1 zone on hot water system not working

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  #1  
Old 01-31-19, 08:37 AM
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1 zone on hot water system not working

WE had a problem with no heat / pilot light not staying lit this morning. I cleaned the thermocouple and it's working now. Heat was off for a couple hours.

It's 3 zone system and 2 zones are heating good. 1 zone is not.

I checked the zone valves (V8043). They all work the same - they make the sound like they are opening... the slide lever moves the same way - when I disconnect thermostat wire to the motor of the problem zone, it makes the closing sound, the manual lever gets difficult to move (vs. when power is applied / the lever moves freely).

The radiator water line is actually cold to the touch in the crawl space under the laundry room next to the garage. Could that line have an ice blockage?! I don't see any water so it's not burst? Is each zone usually a single long pipe run?

Any suggestions what to do? Run the heat in the other zones and the heat gets to the 1st floor (the problem zone)?
 
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Old 01-31-19, 09:06 AM
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Each zone is on its own set of pipes back to the boiler. If that zone runs thru a cold area it may have frozen. Keeping the heat up in the other zones may help to unthaw it.
 
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Old 01-31-19, 09:15 AM
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thanks! nothing higher tech / more advanced than wait? again, other zones are working (so circ pump is working) and that zone valve seems to be working...

considering how cold it is today, anything else come to mind why 1 zone won't heat after the heat went off for a couple /few hours?
 
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Old 01-31-19, 11:36 AM
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As Pete said that line is most likely frozen. The best thing you can do is make sure that zone valve stays open so that when the pump comes on for any zone it will also send water to that zone helping that pipe to thaw.

Outside of getting some type of heat safely into that crawl space to help thaw that pipe there's not much that you can do. They have heat tape and things of that nature you can use. Keep a close watch on that pipe for splits because when it thaws naturally it will leak.

Hope this helps a little.
 
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Old 01-31-19, 12:39 PM
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Thank you again.. .just trying to cover my bases...

I turned up the heat in the rest of the house.
There were some doors between the rest of the basement and the crawlspace - I opened them.
I did a load of wash in that back room and set the dryer to blow back into the room (maybe the radiator would pick up some of that heat...

But still that line is cold.we only lost heat for a couple hours and it's been about 6 hours since heat has been restored.

I took off the motor from the zone valve. I unscrewed the motor housing from the brass part of the valve, but can't take the housing off to manually turn the valve....

What are the odds that the valve is stuck closed (right around there, it's hot to the touch so not frozen there : )
 
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Old 01-31-19, 01:50 PM
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You didn't have to go through all that with the ZV, just put it on manual and if the lever has no resistance than the plunger is down allowing the flow of water.

If you feel the pipe after the ZV and it's hot then it's open. If you have a heat gun or hair dryer to warm the pipe. Be very careful of your surroundings if using heat gun.

If the air is frigid enough it takes very little time for a pipe to freeze and hot water freezes faster than cold water, so if that water was hot when you lost power the water temp accelerated the freezing problem.
 
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Old 02-01-19, 07:16 AM
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Thanks. it's been 24 hours of having the heat back on. That zone still isn't working.

It's supposed to get into the 40s - 60s outside on Sunday? so we'll see if it resolves then, but hate to be waiting around and it's something else I could do to fix it.

I took off the valve motor housing and got to the shaft of the valve. that shaft turns about 1/8 of a turn? Not used to something that small a turning amount (usually 1/4 turn is the least with a ball valve. BUt that 1/8 of a circle is about what the manual lever does, so I guess that's the correct amount. I took the housing off on the slim chance the motor / gears weren't actually turning the shaft. That doesn't seem to be the case.

This is the first floor zone with a finished basement... getting to the pipe in most places is tough. In the 1 room next to the garage where any freeze likely is, it's covered in foam insulation and yeah, the pipe is cold to the touch, but I wouldn't think its cold enough to be frozen and for a day , inside the house.

if after a warm spell the problem still exists, what woudl you do then?
 
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Old 02-01-19, 07:48 AM
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1 zone not working - frozen or other advice?

I have another thread in the gas furnace forum. I realize that at this point I should be in here?

I had no heat for a couple hours yesterday. Got the system working, but 1 of 3 zones is still cold, 24 hours later

It is the zone on the 1st floor. 1 room is 20' x 7'. unheated garage is on 1 20' side. Outside of house is on 7' and other 20' side. another 7' side leads to kitchen. Aboce that room is the garage attic (and has insulation over the room) under it is the unheated basement that we can usually sit down there to watch tv. But Yes, that room is usually cool. Right now, at the far end of this laundry room is 65..

I checked the zone valve motor and even took the motor housing off / saw that the valve stem turns about 1/8 of a turn freely.

That room is our laundry room. yesterday I did a couple loads of laundry and vented the dryer into the room (so the radiators might pick up some of the heat.

We have the other 2 zones running ihigher than usual. We have the gas oven with door open running .

It's going to warn up in the next couple days so if it's a frozen line, that SHOULD clear up. But what woudl you do if that doesn't clear up the problem?

I'd hate to wait for the warm day and meanwhile there's something else I can do...

at 1 end of the run at the boiler is the zone valve. At the other end / return, there's a drain valve and ball valve. I was thinking if there was a drain valve at both ends, I could flush the pipe and see if there's actually a blockage.

Can I just open the drain at 1 end and see if water keeps coming out? ( I did that last night and got 1 cup of hot water coming out. although now that I think... I didn't close ball valve so maybe that was coming back up from the boiler, not the lines : )

I am afraid that makeup water woudl be cold / crack the boiler? (how do I know if makeup water filling is automatic or there's not enough water in the system? Need pictures?

THANKS!
 
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Old 02-01-19, 02:20 PM
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Threads combined and all moved to boiler forum.
 
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