Leaking pressure relief valve on Wail McLain cg-5-spdn


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Old 11-17-11, 11:19 AM
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Leaking pressure relief valve on Wail McLain cg-5-spdn

I first noticed it maybe 2 weeks ago.As you can see water is really nasty. Water leaks when pump is running and boiler gauge is somewhere around 22psi. It reaches maybe 31psi at 165F.
I read some threads already so I know not to trust it and will buy one today so I can verify the "real" system pressure.
I also know that it is not the relief valve as I already tried two new ones with same result.
From what I read it might be the expansion tank which in my case is 8Gal Compression tank made by B&G. I am not sure how this tank can loose charge but I guess it can.
I will try to troubleshoot tonight but in meantime I appreciate anybody's input, tips or advices.
This system used to make noises (before the leak occured) when warming up. I am talking about popping noises in the walls I guess expanding pipes? and become very quite now.

Here is some pics of my setup:

Image hosting, free photo sharing & video sharing at Photobucket

I am not sure if the link would work. If not I will do it again.
 
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Old 11-17-11, 11:38 AM
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You have a conventional expansion tank AND an air elimination device. The latter will deplete the air in the exp tank. Depressurize and vent the tank to fill it with air, and remove the air eliminator.

The top of the air scoop (where the air eliminator is connected now) should be piped to the exp tank, with the piping sloping upward. Your photos don't show the details of the copper pipe going upward to the tank - put probably the new pipe from the air scoop could be teed into that.
 

Last edited by gilmorrie; 11-17-11 at 01:18 PM.
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Old 11-17-11, 11:56 AM
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The add to what gilmorrie stated, your expansion tank should be coming out the top of the airseperator. And that type of setup requires no tupe of airvents. Like the one on top of the air seperator.

I guess you have a choice.

1, remove the air vent, and any other you may have. Drain the expansion tank, and repipe it to where you remove the air vent.

2, Cut that tank out, replace the air vent on the top of the air seperator, and add a bladder type expansion tank below the airseperator where that plug is.

What ever seems easier to you. I would say #2.

Others will chime in shortly.

Also I will have to say that you can be seriously injured with the relief valve with no discharge piping. I recommend you repair ASAP or dont run the boiler until fixed. And pipe that relief valve within 6" of the floor.



Boiler water discharged from the relief valve can instantly turn to steam. If you ever seen this it will scare the @#$% out of you. Let say it will just melt your skin right off.

Mike NJ
 
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Old 11-17-11, 12:33 PM
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Thank you much for such a prompt reply!
What you are suggesting telling me that this was not the best setup possible?
As I am on the budget I will try to depressurize the exp tank for now and then think about options.
While depressurizing I can just follow these steps:

1. close valve going to tank
2. attach hose to drain valve at other side of tank
3. open drain valve. You will get about 5 drops of water out of it
4. take end of hose and BLOW in to it. It will be hard doing it but it will be easy after you get more water out.
*HINT YOU HAVE TO BE FAST OTHER WISE YOU WILL GET A MOUTH FULL OF WATER *
5. you will know the tank is empty when you blow in to it and you get just air out of it.
6. close drain valve, tuck hose under brackets that hold tank.
7. open valve on other side of tank. You will hear water running into tank. It will also be warm. thats ok
8. check pressure gauge on boiler. It should be about 12 lbs, you're done.

Right?

Lawrosa thanks for the warning. I broke the plastic pipe couple days ago while replacing a pressure relief valve.
 
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Old 11-17-11, 12:46 PM
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It will take a long time to drain that tank. You may think its empty when it is not.

Why are you blowing in the hose?

Water will come out and stop. Its like turning a soda bottle upside down. Air will need to enter before more water will come out.

You need to remove that air vent. It will cause the air to come out of the system there instead of goiling in the expansion tank.
If you dont want to remove it, at least close/tighten the cap on top so air will not discharge.


It may work as piped but it really should be piped out the top of the air seperator.




Possibly take more pics of the expansion tank piping.

Once you get air back into the tank your pressure should not rise that high anymore from expansion.

Yes once you drain the tank all the way, refill the system. It will matuarally put the air cushion back in the tank.

Mike NJ
 
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Old 11-17-11, 01:45 PM
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Originally Posted by gugu123 View Post
What you are suggesting telling me that this was not the best setup possible?
As I am on the budget I will try to depressurize the exp tank for now and then think about options.
"Not the best"? No, it's just plain wrong. Until you ditch the air eliminator, you won't go very long before the problem returns. The very least you should do, besides depresurizing and venting the tank, is to remove the air eliminator device and plug the threaded hole where it now connects to the scoop - with a brass or steel plug, maybe 59 cents at any hardware store?
 
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Old 11-17-11, 02:35 PM
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Unless that air separator has at LEAST a 1/2" threaded ( 3/4" is preferred ) connection point on the top which has a bushing in it to screw the air vent into, the option of piping the existing tank to the top of the air sep is not available.

I think the simplest solution is going to be to remove the plug on the bottom of that air sep and install a diaphragm type tank and abandon the other tank in place.

If you do this, the air vent can stay, but should probably be checked for functioning, and replaced if necessary.

What type of heat emitters are in the home? Cast Iron rads? fin tube baseboard?

I broke the plastic pipe couple days ago while replacing a pressure relief valve.
Plastic eh? regular old white PVC ? that's not rated for the temperature it can see... I think some places allow use of CPVC... but I would replace that with COPPER! That water that can shoot out of there can KILL YOU!
 
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Old 11-17-11, 03:02 PM
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When introducing air into expansion tank i use a hand operated air pump and an adapter screwed on to the expansion tank valve ,this eliminates fulling draining the tank.
 
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Old 11-17-11, 03:16 PM
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Originally Posted by NJ Trooper View Post
Unless that air separator has at LEAST a 1/2" threaded (3/4" is preferred) connection point on the top which has a bushing in it to screw the air vent into, the option of piping the existing tank to the top of the air sep is not available.
I "THINK" the copper pipe on the outlet of the air scoop is plumbed up to a fitting on the bottom of the exp tank, which is goofy of course. But if so, there is a path for air to return to the tank. Then removing the air eliminator and replacing it with a plug would be a very simple and inexpensive solution, at least for the time being and maybe even permanently - and certainly a lot better than the present setup. Additional photos of the piping around the exp tank would be helpful.

As long-lived and maintenance-free as conventional exp tanks are, when installed correctly, I hate to see it replaced with a bladder-type tank. My conventional steel tank is 60 years old and has never lost its air cushion or required any maintenance.
 

Last edited by gilmorrie; 11-17-11 at 03:34 PM.
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Old 11-17-11, 03:26 PM
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Originally Posted by saves View Post
When introducing air into expansion tank i use a hand operated air pump and an adapter screwed on to the expansion tank valve, this eliminates fulling draining the tank.
That seems like a good idea - you'd have to crack open the boiler drain valve or a separate tank drain valve to give room for the air cushion to form a bubble, right?

My system has a shutoff valve in the line from the boiler to the tank. I can shut that valve, and open the tank drain valve until it sucks air through the tank drain. But, I never have had to do it - the tank never has gotten waterlogged.
 
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Old 11-17-11, 03:43 PM
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As long-lived and maintenance-free as conventional exp tanks are, when installed correctly, I hate to see it replaced with a bladder-type tank.
I'm actually in your camp on this Gil... the key operator here is:

when installed correctly


Obviously, the first thing to do is to drain the waterlogged tank and get some heat back in the home...

Hopefully that will be enough to get through the winter and then think about making some changes when the heating season is over.

That seems like a good idea - you'd have to crack open the boiler drain valve or a separate tank drain valve to give room for the air cushion to form a bubble, right?
Absolutely! We all know that one can not compress water!

And that could be a LOT of pumping! but maybe there's been a lot of practice?

Oh... one more thought... Rather than pull the air vent and plug it right now, the easiest thing to get through the winter would be to simply screw the cap on the top down tight. In fact, if I'm not mistaken, it appears to already be so! Dollars to Beers, I bet it leaks anyway!

Removing that air vent would preclude using it when maintaining the boiler... for example when re-filling the boiler after some service and having a place to purge air. That may have been it's original purpose, although a regular valve is certainly a better choice!
 

Last edited by NJT; 11-17-11 at 04:02 PM.
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Old 11-18-11, 08:35 AM
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I am not sure if I should use this phrase but for now: "mission accomplished"
It took a while and some 6-7 gallons of water to empty this tank.
I did not have to blow any air in to get the water out. I just opened the valve all the way and waited. When water stopped flowing I just made sure it is empty and filled it up with fresh water. Pressure gauge showed 12-13 after it was filled up.
Then I turn the boiler on and cranked the heat up and made sure the cap on air separator is closed tight.
What is concerning me a little is the pressure in the system when it is not working was at 14-15PSI. It only went up to 18 (while the gauge on the boiler showed 33PSI) when the temp. reached 165F.
Then the boiler stopped working. So I guess it pauses for a while when it reaches it's designated temp. Am I right? Then starts again.

NO LEAKS from the pressure relief valve.

SO the question is: should I be worry about the 14-15PSI reading and lower the pressure little bit or not really?
And another question should I be worry about boiler gauge reading 33PSI while it is working?

I know I have to flush the whole system as I have never done it.
But I'll wait until May to do it as I do not want to monkey with it too much now when I will be needing it the most.

And to clarify some things; expansion tank is not on the same piping loop as the air separator. I am not sure if this changes anything but just letting you know.

Also to answer other question: every room in the house has it own fin tube baseboard.

I attached more pics here so maybe this would clarify some things:

bleeding the exp tank pictures by gugu13 - Photobucket

Thank you all for help, tips and comments. I really appreciate it.
 

Last edited by gugu123; 11-18-11 at 09:46 AM.
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Old 11-18-11, 08:58 AM
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What is concerning me a little is the pressure in the system when it is not working was at 14-15PSI. It only went up to 18 (while the gauge on the boiler showed 33PSI) when the temp. reached 165F.
I would say elaborate on this but it seems you are reading the wrong scale on your boiler gauge. Thats ft H20 scale. The inside is PSI and that reads at 14psi in your pic.

As long as the pressure is staying below the 30psi mark you are good. Sounds like you are not getting above 20psi from your comments.

If above is true about the gauge reading dont feel bad. I have done it myself by reading the gauges wrong...LOL

Now what I am wondering since the gauge may be accurate, and you may have been reading it wrong, why was the relief valve tripping??? I will have to re-read all the posts but possibly just a weak relief valve.

The boiler will turn off if t stat is satisfied or boiler reaches hi limit. Typically the limits are set to 180f. Your aquastat if possibly set lower at 165f if thats when you see the boiler kicking of while there still is a call for heat.

If your hose is heating fine I would leave it. As it gets colder out you may want to bump it to the 180f mark.

Note: And others please chime in.

The aquastat for the boiler will probably be behind the front panal. perhaps you can take pictures of that. I also notice in your post#1 pic thete is a external aquastat. Could this be for the circ? Posibly your circ is being held off on temp? I believe this is inefficient and not sure why its there. Older boilers I remember had aquastats that did this but as far as I know they are not used anymore.

You may want to turn that aquastat down all the way. But take more pics and wait for others to chime in to verify.

Mike NJ
 
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Old 11-18-11, 09:24 AM
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Ok lets clarify:I got readings from two separate pressure gauges:

When system is not working both gauges (bolier's and one I made) show the same pressure: 14-15psi
The gap between the readings appears when the system is running especially at it's peak. The boiler's reads 33Psi (I am looking at the right scale- the one inside I just did not take a shot of it) but the one I made would show only 18Psi?! It was connected to the lowest point in the system - right below the pump ( don't have a shot of this one either but I can take one today).

Why such a big difference?
 

Last edited by gugu123; 11-18-11 at 09:48 AM.
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Old 11-18-11, 01:19 PM
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Why such a big difference?
Probably because the boiler mounted gauge is toast!
 
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Old 11-18-11, 02:43 PM
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I'm down with the toast ... I like toast... whole wheat with LOTS of butter... yeah, clog them arteries...

If you are connecting your made gauge and hose near the pump, and the pump is RUNNING, you may also see some differences because of the pump pressure, but certainly not THAT much difference!

I also notice in your post#1 pic thete is a external aquastat. Could this be for the circ? Posibly your circ is being held off on temp? ...

You may want to turn that aquastat down all the way.
I saw that too Mike, and thought it was a 'reverse acting' aquastat that runs the pump. It looks as though it is pretty much down all the way already. Probably OK.

Note: And others please chime in.
Naaahhhh, yer doing fine!
 
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Old 11-18-11, 02:48 PM
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I just opened the valve all the way and waited. When water stopped flowing I just made sure it is empty
How did you make sure it was empty?

Remember the drinking straw... put your finger over the end and lift the straw out of the drink and the drink stays in the straw. A vacuum created up top (and surface tension of the liquid) is what holds the drink in.

Same thing happens when you drain a tank like that. The water stops, but there's still water in the tank because of the vacuum created.

That's the reason those instructions you read said to blow into the hose... to break the vacuum... but really, that's just silly... who knows what bacterium is in there!

Sometimes all you have to do is simply loosen the hose connection at the tank so it 'gulps' some air. Sometimes removing the hose and draining into a bucket instead will work.

Bottom line is that you may have gotten enough air into the tank to get you through the winter, even if the tank didn't drain completely.
 

Last edited by NJT; 11-18-11 at 03:42 PM.
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Old 11-18-11, 02:52 PM
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One last point... I noticed that one pic appears to be the home made gauge connected to the tank drain, and then the other to the low point of the boiler.

You WILL see a pressure difference due to the height difference. The higher altitude gauge will read lower by 0.431 PSI per foot of altitude. So, if there's 8' difference in altitude, about 3 PSI less.
 
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Old 11-18-11, 03:34 PM
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Originally Posted by saves View Post
When introducing air into expansion tank i use a hand operated air pump and an adapter screwed on to the expansion tank valve ,this eliminates draining the tank.
Bell & Gossett offers two devices that make a conventional expansion tank easy to fill, drain, or to recharge a water-logged tank with air: ATF Airtrol Tank Fitting or DT-2 Drain-O-Tank. Akin to Trooper's piping setup for bladder tanks.
 
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Old 11-18-11, 03:44 PM
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Originally Posted by NJ Trooper View Post
If you are connecting your made gauge and hose near the pump, and the pump is RUNNING, you may also see some differences because of the pump pressure,
The differential pressure across my Taco 0012 pump is a bit less than 3 psi (at the same elevation).
 
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Old 11-18-11, 03:59 PM
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In addition to the ATF and the DT-2 they also had an ABF ( Airtrol BOILER fitting) which was basically a 'dip tube' that separated the air in the boiler and sent it to the tank. They've discontinued that part though... probably because most boilers today don't have a port on TOP of the boiler for the hot supply out.

Here's a PDF for the 'Drain-O-Tank' fitting:

http://completewatersystems.com/wp-c...011/05/615.pdf

available here:

Patriot Supply - B&G DT-2 Drain-O-Tank

[sadly, it seems that yet ANOTHER good old American company has gone and either been acquired by non-American entity, or changed their name to something 'modern'... how far will this go?]
 
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Old 11-18-11, 08:24 PM
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How did you make sure it was empty?
Well, I read some other threads so I knew to give the tank a puff and wait for one in return once there was no water coming out.
The tank was definitely empty.

So you guys all agree that the boilers gauge is bad?

I am only hoping that this is the problem.

Can it be that somehow the reading is correct and there is something going on inside of the boiler?

I will check the pressure at different levels and report as soon as I find some time to do it.

Thank you all.
 
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Old 11-19-11, 06:40 AM
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If you are confident that the tank was/is empty, and the pressure on your new gauge is now OK, and the relief valve is no longer leaking, then I would say you are probably OK to go through the winter now. But please, DO put a pipe to the floor on the relief valve! Even if you have to use plastic, it is better than nothing!

If that valve does open due to some fault and someone is standing in it's path, it's possible that superheated water/steam can come out with a lot of force... it can SERIOUSLY injure, and possibly KILL someone! Perhaps it is a slim chance that this will happen, but why take any chance that can be easily prevented?

Boiler gauges are notoriously inaccurate! I highly doubt there is anything 'going on inside'... in fact, that is nearly impossible.

I will check the pressure at different levels and report as soon as I find some time to do it.
You don't need to do that... my comment was for informational purpose only, in case you were wondering why the gauge would read lower at a higher position... save your time for some constructive activity!
 
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Old 11-19-11, 10:15 AM
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But please, DO put a pipe to the floor on the relief valve! Even if you have to use plastic, it is better than nothing!
It is already there. I did that before I started playing with the exp tank.

By the way I am in the process of buying a new thermostat as the one we have is an old, non programmable mercury unit.
I actually found a used unit in my garage (magicstat) but for same reason it seems that it is not working correctly. It seems to me that it cuts boilers cycle before it is finished.
Is there any other brand or particular model you can recommend for Weil Mclains?
 
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Old 11-19-11, 06:03 PM
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I know I have to flush the whole system as I have never done it.
No... you do NOT want to do that. Leave that stanky old water in the system. Flushing it will create more problems, increase corrosion in the system, and very shortly the water will be all stanky again. Do NOT flush the system! It's perfectly fine as-is.

The 'back story' to this is:

Fresh water has TONS of oxygen dissolved into it. Corrosion occurs when there are three items present; Water, Oxygen, and Ferrous metals.

Remove any one of those and no corrosion occurs.

Water that has been in the system has NO OXYGEN in it, and is INERT... thus, no corrosion.

Remove all that stanky old water and replace with fresh and the corrosion starts all over again.
 
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Old 11-19-11, 06:10 PM
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It seems to me that it cuts boilers cycle before it is finished.
It probably has a defective or mis-adjusted 'anticipator'. Must be a reason it was in the garage... probably broken.

Is there any other brand or particular model you can recommend for Weil Mclains?
Any quality thermostat will work.

Maybe this brochure will help you:

http://www.cleanenergyresourceteams....atBrochure.pdf

You will get a different answer from everyone... Ford vs Chevy
 
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Old 11-19-11, 06:21 PM
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The Hunter brand of thermostats available at big box stores is almost universally frowned upon by heating professionals.
 
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Old 11-19-11, 06:26 PM
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Yeah, I've heard that too...

Gugu, one more thing... when you install the new thermostat, make sure to seal up the hole in the wall behind the thermostat. Cool air leaking out of that hole will royally screw up the way the thermostat reacts to room temperature.
 
 

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