ESPAR Hydronic Heaters – Preventative Maintenance

Espar’s Hydronic Heaters uses the vehicles coolant system to pre-heat the engine coolant to allow for effective vehicle starting in extreme climates. With some modifications, vehicles can be configured to allow for warming the passenger compartment through the existing vehicle heating system.

Espar Hydronic heaters are integrated into the cooling system of the engine and work independently of the engine, thus offers pre-heating of the engine and the vehicle’s passenger compartment. The thermal energy gained is then distributed through the vehicle’s own heat exchanger as forced hot air which heats the interior of the vehicle via existing air vents. The engine is warmed up with the residual heat in the cooling water.

Pre-Season Preventative Maintenance For Hydronic Heaters 

Before the cold weather arrives, it’s recommended that your Espar HYDRONIC  heaters receive a preseason check to ensure the heater is clean, free running and ready for a trouble-free season. Please use the recommended tools and follow the procedures as outlined in the heater manual while removing and reinstalling the different heater components.The heaters should be inspected and repaired by an Espar trained Technician, as follows: 

1. Check all electrical connections from the heater to the batteries. Check for wear and abrasion along the length of the harnesses. Repair or replace the harness whenever the harness insulation is broken or damaged. Check the battery connections. Clean any corrosion at the terminals. Replace the battery terminals if the corrosion is severe. Check the fuse for corrosion and the correct rating.

2. Check all clamps and hoses. Replace as required.

3. Check the condition of the exhaust system. Check for holes and breaks in the exhaust piping. Replace the exhaust as necessary.

4. Check the fuel pump filter ‐ clean or replace it as necessary. For heaters with external fuel pumps, ensure that the mounting angle of the fuel pump is in between 15‐35o. An incorrectly mounted fuel pump may lead to excessive carbon issues. Check the fuel lines for possible leaks, loose clamps, etc. Once the entire fuel system has been checked and issues, if any, are corrected, it is advisable to do a fuel quantity check.

5. Check and clear clogged weep holes on the side of the heater body. Look for any indication of coolant leakages. If leakage is suspected then remove the cover with water pump assembly and inspect and replace “O” rings on the water pump housing. Closely inspect the heater waterjacket for leakages and replace the “O” ring between waterjacket and heat exchanger. If the waterjacket is cracked, replace it.

6. Remove and replace the glow pin screen. Make sure that the new screen is installed correctly as outlined in the repair manual for the heater.

7. Remove and check the glow pin. If it shows signs of dissimilar colour or if the glow pin is in any way distorted, replace it.

8. The coolant pump should be removed and the impeller checked for damage. Any dirt or metal particles on the impeller magnet should be removed and the cavity in the pump should also be cleaned. Please Note: coolant pumps are not covered by warranty if the vehicle’s coolant system is excessively contaminated. Refer to Technical Circular 250.

9. Remove the flame tube and check the condition of the flame tube end. The flame tube should be light brown in colour with no excessive carbon at the end of the flame tube. Check for carbon build up on the burner “nose” at the cold end of the flame tube. Any carbon covering the air slots should be removed. Check the inside of the heat exchanger and scrape any loose carbon out from between the fins in the heat exchanger. Re‐install the flame tube replacing all gaskets.

10. Re‐assemble the heater and test operation. The heater should be bench tested for 15‐20 minutes before returning it to the vehicle.

11. Regardless of the season, run the heater every month for a minimum period of 15 minutes. This will help the heater burn away any combustion residue in the burner chamber and prevent corrosion in the waterjacket and decay of “O” rings.

Preventative Maintenance procedures – see below to ensure all your Eberspaecher heaters perform as expected.
Airtronic Heaters Preventative Maintenance
Carbon Build up – How to check and remove

Arctic Traveler Canada is an MSD (Master Distributor) for Eberspaecher productsand a technical leader actively involved in projects driving the mobility of tomorrow. Call 1-800-295-4156 for more information about mobile heating solutions.