Half cold radiators
#1
01-27-07, 12:16 PM
Half cold radiators
I have steam heat, and on the first floor there are 3 radiators that only have the first few coils getting hot the rest are cold. I closed the valve, disconnected the radiator thinking there was a blockage, but everything was clear. I also with the radiator disconncted, opened the valve and there was very little steam coming out. these radiators have always worked great but all of a sudden last night they started not working. Any ideas of what could be the problem? Or ideas of what to test next? This is a single pipe system, pitched from the radiators.
#2
01-27-07, 01:17 PM
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Check the water level in the boiler. If it's low the boiler could be going off on low water befor it runs long enough to heat those areas. If the water level is ok then turn your stat up 10 degrees and let the system run for a while. Watch the boiler to make sure it doesn't drop out and see if those radiators get any warmer.
There are a few reasons why you would have these symptoms but few that would surface all of a sudden.
There are a few reasons why you would have these symptoms but few that would surface all of a sudden.
#5
01-27-07, 02:56 PM
my apologies, i worded that wrong. the water level is correct, and the boiler does not shut off due to the fact that the thermostat is in the room with one of the radiators that is not functioning properly.
#10
01-27-07, 05:40 PM
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I agree with grady. It sounds as if it's failing to make a head of steam. The biggest problem for me is what changed all of a sudden. Let's reword it.
Steam boiler-oil fired
3 radiators fail to get hot
boiler runs non-stop and rads still won't heat...........
Ok. Is there a main vent on the line that feeds theses three rads? Could this main vent be plugged or bad. If you had the reds disconnected and almost no steam coming out the connections, it means either : No steam through the valve, no air out the main vent, no steam in that header or no steam from the boiler.
Go back & look for a main vent, remove it & try again. Be very careful, steam moves FAST when uninhibited.
Also are these 3 rads all on the same header?
Steam boiler-oil fired
3 radiators fail to get hot
boiler runs non-stop and rads still won't heat...........
Ok. Is there a main vent on the line that feeds theses three rads? Could this main vent be plugged or bad. If you had the reds disconnected and almost no steam coming out the connections, it means either : No steam through the valve, no air out the main vent, no steam in that header or no steam from the boiler.
Go back & look for a main vent, remove it & try again. Be very careful, steam moves FAST when uninhibited.
Also are these 3 rads all on the same header?
#11
01-27-07, 05:45 PM
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HVACGuy
Not to dispute you because I'm sure you know way more about steam than I but if it were a vent problem, would the boiler not shut down on high pressure? Just asking because I don't know & want to. Very little steam in my neck of the woods.
#12
01-27-07, 05:48 PM
The rads are on the same pipes, but i noticed, when i vent the releif valve the steam kinda "trickles" out. I will have to check the strainer for debris. It makes sence. Thanks!!!
#13
01-27-07, 05:54 PM
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the pressuretrol would cut out if:
The boiler could keep up enough steam to out pace the venting of the good rads and outpace the steam cooling & returning via condensate throughout the system.
Steam is lazy. It's balanced by making some areas easier for it to go than others. If it can't vent to the troubled area because it's just a little harder, it'll go right on past to the easier escape route.
Many make the mistake of upping the pressure to get the steam to move by force, but the opposite happens. Higher pressure makes steam sluggish. In a well piped low pressure steam system, steam can move up to 60 mph. That's why steam lines bang, they pick up condensate and throw it into the backside of a elbow or other fitting.
The boiler could keep up enough steam to out pace the venting of the good rads and outpace the steam cooling & returning via condensate throughout the system.
Steam is lazy. It's balanced by making some areas easier for it to go than others. If it can't vent to the troubled area because it's just a little harder, it'll go right on past to the easier escape route.
Many make the mistake of upping the pressure to get the steam to move by force, but the opposite happens. Higher pressure makes steam sluggish. In a well piped low pressure steam system, steam can move up to 60 mph. That's why steam lines bang, they pick up condensate and throw it into the backside of a elbow or other fitting.
#14
02-01-07, 02:40 PM
Bad news....I got home and the boiler was out of water. I filled it saturday when i was cleaning it. Does this give anyone any ides of what this could be? Possibly a cracked heat exchanger?
