A few boiler questions (backflow drip and boiler pressure)

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Old 03-23-11, 01:22 PM
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A few boiler questions (backflow drip and boiler pressure)

Oil fired becket burner with a direct power venter. The pressure guage is always around 24 25lbs when at its hottest. The boiler is in the basement and there are two floors above it all with hot water baseboard. Is this too much pressure? I had brought it to the attention of the service man when I had my tune and his statement was that if he went any lower I could loose heat upstairs from too low of pressure. Is he correct?

Second question is the backflow preventor on here is a watts 1/2" 9d-m3. If I touch the pipe coming off the vent outlet I get a slight bit of water MAYBE a drop on my finger. There is not enough to show any drips on the ground. Is this a problem or a future problem? I heard they do drip from time to time. We have city water hookup so no loss in pressure from a well.
 
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Old 03-23-11, 01:34 PM
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The pressure guage is always around 24 25lbs when at its hottest. The boiler is in the basement and there are two floors above it all with hot water baseboard. Is this too much pressure?
I would say its slightly high.

What is the temp of the boiler at this psi?

How high is the highest baseboard from the boiler in feet?

Could have low air in the expansion tank. Was this checked by your service man?

The fill valve for the boiler can be faulty and adding above the 12 psi cold. So your starting with a higher pressre already.

I could loose heat upstairs from too low of pressure. Is he correct?
Possibly, but it depends on the height your pumping the water.

Second question is the backflow preventor on here is a watts 1/2" 9d-m3. If I touch the pipe coming off the vent outlet I get a slight bit of water MAYBE a drop on my finger. There is not enough to show any drips on the ground. Is this a problem or a future problem? I heard they do drip from time to time.
Mine is like that also. Its just damp and not dripping. And its new. Possibly if you do any service to the boiler, the adding of water may dislodge sediment in the backflow if it is indeed a sedement issue.

The pros out there will chime in soon.

Mike NJ
 
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Old 03-23-11, 02:03 PM
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I turned up the thermostat to make the boiler kick on. When it is running the pressure guage reads a hair less than 20psi with the temp around 180 maybe a little lower. When the burner kicks off the pressure guage goes back up to 24psi. The highest baseboard is approx. 20ft.

Thanks for the help.
 
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Old 03-23-11, 03:08 PM
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Your pressure is okay although perhaps a bit higher than absolutely necessary. The pressure should never be any higher than 90% of the safety valve set point. Most residential hot water heating systems have 30 psi safety valves so the maximum pressure should never exceed 27 psi under operating conditions.
 
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Old 03-25-11, 02:12 PM
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Anyone else confirm that their isnt a problem with the backflow? Now that I have been paying attention to it there is probably a 2 or 3 drips a day from the vent. IF this goes would it flood my basement?
I might be hearing things too but I thought I heard a quick rush of air. It sounded almost like plastic crinckling a few times when the burner kicked off. When I try to listen for it I dont hear it. Sometimes I hear it when working down there though. Thanks
 
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Old 03-25-11, 02:27 PM
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Sometimes when a house main is turned off, sometimes the boiler feed is not turned off. What happens is the pressure in the boiler is greater then the house pressure. The poisenous boiler water wants to back up in the house line, so the backflo preventer starts working. Sometimes a drip, sometimes a steady flow.

I usually correct this by blipping (is that a word) the fill valve a couple times to move some water through the backflow. Sometimes dirt gets in there and this clears it.

Mine is wet also. It may drip but it probably drys on the ground before I notice and spots. Mine is new and I aint changing it unless it leaks alot.

I would say mine is wet from sediment. I have been working on my well and constanly forget to turn off the boiler water when I drain my house lines.

Mike NJ
 
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