hi i need a bit of help i m a carpenter and only have a limited knowledge of plumbing. my daughter has one of these pulsacoil 2000 water heaters in her flat, it used to work fine but now it only gives out warm water not hot, also when i looked at the emmersion heater it was leaking under the cover which i will replace could this be the problem, are immersion heaters all the same (i no they come in different lengths) or do i need a special one. anyone please!!!!