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Need help buying a Rinnai outdoor reset sensor 805000078

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PeteA
PeteA Member Posts: 180

I bought and installed an M090cn series combi boiler. The item was an open box and some of the small items were missing but they were no big deal and were easily replaceable or substituted by other readily available parts. But the one key thing that was missing was the outdoor reset sensor 805000078. I contacted Rinnai to get a replacement and they do have them in stock but they cannot directly sell it to me. I tried Supplyhouse.com to see if I could purchase through them but no luck, Rinnai customer service recommended I try Fergusons but have not received a call back. Anyone have a method I can use to purchase this item? Any Rinnai Pro accounts? The boiler/hot water heater is currently running great but I've heard so much about outdoor reset benefits on this site that I'd like to try it now that I have the opportunity. I am located in the northeast and if any of you has a storefront in NY, NJ or PA or website I can buy through, it would be a huge help.

Thanks

Pete

Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,157
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    there are several Ferguson locations in the tri-state area. And other supply houses handle that brand of equipment. If you were to walk into one of those locations wearing appropriate clothing, (there are not many plumbers that wear three piece suits) and just ask for that part number, you should have no problem.

    Just remember, you are picking that part up for your boss. Not for a DIY project.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    PeteA
  • PeteA
    PeteA Member Posts: 180
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    @EdTheHeaterMan

    Thanks for the advice. It can't hurt to try. I have a location not too far from where I work here in Manhattan. I guess I can pop in and see if they can order it for me.

  • ratio
    ratio Member Posts: 3,676
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    It's likely that it's a standard thermistor, tech support should be able to tell you something like "10k type 2" or "10k type 3" (two pretty common ones). Once you know that, you can substitute anything you like that has the same resistance curve. eBay or Amazon will have them. Might even have the OEM part.

    EdTheHeaterMan
  • PeteA
    PeteA Member Posts: 180
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    @ratio

    Thanks for the info

    Thats exactly the info I am trying to also figure out as an alternative. I don't have a clear understanding of how the thermistor ratios work but according to the sheet in the install manual I have been able to find that the thermistor is a NTC1K @ 77f (25c), so its around 1,000 ohms at 77 degrees. I just don't know how to look this up since most of the ones i've seen on the google search results are 10k at 77f (25c) and that is way out of range for what I obviously need. Here is the chart from the manual. Is the T4 a "type 4"? I noticed you mentioned type 2 and 3 are common.

    Thanks

    Pete

  • ratio
    ratio Member Posts: 3,676
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    Here's one of the tables I've found in the past. It's pretty comprehensive, and you should be able to order a part from it.

    The types 2 & 3 (or II and III sometimes, or A/CP and A/AN) are just specific 10K curves. They'll substitute for one another if your target temp is around 77°F (25°C), but the further you get from the center the more they digress.

    In any case, no 10K sensor will work for you. Go through the table, IIRC there are 1K sensors in it, and see if it matches pretty closely, especially the lower end where you expect an outdoor sensor to operate at.

    If you google 1K sensors, you will likely come across '1K Nickel RTD' and '1K platinum RTD' sensors. These are not thermistors, so you don't even need to look at them.

    Alan (California Radiant) Forbes
  • ratio
    ratio Member Posts: 3,676
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  • PeteA
    PeteA Member Posts: 180
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    Thanks @ratio

    I did a little more digging since your response yesterday and it made me more confident to just go with installing and wiring up my own thermistor in the housing so I found Mouser Electronics has them available with a nearly identical curve on both the low and the high end of the temperature range that is shown on the chart I attached. The sensors themselves are pretty cheap individually and since I already have the housing from the one I bought that did not work it should be a pretty easy install. Thanks for all of the info, I will let you know how it works once I have it installed and tested.

    Alan (California Radiant) Forbes
  • PeteA
    PeteA Member Posts: 180
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    Just a follow up on this since many posts typically don't close the loop with how they eventually made out once advice was provided.

    @ratio and @EdTheHeaterMan

    replacing just the thermistor worked perfect. I found an electronics place Mouser Electronics that specialized in those types of items and went through the different charts they had on their site and found a thermistor that closely matched the testing/troubleshooting table that was provided with the boiler. The outdoor sensor is reading near perfect +/- a degree or two. Can't wait to test everything out this winter and see if outdoor reset lives up to the hype.

  • ratio
    ratio Member Posts: 3,676
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    Awsome, glad you got it working; & thanks for the follow-up!

    PeteA
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,764
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    I have used Mouser with good results.

    There used to be some local electronics stores around now all gone including Radio Shak which was limited.

    PeteA
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,205
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    Ferguson Maspeth Queens, 49th st...on the Scenic SuperFund Wetland, Newtown Creek. Mad Dog

    PeteA