Pulsacoil 2000 - no hot water, everything looks ok!!

Hi, we have a pulsacoil 2000 in our flat which is about 8 years old. Apologies in advance for lack of technical jargon.... I really have no idea!!

For about a year we've had intermittent problems with the water running luke warm then cold then luke warm again, and we've had to ocassionally rely on the boost button (a general 'if we ignore this maybe it'll sort itself out' attitude!!)

A couple of nights ago there was enough hot water for my baby to have a bath. When we put the boost button for an additional bath we noticed the boost light did not come on and we got no more hot water - and since then we've had none no matter what we did with the thermostat/timings.

We called a local heating engineer round who tried to help but admitted himself that he found this type of boiler frustrating. He tested the boiler and said there was nothing wrong with it. When the boiler was turned off at the wall the thermostat started working (very odd!) with the 'off peak' light coming on, although boost didn't work/light didn't come on so it wasn't as it should be. However when the boiler was switched on at the wall, the thermostat returned to not working. The engineer fiddled around a bit, adjusting some wiring until the thermostat lights made it appear to be working when the boiler was on at the wall - however it is not working, the boost doesn't work, we have no hot water and the boiler is not hot to touch. We've switched this off until we can get help, although have now been put off calling someone to come round for fear of them "solving" it again, charging lots of money and yet again not fixed!!!! The engineer left saying we might need a new thermostat..... any ideas appreciated!!

Well you have 2 heaters in your unit both have stats.
If the unit is hot and the hot water is intermittent then that would have pointed to sensors, pump or PCB.
But as you say you used the boost and got hot water sounds weird.
Perhaps the bottom heater (off peak) and or stat had gone.
And you then used the boost (top heater Peak supply) and you got hot water.
These units are very easy to work on.
Heater and stat wise no different to test than any immersion heater.
Look on here home page list of people advertising.
Google one up for your area.
If you had gave a hint of your area then perhaps would have offered their services.
If you look in the post for Pulsacoil 2000 all your troubles have been answered many times.
And I will add to leave anything which is not working properly for about a year is asking for trouble and trouble normally comes during a holiday period.
Mike
MGC/H2O
Norfolk

It sound as if the sensors are not working correctly or the pump is sticking. I would personally recommend you find an engineer who understands the system.