3rd-Floor Radiators Don't Heat During Day

Cory Hartman

Okay, I'm a little confused. By "T-Stat" do you mean "thermostat"? If so, it is located on an interior wall in a large room in the center of the first floor of the house.

And by "is it a programable" do you mean "can you turn the dial to change how hot it gets"? If so, yes. If you mean "can you set it so that the temperature changes according to a predetermined schedule automatically" then the answer is no.

Cory Hartman

PROBLEM: Uneven heating. In particular, third-floor radiators get hot when the heat is turned up in the morning but do not heat throughout the day.

SET-UP: Three mains in parallel flow. Main No. 1 has short feed to two radiators and very long vertical feeds to radiators on second and third floors. Main No. 2 has 15-foot feed to one radiator, long feed to a second, and a very long vertical feed to radiators on second and third floors. Main No. 3 has three short feeds to radiators and two very long vertical feeds to radiators on second and third floors. Mains partly insulated. (I know this is a problem.) Vertical feeds to upper-floor radiators not insulated. Each main has vent positioned at 90-degree downward elbow joint toward wet return. Vents are not elevated; they come right off the joints. Mains Nos. 2 & 3 connect above water line. (I know this is a problem.)

QUESTIONS:

1. Are the main vents properly positioned? (I couldn't tell from your description whether that applied to a parallel flow set-up or just to counter-flow.)

2. Do the long, vertical, upper-floor radiator feeds need to be insulated? If so, how can I do that without them looking ugly? (They pass through living space.)

3. Given the vertical distance between the third-floor radiators and the cellar, can I just not reasonably expect the top floor radiators to get warm during short heating cycles through the day?

4. Do you see any other red flags?

Wayco Wayne_2

What is the

water pressure at the boiler, and how high above that are the radiators in question. For every psi at the boilerwater rises 2.3 feet. So if you have 12 psi your boiler the water level will be 27.6 feet above the boiler. Usually that's enough for a 2 story house. You may need more pressure to get the water level up. WW

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LarryC

Is this is a 1 pipe STEAM system?

Home owner here.

Is this a one pipe STEAM system? If so, what are the cut in and cut out pressures? What size air vents and are they working? Any water hammer? Got pictures of the near boiler piping?

Larry C

Steamhead (in transit)

Also

how long is each steam main, and what pipe size? What vent is on each main?

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Cory Hartman

This is a steam system.

Main No. 1 is 50 feet long with a No. C valve.
Main No. 2 is 23 feet long with a No. 1 valve.
Main No. 3 is 80 feet long with a No. 1 valve.
(All lengths are "round-trip"—i.e., from the boiler all the way back.)

All mains are 2.5" in diameter on the way out and 1.5" on the return.

Valves for Mains Nos. 1 & 3 work. The valve for Main No. 2 was on so tight I couldn't get it off to check it.

There is water hammer at a first-floor radiator off Main No. 2. (I think it's a radiator tilt issue.) That's it.

The cut-in pressure is just over 2 psi. I don't know what the cut-out pressure is, but there is another pressure gauge that is at zero close to the cut-in one.

Sorry; no pictures.

Barbarossa

On time

Where is the T-Stat located and is it a programable?

Barbarossa

3rd floor

Some times the T-stat (thermostat) is located in a place where in the morning when it hast to recover temperature it will stay on long enough to send heat to all parts of the system. But during the day after the system is at the set point; it is satisfied by the local radiators or say; sunlight quicker then the system can get heat to the further parts of the system. This assumes the main vents are properly sized and functional along with the radiator vents. A test would during the day raise the T stat by 5 degrees and then see if the problem radiators now heat with the longer on cycle.