Water coming out of pressure relief tube and gauge is showing in the red


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Old 04-09-13, 02:55 PM
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Water coming out of pressure relief tube and gauge is showing in the red

The last couple of days my oil fired boiler that also is responsible for my DHW has been tripping what I think is the pressure relief valve.

It is the original circa 1960 boiler that was installed when the house was new. I've recently bought the place and right now don't have the funds for a complete replacement, but I know that is on the horizon, certainly before another Maine winter.

Here is link to a bunch of photos I took, note especially the gauge readings. While I was down the basement taking these pictures the boiler fired. It took only a few minutes for the gauge to go into the red and then water to come out of the overflow tub in the back. The temp gauge showed about 160 before the boiler fired and about 180 or so when if finally shut down.

I'm pretty sure the boiler was firing to heat the DHW as the neither pump ever turned on. Any ideas, besides saving $7,000 for a replacement? Thank you in advance.

Link to pictures: Oil fired boiler - ldrider's Photos
 
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Old 04-09-13, 03:05 PM
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Hmmm. You have a lot of gate valves there. They like to break.

Anyway you probably need to drain that expansion tank in the ceiling. Shut that black valve going to the tank. Dont break it... If it does not hold then you need to Close the water feed.

Drain the tank completely. It may take a long time. You also need to close that auto air vent thats on the green device going to the tank. Turn that little screw down tight.

I will try to highlight your pics if you need additional guidance. Dont know how handy you are.
 

Last edited by lawrosa; 04-09-13 at 04:36 PM.
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Old 04-09-13, 03:35 PM
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lawrosa nailed it - the air elimination device needs to be removed and replaced with a plug. It depleted the air cushion from the conventional expansion tank.

Your system shows evidence of lack of maintenance and long-term, ignored, leaks. But, with a good going over, it could last for quite a while longer. It's 10 years newer than mine.
 
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Old 04-09-13, 03:52 PM
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Thank you for the quick reply. I am able to close the black handled valve going to the expansion tank in the ceiling with no problem. I also closed the brass thing (by screwing it down) on the large green device. Ran a hose from the expansion tank to my sump and opened the valve. Heard some gurgling sounds and water is coming out...but very slowly, maybe a couple of cups so far. Is that normal?

Do I leave the boiler on during this process or should I shut it off? A balmy 46 so I don't really need the boiler on for awhile.

Once the expansion tank is empty I presume I should open the black valve to the tank and unscrew (open) the auto air vent on the green device. Is that correct?

Thanks again for your help.
 
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Old 04-09-13, 04:11 PM
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Do I leave the boiler on during this process or should I shut it off?
Shut it off!

Once the expansion tank is empty I presume I should open the black valve to the tank and unscrew (open) the auto air vent on the green device. Is that correct?
Yes and no.

When you open the valve to the tank it will partially refill, don't be alarmed by that. The idea is to get an air 'cushion' above the water at the top of the tank.

No, leave the cap on the 'automatic air vent' closed.

Some tips on draining that tank... when you think it's empty, it's not.

Remember the drinking straw? Put your finger over the straw and lift it from the drink and the drink stays in the straw... SAME THING with that tank. It will build a 'suction' or a 'vacuum' in the tank and it will stop draining. You may also have a lot of 'muck and crud' in the bottom of the tank that will prevent it from draining.

When the flow stops, close the drain, remove the hose, hold a bucket under the drain and the tank should take a 'gulp' of air and start draining again. Reattach hose and let it drain some more. Sometimes it helps to leave the hose quite loose on the drain valve. It shouldn't leak... it should suck air.

Only when you are certain that the tank is completely drained, close the drain and re=open the valve.

The reason to leave the cap on the air vent closed is because you don't want to lose the air that belongs in the tank... but there's a lot more to the story... so just leave it closed for now and see how it goes.
 
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Old 04-09-13, 04:18 PM
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Gil mentioned leaks... that elbow on the bottom of the tank with all that green crud on it is an example:



A slow leak (or 'weep') may never show liquid water. The water evaporates and leaves behind a mineral deposit. The minerals can sometimes become mildly acidic and cause the green corrosion on the copper.
 
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Old 04-09-13, 04:25 PM
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Part of the 'long story' I mentioned in previous post...

The 'green thing' is an 'air scoop'.

It's purpose is to collect the air from the boiler water flow and send it back to the tank where it belongs.

By placing that automatic air vent on top, whoever did that defeated the purpose of the air scoop. The air will vent OUT of the system long before it gets back to the tank.

The piping to the tank should have been done in 3/4" ... it looks like 1/2" ? Anyway, that pipe should slope gently upward toward the tank so the air can get back to it.

If that tank has not been drained in a long while, it might pay to try and flush some of the muck out of it.

After you are certain that the tank is completely empty, and you have opened the black valve again, leave the hose connected to the drain and with pressure on the tank, open the drain again. I bet you will see all kinds of mud and such coming out the hose. Don't do this for too long... just long enough to flush out the pipe leading to it, and the drain valve.

If any 'crud' gets under the washer in the drain valve, it may drip after you close it. Go to HD or Lowes and pick up a brass hose cap and screw it on there... until you have a chance to replace it.
 
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Old 04-09-13, 04:29 PM
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Not sure but I think there is a plug you can remove above the drain valve to let air in and drain quicker,they are nice to have if there.Can't see it well enough. Could be a 7/16 plug if it"s not stripped out.
 
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Old 04-09-13, 04:35 PM
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Ok, I very slightly unscrewed the garden hose that was attached to the tank and there is a whole lot more water coming out. It indeed burped a couple of times and is gurgling quite a bit. Boiler is now off. I can't hear any water getting into the expansion tank from the black shutoff valve, so I'm guessing it is closed. Valve seemed to be operating fine, didn't have to struggle with it.

Right now the black water valve to the tank is closed, the drain is open, and the air valve is closed tight. Lots of gurgling sounds.

Background: This was an estate sale, and the house was empty for over a year. Pre-inspection of mechanics indicated "boiler is working" but should be "replaced soon". Called a plumbing heating guy and he assured me the boiler was "working when inspected" and suggested that it could last a day or another ten years....I'm budgeting for a replacement but would like this to last a bit longer. Thanks again for everyone's help. I'll post up again after the tank stops gurgling and is drained.
 
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Old 04-09-13, 04:43 PM
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Also, stretch the hose out... no loops or coils if possible. Not down to the floor and then back up again into a laundry tub, that will create a 'trap'.

Periodically stop the flow, drain the hose of any water, and start again.

As long as the tank is sucking air, you should be able to get it drained.

I'm betting you can get 10 more years outta that old girl... not efficiently mind you...

Fix a few things and you should be good to go.
 
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Old 04-09-13, 04:51 PM
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This is where you will have trouble...



The gasket between that plate and the boiler probably was weeping... and may have sealed itself up with rust and crud... or it may still be weeping ever so slightly.

I would say to leave it alone... I mean, the gasket could be replaced, but the bolts will break, have to be drilled out, etc... and it's just not worth it.

Looking over all the pics, I don't see anything 'terrible'...

Looking at that pic again though, is that red stuff I see silicone sealant? Perhaps it HAS been repaired already?
 
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Old 04-09-13, 09:44 PM
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These guys have given you excellent advise. I will add that there is a problem with some of the wiring at the oil burner motor that needs to be fixed.
 
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Old 04-10-13, 02:05 PM
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Thanks!

Thanks to all who posted for their help. The problem is fixed.

After draining the expansion tank for several hours last night, there has been not a drop coming from the pressure relief valve. Pressure gauge hasn't moved much past 15psi.

I've kept the air valve closed, the black valve to the tank open and of course the drain on the tank is closed. I will work on replacing that open wiring to the burner motor.

Thinking about moving my DHW to an electric tank. The idea would be that I wouldn't have to run the boiler in the summer months. My rate is pretty low, around $0.09/kw and of course the units are pretty inexpensive.

Thanks again for everyone's help on this.
 
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Old 04-10-13, 03:07 PM
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Good going Rob! Glad ya got it fixed up.

At 9 cents a KWH, an electric could well end up costing less than what you have now, plus the advantage that you will have a more ample supply of water when needed. Three showers in a row can be a bit tricky though...

If you do switch, you should be aware that the just disconnecting the pipes is not going to prevent the boiler from 'keeping warm'. That's a function of the Honeywell control on the boiler. Of course, if you shut it down in the summer it won't fire, but when it's on in the winter it will still fire to stay warm unless you do something with the control.
 
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Old 04-10-13, 03:38 PM
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And, you will probably have to run a 240-V circuit to supply the water heater.

Rob, maybe you didn't read the forum rules - but when somebody has their problem solved, they are expected to buy a round of beers
 
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Old 11-13-13, 03:11 PM
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Came home from work today and the house was cold, which was to be expected since I turned the thermostat down to around 55 deg F before I left in the morning. When I cranked the thermostat to 60 deg or so, I could hear the circulator pumps starting up but the burner never lit. Waited about 10 or so minutes. Still didn't light.

I hit the red restart switch on the gray Honeywell box and the burner immediately fired up and ran fine as the temp gauge slowly approached 180 deg F. (it was at about 90 deg F when I got home).

After half an hour, the gauge is reading a hair over 180 deg F and the burner has shut off. Circulator pumps are still running. Radiators are nice and toasty and the temp is slowing rising in the house.

As the temp gauge dropped, the burner will periodically light and run until once again, the temp gauge reads a bit over 180 deg F. at which point the burner shuts off. I'm guessing that is normal behavior?

Why did I have to hit the reset to get the burner fired up? Is that symptomatic of a larger (more $$$) problem?

Thanks in advance for you help
 
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Old 11-13-13, 04:38 PM
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I'm guessing that is normal behavior?
Yes, the controls are 'bouncing off' the high limit setting.

Why did I have to hit the reset to get the burner fired up? Is that symptomatic of a larger (more $$$) problem?
Dunno? When was the last time the burner was serviced? Nozzle changed, electrodes adjusted, filter changed, etc?

How did you make out fixing all that other stuff?
 
 

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