I have a new McLain Ultra 3 boiler that was a replacement in a older homer. The current baseboard system is a single loop cast iron system with cast iron baseboards. Question is my expansion tank does not seem to hold 12 psi charge. I have shut down system reduced pressure and charged tank and system still builds 30 psi and water comes from relief. No water comes from tank when i press valve. any ideas?

Ken

 

Can you take any pictures of the boiler?

Possibly there are piping errors, but if the tank does not hold a charge I would say replace it.

Was this installed very recently? Should be under warranty, no?

The cold fill pressure starts at 12psi?


Pic, pics, pics, .....We love to see them.

 

Was a new tank not installed along with the new boiler?

Is tank installed with air valve pointing DOWN? If inverted with air valve UP, you may not get water as test for tank integrity.

When new boiler was installed, was a new PRESSURE REDUCING VALVE also installed? If this valve is leaking through it can give similar symptoms as failed tank.

Yes, pictures!

 

New tank with new boiler.

Air valve pointed down.

New pressure reducing valve with new boiler.

Ken

 

I doubt the tank is bad...

At the top of the forum listing are some 'sticky' posts, one of which is titled something like:

http://www.doityourself.com/forum/bo...sion-tank.html

In that post is a step by step on the proper way to check/charge an expansion tank. It's possible that even if you put pressure in the tank that you still don't have a proper charge... follow the step by step and see if that remedies the problem.

If not, the next thing to do would be to verify that the reducing fill valve is not leaking. To do this, fill the boiler to 12 PSI when cold, and CLOSE THE MANUAL FILL VALVE and run the boiler to see if the problem goes away. Then open the manual valve again to verify that problem returns.

Even a new valve can pick up debris from the water line and leak through...

 

Thank you will read and let you know what happens.

Ken

 

I followed the instructions on recharging the expansion tank but still reach 30 psi at times. When i went to recharge there was not any air from the last time but do not get any water when i press on air valve. Any ideas??

Ken

 

Is it possible your air fill valve on the tank has a slow leak? I had one like that once, and it had me scratching my head for a while. A little soapy water on the valve will show a leak. Just an idea-

Steve

 

Yes, the air valve is worth checking, happens quite a lot actually. Easy to fix... the same tool that is used to change bicycle or auto tire valve cores works with these as well... Pep Boys, AutoZone, any auto store will have them for a couple bucks. Pick up a couple of the valve cores while you are there...

Check with the soapy water first, then if it leaks, try 'snugging' the valve with the tool first... if still leaks, replace the core and test again.

The other possibility is that the tank is bad. No water out the valve stem... I forget, is your tank installed with the air valve on the bottom?

 

The valve is on the bottom. I reduced water pressure to zero and still have 15 psi in expansion tank. So i think tank is good. Under domestic pressure and boiler pressure i have over 50 psi if that means anything. Is there anything else to check or will this older piping system run a high psi??

Ken

 

In order to avoid confusion, I'm going to move the 'hijacked' part of this thread to it's own thread.

If you are looking for previous posts, they can be found here:

http://www.doityourself.com/forum/bo...sion-tank.html

I don't understand... Ken, please elaborate a bit...

"Domestic pressure" - do you mean the city water pressure to your home? 50 PSI is fine.

"Boiler pressure" - if you mean the pressure in you boiler, NO, that is NOT fine.

Please double check this. It's possible you are looking at the wrong scale (right Mike? ). There may be one or two extra scales. One may be in FEET, or there may be one in Kpa. You need to make sure you are actually reading the PSI scale.

50 FEET = appx 22 PSI , and if so, then that's fine.

 

OK. When I measure tank pressure after filling from city water the expansion tank pressure is 50 PSI. The boiler then makes it way back toward 30 PSI also. When i took the boiler pressure down to zero to test and see if the expansion tank had pressure it still had 15 psi. Could the expansion tank be undersized. This older single loop system has baseboards and two large for a better word square tanks on the main floor. There are three rooms on the second floor that are heated also. Just trying to give as much info as i can.

Thanks

Ken

 

Just to ask what may be a silly question...

Some domestic water heaters have expansion tanks also... are you sure you are working on the correct one? The one connected to the BOILER piping and not to the DOMESTIC piping?

No offense, but I have to ask...

"Tanks" ? what do you mean by tanks?

It could... tell us what it says on the label.

Can you take pictures or not?

 

Expansion tank is only on boiler. Water heater is elect.

Will have to get expansion tank info.

Square tanks i refer to are large square shaped baseboard heater roughly 3 ft by 3 ft in size.

Here are some pics.

http://i1341.photobucket.com/albums/...ps98751ef3.jpg

http://i1341.photobucket.com/albums/...ps2b803649.jpg

http://i1341.photobucket.com/albums/...ps65771b12.jpg

http://i1341.photobucket.com/albums/...ps99bf8de4.jpg

http://i1341.photobucket.com/albums/...ps606f31d6.jpg

Thanks

Ken

 

Who installed this boiler?? Get him back. they installed the exp tank at the strainer of the fill valve..., Thats your whole issue from what I can see...

Never in my whole plumbing carreer have I seen such a thing.

http://s3.pexsupply.com/product_file...96-Install.pdf

Exp tank needs to be moved to the air seperator..

Here is the ideal piping of the fill valve and exp tank..





Take some more pics. Compare your set up to whats in the manual here.

Page 48 here.


http://www.weil-mclain.com/en/assets...ler_manual.pdf

 

Wow... well if that don't beat all!

Mike, does that gas piping look OK to you?

 

So if i remove the expansion tank shut of refill water and any other isolation valves i can cut the copper between the air seperator and fill valve and solder a fitting there and reinstall expansion tank??

Correct.

Ken

 

Ken, after seeing something like this, it really calls into question the entire install...

 

is there anything else you see??

As far as the heating it works well.

Ken

 

Take a few shots of the piping that is hidden behind the pvc exhaust...

I don't think it's OK to use white PVC for the down pipe on the pressure relief valve... at least in my town the inspector would shoot that down.

I don't think the gas piping is correct...

Not too sure about the placement of that B&G SA check valve on the top of the boiler, or if what appears to be galvanized piping parts is OK...

In the one pic at the upper left is a pump... can you get a better shot of that please?

 

Am i correct in how to move the expansion tank??

 

Yes move the tank over as you describe.

Take more pics if you can....


I wonder if that fill valve was compromised installing the tank like that. I would have to look into it.


I would like to see more pics and will check the gas piping.

 

Not from what I can see....

1. The flex line looks to be longer then 36" which is the max by code.
2. My bigger concern is the BTU rating of that flex line. Its 1/2" and the tag needs to be checked for BTU rating. Then tell us the model of the boiler.. 80,155, etc...

I could bet no more then 100k can get through there.

What will happen is the unit will carbon up from lack of gas.... Then co issues..... etc.

 

Thank you. Will get more pics and info to you. Thanks for your help.

Ken

 

OK, I just looked at the manual and I popped back in here to defend the installer that we 'ran down' ...

Take a look at page 11, figure 4 (and all the other line drawings). Item 1 is the tank, obviously. The table says that item 4 is "fill valve, typical" ...

And I bet the guy was thinking: "Never in my whole plumbing carreer have I seen such a thing... Wow, well if that don't beat all?!" and he figured: "OK, I think it's wrong, but who am I to second guess the manufacturer's diagrams" ?

So, I'm gonna cut the guy a little slack... and fire off a letter to W-M about the diagrams... because IMHO they are misleading, and just plain wrong!

On the positive side, it means that the installer obviously read the manual!

 

Odd.. The only thing I can think of is they are depicting an autotrol.....

I have to look at the data sheet for the OP's fill valve, but I believe the exp tank is isolated because of its position on the fill valve....

Make sense????

 

You mean FILLTROL? Possible, but they should SAY SO if they are! More I think about it, you are probably right about that.

Yes, absolutely.

I believe that there is a check valve in the FB-38 (as most of the reducing valves have), and the inlet screen is just that, on the INLET ...

Further evidence by the fact that the tank pressure went up to 50 PSI, it was registering city water pressure!

 

One more thing about this problem...

That cap on the bottom I'm certain has STRAIGHT threads. So when the tank is removed, there is no proper plug with O-ring as supplied with the valve to re-insert.

It sorta amazing that the guy got a good seal between the tapered and the straight thread... and I have to think that at some point in the future it would have started leaking.

 

OK after reading the last few post i want to verify my instructions. Should i remove the expansion tank and cut the line between the fill and air seperatior and put in expansion tank. You also mentioned something about

 

Yes if thats easiest for you....

Yes... The old plug will not work most likely because the threads are all jacked up from screwing that nipple in there.

A. Try a brass plug ( might work. You can crack the fill valve body though. May leak down the road.)
b. Replace the fill valve.


Oh and geez... How you making out with no heat? I would assume as it is configured it has not not been running???