the radiators for the permanent new heat loss and size the boiler to the radiation. Simple. Direct. All Good. That to me is the best, correct approach, but few people take the time to do that. If you do, my hat is off to you. Do that if you can.



But if not, here is the issue:



Suppose you have eight rooms, five with original radiators and three new salvaged ones to add to the family, within your insulated house.

Your existing radiators might well be 50% over-sized because the heat loss is less now. Your newly adopted radiators should ALSO be 50% over-sized, such that they all respond the same way and have similar mass and warm-up/cool-down characteristics. If you do not up-size them, you may wind up feeling cooler in those adopted radiator rooms. This especially so if the room with the thermostat is in a room served by an original radiator, because that surplus will be sensed and controlled accordingly. Your under-radiated rooms would cool off sooner, after the thermostat is satisfied.

Make sense?



So for balance and if I were keeping the original remaining radiators in place, that is what I would do.



Plan B: Another way to do this. If you are keeping those radiators and adding new ones sized for the heat losses of the rooms, you might install thermostatic radiator vent valves (TRVs) on the existing radiators. This will to an extent force them to close off when the room is at temperature and allow the adopted radiators to catch up. This is NOT a perfect solution but something to improve what might have been a mistake.



My ideal solution short of re-sizing all radiators to the heat loss: Take my first suggestion and make all radiation proportional, "over-sized equally", AND put TRV's on the radiators. You may get a larger boiler and larger radiators, but it will be even.

jhosef

thanks

I'm not planning to add any extra radiators in, so that's not a concern.



I guess that I need to determine the EDR of the existing radiators then and compare to what is getting replaced.



right now, I'm pretty happy with how warm the house gets, even with the uninsulated walls (woodframe BTW) and cracked radiators, so someone must have done it right to begin with.



thanks for the sizing tip, but besides that, will undersizing cause knocking?

Brad White

Well that is a relief!

I had gone on the assumption that the cracked radiators were long gone, just a hunch, so that you may not have guidance. That makes it all simple. Match the EDR to the radiators you have.



What causes knocking is steam hitting water (meaning poorly pitched pipes), or when steam hits uninsulated pipe and suddenly collapses, forming a vacuum. This in turn draws in water and/or steam to fill the void, which will collide with something... Also water borne along by steam hitting an elbow. Those kinds of things.



An undersized radiator, pitched properly, should not make any noise at all. The person seeking comfort in that room might get a bit ornery, but the radiator? The radiator will not care.

jhosef

now to identify them

I'm certain that as long as there are negligent homeowners, there will be busted radiators.



It seems that the next step is to id these radiators and get the EDR



In case you have this info, I have attached some pictures.



The dimensions are as follows:

American 1: 5 tube type / 8"W X 21.5"L X 38"H / 9 sections

Unknown 1: 2 column type / 7"W X 21.5"L X 38"H / 9 sections

Unknown 2: 2 column type / 7"W X 11.5"L X 38"H / 5 sections



Otherwise, thanks for putting aside the knocking worry. the basic thing that I do understand about these things is to insulate and not mess with the pipes.

Steamhead

You may have

an acid-condensate problem there. Radiators don't usually leak like that unless something makes them, and in a steam system they should not have frozen up.



Acid condensate is often caused by poor steam-main venting. Look at the ends of your mains- are there vents mounted there?



EDR figures are: American Corto- 45 square feet, Unknown 1 (2-column type) 36 square feet, Unknown 2- 20 square feet.

jhosef

more to look into

I was a bit surprised as well that they were as cracked as they are since they would not be filled with water. I found your other post about this and will read up on it in Dan's book.



The first thing that I did when I moved in (5wks ago) was replace all the vents on the radiators and the mains, so perhaps I solved the future problems? On the other hand, I did not test whether the old ones were bad. From the rust on the radiators, these are not recent leaks. I hope that I don't have to replace all of these as I go along.



Thanks for the EDR figures. Those are twice what the replacements are rated at.

Steamhead

Main vents are real important

and it's easy to under-vent them. Tell us how long each of your steam mains is, what pipe size and what main vent is on each one. We can tell you what you really need. 

jhosef

the info

I have two main runs. On each run I have put a Hoffman #43. This was the only one my supplier had.



One run is 53ft of ~2" (26.5ft both ways) and the other is 26ft of ~1-1/4" (13ft both ways)



When I replaced both of these, I ran a stiff wire into the little pipe that attaches the vent to the pipe to clear debris. When I removed the old vent from the smaller run, that small pipe broke off at the elbow and I saw that someone had tried to clear with a heavier gauge wire, since it was lodged in the pipe. Certainly this was not getting any venting.



These vents do work, since I have observed them hissing and that click of them switching off.



Attached are pics of the layout at the boiler as well as the old vents that I removed. The old vent on the left (#76 Hoffman) is for the longer main and the other (#6B Dole) is for the smaller. Looking now at the existing, maybe I did undersize one of them.



What's your diagnosis?

Steamhead

Vent the longer one

with a Gorton #1. These are available in several thread sizes- looks like yours is 1/4" or 3/8". Put both your existing Hoffmans on the short main. Then watch how much better it works.



Note that these are based on the distance from the boiler to the end of the main. The trip back to the boiler is not so critical unless there are radiators connected to that part.



You can get Gortons on State Supply's or PEX Supply's web site.

nicholas bonham-carter

venting capacity

put as much venting on as you can. gorton #2's are the biggest available, and not that much more expensive than the gorton #1. you can never be over-vented, but the problems of being under-vented are serious, so err on the side of caution. if you had a good low pressure gauge, you could see what the back-pressure of venting was [ideally 2 ounces].

your piping looks to have no equalizer, and hartford loop. is that so? if so, then a bit of re-piping would be in order.--nbc

jhosef

thanks

This all makes sense from my reading and sound like great things to add to the boiler upgrade in the (hopefully) impending warm months. thanks for all the help. I'm sure there will be more questions...