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Relief valve leaking, bad indirect?

BrianF Member Posts: 14
edited July 2022 in THE MAIN WALL
Just looking to make sure I’m not nuts here.   I have a custumer with a Burnham Alpine and an indirect. They’ve had the boiler about six years with no problems. The indirect is 20 years old. 

Whoever installed it is a complete hack and most of what they did should be cut out. Expansion tank in the back of a flo check, aquastat for the water heater is a strap on attached to the hot outlet line, etc, reused the old headers, control, pumps, feed valve. 

Recently the relief valve started leaking. They had someone come out and do the feed valve expansion tank and relief valve.  It still leaks and the guy can’t figure out what’s wrong so they called me. 

My first though was the indirect coil leaking. I shut off the feed valve to the boiler and came back a couple days later. Now there’s 32psi in the boiler with a bucket full of water under the drip leg. No other way to get that water out and still maintain pressure except the indirect leaking right?  

Normally when I see this I can just valve off the indirect as a proof.  Usually the pressure will shoot up in 20 or 30 minutes with the valves open and stay normal with the valves closed. Here it’s taking days to overpressure so I can’t do that. 


  • Jamie Hall
    Jamie Hall Member Posts: 20,525
    Basically, I'd say your instincts are most likely correct -- that there is a small leak in the indirect. However, to be sure... can you close off the domestic water inlet valve to the indirect? If that's shut off and the pressure still rises -- barring a cross connection somewhere in the domestic plumbing (it's happened)) --you've got your villain.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Zman
    Zman Member Posts: 7,435
    How is the system piped? I have seen systems where the circ is pumping into the expansion tank and the fill is on the suction side. The pressure gradually ratchets up as the fill valve sees the pressure drop and reacts by filling a little at a time.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • BrianF
    BrianF Member Posts: 14
    Thanks for the replies. 

    Valving off the indirect doesn’t do anything as it takes a couple days to over pressurize and I can’t leave them with no hot water that long. 

    It is piped horribly but well enough to work. The expansion tank is on the feed side into the back of a flo check. The feed is indeed on the return. However I left the ball valve to the feed turned off to see if that solved it. It has also been operating like this for years and working.

     I’d love to repipe the whole thing but they told me they don’t even have the money to replace the indirect and I know they really don’t. So they’re saving pennys for that and emptying the bucket for now. Fixing the near boiler piping is going to be a hard sell. 
  • HomerJSmith
    HomerJSmith Member Posts: 1,927
    edited July 2022
    It's hard for me to figure out what you are saying.

    Is it the boiler PRV leaking or the indirect PRV leaking? I assume it is the boiler PRV leaking which is why you mentioned 32 psi. I would think that a leaking HX would be immediately apparent, flow goes from hi pressure to low pressure. That it take several days to reach 32 psi and the boiler feed is shut off indicates a leaking HX as you surmised. Of course, there aren't any shut off valves on the piping from the boiler to the indirect HX, right. If there are and shutting the HX off and monitoring the boiler pressure would certainly confirm your assessment.

    I would want to confirm that the boiler feed valve is completely shut off and no water from the street is squeezing thru the feed shut off valve and Pressure Reducing Valve, but I guess that is all new?

    I think I would solder in a couple of full ported ball valves between the HX and boiler. Ya, you are going to drain down the sys, but you are going to do that anyway if you have to replace the indirect tank. Shutting those valve off would be definitive.

    I like to know why things fail, but you can say to Mr Customer, "You need a new indirect tank", install it and hope for the best.

    If a leaky HX, you are putting O2 rich water into the boiler sys.

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,999
    edited July 2022
    @BrianF has the right idea. The indirect HX is probably the cause. The problem is... there is not enough money to just replace the indirect and hope for that to be correct. I always asked my mechanics "After you make that repair, and the same problem still exists, what will you check next?" Usually there is some lower cost answer like replace the fuse or make sure the valve really turns off.

    Since the HX leak is so slow... there is no way to be absolutely sure that the fill valve isn't passing. So in this case I would put on a new manual ball valve on the fill line to be sure that the fill line is not the problem for sure. That valve should be a lot lower cost than a new Water Tank.

    If the problem persists after you eliminate the boiler fill valve, the only other thing left is that Tank. I might even apply the cost of replacing that valve to the price of the new water heater job as a good faith gesture. But that's just me.

    Edit: What is the warranty on the indirect? Some of them had "Limited Lifetime warranties". You may get a free tank or at least a substantial discount on the replacement tank.

    Another Edit:
    This afterthought is: because there is not a lot of money in that household, the customer may have gotten what they paid for 6 years ago. Now you need to ask them "If you don't have enough money to do it right, Where are you going to find the money to do it again?"

    Consider this the next time you go over a bridge. You can have confidence because it was probably built by the lowest bid contractor!
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • Zman
    Zman Member Posts: 7,435
    edited July 2022
    The only thing worse than the lowest bid contractors is the low bid engineer...
    In their quest to build it as light and affordable as possible, they forgot about uplift and harmonic motion, oops...
    This is one of my favorite books https://www.amazon.com/Why-Buildings-Fall-Down-Structures/dp/039331152X

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • mattmia2
    mattmia2 Member Posts: 7,217
    You could disconnect the indirect coil, plug one end and put fittings and a gauge for an air test in the other end. The air will leak faster and you will be able to see it on a gauge. You might also be able to see the air in the indirect tank.
  • heatdoc1
    heatdoc1 Member Posts: 14
    Sounds like a bad indirect to me but as someone else replaced the expansion tank I would check the charge just to be sure
    John Ringel
    Senior Technical Support Specialist
    Energy Kinetics
  • BrianF
    BrianF Member Posts: 14
    edited July 2022
    Thank you for all the replies. I still have not heard back from them so I assume they either found a better price on an indirect or are still emptying that bucket. The feed valve is brand new and had ball valves on either side. So I’m pretty positive it was not Street water leaking in though three valves failing wouldn’t be the weirdest thing I’ve ever seen.

    I just wanted some affirmation of my belief I would feel really bad if I charged them a whole bunch of money for something they didn’t really need.  The indirect is 22 years old and a Triangle Tube which I don’t believe has a lifetime warranty. Most of the lifetime warranty ones that I’ve come across anyway usually either require it to be registered upon installation or they want a receipt showing you’re the original owner.