Lukewarm water and not enough

We just moved in our new flat last week, we're 2 couples in a 2 bedroom flat with one bathroom.
We're having problems with our pulsacoil 2000 since the beginning.

We set up the clock so the boiler can heat from 6am to 7am and from 9pm to 10pm.
We can only take our shower in the evening around 11pm because of our tight schedule.

We don't have enough hot water for 4 showers, not even for 2. The water is never really hot, just warm. And after the first shower (7-8mn max), the water is only lukewarm. After that it's between lukewarm and cold.

Yesterday I checked the feed tank, it was really low so i filled it up (I'll check tonight if it's ok).

We really need to sort this out because we can't change our "shower schedule" :/

Hi

Heating the unit for only one hour is not enough. Depending on the size of Pulsacoil you have, it will take between 3.5hrs and 4.0hrs to heat from cold to its maximum working temperature.
Try setting your time to make use of the cheap rate economy 7 electricity overnight between 1am and 7am and you should find that this will rectify your problem.

Thanks for your reply, we will try that tonight.

A last quick question, if we set our time between 1am and 7am, will it consume energy to maintain the heat until we use hot water? Because we don't use hot water until 10-11pm...

Do you have a 'cheap' overnight tariff? I only ask because I attended one recently that had only daytime tariff, no overnight tariff. That's not as bad as it sounds though. You can get daytime electricity for as low as 10p per kWh, so a 3kW immersion will only cost you 30p an hour. That means a day's worth of hot water for £1 - even at daytime rate electricity. Use uswitch to get the best deal. On my website I have added a page that shows the best deals at the moment:
http://www.scalgon.co.uk/electricsupplyprices.html
When it gets towards peak heat it will actually cut off on the thermostat setting, so don't worry about it. If you set your heater to come on between 1 and 7 a.m. then it will still be hot at 10-11 p.m. and it will only consume more energy if you have the daytime boost on.

Actually I don't know, I don't even know who my electric supplier is, I'll check that this week end.
Yesterday we set the clock between 7am and 11am and everybody has (really) hot shower, so everything's fine. We will try the 1am 7am settings this week end.

Thanks to everyone for your help.

You don't know who your supplier is!?! You really need to check that out, and very possibly get a cheaper rate. Your Pulsacoil should only use daytime energy if you have an 'overnight' tariff that kicks in around midday for about an hour. Some of them do that - to give it a boost of heat. Otherwise you have to use the actual 'Boost'. Don't forget... give uswitch a visit!