New House - Having Steam Issues


Old 11-08-15, 08:07 PM
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New House - Having Steam Issues

Hi All:

Excuse my inexperience, but I've been searching around the net, and can't find quite the answer I'm looking for.

I closed on a 6,000 Sq ft house last week. It has 2 furnaces - both a natural gas forced air system, and natural gas steam system. The first floor's room has a combo of forced air and steam heatin (never 2 in the same room), second floor also has a combo, and 3rd floor is strictly steam. There are 2 thermostats - 1 for each heating system. Seems to be a wire also connecting one to the other.

Temperature has been pretty mild here in PA (lows in the 50's - my thermostats are typically set to 60), I think that may be an issue - will come back to this later.

Forced air system works fine - won't speak any more of it.

Steam radiator fires, all radiators on 1st floor heat, and all but 1 radiator on 2nd floor heats (at the end of the line), NO radiators on 3rd floor heat. Seems like steam is only getting to 2/3 of the house. I also hear banging on one of the radiators towards the end of the line on the 2nd floor - going to explore pitch and venting soon.

Absolutely zero heat to radiators on 3rd floor - completely stone cold. The 3rd floor is vacant, but I am a bit worried about pipes freezing in extreme cold.

Any idea on where to start? So far I checked water level on the viewing tube and everything is fine. I have a few hypothesis, if I can get your feedback:

1. It simply isn't cold enough for the furnace to be on long enough to make enough steam to get to the 3rd floor. This may be a ridiculous assertion, but for some reason it makes sense to me.
2. The forced air system may be 'beating' the steam system - even though both systems turn on, the forced air warms faster, and doesn't give the steam enough time to rise to the 3rd floor.
3. Air in the system - I don't know a lot about this, but I've read that it may need to be purged. Not sure if the above fact pattern supports this.

Sorry for writing a novel here - but I'd really appreciate your feedback.

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Old 11-08-15, 08:12 PM
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Hi Jim,

You may be looking at a venting problem on the radiators.

Have you looked at the vents yet?

Required reading for steam heat owners is this book:

Has all the answers you need and you'll know more than the techs that come to the house.
Old 11-08-15, 10:45 PM
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First thing to check is that the radiator shut-off valves are wide open on all radiators. Most likely your third floor problem IS a venting problem. You can temporarily remove the air vent from one radiator to see if it then heats.

Answers to your questions.

1. As you assume, this is ridiculous PROVIDING there is a way for the air to be expelled. The speed at which the steam travels in the piping is extremely fast unless there is air blocking the way. Do you have working main line vents, probably in the basement?

2. No connection between the two systems operation.

3. Of course there is air in the system, it is part and parcel with a steam heat system. There is no "purging" necessary as there is with a hot water system.

I second the motion of getting the book that NJT linked to.
Old 11-14-15, 12:39 PM
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Unless your thermostat is shutting the steam system before the third floor gets a chance to heat up...I would check all your steam vents and especially your main vents
Old 11-14-15, 02:38 PM
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Have someone bang on the steam pipe(may be one for each floor from a common manifold) in the basement while listening on the first and second floors to determine where the pipes are located. Hopefully they run thru closets or have an access panel(maybe there is a valve between the 2nd and 3rd floors in a single pipe feed ) . If not, you have a good idea where the 3rd floor pipe is. Remove the steam pipe from the first radiator on the 3rd floor. Turn the steam furnace t'stat to 90 and see if the 3rd floor gets steam after the 2nd floor radiators get warm. If not feel the wall to determine where the 3rd floor pipe goes cold. Could be a blockage in the pipe (not likely) or the steam is condensing before it reaches the 3rd floor (furnace undersized). Turn t'stat off and reconnect radiator on 3rd floor. If this is a new house, call the builder. If not call a heating contractor unless there was some contingency in the sales agreement about HVAC working. Good luck.
Old 11-14-15, 08:24 PM
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For more steam info check here
Comfort Calc
Noise is caused by steam and water contacting in horizontal pipes or radiators.
As stated by others check main line vents and as the weather gets colder the third floor may heat better, I remember customer complaints that rad's were not heating all the way across in shoulder seasons. Boiler will run although possible cycling on and off on pressure until the thermostat is satisfied. If the heat loss is low due to warm temps all the radiation may not be required.
Good test, remove the 3rd floor vents and see if there is an improvement. Make sure you re-install them when test is completed.
What is the pressure settings on the boiler?

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