Expansion tan w/pics...need advice


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Old 05-24-06, 04:48 PM
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Expansion tan w/pics...need advice

After reading several webs, i learned that the expansion tank needs to replaced if

1. There is leaking around the pressure relief valve
2. Tap both ends of the expansion tank and if the sounds are different, replace the tank
3. check for leakage in the tank

If any sees the pressure relief valve in any of these pics, please point it to me.
I dont feel that reason No2 is strong enough to go ahead and do the work...
Also, do i need to purge the system after replacement?
I got the Extrol No 30 pre-charged tank for closed loop heating ..Pre-charged means that i dont need to charged it. Should i still check for the pressure and how?
How to get rid of the rust in the pipe, 2nd pic?

I'll appreciate any help, newbie here


http://i4.photobucket.com/albums/y14...k/IMG_0853.jpg
http://i4.photobucket.com/albums/y14...k/IMG_0851.jpg
http://i4.photobucket.com/albums/y14...k/IMG_0845.jpg
http://i4.photobucket.com/albums/y14...k/IMG_0854.jpg
 
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Old 05-25-06, 06:43 AM
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In 0851, the pressure relief valve is behind the gray circulator pump and has a red tag. I assume the dripping on the floor in 0854 is from the end of its pipe. Relief valves are generally set to pop at 30 psi. They typically start to open at a bit less, then go full blast at 30. Grady can correct me, but I think most pressure reliefs are supposed to be installed in a vertical, not horizontal position, but that may in real life not be a big deal.

Check your pressure on the gauge on the side of the boiler. It looks like the upper gauge is temperature and the lower is pressure. Pressure should read in psi or feet (or both). When cold (boiler's been off for a while), pressure should be about 12-15 psi. When running, it might be a bit more.

Depending on the pressure behavior of the system, you may or may not need to replace your expansion tank; the drip could also be the pressure relief valve failing. Tank replacement should be relatively straightforward. There is a red shutoff handle at the tank connection. You should turn off the power and drain down the system to reduce pressure if the tank has actually failed as it will be pressurized to the system pressure. And since all the connections are over your boiler and electronics, make sure you take precautions to avoid water getting all over the place and REMEMBER THAT ELECTRICITY AND WATER TOGETHER CAN BE DANGEROUS OR DEADLY.

If you're at all unsure about any of this, then get a heating person over there.

The rust is from a leaky gasket at the base of your circulator. Grady or other knowledgeable source could tell you the proper procedure (turn off power, water supply, drain -- there's a valve underneath the rusty area that appears to be the system drain) to drain the system. Then you'd need to get the circulator out of there and clean the flanges. If the bottom flange is really corroded, you might need to replace it. Stick a new gasket in there and you should be good.
 
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Old 05-25-06, 05:50 PM
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Xiphias:

Checked the pressure relief valve and is not leaking at the connection joint. But looking at pic 4, the outlet pipe (or whatever is called) from this valve sometimes leaks, look at the stain water drops..What does this mean?

One plumber told me that draining the system is not needed. Is this true?

The circulator is the gray valve in pic 2, right?..Also, i read that i need to know the type because there will be maintenace to be done. except on automatic circulators...Is this so? so what do i have?

thks
 
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Old 05-26-06, 06:49 AM
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The pressure relief valve may be leaking internally, rather than at a joint. But we need to know what the system pressure is first.

What is the system pressure when the boiler has not been running, and what is it when it is running?

You can also get a general idea of whether the tank is shot by tapping lightly at each end (I think you've mentioned this). The end connected to the piping should have a kind of dull thud (that's where the water is). The other end should have a dry ping (that's where the air is). In between there is a flexible diaphragm. It's when that diaphragm leaks or breaks that system pressure problems can develop.

Since you have a valve on the expansion tank connection, you could shut this and remove the old tank. Plumber correct. Just beware of the water. There's a gallon or three in there, and since it's mounted sideways....

The circulator is the gray pump in 0851 that says "Taco" on it. The flexible metal cable is the electrical supply. Taco is a very common, very reliable circulator. It is of the "wet rotor" type and requires no maintenance. But you do have a somewhat gnarly-looking leaky gasket and/or corroded flange. Leaks in what should be a leak-free system are a thing to be avoided for a variety of reasons.
 
 

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