Help With Two Pipe System

JSR

Last summer we purchased a two-story house in Zeeland, MI, not far from Grand Rapids, MI, with a two-pipe, natural gas steam system. We believe the house was built in the early 1920’s. I am a steam newbie, but I have been trying to educate myself on steam heat by reading Dan's books.

I posted last week asking if anyone knew a good steam contractor in the Grand Rapids, MI area. Steamhead and BobC replied suggesting I post pictures of the system for advice and help in identifying it.

I am following up on their good counsel. I have posted a few pictures of the boiler and the piping around the boiler.

In addition, here is what I have figured out about the system so far.

BOILER: The boiler is a Hydro Therm Model VGA 2505 that was manufactured in 1982. It has a McDonnell No. 67 low water cutoff. The net IBR Rating Steam is 144,800 btu/hr (Sq. ft. steam: 603).

I believe that the boiler has started leaking and needs to be replaced. I have been adding water to the system twice a day this winter and if I look under the boiler where the burners are I can see a slow drip. When the weather is warmer and the boiler isn’t firing as much, the drip causes dampness on the floor around the boiler.

EXISTING RADIATION: With the exception of the Kitchen, all of the rooms on the main floor have cast iron baseboard radiators. I haven’t been able to determine the manufacturer. I am pretty sure these are not original to the house, but were probably added to replace traditional type radiators, like the ones upstairs. This is based on finding radiator pipe holes in the wood floors when we took up the carpet and had the floors refinished. Also, we found some long sections of baseboard in the garage that were apparently removed to make room for the baseboard radiators.

The Kitchen has a National Radiator Co. Aero model cabinet convector with a cast iron element that is partially recessed into the wall.

The rooms on the second floor have American Radiator Company radiators that appear to be original to the house. Per Dan’s E.D.R. Ratings for Every Darn Radiator, three of them appear to be Rococo Window Radiators and the other two appear to be Peerless Three-Column Radiators.

Per my calculation using Dan’s books, the total EDR for the house is 506.5 sq. ft.

MISSING RADIATION: There are at least two radiators that were removed and not replaced. One in the master bedroom walk-in-closet and one in a first floor half bath. The piping to both has been disconnected from the system in the basement.

RADIATOR SUPPLY VALVES: All of the supply valves to the baseboard radiators on the first floor are basic looking Hoffman with round black plastic handles.

There are a variety of different valves on the second floor radiators. Two are Hoffmans like the ones on the baseboard radiators. One is a Trane Hermetic with a round black plastic handle that has a pointer under it. The other two are Richmond’s with lever handles and a round disc with “Hot” and “Cold” marked with gradation lines between. The valves are also marked with the number “44.”

STEAM TRAPS: All of the radiators, baseboard radiators and the convector in the kitchen have Hoffman 17c steam traps. The best information I have is that they were replaced in November 1997.

PIPING AND VENTS: This is a two-pipe system. There is one 3” riser off of the boiler and a 3” header with three 2” steam mains rising off of the header. There is a 2” equalizer pipe off of the header.

One of the steam mains supplies steam to 123.3 sq. ft. radiation; one supplies steam to 139.9 sq. ft. radiation (this one has the missing radiators and probably had an additional 50-60 sq. ft.) and the third main supplies steam to 243.3 sq. ft. radiation.

The system has three return mains. These are dry returns until they reach the boiler and drop down into the wet return.

One of the return mains connects to 139.9 sq. ft. of radiation and has a Hoffman Vacuum Vent No. 76A where it drops into the wet return.

The second return main connects to the remaining 366.6 sq. ft. of radiation and has a Hoffman Vacuum Vent No. 6 on it where it drops into the wet return.

The third return main does not drain any of the radiators, but rather connects to each of the three steam mains near the end of their runs. These are just simple connections; there are no steam traps at or near the connections. This return main has a Hoffman Main Vent Air Valve No. 75 on it where it drops into the wet return. I have attached a pic of where it connects to one of the steam mains.

SYSTEM PERFORMANCE: This steam system heats the house adequately. However, the rooms on the side of the house farthest from the boiler on both floors are noticeably cooler than the rooms closer to the boiler. There is no loud knocking or banging in the pipes. When the heat goes on we hear some soft “clicking” or “ticking” sounds for a short period of time.

QUESTIONS:

1. I would appreciate any help anyone can give me in identifying what type of system this is and any advice for upgrading, balancing, improving, etc. this system.
2. Any thoughts on replacing the boiler? I have read Dan’s books so I am pretty familiar with the issues I should address with the contractor, but would welcome any comments. One issue I have is that the present boiler is sized for 603 sq. ft. steam. My existing radiation is 506.5 sq. ft. We are, however, contemplating adding radiation to an unheated “sleeping porch,” hopefully at some time in the relatively near future. Should I size the boiler to accommodate the future radiation needs?
5. Should I replace the steam traps on the radiators/baseboards since they are almost 20 years old? If so, what do I replace them with.
6. Should I install thermostatic radiator valves on the radiators?
7. The cabinet convector in the kitchen has both a steam trap and a steam vent on it. Is that usual? Should I remove the vent?
8. The main vents on the returns look ancient. Should I replace those? What should I replace them with? How do I figure out how to size them?
9. Should there be F&T traps where the steam mains connect to the condensate return main? This is a dedicated return main that serves only the steam mains. It has no radiation returns connected to it.
10. Any other thoughts or advice?

Thanks so much for your help.

Jeff

Jamie Hall

Well, let's see here.

On the traps -- item 5 -- unless they are failed, I wouldn't worry about them (the ones on the system I care for are 80 years old, and work just fine, thank you). If they are failed, then yes, replace the innards. Traps fail in two ways -- open and closed. Closed and the radiator will heat very poorly, if it heats at all. Open, that radiator heats just fine -- but so does the return from it, which is how you can tell (returns can be hot, but not steam hot). An open trap will hurt the performance of other radiators on the same return.

Item 6 -- thermostatic radiator valves. Don't bother. But if a room is too warm, you can turn the valve to close it somewhat until you are happy (NOT the room with the thermostat, though!).

Item 7 -- that is a bit unusual, and may suggest a problem with the trap on that unit. But it won't hurt anything to leave it.

Item 8 -- those vents probably are a little small. Others will chime in on that, I'm sure. Giving the system more main venting may help to get the heat a little more even, though -- that and partly closing the valves on the radiators in rooms which are too warm.

Item 9 -- F&T traps are not required on this type of system and, in fact, aren't desirable. If it ain't broke...

aircooled81

Wow, great detail, great post. Reading this was like walking through your house a quickly marveling at the gravity return two pipe.
Thnx

nicholas bonham-carter

Your description of your system was excellent!
Until you know the inlet valves are leaking, or have failed closed, let them stay in place, as they are.
The traps can all be rebuilt with new elements from Barnes and Jones, and perhaps if you could send any problem elements to "Sailah" there, he might be able to test them this summer. Removing the cap and element should be easy this summer, using a socket, or open end wrench, instead of channel lock pliers.
You will definitely need new main vents, and if you desire to continue the vacuum operation which must have started the life of the system, then Hoffman #76's would be a good choice for each of the 3 locations.
A vaporstat instead of the boiler supplied pressuretrol will keep the pressure low, (only a few ounces are needed).
There are some boilers in the Peerless line, which are the same block for each of two different EDR ratings, with only the burner tray being different. There may be such a pair which would allow you to have 500 feet of EDR to start with, and then when you have added the extra radiator to the sleeping porch, the larger burner tray could be installed, if needed.
An analysis of the fuel used and the degree-days during which it was burned could tell you how oversized the present boiler is, and how much capacity you need.--NBC

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