[adamneedshelp]

My expansion tank needs to be replaced.. I am new to this so how do I go about doing this? Do I need a specific one? Which one should I get at Lowe's or homedepot? Do I have to drain the system? And if so how do I do this? I do know how to clear the lines if they have air in them..

[talaniman]

What model and brand is it, and WHY are you replacing it?

[massplumber2008]

I can see why the expansion tank needs to be replaced... the boiler relief valve is blowing off, and I'll bet it only happens at peak heat when making hot water in this case.

If you come back and let us know you are around we are glad to walk you through the steps. From the pictures you posted, it looks like everything is pretty well isolated so it should be a pretty easy job!

Back to you...

Mark

[adamneedshelp]

Thank you mark.. yes it only leaks when the heat is on.. you were to one that told me how to bleed the lines of air. Thank you again for that..

So I can I get this expansion tank and Lowe's or homedepot? And do you recommend one or should I try to get the same exacty one?

[massplumber2008]

Hi Adam


Lowes or Home Depot will have a HYDRONIC expansion tank exactly the same size you have there.

Go to one of those stores and pick up the following:

1) 1/2" x 2" black nipple
1) 1/2" IPS (threaded) ball valve
1) roll of 1/2" Teflon tape
1) hydronic expansion tank AND
1) 3/4" boiler pressure relief valve (factory set to 30LBS)

Now:

shut power off at the switch to the boiler
shut ALL yellow handle shutoff valves associated with the boiler (especially water feed into boiler).
open relief valve to bleed pressure and water flow down to a trickle
hookhose to drain valve at front left of boiler and drain a few gallons off (leaving relief valve open)
don't touch the zone valves...they should act as return shut off valves if left off.

Now, as long as you are sure water is under control, you can remove the expansion tank. CAUTION HERE! THIS TANK IS FILLED WITH WATER AND IS EXTREMELY HEAVY. Wear gloves and expect some water to cascade down the sides of the tank so it will be slippery and heavy, OK?

Once the tank is removed you'll wrap say 6-7 wraps of Teflon tape around the 1/2" nipple and install that and the shut off valve to the expansion tank connection at the boiler. Do NOT install the expansion tank yet. Close this shutoff partially.

Now, at this time I would recommend installing the new pressure relief valve... the one there now is old and its seal has been disturbed.

Next, after the relief valve is installed, open the water feed shut off valve and let water feed into the boiler until it flows out the relief valve (lift lever on relief valve). Close the relief valve when water comes out.

Finally, let water fill to the point that water starts to flow out the partially opened shut off valve you installed. When water flows out that valve close it and you now finally install the expansion tank and let the system come up to pressure. Once you are sure there are no leaks you can open all shut off valves and purge air from the system via radiator or baseboard vents.

In the future, if the expansion tank ruptures again you'll only need to shut the valve off that you installed!!

Turn power back on to boiler!

There you go! Questions?

[adamneedshelp]

I have plenty of questions... lol..

1) can I just replace the tank? And not have to get the shutoff and boiler pressure relief valve... I am not going to live in this house for very long I want to flip it

2) the yellow handles.. shut all 5 off in the pictures?

3)open relief valve to bleed pressure and water flow down to a trickle.. is this the red valve to the right hand side of the boiler?

4)where is the pressure relief valve in the picture (if I have to replace it)

[massplumber2008]

1) yes

2) yes, can't hurt anything so shut all of them... just be sure to open all of them when done.

3) the relief valve is the valve that has the 3/4" copper tube coming out of it... it is the valve where the water is coming out of now when peak heating happens.

4) on top of boiler

[adamneedshelp]

Sorry I just want to make sure I understand this correctly but do I need a new relief valve or can I just replace the expansion tank?

[massplumber2008]

A relief valve is cheap so I would strongly recommend replacing it at this time. In most cases like yours, the old relief valve is cooked and now that it has been disturbed it is unlikely that it will reseal and work fine for any amount of time, especially with heat season upon us.

Replace the relief valve and the expansion tank now and you shouldn't have to worry about the boiler again!

Good luck

[adamneedshelp]

I was rereading when I install the expansion tank.. if I don't use a ball valve before it.. how can I tell it is to the right level before I turn all the valves open? I noticed you said to install a nipple and then the ball valve and then the expansion tank. What if I just did what they have currently and replace the ball valve ?<br><br><br>

[massplumber2008]

I said all that to make changing out the tank easier in the future, if needed. You were clear that you didn't want to do the valve, so nix that and just install the tank back to original. Let water flow from the hole you'll put the tank into and then install the tank. Then open valves and purge system. In this way you introduce as little air to the system as possible.

[adamneedshelp]

Sorry for being a pain.. just wanted to make sure.. thank you thank you thank you for the help

[massplumber2008]

Asking questions to clarify is never a pain! Hopefully this is a quick swap out... remember, that tank is going to be heavy and wet, so be VERY careful when you spin the tank out!

[adamneedshelp]

OK I will.. what about the expansion tank.. do I need to fill it with air?

[massplumber2008]

In most cases, the factory set pressure works fine and there is no need to add air, but read the literature supplied with the tank so you can be 100% sure.

[Mike45plus]

Adam,
You do need to check the new tanks precharge - it should match your expected cold start pressure, typically 12 - 15 lbs for a two story residence. Follow the tank manufacturers installation instructions which will have you test the pressure before you install the tank - we have had bad tanks right out of the box.
I would test the existing tank, and for that matter, test the feed valve & tankless coil, all of these components can cause weeping or discharge at the relief valve. The expansion tank can be tested once it is isolated from the feed valve and after the boiler & piping are depressurized.
I noticed blue / green staining near some solder joints; this may indicate a water condition issue - low pH can cause pin hole leaks in your domestic water piping.
We never install an isolation valve for an expansion tank, it is just our way to reduce the potential for an accidental valve closing, besides, tank change outs are easy enough with out a valve. We always install an isolation valve where automatic air vents connect to the system.
The auto vents are going to perform important work for 6 - 8 weeks after you complete your repairs; it takes this long for entrained O2 to be released from fresh make up water. You do have one fantastic feature on your near boiler piping - someone correctly located the circulator pumping away from the expansion tank... Google " pumping away " for interesting info on this subject.
Oh, and one more tip - always cover the burner & other electric components with something ( we use contractor trash bags ) before you start the repairs - this will prevent an accidental drowning..................

[Mike45plus]

Adam,
When I am forced to change out a waterlogged expansion tank alone, I will support the tank with a suitably sized pail wired in place from the air scoop or piping above. Also, please follow Marks advice and replace the relief valve; it is probably the most important part of any closed loop heating system......

[adamneedshelp]

Hi guys.. its me again.. so I replaced the expansion tank the air scoop and the thing about the air scoop along with the pressure release valve.. I bleed the heating lines and fired the system back up.. worked great for a few days.. then I wanted to make sure I didn't have any air in the heating lines so I turned the boiler off and bleed the lines again.. when I turned the boiler on it fired up and then shut off and had a red light.. so I hit the red reset button.. and it fired back up and then shut off.. it did this one more time and then a solid red light.. so I shut the boiler off.. any suggestions?Attachment 47854

[massplumber2008]

Sorry, but I have to ask: Did you run out of oil? In most cases like this, the oil has run out and the oil burner has simply shut down as a result. Getting oil delivered and purging the oil line would get you back up and running quickly.

If you have plenty of oil, then it gets a lot more complicated to diagnose the issue. Oil burners are not something most people should be messing with if they are not familiar with these units!

Check the oil... post back!

[adamneedshelp]

The gauge says I have 5/8 of a tank but the gauge was acting up in the winter..