Unable to purge forced hot water line for baseboard

rob51

Hi all,
I am trying to purge the zone with the orange tape on it. I can’t get water to come out of the purge valve when I close the ball valve below the purge. When I open the ball valve and the purge, water comes out. Why is this? I am able to purge all the other zones by closing the ball valve below the purge and then opening the purge. Is there something I am missing? Also, I turn the boiler off when I do this, but I’m reading maybe leave the boiler on while purging.

rob51

rob51

EdTheHeaterMan

Turn off boiler and allow to cool for 1 hour
Close the ball valve (yellow handle mostly obscured) just below the faucet (Red Handle that accepts a garden hose)
Connect a garden hose to the red handle faucet
lift the fast fill lever on the water feed line
wait until the water pressure gets to about 25 PSI on the boiler gauge
open the red handle faucet and let the pressure force the air out.
You man need to do it more than once if that is a 3rd floor loop
once the loop is air free, put the fast fill lever back to the automatic position
close the Red handle faucet
open the ball valve
open the red handle to reduce the cold pressure back to 12 PSI or 15 PSI or whatever you system might require (depends on how high the radiators in the house)
Then allow the Auto fill (PRV) do it's thing and get the water pressure to normal
That should do it.

rob51

Thank you so much.  I will try that tomorrow. 

yellowdog

what makes you want to purge that zone? is it because the heat stopped working? is it possible that the loop is frozen and that is what is preventing flow?

rob51

Good question. The loop was installed a while ago, but the pump wasn’t hooked up to the relay box nor was it attached to a thermostat. When everything was hooked up, I turned the thermostat to call for heat. The pump turned on and I could hear water moving in the pipe, but no heat from the baseboard. The temp has been in the 50s in the basement for a while now, so I would think that if a pipe had burst, I would see a leak somewhere. Also, if I attach the hose and turn the ball valve on, I can get water to flow, which makes me think there is no blockage other than air. I didn’t try the method of increasing service pressure like the above post suggested. Will do that today.

rob51

I have the pressure up to 25 psi, but no water is coming out of the spigot

rob51

The pressure relief valve engages and water spills onto the floor if I go any higher.

rob51

A friend of mine said to check the supply side. That there might be a ball valve closed (there isn’t) or a check valve that might be stuck closed. I’ll look into those and try again. If anyone has another suggestion, I’m all ears.

rob51

For some reason there are 2 ball valves on the supply side of this loop. I assumed there was only one. It was also in a strange place. I’m going to shut the boiler down and try again.

hot_rod

if there is a check or flow control valve in the circuit you will only be able to purge in one direction 

EdTheHeaterMan

rob2816 said:

For some reason there are 2 ball valves on the supply side of this loop. I assumed there was only one. It was also in a strange place. I’m going to shut the boiler down and try again.

Since there was a closed valve you cant expect to get heat to go into that loop. Did you try to see if the zone/loop heated once all the valves were open? In a series loop, all valves must be open for flow to happen.

rob51

I opened the valve that was closed on the supply side. I adjusted the screw on top of the flocheck valve. Still unable to purge air from the system. Something makes me think the flocheck valve is bad.

rob51

rob51

This is the flocheck valve.

EdTheHeaterMan

Then there is something blocking the path, OR you are following the wrong path. Are you sure the valve you opened on the supply side is connected thru the radiators > to the return side with no other valves in the loop?

It appears that there are flow valves on the supply and circulators on the return. I'm guessing there are some type of radiators in between those two points of the loop. But are you sure you are not looking at zone 3 supply and purging zone 2 return? If zone 2 supply is closed off then opening zone 3 supply side valve will not get water to flow > to zone 2 return.

rob51

Thank you for your help, Ed. I will check again to make sure I am following the correct path and check to see if anything else like a closed valve is blocking the path.

EdTheHeaterMan

This illustration shows something similar to your system. The fill valve causes water to enter at the top of the boiler where the relief valve is located. (Not the ideal spot) once the boiler is full of water the water will go out the return and try to go past the circulator pumps. Since all the valves at those pumps are closed the only escape for the water pressure is the supply pipe or the relief valve.


Look closely at the light blue arrows to show the path of the water pressure out the supply > thru the flow control valve > then the radiators then > the red handle faucet > out the garden hose. If you have no other outlet for the water pressure, then there is a blockage. Find and open the valve or check valve or other blockage and the water will flow.

Look at all the radiators to see if there is a valve inside the covers. Could there be zone valves on that circulator loop in the actual rooms?

rob51

The heating loop works now! Thank you so much to everyone in this community for helping me out. I can’t thank you enough. Special thanks goes to EdTheHeaterMan for being so patient and explaining everything to be with diagrams and the whole 9 yards. The problem was I was trying to bleed a zone that wasn’t hooked up. When I switched to the other zone, presto! The pumps were also labeled incorrectly. Eating my humble pie on this one, but again, thank you!

EdTheHeaterMan

Trying to purge a disconnected loop, DARN! I hate when that happens!

Especially when you are a professional and the customer is watching

rob51

EdTheHeaterMan said:

Trying to purge a disconnected loop, DARN! I hate when that happens!

Especially when you are a professional and the customer is watching

Hahaha. I am most definitely an amateur and forever in debt to the expertise here.

archibald tuttle

That system looks like its been in place for a while and there is often a case for, if it ain't broke–don't fix it. But if you experience any regular need to purge and haven't been eating bran cereals, @EdTheHeaterMan is right that the water feed to the boiler itself is not ideal.

first, there is the whole "pumping away" philosophy, i.e. that the pumps should be on the feed side of the boiler rather than returns in a pump zoned system (with zone valves and a single pump you have more options) so that the pumps aren't trying to pump water towards the highest pressure, i.e. where the hottest water and least amount of hydraulic resistance of travel from the fill means you are pumping toward the highest pressure in the system and raising it by the very action of the pump (don't see your expansion tank in the pictures which seems a little surprising but maybe there is tee i missed and it's just out of frame somewhere, but the capacity and charge are important).

But if you're not tripping the relief valve regularly and you get heat to all the zones nothing to obsess about. Many systems were built like yours (on the theory, inter alia, of showing the pump 10 or 15 degree cooler water which it was presumed in the older open architecture pumps was nicer on the seals) and have worked fine for decades. And a major change there would be costly on a pump zoned system like yours, even DIY and not counting your opportunity cost.

But I like to add an isolation valve on your steel feed riser and bring the fill in just above that. i separate the backflow preventer and pressure regulating fill that often come as a unit but are threaded together. Then I tee and add a ball valve for bypass that is protected by the backflow preventer but allows easy feed of full domestic water pressure to the loop. Some of the autofills or quickfills (which is what the purpose built pressure regulating fill valves in this case are often called) can be hinky or a PIA to hold in high pressure mode. You do this with the isolation valves on the single main feed and the multiple returns closed so the boiler is not exposed to the higher pressure and you don't have your relief valve tripping every time you restrict the purge valve to the hose as a deliberate strategy for slowing and speeding up the flow during purging which can be helpful on difficult loops that have a lot of ups and downs or run to high floors in the building.

but if you haven't had much trouble with airlocks requiring purging and have found it easy to purge zones once you got the right one, then what you got is just fine and i'm just blowing off steam :-)

rob51

archibald tuttle said:

That system looks like its been in place for a while and there is often a case for, if it ain't broke–don't fix it. But if you experience any regular need to purge and haven't been eating bran cereals, @EdTheHeaterMan is right that the water feed to the boiler itself is not ideal.

first, there is the whole "pumping away" philosophy, i.e. that the pumps should be on the feed side of the boiler rather than returns in a pump zoned system (with zone valves and a single pump you have more options) so that the pumps aren't trying to pump water towards the highest pressure, i.e. where the hottest water and least amount of hydraulic resistance of travel from the fill means you are pumping toward the highest pressure in the system and raising it by the very action of the pump (don't see your expansion tank in the pictures which seems a little surprising but maybe there is tee i missed and it's just out of frame somewhere, but the capacity and charge are important).

But if you're not tripping the relief valve regularly and you get heat to all the zones nothing to obsess about. Many systems were built like yours (on the theory, inter alia, of showing the pump 10 or 15 degree cooler water which it was presumed in the older open architecture pumps was nicer on the seals) and have worked fine for decades. And a major change there would be costly on a pump zoned system like yours, even DIY and not counting your opportunity cost.

But I like to add an isolation valve on your steel feed riser and bring the fill in just above that. i separate the backflow preventer and pressure regulating fill that often come as a unit but are threaded together. Then I tee and add a ball valve for bypass that is protected by the backflow preventer but allows easy feed of full domestic water pressure to the loop. Some of the autofills or quickfills (which is what the purpose built pressure regulating fill valves in this case are often called) can be hinky or a PIA to hold in high pressure mode. You do this with the isolation valves on the single main feed and the multiple returns closed so the boiler is not exposed to the higher pressure and you don't have your relief valve tripping every time you restrict the purge valve to the hose as a deliberate strategy for slowing and speeding up the flow during purging which can be helpful on difficult loops that have a lot of ups and downs or run to high floors in the building.

but if you haven't had much trouble with airlocks requiring purging and have found it easy to purge zones once you got the right one, then what you got is just fine and i'm just blowing off steam :-)

Thank you, archibald. Yes, there is an expansion tank out of view. Good that you brought it up as it’s important. I like your idea of adding an isolation valve. That auto fill is a pain in the neck! I have to hold it then crane my neck to the pressure gauge to make sure I’m not over pressurizing. I have had problems with air lock, but only on the domestic hot water- maybe a couple of times a year I need to purge it. All great ideas and I thank you. I will likely wait a bit to do some work, so I don’t need to shut the boiler off for extended periods during the heating season- need to keep my wife happy. Haha.