Paloma PH-28 issues being used as solar backup

Jeremy.Flaugh
Jeremy.Flaugh Registered Users Posts: 6 ✭
in Energy Use & Conservation #1
Hi everyone,

I bumped into this thread
http://forum.solar-electric.com/showthread.php?t=3494
and it inspired me to post my issues that I am having with my heater.

I have a Paloma PH-28 as a backup for my solar heater I love the solar but I used to love the PH-28 before I had the solar heater because I am having issues with the PH-28 shutting off "no errors" with preheat water when the water is in the 90F range I cannot get this heater to raise the temp from 90F to 106F so when taking a shower I have two choices cold/warm or really hot because i need to set the heater to 120F and not mix in cold water or very little.

I think the issue is related to the PH-28 inability to lower its BTU output enough to make this work the move water I move GPM the issue gets better but not good. I really need a heater that can pull this off I have found the Bosch 1600PS this unit is designed for preheated water but it has a pilot light and it has manual controls. Sorry I like the remote control.
Can someone that has experience with solar recommend a heater that can do this job.
Thanks Jeremy
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Comments

  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #2
    Re: Paloma PH-28 issues being used as solar backup

    Tagaki Tk Jr works great with preheated water, always putting out 116f (or whatever you set) regardless of incoming temp (assuming that the solar pre-heat is not hotter already!). It can be used with a remote. It also uses some power for the control board, as well as the combustion fan.

    Tony

    PS. I am not familiar with the PH 28. I assume it is an electronic model, not a standing pilot unit like the PH 6-24 units.
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  • Jeremy.Flaugh
    Jeremy.Flaugh Registered Users Posts: 6 ✭
    #3
    Re: Paloma PH-28 issues being used as solar backup

    Hey thanks for the info the Takagi is on my list now.

    Something I noticed is the specs when comparing is that my Poloma cannot support hydronic heating and all of the others can don’t know if that is a sign.

    And yes this is a electronic version here is the link to the PH-28 http://www.palomatankless.com/products/74/tankless_74.html
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #4
    Re: Paloma PH-28 issues being used as solar backup

    While I am a huge fan of the now discontinued standing pilot PH 6-12-24 series, their being bullet proof and very long lived, I don't have much experience with the newer series of Palomas. My sense is, with little evidence to back it up, is that they are not as good as the Takagis or the Rinnais.

    If I was to install one now I would use either a Takagi or Rinnai, depending on who had a better local presence. I would NOT install a Bosch electronic unit. I think their QC is poor and they are (in my experience) quite finniky!.

    Tony
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  • Jeremy.Flaugh
    Jeremy.Flaugh Registered Users Posts: 6 ✭
    #5
    Re: Paloma PH-28 issues being used as solar backup

    I second the quality on the old Paloma units the reason I bought a Paloma is because my parents have a the old modulating model.
    http://www.palomatankless.com/products/ph24/legacy_ph24.html
    and it is 25 or 27 years old with no issues in it's past the only maintence we do to it is take it outside and blow it out every 2 years.
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,022 ✭✭✭✭
    #6
    Re: Paloma PH-28 issues being used as solar backup

    Tony, have you actually had that good an experience with a Tkjr? Mine will cycle on and off with pre heated water, depending on how close it's temp is to the target burning temp. Sometimes the target burning temp (I have the remote) is over shot by 20-30 degrees F, not comfortable.

    Ralph
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #7
    Re: Paloma PH-28 issues being used as solar backup

    Ralph,

    I built a small flat plate collector system in front of a TKjr for some folks and it performs flawlessly. We didn't use the remote however. I have also used A TKjr in a seasonal rental just as a demand water heater and it works great. The only issue I have ever had is with very low flow rates. Sometimes if you reduce the flow rate too far the heater will quit firing. (A problem with most demand water heaters. My Ph6 will flow down to about 1 ltr/min or a bit less @~40 psi.

    Tony
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,022 ✭✭✭✭
    #8
    Re: Paloma PH-28 issues being used as solar backup

    Lucky you Tony!

    Perhaps my problem with on and off firing is with the flow rate. When you add cold water at the shower the flow rate through the tkjr can drop to .5gpm. If I could only find a high volume shower head?

    Ralph
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  • Jeremy.Flaugh
    Jeremy.Flaugh Registered Users Posts: 6 ✭
    #9
    Re: Paloma PH-28 issues being used as solar backup
    Ralph Day wrote: »
    Lucky you Tony!

    Perhaps my problem with on and off firing is with the flow rate. When you add cold water at the shower the flow rate through the tkjr can drop to .5gpm. If I could only find a high volume shower head?

    Ralph


    I did MOD my shower head to move more water it did help the issue but it is far from solved.
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,022 ✭✭✭✭
    #10
    Re: Paloma PH-28 issues being used as solar backup

    Does showerhead modification require a 1/8 inch drill bit? :p

    Ralph
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  • Jeremy.Flaugh
    Jeremy.Flaugh Registered Users Posts: 6 ✭
    #11
    Re: Paloma PH-28 issues being used as solar backup

    Actually I started with a 1/2 bit then I discovered I could pull the restrictor out.
    Ralph Day wrote: »
    Does showerhead modification require a 1/8 inch drill bit? :p

    Ralph
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #12
    Re: Paloma PH-28 issues being used as solar backup

    Ralph,

    Have you tried playing around with the pre-set temp of the TKjr? I don't know how it works with the remote. Intuitively it seems like you should be able to find "a sweet spot" that will allow the Tk to do it's thing and perform properly. Have you contacted Takagi?

    Tony
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,022 ✭✭✭✭
    #13
    Re: Paloma PH-28 issues being used as solar backup

    Tony,
    I can change the burn temp quite easily via the remote. The problem comes when the input water (solar heated) varies depending on the amount of solar heat collected.

    Ralplh
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  • Jeremy.Flaugh
    Jeremy.Flaugh Registered Users Posts: 6 ✭
    #14
    Re: Paloma PH-28 issues being used as solar backup

    Hi everyone,
    After doing some research and testing I have resolved the issue!
    I ended up calling every water heater manufacture that I could think of my question to them was what water heaters do you have that is compatible with preheated water? and the engineer or sales person or tech support guy I talked to said all of our models BUT a minimum 20deg F below the set point needs to be kept.

    I found that the lower the minimum BTU the heater is capable of going down to the lower the separation temp required so for example the Rinnai RC80hpi has a 10K BTU minimum the engineer from Rinnai says I may be able to run at 10deg below my set point without issues. My PH28 has a 20K BTU minimum.
    To resolve my issue I did something that I really did not want to do I changed the high limit to 140F and installed a anti scald control in the shower so when we take a shower we crank the heater to 130F and mix in cold this method has been working fine since thanksgiving.

    One positive side affect is we are able to supply the dishwasher with 140F water to keep it from complaining it used to display LO after running and was activating the electric heater I think it is more efficient to heat water with propane than electric anyways.

    The procedure for changing the high limit is in the owner’s manual for the Paloma PH28 they do support changing this setting but do not seem like they are big advocates of 140F water.
    Thanks Jeremy
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