Remote Switch?

I have a Rinnai on demand propane fired unit that is fed pre-heated water from my solar array. Because of the house layout, the Contender (solar hot water tank) is about 75' from the Rannai, so even when I have 60 gallons of 150 degree water in the tank, the Rinnai still kicks in until the hot water gets to the Rinnai (the water sitting in the pipe is cool) and it realizes it does not need to be running and kicks off. It makes me crazy to hear the propane unit kick on for 1 minute or more every time.

I want to install some kind of remote switch or delay that forces the Rinnai to wait until it kicks in, but I am a bit stumped as to the best way to do this. I realize it's not the most elegant setup, and that in a perfect world I would move the rinnai closer to the contender, but there are some other challenges with that which I won;t get into in this post.

Any suggestions for remote switches or sensors much appreciated.

Thanks,

billy

Comments

  • BB.BB. Super Moderators, Administrators Posts: 31,684 admin
    Re: Remote Switch?

    Welcome to the forum Billy!

    An remote on/off switch based on the water temperature in the storage tank to the system AC power (or if they have a remote on/off switch)? Over 120F on the tank, tankless heater off.

    Hacking the unit could be dangerous. Many gas appliances have many interlocks/safety devices to prevent explosions, over heated water, etc... I would be worried about doing anything to the internals of the unit.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • fxvinylfxvinyl Registered Users Posts: 2
    Re: Remote Switch?

    Thanks, Bill. That's definitely the way to go. I'll see if I can get a sensor in there (or use one of the ones that is in the tank) and use that to fire a power switch.
    BB. wrote: »
    Welcome to the forum Billy!

    An remote on/off switch based on the water temperature in the storage tank to the system AC power (or if they have a remote on/off switch)? Over 120F on the tank, tankless heater off.

    Hacking the unit could be dangerous. Many gas appliances have many interlocks/safety devices to prevent explosions, over heated water, etc... I would be worried about doing anything to the internals of the unit.

    -Bill
  • Ralph DayRalph Day Solar Expert Posts: 941 ✭✭✭✭
    Re: Remote Switch?

    I have a Takagi unit with remote (to see inlet/outlet temps, adjust temps, turn on/off) located in the bathroom cupboard. You can check the incoming water temp (from a glycol type sdhw system) and decide if you need to fire or not. I also wired a regular house switch to the same location that controls the outlet that the Takagi is plugged in to. I can shut down the propane either way after checking to see what temp is headed in to it.

    You might need to have another sensor and display (or only a sensor and display) from the Contender and a master power switch for similar function.

    Ralph
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Remote Switch?

    Have you insulated the delivery pipe to the Rinnai? It should help retain heat in the pipe before the Rinnai.
     
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  • zonebluezoneblue Solar Expert Posts: 1,218 ✭✭✭✭
    Re: Remote Switch?

    Any thoughts on the best brand of on demand water heater unit for preheat applicatons? Ive tried a few and not been real happy yet. Most wont run low enough to cope with that in between land 40-60*C. Are temper valves the way to go?
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


  • mike95490mike95490 Solar Expert Posts: 9,274 ✭✭✭✭✭
    Re: Remote Switch?
    zoneblue wrote: »
    Any thoughts on the best brand of on demand water heater unit for preheat applicatons? Ive tried a few and not been real happy yet. Most wont run low enough to cope with that in between land 40-60*C. Are temper valves the way to go?

    I've got a gas Eternal which has a multi-stage burner and a gallon buffer tank. And a tempering valve from my 150F solar preheat. Winters my wood furnace preheats to about 90f It's been working real good.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
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  • zonebluezoneblue Solar Expert Posts: 1,218 ✭✭✭✭
    Re: Remote Switch?

    But gees the amazon reviews on those are a bit worrisome though?
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


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