Boiler Pressure Too High

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  #1  
Old 01-21-16, 10:35 AM
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Boiler Pressure Too High

Hi..

I have an old RUUD boiler, steel expansion tank. The pressure has been moving up to the red zone above 30 PSI. I checked Pressure Relief Valve and it was bone dry. I shut the system off and drained the expansion tank. I brought the PSI to 20. Four days later the pressure is back at 30 PSI. Next, I thought the manual fill valve was leaking so I shutoff the water supply line and again PSI is up at 30. Any help would be appreciated.

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  #2  
Old 01-21-16, 07:39 PM
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Is there a domestic hot water coil (tankless) inside this boiler?
 
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Old 01-21-16, 11:13 PM
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No way that is a pressure relief valve for anything. You better post much wider angle pictures of the near boiler piping.
 
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Old 01-22-16, 12:39 PM
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Closeup of relief valve
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Wide angle
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Relief Valve back of boiler
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Wide angle boiler
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Old 01-22-16, 12:43 PM
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I do not believe there is a hot water coil. How do I check? What will that tell me?
 
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Old 01-22-16, 12:56 PM
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Your photo seems to indicate that it is of a Watts Pressure REDUCING Valve.

Am I mis-reading the Tag on it ?
 
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Old 01-22-16, 02:26 PM
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no correct. label on photo, reducing valve set 12-15 psi and relief valve set 30 PSI. Boilers gauge was above 30 PSI and there was no water dripping. I had to manually release the pressure. Could the valve be defective?
 
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Old 01-22-16, 03:55 PM
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Open the supply water valve and close the isolation ball valve, and wait for the valve to discharge.
See: http://media.wattswater.com/1910725.pdf
 
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Old 01-22-16, 07:07 PM
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If the system is indeed over-pressurizing, causing the relief valve to pop, then it might be that the compression tank (pic#2) is water-logged.

Check out: How to Drain a Heating Boiler Expansion Tank How to service the expansion tank (compression tank) on hot water heating systems
 
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Old 01-22-16, 07:31 PM
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No way that is a pressure relief valve for anything. You better post much wider angle pictures of the near boiler piping.
Actually, it IS a pressure relief valve. However, it is NOT an ASME boiler safety valve. All it protects is the piping downstream of the reducing valve from overpressure should the reducing valve fail.

Many decades ago systems WERE piped like this without any boiler safety valve. It has not been acceptable to do that for at least forty years. Note also that the boiler itself has a safety valve although incorrectly piped. Safety valves should ALWAYS have the stem in a vertical plane.
 
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Old 01-22-16, 11:42 PM
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Thank you Furd, I was a little bit jumpy after watching a Boiler Explosion Surveillance Video.
 
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Old 01-23-16, 12:21 AM
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I do not believe there is a hot water coil. How do I check? What will that tell me?
No coils on your boilers.
We were just looking for places that high pressure potable water might leak into the system such as a water to water heat exchanger.
 
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Old 01-23-16, 08:35 AM
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If the system is indeed over-pressurizing, causing the relief valve to pop, then it might be that the compression tank (pic#2) is water-logged.

Check out: How to Drain a Heating Boiler Expansion Tank How to service the expansion tank (compression tank) on hot water heating systems
I drained the expansion tank. my tank has an air inlet valve at the top and drain at bottom, so I hooked up a hose. Pressure went down to 10 PSI. I opened the shutoff valve to fill the system to 15 PSI. I can hear the water flow stopped. I check the gauge everyday and the pressure goes up by 2 PSI, currently at 26 PSI. I'm not sure whats causing the pressure to go up?
 
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Old 01-23-16, 08:58 AM
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Open the supply water valve and close the isolation ball valve, and wait for the valve to discharge.
See: http://media.wattswater.com/1910725.pdf
I closed the supply water valve (in case Watts Feed Water Pressure Regulator is damaged or leaking) and drained the expansion tank. Pressure still keeps going up, about 2 PSI per day. Water is turned off to the system. How is the pressure going up?
 
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Old 01-23-16, 11:18 AM
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1) Open the supply water valve (Blue handle) and close the isolation ball valve (Between the relief valve and the system), and wait for the relief valve to discharge -- testing for leaking reducing valve.

2) How is hot water generated in the building.
 
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Old 01-23-16, 01:41 PM
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I drained the expansion tank. my tank has an air inlet valve at the top and drain at bottom, so I hooked up a hose. Pressure went down to 10 PSI.
My first thought is that the pressure gauge you are reading is incorrect. With the other problems I suspect that you have air trapped somewhere else in the system.

With a compression tank the system is supposed to return any air to the compression tank, not vent to atmosphere. IF you have any atmospheric air vents in the system they are causing you problems. Further, there needs to be an "air removal device" that is piped back to the compression tank.

Your gradual increase in pressure could be from trapped air being re-absorbed into the circulating water, lowering the pressure enough to activate the make-up pressure reducing valve.

What kind of heat emitters do you have, perhaps tall cast iron radiators? Do they have any air bleed valves, either manual or automatic? A few pictures of the heat emitters might help.

The FIRST thing to do is to connect a known good pressure gauge to the system.
 
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Old 01-23-16, 06:34 PM
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Is there a hot water tank that uses the boiler as the heat source?
 
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Old 01-23-16, 07:17 PM
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1) Open the supply water valve (Blue handle) and close the isolation ball valve (Between the relief valve and the system), and wait for the relief valve to discharge -- testing for leaking reducing valve.
I live in a 3 story house, w/cast iron radiators. I went around the house and bled all the rads. The rads on the 3rd floor had a lot of air. I bled all the air out and then checked the pressure gauge, PSI dropped from 28 to 20 PSI. I decided to leave the reducing valve test for a couple of days. Could the air inside the line cause the pressure to increase?

2) How is hot water generated in the building.
I have a standalone hot water heater.
 
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Old 01-23-16, 07:24 PM
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What kind of heat emitters do you have, perhaps tall cast iron radiators? Do they have any air bleed valves, either manual or automatic? A few pictures of the heat emitters might help.
I live in a 3 story house, w/cast iron radiators. Air valves are manual. I went around the house and bled all the rads. The rads on the 3rd floor had a lot of air. I bled all the air out and then checked the pressure gauge, PSI dropped from 28 to 20 PSI. Could the air inside the line cause the pressure to increase?
 
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Old 01-23-16, 07:28 PM
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Is there a hot water tank that uses the boiler as the heat source?
No.. hot water tank is standalone.
 
  #21  
Old 01-23-16, 08:51 PM
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Hydronic system water builds up either because !. city water is leaking thru shut off valve if closed and/or defective regulator valve, 2. expansion tank system is not functioning.

Pressure buildup over a few furnace cycles is usually do to the regulator leaking, either the diaphragm or washer is bad. If you have separate shut off valve before regulator that could be also be leaking. Expansion tank problems can make the problem worse.

After pressurizing the system to 12 psig You should be able to run the system with the shut off valve closed. Beyond filling the system to 12 psig the regulator main function is safety, keeping the boiler filled with water so steam is not generated from lack water. If temporarily shutting off feed stops pressure building to 30 psi then it is the regulator.
 
  #22  
Old 01-23-16, 09:05 PM
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If there is an indirect hot water tank or an internal coil, a pinhole leak would also cause the boiler pressure to rise.
 
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