Coolant Shut-Off Thermostats

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Coolant Shut-Off Thermostats

The electronically controlled engines found in today's vehicles and equipment operate best when fuel temperature is not excessive.

Arctic Fox Heat Exchangers are very efficient, and if not controlled have the potential to add too much heat to diesel fuel. To keep temperatures at a proper level, Arctic Fox offers four different models of fuel temperature sensing, Coolant Shut-Off Thermostats in two different temperature ranges.

Those temperature ranges are:

For all of the S-400 series, full coolant flows when the fuel is at or below +78° F (+25° C), coolant stops flowing when the fuel is at or higher than +95° F (+35° C).

For all of the S-440 series, full coolant flows when the fuel is at or below +104° F (+40° C), coolant stops flowing when the fuel is at or higher than +125° F (+52° C).

It is VERY important that any coolant circuit connected to these thermostats is not also connected to any other coolant dependent device, such as a heater core, fuel fired heater, or APU. Because the coolant flow is shut off, and NOT by-passed. Any other dependent device in the circuit will not receive any coolant until the fuel temperature decreases to allow flow.

Regardless of model, all Arctic Fox Coolant Shut-Off Thermostats operate the same way. They are analog valves, not digital. What this means is that there is a natural hysteresis in their action. Simply put, as the fuel temperature rises, the internal valve mechanism gradually closes until it is fully closed. Likewise, as the fuel temperature decreases, the internal valve mechanism gradually opens. So, it is not an ON/OFF device, but rather a slow acting valve that in cold weather is typically somewhere between fully open and completely closed, modulating the fuel temperature similar to how the engine thermostat modulates coolant temperature.

Another feature that they all have in common is the size of the fuel and coolant ports, they are all 1/2" NPT thread so they can be connected with common fittings.

Arctic Fox does also supply a wide array of fittings to simplify your search for components, and help make your installation professional. Other products to consider when installing a Coolant Shut-Off Thermostat are, Fuel and Coolant Hose Insulation to help retain as much heat as possible, STEEL Tee and Wye Fittings, hose clamps for the coolant lines, and reusable swivel fittings and flare seat fittings for the fuel line connections. Arctic Fox can provide all of these components and more.

To see more detailed information of the Arctic Fox Coolant Shut-Off Thermostats, product data sheet and installation instructions, as well as information on hose insulation, clamps and fittings, please go to the "Product Information" section.

Where To Buy Shut-Off Thermostats

All of our products are available in the aftermarket programs for most heavy duty truck dealers. For information on where you can purchase Arctic Fox fuel heaters from a distributor, contact us online, or call our customer service department at 1-800-654-5382 or 763-972-2758.