IMI Range Powemax.
This article is incomplete and is still being added too.
If you are the home-owner I have written this guide for you in the hope that you might get a better understanding of the system and be able to extend the life of the boiler. First thing to say is that parts are still readily available regardless of what others may say.
These boilers need careful servicing, the manufacturers instructions instruct the engineer to replace various seals, in fact, the main burner seal is so fragile it needs replacing regardless.
1.Hot water runs hot to start with then runs cold. Problem is most likely to be the thermostatic blender valve, cold water mixing with hot water in a hard water area is never going to end well. The blender valve needs replacing.
2. Hot water but no central heating. Most likely is that the central heating pump has ceased, please switch off the room thermostat. Stop calling for heat as this will prevent causing damage to the pump and simply release the pump spindle. The other cause to this fault is that the Powermax programmer has become faulty.
3. Overheat thermostat keeps tripping. This could be one of three possible faults and testing the electrical circuitry will identify which component it is. The most expensive part being the stratification pump.
4. Lock out "1", with pressure gauge on zero re-pressurise system fault then re-occurs a few days later. There are two small valves located in the boiler which has become stuck or are open and need replacing. It is more cost effective to replace both rather at once than go through a process of elimination.
5. Lock out "2", Red light on and boiler refuses to light. On systems located in Ely/Witchford there are two possible faults the first is the small water level switch and if that is found to be serviceable, the gas valve needs to be checked.
6. Lock out "3", Continual boiler lock out with red light on. The boiler continues to lock out randomly this fault is a process of elimination. With several parts that need to be replaced and can not be checked this fault can become expensive. Three test can be undertaken to establish the system is set-up correctly and then there is a possibility of changing four different.
7. High pitched noise when boiler is running, on some occasions this can be quite loud! This one is a process of elimination, starting with CO ratio, then re-calibrating the burner, replacing the gas valve, finally replace the burner head.
8. This problem will/can be found on service and is an expensive fix due to the fact that they are a mare to replace if broken. The turbulators or baffles which are sited vertically through the heat store overheat and if they break they fall down into sump. If they have have broken the operation to removing them from the sump is devilishly difficult. Regular servicing will help identify when these are at the end of the serviceable life.
9. Boiler is not running properly and is making a sound like a washing machine with whooshing or gurgling of water. If this happens on a 140, 155 and the 155x, this a terminal fault, as there is a hole in the heat exchanger which is not removable.