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  • Generator block heaters

    One of our radio sites has a 15 KW Kohler 15REYG standby generator with a 1.6L GM engine in a concrete block hut that gets well into the freezing temps at night. Most nights are probably 0 to 20 degrees F in the winter. It had a propane block heater that has been unreliable and we're thinking of putting in an electric block heater, but I don't know if that will be enough. They have 500 and 1 kW versions. I can only spend around 1 kWh a day heating this, so continuous heater operation, even if cycled with a thermostat, is probably not possible. Do these need to be run continuously in temps like this, or could it be run for an hour or so before starting the engine? Anyone have experience with these?

    Steve

  • #2
    My experience with block heaters are they keep a warm engine from freezing but not very effective at bringing them back from freezing. They are intended for 24/7 operation. The standard approach on diesels would be a Webasto, that heats and pumps the jacket water though the engine using fuel to do it. It may just be a variation of what you already have although Webastos have a good rep (be careful there are some Russian clones that have a bad rep). I assume you have changed to a synthetic motor oil ? It really cuts down on the starting torque as its viscosity is far less affected with temperature. I know folks who use a battery warmer and synthetic oil and have pretty good luck.

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    • #3
      The block heaters I used on car V8s were probably a lot more efficient than the 1.5KW external heaters
      that circulated the coolant. But the 1.5KW turned on an hour or so before start were enough to guarantee
      a start; the 500W in block needed more time which at some temp probably cancels their efficiency. Not a
      fan of battery warmers here; use a bigger bat if necessary. Bruce Roe

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      • #4
        Steve if this a Critical Mission, 1 Kwh/day is not going to work out my friend. Perhaps replace the LPG heater?

        I have thousands of genny's out there with Block Heaters and they keep the engines at around 100 degrees circulating coolant on electric heaters. Those 20 to 30 times more than 1 Kwh/day and that is in TX where it is warmer. .
        Last edited by Sunking; 02-23-2017, 06:02 PM.
        MSEE, PE

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        • #5
          I've had no problems with using a block heater for about 2hrs and then firing up an engine in cold weather. Been doing that almost every morning for several months now. Do you have that time if it is a standby generator? Also, 0F isn't that cold for starting a cold engine. Our gas cars will start at that temp fairly easily without pre-heat. My diesel pickup will start stone cold down to about -15F. Doesn't like it but it will do it.

          Make sure you have appropriate oil and fuel for the season. Summer gas and diesel are different then winter blends.

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          • #6
            Make sure you have appropriate oil and fuel for the season. Summer gas and diesel are different then winter blends.
            But be aware, you buy fuel in the lowlands, and it's not the alpine mix.

            Starting diesels have 2 requirements
            a) Chamber temp for the fuel spray
            b) lube oil thin enough to crank the engine

            a) is solved either with pre-heated air in the manifold (elec glow grid intake pipe or glow plugs)
            b) solved with oil choice or heater. I'm thinking of a can of sterno under the block for a couple hours preheat

            My Hatz diesel manual has a RUG/Diesel mix vs temp guide, to mix a few % of gasoline into the diesel for cold season starting.
            it will lower the HP the engine can produce.
            Hatz_winter fuel mix.png


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            • #7
              Originally posted by NorthRick View Post
              Make sure you have appropriate oil and fuel for the season. Summer gas and diesel are different then winter blends.
              That is not quite accurate. A generator using diesel or gasoline does not use Road Grade fuel. Only a fool would do that. Smart money uses died diesel or gasoline that has no state or federal fuel tax applied, or blended for the seasons. Other than die is pretty much straight kerosene or gasoline with no ethanol. I spend the extra money to buy Av Gas for lawn equipment. It has no Ethanol, higher octane, and is leaded.

              MSEE, PE

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              • #8
                Originally posted by Sunking View Post
                That is not quite accurate. A generator using diesel or gasoline does not use Road Grade fuel. Only a fool would do that. Smart money uses died diesel or gasoline that has no state or federal fuel tax applied, or blended for the seasons. Other than die is pretty much straight kerosene or gasoline with no ethanol. I spend the extra money to buy Av Gas for lawn equipment. It has no Ethanol, higher octane, and is leaded.
                You don't want to go through the hassle of replacing the carbs every other season? I've been fighting it trying to split the difference with TruFuel (expensive) can in winter and 92 octane with stabilizer rest, and add a fuel filter and shutoff valves to each.

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                • #9
                  I would try supplementing the glow plugs with an intake air heater. That will help it light off.

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                  • #10
                    Thanks for the responses. It's fueled with propane. One thing I've wondered is what the problem is with cold starting. Is it cylinder wall scuffing, not being able to pump the thick oil, or something else? Or a combination? I've never been around one that was trying to start when "too cold" so I don't really know what the problem is that the block heater is trying to solve. Dereck: It's mission critical, a microwave site that provides the only connection to a highway maintenance facility. Offices, garages for the snow plows, etc. The generator in the picture is the old Generac, I replaced it with the Kohler about six years ago but never took a picture of it. These pictures are from about 8 years ago, today the snow is about two feet above the roof hatch on the far left of the picture with the Snow Cat.


                    .IMG_8743_pt.JPGIMG_8764_pt.JPGfrozen panels.JPGDeep snowcat.JPG
                    Attached Files
                    Last edited by sdold; 02-24-2017, 12:43 PM.

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                    • #11
                      Cylinder wall scuffing doesn't go away when it gets warm out, low compression. One would hope it has the proper oil in it. I would say fuel delivery. At 0 degrees propane has 24 PSI so that shouldn't be a problem. You very may well have moisture freezing in the regulator. Methanol can be injected into the tank to solve that. The vent on the regulator also can't be covered by 10 feet of snow. Since the state has piles of money I would throw regulators at it and have the gas company do the methanol injection.
                      Last edited by SWFLA; 02-24-2017, 02:08 PM.

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                      • #12
                        SWFLA, I didn't know about adding methanol, thanks for mentioning it. I found this link, it looks like good info, should I follow the recommendations?

                        http://www.propanecouncil.org/upload...%20Propane.pdf

                        The regulators on the tanks and at the building entrance are under at least ten feet of snow. What can be done, can vent piping be added to the regulators?

                        There is a chance I'll visit the site soon, in a Delorean of all things.

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                        • #13
                          You really need to talk to the gas people I'm not in that business. Extended vents are done. Good luck and don't forget to charge the flux capacitor in your DeLorean!

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                          • #14
                            Steve I am a bit out of my element here, but cold weather starting depends on the fuel source. But there are 3 common reasons why engines are hard to start in cold.

                            1.Oil thickens up, and thus more friction the starter motors has over come.
                            2. Fuel is much harder to evaporate when cold
                            3. Battery cranking amps are much lower, and couple with #1 makes it harder..

                            In diesels there is a forth problem. Ignition is accomplished by high compression which generates heat to ignite the fuel. Easy to over come with Glow Plugs, and or Block Heaters.
                            MSEE, PE

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                            • #15
                              Cranking amps is a big one there, if you're not getting enough RPM during cranking the engine won't create enough vacuum to let any gas flow from the regulator on the engine. You probably need a scan tool to measure that, or a good digital timing light. The battery voltage should not drop below 9.5 While cranking. Voltage drop between any two interconnections should only be .1v max while loaded. battery terminal to solenoid terminal. Solenoid terminal to solenoid terminal. Solenoid terminal to starter terminal. And of course neg. battery terminal to the starter casting. Hopefully you'll be able to duplicate the problem.

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