3rd Floor Hydronic Radiator

[djmorgan010]

Hi. I know this is a somewhat common problem. I have a 100yr old house, hot water radiator sytem. Converted to a 2-zone system many years ago. Have tolerated not getting hot water to 3rd floor radiator for too long. Want to solve.

Background data:
1. Water pressure about 22 PSI at boiler (located in basement)
2. Boiler has been cranking for a day as the temp outside is -7F! Thus, at full temperature
3. Water temp heated to about 180F.
4. Zone 1 - Basement, 1st floor and 3rd floor (only 1 radiator on the 3rd floor)
5. Zone 2 - 2nd Floor
6. I have the 3rd floor on Zone 1 so that it gets more calls for heat. Zone 2 turns on less frequently due to hot air rising from 1st floor.
7. When bleed 3rd floor radiator, got a lot of air for about 30 seconds. Then stopped. Went back a few times hoping the pressure would build again. No more air discharged.
8. 3rd Floor radiator seems to only have water going up about the bottom first foot. Remaining 3 feet of radiator cold to touch. Thus, not enough heat to matter.

So, do I add more pressure to system? Thought 22PSI would be enought

Is it possible to add an extra pump in line with the 3rd floor radiator pex line? Note that pex is only in basement. Riser to radiators is old case iron piping.

Hopefully this picture help to understand the current set up.

 

[John Gayewski]

Can you balance down the first floor radiators and only have the pump move water up to the third floor for a while? It sounds like there's still air, but you need to drive the air out from up there.

If that works to remove the air, you might need to leave the first floor radiators balanced down a little more than your had it before to keep the loops more even.

 

[Sponsor]

 

[Fitter30]

22 lbs with pumps and boiler off water under 100° is 50.82' 2.31' per lb. What are your heat emitters radiators? What is your pumps are pumps per floor or just one brand and model. Any zone valves?

 

[djmorgan010]

Thank you for your quick suggestions and questions. I will close the others on the 1st floor manifold to see if I can more flow up there.

To the other questions...the radiators are old cast iron rads. There is only one pump...and that is the main boiler pump as shown here. The zones are controlled by these Honeywell valves as shown in this pic.

 

[Fitter30]

Don't have enough pump 7 zones? Bet none are piped reverse return. Meaning take two manifolds supply and return first out last in. 007 f5 pump has only 10 lbs of head. Your manifolds with ball valves don't regulate flow very well that is why there almost closed.

 

[John Gayewski]

Don't have enough pump 7 zones? Bet none are piped reverse return. Meaning take two manifolds supply and return first out last in. 007 f5 pump has only 10 lbs of head. Your manifolds with ball valves don't regulate flow very well that is why there almost closed.

Feet of head only relates to length of longest run. Unless the op's longest run is longer than about 165ft they should have enough pump.

 

[djmorgan010]

None of the runs are nearly that long. The 3rd floor run is really not much longer than the others.

To Fritters comment, all rads get enough flow (even if maybe not even) except that damn 3rd floor.

Any thoughts on adding an inline pump/injector that can assist with pushing the water to the 3rd floor? (novice question I am sure!!!).

 

[John Gayewski]

None of the runs are nearly that long. The 3rd floor run is really not much longer than the others.

To Fritters comment, all rads get enough flow (even if maybe not even) except that damn 3rd floor.

Any thoughts on adding an inline pump/injector that can assist with pushing the water to the 3rd floor? (novice question I am sure!!!).

If you wanted to make your third floor a seperate zone you could add a circulator. But I don't think you need to and it's not as simple as just cutting the circulator in. You'd need to actually create a new zone and have it hydraulically seperated from the others.