The heating system won’t work without heating fluid, so you must make sure that the system is fully topped up. When cool, the fluid level in the expansion tank should be 1 cm above the minimum marking.
Using your ethylene glycol hydrometer, you can test the fluid. You can also check its smell and appearance to verify its condition – if it smells fishy or looks turbid, your fluid needs replacing.
If you can’t verify the fluid, you should replace it as soon as practicable. It should be replaced with an Alde-approved product.
