Hot Water System Top Zone (3rd Floor) - No Heat.

MikeC_3

I have a four zone hot water heating system.  I am currently not getting any heat up to the top floor - the basement, 1st and 2nd are fine.



Starting with a fully drained system and with all valves in their off positions, I turned the boiler on, filled it by opening the main fill valve and let it come up to temperature/ pressure (210/16 respectively).  I then shut the boiler off and leaving the main system fill valve open, lifted the lever on the pressure reducing (bell) valve.



Starting with the basement, I attached a hose to the purge spigot on the return, opened both the spigot and the corresponding fill valve and allowed it to run until no air bubbles were present in a bucket for about a minute.  I closed the spigot, opened the return valve below the purge spigot and then repeated the process for the remaining 3 zones. 



I closed the pressure reducing valve and turned the boiler on and proceeded to go zone by zone starting with the basement and working upwards, turning on the corresponding thermostats.  The basement, 1st & 2nd floors all received hot water and the heat worked fine.  The 3rd did not.  I removed the thermostat and jumped it to rule out any issue with it.



I shut the system down again, isolated the 3rd floor zone and repeated the above process to no avail.  I received hot water from the boiler through the return spigot so I was sure water was circulating through the zone freely and without air.



I let the system run for a week hoping the problem might resolve itself but it did not.  I am at a loss. The one difference now is that when I attempt to purge the zone (with the boiler off, zone isolated, fill valve on) the  water will just stop flowing.  I left the purge spigot open for hours thinking that it might be a large amount of air that needed to be removed - nothing happened still.  Now whether I was supposed to do either of the following the point is moot because I did, but while in this purge setup if,



A -  I flip the switch on the boiler to the on position, water immediately begins to flow  out the purge spigot



B - with the boiler off, if I manually slide the motorized valve below the purge spigot to the left ,water also immediately begins flowing out the purge spigot above (that seems odd).



Help please!

Unknown

repipe

Repipe the boiler correctly, you won't have air problem

MikeC_3

?

Everybody seems to have a different opinion regarding what should go where.



Being that this setup has been functional for 8 years, I'm just looking for the solution to get it up and running again.

Zman

Expansion Tank

Is your circulator pumping directly into you expansion tank? It looks like it is, this make air elimination very difficult.

Do you have any bleeders on the upper floor?

Do you know how that floor is piped?

Carl



I would have to agree that short, grumpy answers are not that helpful.

JStar

Hot water

1psi = 2.34 feet.



You need 1psi of cold fill pressure to lift water 2.34 feet high. How high is the 3rd floor from the pressure gauge?

MikeC_3

34 feet

34 feet from the gauge to the top of the system - 18.7 psi required.

JStar

Pressure

It's actually about 15 psi. I think you divided 43 instead of 34.



EDIT:



If the cold fill pressure is 15, as soon as the pump turns on, the top of the system may actually be drawn into MUCH lower pressures, resulting in a loss of flow.



Ideally, you should have the pump on the supply, but you may be able to cheat, and raise the cold pressure a few psi. No more than 18psi max.

MikeC_3

Pump

No, the pump is on the line with the zone fill valves, the expansion tank is on the boiler fill line.



No bleeder valves, just a closed circuit.



Not sure exactly what you mean by piped but there are three radiators running the length of the building in three rooms.  It goes up the front of the house, along the length of the building  (45 feet) and down the back across and back to the boiler.

Zman

Expansion Tank

I am having trouble following the picture. Is the circ on the return side pumping into the boiler? Is the expansion tank on the supply side just after the boiler? Is the zone in question piped from one to the next (series) or are there tee's?

Carl

MikeC_3

Pump

No, it is on the supply side.  The yellow handle valves are fill valves for each zone (not in series, I can isolate and drain each zone individually).  The pump is prior to these before the air separator.  So it goes boiler/ circ pump/ air separator/ fill valve.



The expansion tank is on the return side - past where the water returns to the boiler.

Zman

Try..

You could try a bit of dawn detergent to get it unlocked.

A bleeder on the upper floor will also help.

Carl

MikeC_3

Restrictor Valve

It was user error.  I was opening the fast-fill lever on the restrictor valve too far - essentially closing it on the other side.

Weezbo

Mike ,

i like to see valves on the boiler .having a purge on the supply and return on the field side valved away from the header helps too. for instances like this .

then you can back purge every zone and prove circulation , and re pressurize the individual zones .

some things that could happen to an existing system is part of a zone valve could go clog a line , you could have a line with a vacuum rather than a pressure ,field parts and pieces may be broken and you may have by passes in the field in the form of trv's etc. the service guy can figure things quicker and see visual clues with temp gauges on pipes as well.

they enable to one to see quickly when there is or is not flow .

above the quarter turn ball valves would be an ideal place for some more boiler drains/purge valves. might make your day too to have a return temp gauge and a supply temp gauge just incase you are ever the proud owner of a pressure temp gauge that always tells the same story no matter in the boiler or out. : )

we refer to them as "Guaranteed 12lb 180 degree temp pressure gauges.

i hope that helps.

Weezbo.

MikeC_3

Good advice

No doubt this is good advice.  Some changes will definitely be made before next winter.  For now I am just happy to have it up and running again.



Thanks!

SWEI

Pressure

15 PSI will get to the top of the system.  Add another 5 PSI and it will be a lot easier to get and keep the air out.