No heat to one zone... help!

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Old 01-19-09, 12:35 AM
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No heat to one zone... help!

I recently puchased a house with an oil boiler and baseboard hot water heat, a first for me. The other day I woke up to the house being cold and found that oil was not getting to the boiler. I figured out how to reprime the system and got the heat running again. However one of the the three zones was not getting heat anymore.

The only thing I could think of is that maybe some air got into the zone and the circ pump couldn't send hot water to the zone. I tried bleeding the zone but still nothing. I'm getting heat to the other 2 zones and it doesn't sound like there is any air in the system. I also thought maybe I might have a bad zone valve but when it calls for heat you can feel the pipe get hot on both sides of the open valve but the pipe does not get hot after a foot or two. Also you can hear what sounds like water flowing if you put your ear close to the pipe.

Is there something else that might cause this zone to not be getting heat? I'm pretty sure I'm bleeding the system properly but am not sure since this is the first time i've tried bleeding. I could not find any valves on the baseboard heaters and only a drain valve on each zone. Any help would be helpful.

Here are some pictures of the system and zone in question. I can take more if it would be helpful.



 
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Old 01-19-09, 04:41 PM
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I'm really hoping that you didn't have a freeze-up in that zone when the heat was off... do any of the pipes in that zone pass through or near unheated areas?

You had all the zone valves closed when you tried purging the zone? If not, they should be.

When you do purge, it's a real good idea to allow the boiler to cool to below 100F or below before starting... don't want to 'shock' the boiler with cold water in a hot boiler.

So, you hooked a hose up to that drain, and opened it? Then what? Any water come out under pressure?

One thing I don't like about the type of 'fill valve' (FillTrol system) that you have is that there's no 'fast fill' whereby you can temporarily bypass the fill valve regulator. You will be limited to the amount of water you can get through the system, and it may not be fast enough to move any air bubbles. I can't see enough of the piping to determine if you have an auxiliary 'fast fill' valve installed or not... Look for a valve that goes from your water supply, directly to the boiler water system.

If you can locate a valve as I mentioned, you can open that to force a fast flow through the zone.

Take some more pics of the piping behind the flue pipe, particularly the feed water piping if you can... I'll look to see if I can spot a 'fast fill' ...
 
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Old 01-19-09, 06:18 PM
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I don't think there was enough time for them to freeze seeing it was only off for a few hours while I slept and I don't think the house temp went much below 50 even in that zone that I keep cooler. The baseboards are along an unheated garage wall and like many others in this house some are along exterior walls. I have a space heater in the room now and am keeping the door open to the other zone to keep the room warm for now so nothing does freeze.

When I purged the zone I had the boiler off and cooled down and the zone valves closed at first. This particular zone, unlike the others, has a vavle to shut it off on the inlet side of the zone (side water is coming from the boiler) and the zone valve on the return side (above the circ pump) will shut it completly off from the rest as far as I can tell. At one point I closed the inlet valve and opened the zone with the drain vavle open and a hose going into a bucket of water and was getting air bubbles. I'm going to try to purge the zone again to see if I didn't get everything because I'm still not getting heat there. The other two zones are still running strong.

I looked around and think I have identified what every valve on the system does and could not find one for fast fill. I tried to get some better shots of the of where the water enters the system but it was hard to get a good angle in the tight space.

Thank you for the help.









 
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Old 01-19-09, 07:13 PM
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in you r first post you say the pipe gets hot up a foot over the zone valve...are you sure it is opening the position of that valve i think could get hot for a foot on siphoning

can you open the zone valve manually (or somehow make sure it is in fact opening)

just a thought
 
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Old 01-19-09, 07:30 PM
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There's two things you could try ...

1. create a 'cross connection' using a washing machine hose. Connect one end to the drain valve below the 'crusty' red handle one (more about that in a minute), and the other to the boiler drain down near the floor. This will allow you to use full house pressure to purge the air from that zone. In addition to making sure the zone valves are closed, I would also turn that screwdriver valve just below the zone drain perpindicular to the pipe... just in case the zone valve doesn't hold shut. If you don't stop the flow with the zone and/or the 'balancing' valve below the drain, the water will never go through the zone... it will 'short circuit' into the boiler, up through the pump, and out the drain...

Possible problems... either or both of the drain valves may not seal again when you close them... so have some hose caps on hand. And if the drain doesn't seal and you put a cap on the valve, the gland nut may start leaking around the stem... that's what that green crud is on that one valve... the orange/red handle valve is leaking around the stem. There is a 'packing' in there that is compressed by that 'gland nut' ... you may be able to stop the leak by tightening that nut slightly... you may not think it's leaking because you don't see any water but that's only because the pipe is hot and the water evaporates quickly, leaving behind it's minerals... I'm afraid that tightening that won't stop the leak... too far gone... you may ultimately have to replace the packing... easy job if you have the valves to shut off and isolate that section of piping.

2. Increase the air charge temporarily in the expansion tank to 25 PSI. This will cause the boiler pressure to increase to 25 PSI, and that may be enough to get the air out of that zone. When finished, return the air charge in the tank to 12-15 PSI.

The FillTrol valve sets the system pressure to whatever the air charge in the tank is. When finished, let the air back out of the tank to 12-15, and open a drain to drop the boiler pressure back to normal.

Problem with this approach is that 25 PSI may not be enough pressure to get the bubbles out.
 
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