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DHW Mixing Valve on Steam Boiler Incorrect?

Kafox15Kafox15 Member Posts: 20
Hi All,

Our Peerless steam boiler also provides hot water using a tankless coil. The mixing valve on the hot side of the coil (Watts LF70A) had a slight leak which I corrected by tightening the packing nut.

But while I was doing some research in case I needed to buy replacement parts, I found the installation guide for this mixing valve and the setup looks NOTHING like how mine is configured. I am curious if its worth the effort to reconfigure my mixing valve per the instructions or if it doesn't make much of a difference.

Here are the instructions:
https://www.watts.com/dfsmedia/0533dbba17714b1ab581ab07a4cbb521/11899-source/1910210.pdf

My setup:

Comments

  • Intplm.Intplm. Member Posts: 1,093
    @Kafox15 I didn't need to read your directions attachment to know what's wrong with your installation. It's not trapped/installed below the domestic hot water coil, and it will surely leak again.

    But before you go to the trouble of reinstalling it, please do this instead..........get rid of it.
    What you have is a incorrectly installed "tempering valve" These things are notorious for failure and incorrect installation. This type of valve needs to be installed below the coil to have it last.
    But even when you do install them below the coil they fail (old technology). So, get rid of the thing and install in its place a "thermostatic mixing valve."
    This type of mixing valve can be replaced in -almost- the same way as your current defective valve and will last much longer with little to no trouble while providing a more comfortable temperature.
    They often look like this one from the honeywell company. There are other brands that I have found that work comparatively from Caleffi, Watts, Webstone, Symmons.
    So before you go to the trouble of reinstalling the one that you have, change it too. You will be happier in the long run.
  • Kafox15Kafox15 Member Posts: 20
    Intplm. said:

    @Kafox15 I didn't need to read your directions attachment to know what's wrong with your installation. It's not trapped/installed below the domestic hot water coil, and it will surely leak again.

    But before you go to the trouble of reinstalling it, please do this instead..........get rid of it.
    What you have is a incorrectly installed "tempering valve" These things are notorious for failure and incorrect installation. This type of valve needs to be installed below the coil to have it last.
    But even when you do install them below the coil they fail (old technology). So, get rid of the thing and install in its place a "thermostatic mixing valve."
    This type of mixing valve can be replaced in -almost- the same way as your current defective valve and will last much longer with little to no trouble while providing a more comfortable temperature.
    They often look like this one from the honeywell company. There are other brands that I have found that work comparatively from Caleffi, Watts, Webstone, Symmons.
    So before you go to the trouble of reinstalling the one that you have, change it too. You will be happier in the long run.

    Thanks for the advice and sorry for the late reply! Looking at supplyhouse, there are over 100 different options of thermostatic mixing valves just from Honeywell-Sparco. How should I go about determining which one I need?

  • GrallertGrallert Member Posts: 429
    If I recall the temperature range will be listed and marked on the sticker on the valve. I forget the ranges put you'll want one that goes no higher than 120 I think. Though that's very hot. Looks like that piping is 3/4"? You will also have to do some pipe rearranging.
  • hot_rodhot_rod Member Posts: 12,959
    edited January 21
    You want a valve with a ASSE 1017 listing, that is considered a point of distribution valve.

    An ASSE 1070 is a point of use valve, lower Cv, limited to 120F maximum.

    Look at the max, inlet temperature also, some are 180, some 200°

    Install it with a heat trap as Intplm mentioned, the directions should detail how to do that.

    The Caleffi 2521 is a solar rated valve, 210°F inlet rated for high temperature systems.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • hot_rodhot_rod Member Posts: 12,959
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • Intplm.Intplm. Member Posts: 1,093
    Kafox15 said:
    Yes that is a very common one. It may also be offered in different connections other then "sweat ends", if you want.
  • Kafox15Kafox15 Member Posts: 20
    Intplm. said:

    Kafox15 said:
    Yes that is a very common one. It may also be offered in different connections other then "sweat ends", if you want.
    Yea, my only experience with plumbing so far has been Sharkbite, so I would need to practice soldering before I took this on.

    I see that sharkbite does make a version of this, but looks like the max temp is 200 and I know steam gets to 212.

    Any other options that wouldn't require soldering?
  • ethicalpaulethicalpaul Member Posts: 1,515
    Watch a couple youtube videos and practice on some pipe and fittings from HD and you'll have it in no time.
    1 pipe Utica 112 in Cedar Grove, NJ, 1913 coal > oil > NG
  • Kafox15Kafox15 Member Posts: 20
    Finally bought the AM-1 valve. Would somebody be so kind as to draw me a diagram of how I need to re-arrange the piping? I am having a hard time figuring out how to do it without having the Cold and Mix cross over each other.


  • Intplm.Intplm. Member Posts: 1,093
    The directions included with that valve are pretty good. I hope they came with the valve. They should explain how the installation should be done with a drawing.
    As to your question. You can install this with a "cross over". And it looks like you have to because the old valve does not have the same orientation, inlets and outlets etc. as the new.
    This is not unusual. So, just make sure hot is to the hot, cold is to cold and mix is to the mix. That will do fine.
  • Kafox15Kafox15 Member Posts: 20
    Intplm. said:

    The directions included with that valve are pretty good. I hope they came with the valve. They should explain how the installation should be done with a drawing.
    As to your question. You can install this with a "cross over". And it looks like you have to because the old valve does not have the same orientation, inlets and outlets etc. as the new.
    This is not unusual. So, just make sure hot is to the hot, cold is to cold and mix is to the mix. That will do fine.

    Yea, I have the directions and I understand in theory how its supposed to be installed. I am just having a hard time picturing how I can adapt my current setup to the new valve due to the different orientation.
  • Intplm.Intplm. Member Posts: 1,093
    That's understandable.
    Try and take one inlet/outlet at a time.
    You mention that you have used shark bites. Why not use them again if this fitting is what you have used before?
    Purchase a few different ninety degree elbows, fourty five degree elbows. Adapters, and some copper tubing.
    Use a little installation imagination and you are on your way.


    What type of connecting ends are in the valve?

  • Kafox15Kafox15 Member Posts: 20
    Intplm. said:

    That's understandable.
    Try and take one inlet/outlet at a time.
    You mention that you have used shark bites. Why not use them again if this fitting is what you have used before?
    Purchase a few different ninety degree elbows, fourty five degree elbows. Adapters, and some copper tubing.
    Use a little installation imagination and you are on your way.


    What type of connecting ends are in the valve?

    I bought the sweat ends option. I had considered sharkbite, but they are only rated for a maximum of 200 degrees F. I know its unlikely that the water actually flowing through the pipes is more than 200F, I just thought it might be risky since the water is heated to 212F when it needs to make steam.
  • hot_rodhot_rod Member Posts: 12,959
    this would be the easiest. The connections should be labeled H C and mix? I'd add valves on the mix out and cold in. Makes it nice to fix leaks or work on the valve.

    A temperature gauge is nice also. Or get a strap on type.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
    SuperTech
  • Intplm.Intplm. Member Posts: 1,093
    @Kafox15 This ^^^^^^^^^^^^
  • Intplm.Intplm. Member Posts: 1,093
    If you are worried about the heat rating close to the valve, you will need to solder . If you are not comfortable with soldering, you can return the valve you have for one that has female pipe threads. Then you can try using male by compression adapters to complete your installation

    Are you starting to consider hiring a professional?
  • Kafox15Kafox15 Member Posts: 20
    hot_rod said:

    this would be the easiest. The connections should be labeled H C and mix? I'd add valves on the mix out and cold in. Makes it nice to fix leaks or work on the valve.

    A temperature gauge is nice also. Or get a strap on type.

    Wow. I did not even consider that the valve could be installed upside down. This make so much sense. Thanks!
    Intplm. said:

    If you are worried about the heat rating close to the valve, you will need to solder . If you are not comfortable with soldering, you can return the valve you have for one that has female pipe threads. Then you can try using male by compression adapters to complete your installation

    Are you starting to consider hiring a professional?

    I've practiced soldering and its not too difficult, just need to take my time!
    Intplm.SuperTechBillyO
  • hot_rodhot_rod Member Posts: 12,959
    Take the connections off the valve of course, solder, cool, install valve.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • Kafox15Kafox15 Member Posts: 20
    FINALLY got around to doing this today, being stuck in the house and all. I'm not going to win any awards for nice looking joints but they hold water (so far). I'll probably be checking on them twice daily for a week before I trust them. Thanks everyone for your help!

    Side question - I had to use the pressure release valve to fully drain the water and it has now developed a very slow leak. Is it worth me taking it off and cleaning it to see if that resolves the issue or should I just buy a new one? Its a Watts LF53L and is threaded.


    Intplm.
  • HVACNUTHVACNUT Member Posts: 3,098
    Where is that relief valve located? It's a pressure only domestic relief valve and I dont see it on the hot in the pic.
  • Kafox15Kafox15 Member Posts: 20
    Here's a wider shot. Pressure relief is at the bottom.


  • HVACNUTHVACNUT Member Posts: 3,098
    You can try to pop it manually. Be careful.
    If it doesn't re seat properly, replace it.
    How old is it? Older than 5 years? Replace it.
  • Kafox15Kafox15 Member Posts: 20
    edited March 22
    It's probably 5-7 years old. I'll replace. Thanks!

    EDIT: The one on there now is the 175 psi model. Is that necessary or can I replace with the 100 or 150psi models? 175 is OOS on supplyhouse.
  • Intplm.Intplm. Member Posts: 1,093
    It looks good. I trust its working better then the old one ?
  • Kafox15Kafox15 Member Posts: 20
    Intplm. said:

    It looks good. I trust its working better then the old one ?

    It is! thanks for the help.
  • HVACNUTHVACNUT Member Posts: 3,098
    > @Kafox15 said:
    > (Quote)
    > It is! thanks for the help.

    If you posted a pic of the new one, I cant see it.

    I like 150 psi. 175 with a tankless is the norm maybe.

    Is there a domestic extrol?
  • Kafox15Kafox15 Member Posts: 20
    HVACNUT said:

    > @Kafox15 said:

    > (Quote)

    > It is! thanks for the help.



    If you posted a pic of the new one, I cant see it.



    I like 150 psi. 175 with a tankless is the norm maybe.



    Is there a domestic extrol?

    Sorry - that comment was referring to the mixing valve, not the relief valve.

    The 175 is OOS on supply house, but ill see if I can buy it somewhere else. There is no expansion tank.
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