relief valve problem

rmsongs

I have an oil-fired boiler. The relief valve started leaking; drips at first, then about 100 gallons per day. I had the relief valve changed by my boiler guy. He also charged the Xtrol tank (grey tank hanging from a joist) to 18 psi. Fifteen minutes later, the relief valve exploded out of the boiler (the top w/ spring) shot out and water hit the ceiling. He then told me that I needed to change another valve (something with a flow-check or flow-back??). Long story short, I changed that myself and put in the new relief valve. It started dripping almost immediately. I checked the charge on the Xtrol and it was over 25 psi. (I thought maybe he overcharged it) I bled some air out and it stopped dripping. Half an hour later, it was dripping again. I checked the pressure and it was back up over 25. I bled it down to around 12 and the leak stopped. Fifteen minutes later, it was back over 25 psi. I finally shut off the boiler, but it kept dripping, so I shut off the cold water feed to it. According to the boiler guy and the guy at the plumbing supply where I bought the parts, the only other thing that could be wrong is the Xtrol tank is bad, but the boiler guy said it should sound hollow on the bottom and full on the top (it does) and it should get warm on the top but stay cold on the bottom (it does). If it is the Xtrol tank, I'll change it, but I don't want to do it if that's not the problem. Any advice would be appreciated.

Steamhead

Does the boiler

have a coil that provides hot water to your faucets?

rmsongs

relief valve problem

There's nothing that looks like that picture. The hot water goes to an Amtrol tank (blue, maybe 40 gallons) model WH7L. I hope this answers your question, because I'm (almost) clueless about this stuff.

nicholas bonham-carter

Hot water system problem

It seems as though the water pressure from your potable water system is forcing its way into your boiler. This must be due to a leak between the DHW heat exchanger and the boiler, or from the auto-fill valve.

I am amazed that your serviceman was not able to diagnose and repair(or temporarily control) the problem on the first visit. If you have any doubts about the technical expertise of the service you are getting, then use the find a pro button at the top of the window.

Don't live with this problem too long as the pressure from such a leak is higher than the boiler design capacity.--NBC

rmsongs

relief valve problem

This is the part I changed (in addition to the relief valve). I was told that this, the relief valve, and the Xtrol are the only things that could be causing the problem, but your reply makes it sound like there's something else I should be looking at.

nicholas bonham-carter

Something else to look at

Can you isolate/ turn off the DHW inlet (tankside), and see if the pressure remains steady? Those pressures are much higher than anything produced by the boiler itself (usually).--NBC

rmsongs

relief valve problem

I don't know what that is. And the only pressure gauge is on top of the boiler and it's completely blank; just a white circle, no numbers, no lines, no needle, nothing. So I have no way of knowing what the pressure is. Are you thinking it has nothing to do with the tank? Is there any other way to check the pressure? I don't know why there's no usable gauge.

Jean-David Beyer

This is the part I changed

That "part" you changed is actually two parts. From left to right, an anti-backflow valve and a pressure reducing valve. Where I live, the drain port of the anti-backflow valve must be connected and come within six inches from the floor, so it it opens and hot water comes out, it will not splash all over everything, including your face, or your kids. I am not a professional, but most installations I see also lack that drain pipe. Maybe it does not matter, or maybe the inspectors around here do drive-by inspections.

rmsongs

relief valve problem

Yes, it is 2 parts, but it came as one assembly. Also, there is a pipe that extends down to within a few inches of the floor. I took this picture while I was removing the assembly & I had already taken the pipe off.

chapchap70

Turn off the water going to the blue tank.

Turn the water valve off so no new house water can get into the Amtrol tank, then turn on a hot water faucet until water stops flowing out of it then turn it off.  Drain the boiler pressure down to 12 PSI like you did previously.  (I am assuming you checked the pressure with a tire gauge at the extrol tank.) 



Turn the boiler switch back on.  With the water turned off to the Amtrol tank, if the pressure in the boiler remains the same for a while, it is probably because the normally 70 psi street pressure into the tank cannot get into the inner coil (12 psi) of the tank because the valve is closed. 



If you open the valve to the Amtrol tank and the boiler pressure goes back up again, it is most likely the water with the higher pressure is entering the boiler water system because there is a hole in the coil. 



Boiler water normally circulates through the coil heating up the water in the tank.  It is supposed to be isolated from the water that is heated and flows out of your faucets.  The boiler water does not flow into the tank water if there is a hole in the coil.  The tank water flows into the boiler water which causes an increase in pressure inside the boiler which causes the relief valve to release pressure if it is working properly.



If this is true, you most likely would need to get a new indirect tank installed before your boiler can make hot water without half of it ending up in the basement instead of where it is supposed to go.  I'm not sure if it would be cost effective to change the coil/heat exchanger.

bill_105

What I'm wondering?

Is that a train set in the backround?

nicholas bonham-carter

First job for the new service tech

Every system should have a working gauge; otherwise how will the tech know when he has got to the root of the problem?

If the parts you changed had any effect, it would have shown up as a reduced/normal pressure for the system on the gauge.

They are not expensive:



http://www.pexsupply.com/pex/control/search/~SEARCH_STRING=Tridicator



--nbc

billtwocase

that part

is a combo feed and backflow preventer. The vent is for the vacuum breaker, and is not a relief valve. It should be piped to the floor, but you wont see hot water come out of it, so no real danger there. I would first post some pics for all to see, and consider replacing the expansion tank. It may also be the coil for the indirect, but I have replaced more Extrols tanks than Amtrol coils that caused pressure problems

Paul48

As stated

You have to have an accurate gauge for pressure on the boiler. The air charge in the expansion tank must be put in when the tank is not in the system. Be careful if you try to take it down, it is deceptively heavy.The part you changed on the boiler supply has to be adjusted to pressurize the system to match the air charge in the expansion tank. Under that little lever assembly is a screw to adjust the pressure per the instructions that should have come with it.

rmsongs

relief valve problem

There were no instructions with the part. How do I know how to adjust it? Also, if I do change the expansion tank, isn't it charged when you buy it? Also, I know it's going to be heavy because it sounds like it's full of water now. Is there any way to drain it before I take it down? And there's a fitting above the expansion tank that, when opened, let's water out leak out. Should that be open a bit or closed tight? Thanks.

rmsongs

relief valve problem

This is the pressure gauge; not only does it not have any markings on it, but you can see that it's not centered in the hole, so I can't even take it off and replace it. The other picture is the thing on top of the Extrol tank that seems like a bleeder. But, it's closed tight, so I'm not sure how it could bleed off pressure, if that's what it's for.

Paul48

Here

is the instructions for the regulator.There needs to be a valve to isolate the expansion tank from the system.You close the valve,release all the air from the tank, then remove the tank. http://media.wattswater.com/1910265.pdf

Paul48

You

really should bring in someone qualified to work on your system. It is not something you can learn, "on the fly". You can get hurt, or destroy the boiler, which judging by that gauge, already has quite a few years on it? Has the boiler been maintained annually?

Zman

Have you?

Have you tried to isolate the problem? Can you isolate the domestic water heater on the heat side or the water side? This will prove or disprove the most probable cause, I leaky dhw coil.

You may need to either open or remove the boiler jacket to replace the triadicator on the left picture (you need one that works).I would not be to concerned with it not being centered in the jacket. The device in the right pictures is an air eliminator. It should let air out and the keep water in. You should be able to leave the cap loose.It sounds like it needs replacement.

rmsongs

relief valve problem

Thank you for sending the instructions. The boiler is serviced every year, although now I'm wondering why they never replaced that pressure gauge. I shut the boiler off this morning and the water feeding it is off, as well. I turned it on this morning so we would have hot water (the pressure in the Extrol tank is 0 because I kept bleeding it yesterday when the pressure kept building up, which was making the relief valve leak). As soon as I turned it on, it started dripping, then every few minutes it would shoot out a jet of water, then stop, then after a few minutes it would start dripping again. I don't know if I should change the Extrol tank myself and then call the oil company (to save some money. They wanted $165 plus labor to put in the valve/backflow preventer and I bought it for $70 and put it in myself; money is tight and I can buy the tank for $34). The boiler guy told me that the only things that could be causing the original leak were the relief valve (changed), the backflow/valve part (changed) or the tank, but from some of the answers I've gotten on here, it seems like there could be other problems.

Zman

have you??

Have removed the expansion tank and check the pressure? I thought you had.

Does the problem only occur as the system is heating up?

Can you post more pictures of the system.

We really are not supposed to discuss pricing.

Carl

rmsongs

relief valve problem

Thank you to everyone for taking the time to respond. Obviously, this is a much more complicated problem than I was led to believe by my boiler guy. I think it's time to call a pro before I damage something. As far as me mentioning prices; if that's a violation of site policy, I apologize. I only mentioned it to illustrate what I could save by doing the job myself as a way of explaining why I was even attempting it. It was not to try and solicit info about what the job itself should or shouldn't cost. Thank you all again.

rmsongs

relief valve problem

Yes, a very much "under construction" HO layout.

Zman

Good call

I think getting a pro out is a good call. You might save some money by letting them know that you need a triadicator,air eliminator and most likely an expansion tank. This should be stuff guys carry on a service truck, but you may save him a trip to the supply house. If your tank is more than 10 years old, I would replace it while you have the system drained anyway.

Hopefully you have gained enough knowledge here to be able to tell the knucklehead from the pro.

Carl

rmsongs

relief valve problem

Thanks, Carl. I learned a lot on here, but I'm still over my head.

Zman

Lttle knowledge...

When I was 17 (more than a few years ago), I took apart my car. When I went to see the old timer at the junk yard to show him all the parts I had broken and needed to replace (I was a knucklehead) He looked at me and said "Little knowledge can be worse than none at all". That was some of the best advise I have ever received. Every time I look at something I don't understand, I can still hear his voice. I know it is time to slow down and figure it out before proceeding.

Best of luck

Carl

rmsongs

relief valve problem

Yeah, I hear you. I took apart a typewriter years ago and it's still in pieces in my parents' basement. I don't want to have the same problem with the boiler. I'm just glad this all happened in August instead of February. Thanks for your advice.