Ideal Mini problem....serious confusion....

[BobTheBreaker]

Life's not been smooth since buying a new build back in 2004, at least as far as hot water is concerned. We've got what seems to be an Ideal Mini S24/28 (at least going by the Ideal installation guide (that's a low water content system gas boiler), which seems paired with a SystemMate 2000 in the garage.

There's always been air in the sealed (?) CH, which we've just tolerated by bleeding and topping up the pressure as needed (not that often to be honest), but now we never seem to have enough hot water. Two short showers or one medium bath is enough to empty the boiler, and for some reason if the CH is on, we seem to have even less.

Just wondering if anyone's got any pointers on where to start, or if I should just go straight to having someone come and look at it. It's not been serviced since we moved in, so that's probably my first port of call, but there's things that strike me as odd, so thought I'd post first.

1) The Mini isn't the combination model. Doesn't it need to be if it's combined with another unit in the garage?

2) The Mini doesn't ignite when the hot water tap turns on. It comes on intermintantly for about 30 seconds, then cuts off....about ever five minutes or so. Then you'll get a burst of hot water from the tap for 30 seconds....

3) Radiators are always hot, even if there's no hot water, and if the Mini isn't igniting.

Anyone got any ideas? I hate not being able to understand the system.....and now when the wife can't have a bath in the morning, or even worse, a cold bath.....it's having a detrimental affect on my health

Any help very much appreciated.

 

[gas4you]

As you say, you have the S24/28, which is the system boiler, not the combi. Therefore it will NOT fire when the hot taps are turned on.

I would check your system controls, especially any zone valves you may have. One may be stuck on making the boiler fire all the time (CH one).

Another possible fault could be a frost stat failed if you have one in the garage.

 

[nickso]

1. as dave says, its a system boiler feeding the store.

2. everything runs off the store, the mini is only there to provide the actual heat. hot water and heating water both come from the store hence the reason you may have less hot water when the heating is on.

3. the mini will only be told to fire when the store goes below a certain temperature. if its already below that temp when you ask for hot water you may not get satisfactory heat from the taps, this is unlikely if its working properly as it should keep the store very hot in order to provide both heat and water.

if the mini is firing ok then i would say the store is faulty. if you have the instructions you can ask it if it is faulty or check the operation using the ludicrously difficult to remember leds.

common faults are scaled plate h/e and faulty thermistors.

 

[nickso]

this may help you understand it a bit but the instructions you should have with the store tell you all you need to know really.

http://www.gasapplianceguide.co.uk/systemate_technical_specificati.htm

 

[Agile]

As Dave has said, it sounds like a control problem.

Unless you can get very involved with the system it may be better to call in a professional.

After four years your boiler is rather overdue for a service too!

Tony

 

[gas4you]

I missed the bit about it being a thermal store

The boiler stat should be turned up to max and the boiler should not have a timer on it. It will fire 24hrs a day as nick says when the water store temp drops.

The timer for the ch should be supplied on the system mate unit.

Could also possibly be a fault on the DHW pump (right hand pump), control board, or possibly the plate heat exchanger partially blocked/scaled up.

 

[BobTheBreaker]

Thanks a lot to everyone for all your help....I'm always on the look out for helpful and informative forums, and given the response I've seen on here I think I'll be hanging around. I'm sure my wife's list of things to do around the house will certainly get a lot shorter with the amount of help offered in here.

Does anyone know if British Gas' boiler protection service is worth getting (I forget the name of the scheme) or is there a better alternative on the market?

 

[Agile]

Most of those kind of things are quite expensive and your problem sounds quite simple.

Tony

 

[BobTheBreaker]

Problem seems to be getting worse...

We had two radiators on last night (out of a total of 13) for a couple of hours. When I got up this morning I had enough water for my very brief shower (about 2-3 mins running time max) and I think the wife got about a fifth of a bath before it started to run cold.

So do you guys think that it's something to do with the SysteMate? It's almost as if it doesn't know what temperate the water is it's storing. But wouldn't that mean that whenever the Ideal Mini kicks in, the water it's heating would just get added to the cold water in the storage tank? Instead we get short bursts of hot water every time the Mini fires....almost as if it's bypassing the storage tank.

Any recomendations on who to call in West London for a service?

 

[Agile]

Any recomendations on who to call in West London for a service?

The boiler will probably need a service after four years but initially you will need a repair to the system fault(s)

Tony

 

[gas4you]

I would still tend to think it is a fault on the system mate. Gledhill's are not the most reliable on their control circuits I have found.

Could be DHW sensor fault, boilermate 2000 suffers badly from these failing, don't know if the same sensors are used on yours.

 

[nickso]

BG can be good for these, if they go wrong a lot you will save money. the mini isnt a particularly good boiler either so it might be worth it in your case.

despite what tony says the most common faults on these are thermistors and scaled h/e's. the pump can fail like any other but as its speed is controlled through the thermistor its still more likely to be the thermistor.

if your heating is ok it rules out the mini this time.