I think HVAC tech created a dangerous situation - please help me fix it!

Rooster1

Good evening,

I have a two-story house with a 9-zone in-floor radiant PEX system heated by a Weil-McLain GV-5 Series 2 boiler. We had trouble with weak upstairs zone heat since the middle of winter, wherein I had to have the basement zone running in order to have hot water make it to the second floor zones. System also has an indirect water heater, and we have had hot water all the while. Two circulators on the system - a UP 26-99F by the basement manifold and a UPS15-58 FC atop the boiler.

Fastforward to recently - I was lazy and waited too long to call a serviceperson. I suspected a failing pump was the problem over the winter, but then the T&P started leaking, so I finally called a company to come out. They diagnosed the pump atop the boiler as bad and replaced it and the T&P valve. Fired up the system again, and the bigger pump was locked up. Came back and replaced it just today while I was at work and my wife was home.

Here's the problem - I get home from work and start checking things out, and I see that the pressure gauge near the boiler is at 60-65psi. This I know is not right at all, so I start getting anxious and trying to figure out what to do. Shut the system off entirely, and the first thing I could find to drain and release pressure is a valve on the return from the indirect water heater. Drained it completely, and between that and the system cooling, pressure gauge finally reads nil. Found the boiler's drain valve later, but at the time I was looking for any way to get water out, because I don't know at what point these become an explosion risk, but I do know 60psi is far too high and much higher than the gauge ever read when the system was functional.

As I'm inspecting, I realize the new T&P they installed is a Watts 100XL-4 that has 210F and 150PSI on it. This is absolutely the wrong valve, right? Shouldn't I have a 30psi? Best I can tell, this is a valve for a water heater.


Aside from my question on the valve, my other questions are as follows:

1) What are the first things I should look at to figure out why the system was overpressurized in the first place? Could the technician have simply overfilled it to that extent, which, in combination with the wrong T&P, led to me seeing 60-65psi on the gauge?

2) Could anything in the system have been ruined by that level of pressure? Expansion tank bladder?

3) Should I be at all worried that the boiler itself was exposed to such high pressures? Could metal fatigue be an issue as it gets back into service?


I'd think at this point the boiler itself needs fully drained, the T&P valve needs replaced with a correctly spec'd one, and then the system would need to be filled and purged. I'm probably going to call another company in the area tomorrow to have them come out. I just don't feel like I know enough to safely get this thing fixed and back in service. But it's hard when you can't trust the "experts" to keep your boiler from exploding.

Appreciate any help or thoughts!

Zman

Good call on noticing the wrong valve was installed. Your tech is an idiot.
A failed expansion tank was likely the original problem. Thermal expansion with no place to go spiked the pressure.
Your system will probably be OK, I would document the incident and put the company on notice that they will be responsible for any resulting damage.

Rooster1

Zman said:

Good call on noticing the wrong valve was installed. Your tech is an idiot.
A failed expansion tank was likely the original problem. Thermal expansion with no place to go spiked the pressure.
Your system will probably be OK, I would document the incident and put the company on notice that they will be responsible for any resulting damage.

Thank you for replying. Is there a way to test the expansion tank before replacing?

Rooster1

Rooster1 said:

Zman said:

Good call on noticing the wrong valve was installed. Your tech is an idiot.
A failed expansion tank was likely the original problem. Thermal expansion with no place to go spiked the pressure.
Your system will probably be OK, I would document the incident and put the company on notice that they will be responsible for any resulting damage.

Thank you for replying. Is there a way to test the expansion tank before replacing?

In trying to answer my own question, if there was any water present at the valve stem of the tank when I removed its cap, I'd assume that to be bad. Is that correct?

Rooster1

Zman, you're my hero. Tank had more water than air come out of it when I put an air pressure gauge on the stem. Replacement Fill-Trol 109 on order, along with the correct T&P. I've got the boiler drained and can handle replacing both of those.

Not sure if I can tackle filling and purging after that though. Just have never done it and don't know where to start looking for a how-to.

mattmia2

The no heat in the zone could have been where the air from the expansion tank went.

EBEBRATT-Ed

@Rooster1

What @Zman said +

Just be sure you put on a 30# relief valve ....not a T & P. The relief valve has to be rated for more BTUs than the gross boiler output.

I would replace the expansion tank.

Also how did the water pressure get that high? Did the tech over fill it or is the pRV bad?

I would definately let your service company know by phone call & In WRITING.

It's possible you could (but hopefully not!) have more damage.

The tech was an idiot, thats how people get hurt. Take pictures , document and don't throw the T & P he put in away

mattmia2

Did the system climb to 60 psig as it heated or was it at that pressure cold? You could have a PRV that is leaking or an indirect coil that is leaking if that was cold pressure.

Rooster1

EBEBRATT-Ed said:

@Rooster1

What @Zman said +

Just be sure you put on a 30# relief valve ....not a T & P. The relief valve has to be rated for more BTUs than the gross boiler output.

I would replace the expansion tank.

Also how did the water pressure get that high? Did the tech over fill it or is the pRV bad?

I would definately let your service company know by phone call & In WRITING.

It's possible you could (but hopefully not!) have more damage.

The tech was an idiot, thats how people get hurt. Take pictures , document and don't throw the T & P he put in away

I believe I've got the right relief valve. Watts 0342692. Expansion tank with valve is on order as well.

I also don't think that was the cold pressure, but of course I came home from work to the system already at temperature.

What is a PRV and where in the sytem would it generally be located? This is different than the boiler relief valve, right?

Thanks for your help!


EDIT: looks like PRV goes on the water supply and drops pressure to 12psi - I have a Fill-Trol tank (which has its own Amtrol fill valve on top) and ball valved tank bypass; next in line is an American Air Purger unit with what looks like an automatic purge valve sitting atop it, and then I have a Spirovent. I don't see a separate PRV. Is it possible that the Amtrol fill valve performs this same function and is my PRV? If so, it's getting replaced with the tank.

While we're here, what is the purpose of the Spirovent? There were generally always a couple of drops of water on the floor coming from the Spirovent's discharge pipe - is that normal operation?

Thanks again.

psb75

PRV is "pressure relief valve. It should go where the bad tech put the wrong T& P relief valve. It should be rated at 30psi. A Spirovent "grabs" and releases micro-air bubbles. And it is a general auto air-release mechanism. It has outmoded the old fashioned air-scoop with the Hy-vent canister on top. If you have both era of air release mechanisms that is fine.

Rooster1

psb75 said:

PRV is "pressure relief valve. It should go where the bad tech put the wrong T& P relief valve. It should be rated at 30psi. A Spirovent "grabs" and releases micro-air bubbles. And it is a general auto air-release mechanism. It has outmoded the old fashioned air-scoop with the Hy-vent canister on top. If you have both era of air release mechanisms that is fine.

Hi. Thanks. I think in the context of Ed's post above, he was talking about a pressure regulating valve that drops the pressure of the incoming supply water. Not sure, but he also discussed the boiler relief valve, so I think he's talking about two separate things. Either way, both the boiler relief valve and the expansion tank with the associated Amtrol fill valve are going to be replaced.

Then I think I'm going to find another local company who knows what they are doing to check the system over and fill/purge. Too dangerous if done incorrectly, it seems. I just need it safe and fully functional, as the house hit the market to sell yesterday.

Ironman

PRV can also mean Pressure Reducing Valve, aka the fill valve. That’s  what Ed was referring to. A bad one can stick open and overfill the system.
IDK if any of us care for the extrol  valve that comes with the tank, but that’s your fill (PRV) valve.
If your house is 2-3 stories, you’ll need more than 12 psi cold fill pressure.

Rooster1

Ironman said:

PRV can also mean Pressure Reducing Valve, aka the fill valve. That’s  what Ed was referring to. A bad one can stick open and overfill the system.
IDK if any of us care for the extrol  valve that comes with the tank, but that’s your fill (PRV) valve.
If your house is 2-3 stories, you’ll need more than 12 psi cold fill pressure.

Thanks.

Like I said, I just need it running the way it did prior to this last winter, and it was functioning, so that the house can be sold. The house is basement, main, and second level, but like I said, everything was functioning - the heat upstairs may have been suboptimal, but it was there.

The valve’s pressure regulating function is separate from the tank’s job, right. They just both happen to use 12 psi? Or does the pressure in the tank change the regulated cold fill pressure?

JUGHNE

The Pressure Regulating Valve (PRV) and the tank work together to maintain system pressure.
They usually both come preset for 12 PSI. You check the air in the tank before ever installing it or with absolute zero in the system. 12-15 for both is what you want.

As far as the over pressure damages, the piping, tubing and boiler may be OK.
However the tubing connections at manifolds may not have liked the pressure boost.
After they heat up again, I would check them for leaks.

Certainly put that repair company on notice, send them a picture of the water heater T&P they put on your boiler.....do not let them have it back!.
Pay no bills. If they itemize a bill, note if they list a T&P or a simple 30 PSI relief valve.

rick in Alaska

Just to be clear, could you show us a picture of the system with the relief valve location? I just want to make sure we are all understanding this correctly, before commenting.
Thanks
Rick

Rooster1

Blue is what the tech installed. Red is what I'm planning to replace it with. I just finished swapping in a new fill valve and expansion tank, as I confirmed the tank to be bad after it was suggested above.

Rooster1

Oh, one more thing - I thought I'd order to new tridicator just to be sure my gauge is functional.

1) Is it OK if the stem protrudes into the piping? The one I ordered would extend about half the diameter of the pipe, whereas the one I removed had its stem entirely contained in the bung off of the pipe, so that the stem isn't directly in the water flow.

2) Should it read 0 psi fresh out of the box, or should it read about 15psi (i.e. about 1 atm). The gauge currently installed reads nil, the new gauge is around 15 psi out of the box. It's a Caleffi unit.

JUGHNE

New gauge should read 0 PSI....is there a zero adjustment screw on it?
Usually those screws correct only with a few points.

Rooster1

JUGHNE said:

New gauge should read 0 PSI....is there a zero adjustment screw on it? Usually those screws correct only with a few points.

Thanks. It seemed wrong. Will see if it can be adjusted or if it’s just junk.

JUGHNE

Can we see a picture of the entire boiler, what type of material is used for exhaust venting?

Rooster1

JUGHNE said:

Can we see a picture of the entire boiler, what type of material is used for exhaust venting?

Sure thing. Here's the whole system.

Steamhead

EBEBRATT-Ed said:

The tech was an idiot, thats how people get hurt. Take pictures , document and don't throw the T & P he put in away

Indeed. You can't fix stupid. That "tech" should get fired, and never work in this industry again.

Rooster1

Do any of you know the factor of safety that goes into the equation for a boiler’s MAWP?

EBEBRATT-Ed

@Rooster1

If I remember right you can test to 1.5 x the maximum allowable working pressure

HVACNUT

What's a picture worth?

Larry Weingarten

Hello, I'll add that it looks like the pump on top of the boiler is oriented incorrectly, so that it will trap air and ruin its bearings.

Yours, Larry

Rooster1

HVACNUT said:

What's a picture worth?

Can’t say for sure, but apparently the sticker itself wasn’t even worth looking at, at least to the “professional” I trusted to do the work.

Steamhead

Rooster1 said:

Do any of you know the factor of safety that goes into the equation for a boiler’s MAWP?

Doesn't matter. The safety valve cannot exceed the MAWP rating. Period.

Rooster1

Steamhead said:

Do any of you know the factor of safety that goes into the equation for a boiler’s MAWP?

Doesn't matter. The safety valve cannot exceed the MAWP rating. Period.

Asking for my peace of mind, since the system was pressurized beyond the MAWP - caveat being the accuracy, or lack thereof, of my tridicator.

Steamhead

Rooster1 said:

Steamhead said:

Do any of you know the factor of safety that goes into the equation for a boiler’s MAWP?

Doesn't matter. The safety valve cannot exceed the MAWP rating. Period.

Asking for my peace of mind, since the system was pressurized beyond the MAWP - caveat being the accuracy, or lack thereof, of my tridicator.

That's a tough one. Is anything leaking?

Rooster1

Steamhead said:

Steamhead said:

Do any of you know the factor of safety that goes into the equation for a boiler’s MAWP?

Doesn't matter. The safety valve cannot exceed the MAWP rating. Period.

Asking for my peace of mind, since the system was pressurized beyond the MAWP - caveat being the accuracy, or lack thereof, of my tridicator.

That's a tough one. Is anything leaking?

It wasn’t when I shut it down. System is currently empty. I replaced the bad expansion tank and installed an appropriate relief valve. Having a different contractor come out to fill and purge and check everything over this coming week.

I’m no engineer - I am just curious if there is any safety risk with the boiler after an overpressure event like that. My assumption is no, but like I said, I’m not a structural engineer.

JUGHNE

I have a GV 4, series 2 stored in my basement.
Used it until I redid with a ModCon.
The max working pressure they are tested for is 50 psi (got all the books for it)

So if you were at 60-65 there is probably a fudge factor in that 50 Max working pressure.

As stated above the manifold connections of the tubing may have seen more than they like.

BTY, that boiler series is rated 87.2 DOE seasonal efficiency %.

Can you get the top cover on the boiler?
As Larry said the pump is rotated wrong, motor shaft should be horizontal.
That would probably let you get the cover on.

Note: my GV 4 is for sale, all parts working and 3" SS venting...make an offer.

mattmia2

The ratings plat states the max working pressure is 50 psig. Many of the other components will have a test pressure listed higher than the working pressure. If nothing is leaking i wouldn't be worried about hidden damage from 60 psig assuming that was as high as it got.

unclejohn

Looks like they hired a parts changer. Getting the top on that boiler will be tuff. Do not get me wrong but I would place more blame on the service manager then the tech. My guess is there was a phone call before any work was done. The tech is obviously mighty green and was told to replace the pump and perssure relief valve. If he dosen't know the difference between a T&P and pressure relief valve then the service manager sent the wrong guy. My other guess is that the boiler has a bad bypass valve and the pumps were fine.

Rooster1

By bad bypass valve, do you mean the pressure relief valve or something different?

The lid does fit on the boiler. The last pump was oriented in the same direction - not that I’m disagreeing with you all that it’s wrong.

JUGHNE

At 87% efficiency these boilers are nearly condensing.
If the return water was too cool the condensing would take place inside the CI sections and rust the boiler away.

So the by pass valve, near the pump, would divert some hot water into the return water to prevent this. But the thermostatic control element in would fail and no replacements were available.

A simple fix it solution was advised by the company. It would put a fixed amount of supply hot back into the return water. Preventing condensing inside the boiler.

I just found it; Technical Service Bulletin #SB0401R1 dated 2-25-2004.

It looks as you have a mixing valve for your tubing in the floor, so your return temp may be high enough to prevent damage.

Rooster1

Which one is my mixing valve? Is that the thing with the white post coming out of it and the Oventrop dial on the wall? I thought that had something to do with freeze prevention.

Rooster1

Also - should I go ahead and try to fill and purge this thing, or should I leave it to the pro I scheduled to come out on Thursday? How badly could I screw it up?

If I did want to give it a shot, based on the photos of my system, can anybody give a quick version of the step by step?

JUGHNE

A mixing valve for the tubing would take the boiler water of maybe 140-150 and mix/temper it down to perhaps 100-110 or so for your floor heat.

The Oventrop dial has 2 very small capillary tubes coming out of it.
One senses the temp of the pipe it is strapped to. The other might go outside for ambient temp sensing. If so then this is a reset control to raise the water temp as the outside temp drops.....I am not familiar with this particular control.
Maybe someone else will educate us both.

The by-pass valve is inside the boiler at it's pump. It too was a mixing valve, but for a different reason of boiler protection.

Is there a brand name on the red tubing you have?

Rooster1

The pex itself? Stadler Pextron.

Do I need to check (or can I even check) this bypass valve in the boiler before trying to fill/purge/run the system?

JUGHNE

There is not much you can do to the boiler bypass. It either works or not.
What temp do you run on the supply side of the boiler?
A thermometer on the return would be helpful.

You want a minimum of 130 on the return water assuming the bypass is NOT working.

I never found out that my bypass had failed until removing the boiler from service and seeing some deterioration on the CI discharge horn of the heat exchanger where the SS vent connects at the bottom front of the boiler.

You may be running fairly high water temps because of having the indirect water heater tank.