Hot Water pressure is zero. It’s oil furnace , but thought community might help.

Dmitry Posted By Dmitry, Sep 18, 2018 at 7:48 PM

  1. Dmitry

    Dmitry
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    Oct 4, 2014
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    Thought it worse a shot asking here . My kids just called me . They have no hot water . Apparently there is no water pressure. See pics . Going there tomorrow. What should I look for first . Thank you , guys in Advance
     

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  2. Chas0218

    Chas0218
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    Check pressure relief valve first so it isnt just dumping out. Is it a sealed system? Mine is hooked into my water supply with pressure reducing valve.

    Sent from my SM-G930V using Tapatalk
     
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  3. maple1

    maple1
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    That guage looks like there is some pressure there? Looks like it's off the stop - there could be over 10psi there. Hard to tell with a guage with a scale like that. But it doesn't look like zero pressure.

    First thing to look for would be signs of water leaking from somewhere. And other guages on the system to check pressure at. Where to go from there might depend on what can be seen first hand.
     
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  4. maple1

    maple1
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    And, the guage clearly shows there is heat there - water temp of 170+. I don't think it's a pressure or boiler issue.

    Are you talking domestic hot water? (At the tap?). Or heating hot water? And by none - do you mean no water coming out the tap? (If domestic?) Or do you mean water coming out but it's cold?

    We also don't know anything about the system. So way light on info, for us to offer much help...
     
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  5. hobbyheater

    hobbyheater
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    The screen in the purge valve /pressure regulator could be clogged !

    100_4585.JPG
     
  6. Dmitry

    Dmitry
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    Oct 4, 2014
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    Guys , sorry for delayed response, took long time to get the part that I thought might be broken. When I inspected the system I've noticed that tampering valve is leaking. I just got valve thermostat in mail and changed it. It did not fix the problem.
    The water is coming but it lukewarm at best.
    Pressure on a gauge is about 20 psi and water is 180 F. The first time I saw it was less Furnace uses well water . The house water pressure is 60 psi.
     
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  7. Dmitry

    Dmitry
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    Its domestic tap water. It's coming lukewarm and than gets colder.
     
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  8. Dmitry

    Dmitry
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    That’s the gauge now . Is pressure high enough to work properly?
     
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  9. Dmitry

    Dmitry
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    C78CD6E8-C095-49EC-8FE7-42A7DD18AAFE.jpeg Here is the gauge
     
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  10. maple1

    maple1
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    This is pretty well impossible for us to diagnose. We know nothing about the system, and can't see it from here. Pics of everything might help. By the pics we can see it looks like nothing is wrong with the boiler.
     
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  11. Dmitry

    Dmitry
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    Oct 4, 2014
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    Its oil boiler that supplying hot water for heating and hot water for tap water. Uses well water. Ill post pictures in a bit. What specifics do you need? let me know
     
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  12. Dmitry

    Dmitry
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    Pics
     

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  13. Dmitry

    Dmitry
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    Don't see any leaks. How can I check if it works properly?
     
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  14. maple1

    maple1
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    So - looks like it's a coil inside a boiler? As opposed to say an indirect tank?

    Based on what is posted so far I would first suspect what looks like a mixing valve (scald protection) in that last pic - could be mixing too much cold water in? Maybe dirty? Or gone bad? You should be able to follow where the heat is or isn't going by feeling pipes with your hand along their travel. If I am seeing & understanding right in that last picture - the top line going into the boiler should be cold, and the bottom one should be hot when a hot water tap is running (too hot to hold - don't burn yourself). Or vice versa, can't tell which is in & which is out for sure. (Is that drain on the cold or hot?). Then the hot would get mixed down a bit by that mixer T'd in, before it goes on to the taps. If you feel along hot out of the boiler then it goes too cool past the T (again, with a hot water tap turned on), that means that mixer is mixing too much cold in.

    Is the oil burner cutting in & out like it should be? Could also be an outside chance it isn't - and the temp guage is stuck. I suppose. But I doubt it since it reads different in the 2 pics. Feel all the pipes first.

    Also if the boiler isn't heating the house yet, I would likely set its temp down - that is, if you're comfortable doing something like that. That's pretty hot to keep a boiler just for DHW. Or even maybe also for heating the house. You're losing a lot of heat up the chimney. I wouldn't run it up past 180. At the most. When I had mine, 175 was my upper limit in heating season, and 155 in summer for DHW.

    EDIT: Looking closer, exactly what is that on top of what I was assuming was a mixing valve? Is it an air bleeder - or is it the stub of a valve that the handle is no longer attached to? My mixing valve has a handle (knob) there, that you can use to adjust the amount of mixing. When I first looked I assumed a bleeder but I don't think I've seen a bleeder on a mixer before. So if it's a valve stub/stem, it could be a simple matter of turning it in or out to adjust the mixing. I forget which way to turn it to make it hotter - I think out but not sure. Could use pliers or vise grips - kinda odd the handle/knob isn't there tho....

    EDIT again: OK I googled a bit. Yes that is a mixing valve, same as mine, and yes the adjusting knob is missing from the top. If it's plumbed right, cold feed is on the bottom. So try turning the stem to adjust it. These things don't last forever tho - turning it could start a leak around the stem. So it could also need to be replaced (there are better ones on the market now than that one). But try adjusting it. If the knob was still there it would tell you which way to turn it. That might get you hotter water, for now - but it went out of whack for a reason. You used to be able to get rebuild kits for them, not sure if still available.

    https://www.supplyhouse.com/Watts-0559129-1-2-LF70A-Lead-Free-Sweat-Tempering-Valve-120176-160176
     
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  15. Fred61

    Fred61
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    A few years ago I experienced the same symptoms at my home. Hot supply but cold output.

    Didn't take me long to figure out the problem. I have an outdoor sill cock that I supplied with both hot and cold lines with a ball valve on each line to choose either hot or cold, It turns out that I had accidently left both valves open allowing the cold water to flow right into the hot side. Apparently it was the route of least resistance over the hot water supply.

    I have a friend that this happened to on his RV. He left both the ho and cold water supply spigots open and shut off the water flow at the outside shower head. Lucky for him I was camping with him and diagnosed the problem in short order.
     
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  16. maple1

    maple1
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    In other words - follow the heat. :)
     
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  17. Dmitry

    Dmitry
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    Oct 4, 2014
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    Hey, thank for your time and replay. That's exact same way I was thinking. I checked the valve , tuned it all the way to hotter water setting and even changed thermostat in it. Nothing changed.
    I run into HVAC guy yesterday at work by accident , told him all about the situation and he says it's coil inside the boiler clogged, given water quality in our area. He says I need to flash it. You are saying same thing. Prolly coil needs to be flushed. There is no valves installed, so its quite a project. Have you or your friends done it before?
     
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  18. peakbagger

    peakbagger
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    I know folks who have tried to clean a domestic water coil and most end up replacing it if they can find a replacement or having to blank it off as it sprung a leak.There is product called sulfamic acid used to clean out lime scale that can be used. Ideally the best approach is to soak the coil but the alternative is if you can get any flow through it is to circulate the acid through the coil with a pump and appropriate safety equipment. The coil is typically inserted in the water side of the boiler and once it springs a leak it potentially mixes boiler supply water in with drinking water, the typical tell tale is if the boiler pressure relief valve starts leaking as the domestic water pressure is usually higher than the relief valve pressure, so the safety relief does its thing to try to relieve the over pressure. Note that this also happens on occasion when a boiler makeup water valve fails open. I think the hack fix is if the coil is leaking is cut cut off the lines and cap them. That means putting in another zone and a hot water maker type unit that heats a insulated tank with a separate zone off the boiler.
     
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  19. maple1

    maple1
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    I had a coil for 17 years and it never got dirty - but might come down to water quality. That would be a bigger issue to fix - you never know what snowball effect that will have on things. Flushing would require cutting in valves & drains. Not a difficult thing - depending on DIY skills. Replacing likely wouldn't be cheap. And would be more difficult and you never know about things like getting sealed tight again & rusted bolts/studs/nuts.

    I would still first check all the temps in the piping while the hot water tap is turned on. The touch method could be iffy and usually an IR gun is better - but should be adequate in this case. Is there much difference at the taps in water pressure, between when just hot tap is on & just cold tap is on? How old is the coil/boiler? Dirty coil still seems like a longer shot to me - but could be.

    Are you sure you turned it the right way? Should be out (counter clockwise) to make it hotter - turn it full out when you're checking tap pressures & pipe temps. Was it dirty or scaly inside? Did you have all the guts completely out of it?
     
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  20. Chas0218

    Chas0218
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    Does that red valve on top only run to the heat or is it also plumbed into the hot water? That is a reducing valve and could causing some issues if it is rusted shut, I wouldn't think it would be plumbed into the domestic hot water but have seen stranger things.

    So is the pressure good at the tap or is dribbling through? From what you are saying it seems like you have plenty of water pressure but could be caused by the mixing valve if you have one. I would be checking the output water temps in the heating circuit and the tap water. If there is a clog in the coil the heating circuit will be cold on the return compared to the supply. This isn't making sense, if you had a plugged coil you wouldn't be getting pressure at the tap or in the heating circuit and it wouldn't have barely any heat left at the end of the heating circuit.
     
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  21. maple1

    maple1
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    The coil should have no effect on the heating circuit.

    This is a DHW-only tankless coil.

    I think.
     
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  22. Chas0218

    Chas0218
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    Yeah I wasn't sure based on the info given. If you try to follow the piping it all looks tied together coming out of the bottom of the boiler on the circulator side. It is piped into the back of the boiler where I'm thinking is the mixing valve to the right of the aquastat. Personally I have never seen them all piped together instead piped as separate entities.

    OP if you could label your photo a little maybe take a picture so it shows the entire right side of the boiler with piping. Plumbing is difficult as every plumber will do something different. Then if you add one of the self proclaimed plumbers into the mix...well it can get messy quick.

    I will add I'm not a professional and have only worked on my own system and a handful of others so take my suggestions for what they are worth.
     
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  23. maple1

    maple1
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    I think it's just the way you're looking at it. As I was seeing things, the DHW side is only the piping in & out of the coil, best seen in the last 2 pics.
     
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  24. hobbyheater

    hobbyheater
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    This picture shows the pressure regulator to be working properly .
     

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