Combi Boiler - Getting Hot, but not much cold

[aurora83]

Moved in to a new flat, now having a nightmare with the shower, bathroom basin and kitchen tap.

With the shower, turn on the taps, about 30 seconds later, start getting hot water from the combi. The problem is that I can't mix in enough cold, because there is not enough coming through. So the water just keeps on getting hotter, unbearably hot. So I have to turn the shower off, then on again so I can catch the first bit of warm water. In the kitchen, I can't get the temperature right unless the tap is opened quite a lot. But then the pressure is too high and the water just sprays everywhere.

I have tried changing the thermostat on the boiler, but this has no effect. Any ideas what the problem might be/what can be done? I already had one plumber in who said nothing can be done because there is no valve to regulate the pressure on the mains I don't really understand what he was trying to say. I know that there is the stopcock which can regulate the pressure from the mains and turn it off. To me it seem like the boiler is demanding most of the pressure from the mains. So when the cold water is turned on, it only gets a small share. This still doesn't make sense though, because when the boiler is off, and I only turn on cold water, the pressure is nothing like that of the hot water.

I don't know...

[Hymie]

The best thing that can be done is for you to take a bath, rather than a shower.

[butterflies]

I had this problem with our taps and boiler but have now got it down to an art. In the shower, I turn the hot tap on only a little but enough to kick the boiler in then add cold water to the recquired temperature, this takes about 30 seconds overall (but now I can turn both taps on and by the time I'm undressed the water is fine). Funnily enough to get hot water into the washbasin I need to turn the tap quite high before the boiler kicks in.
It's a nightmare when we have guests...

[aurora83]

Yes I understand butterflies. Unfortunately I can't get enough cold water to mix.

In the wash basin i can just about get it right.

Having a bath is not a solution now is it. Plus the bath just ends up filling with burning water, and then i'd have to wait ages for it to cool down. Plus I don't have baths, waste of water.

[The Builder]

Aurora.........the hot and the cold with a combi are both mains fed - as you know - if anything, the hot should come out at a slightly lower pressure because it has to flow through the heat exchanger. You mention the thermostat - forgive me if you've tried this, but, there should be a temperature control for the hot water..........have you seen that anywhere?

[gasman]

Yes The Builder is correct there should be a control on the Combi boiler to turn down the temperature of the hot water. What is the make and model of it by the way ?

[aurora83]

The boiler is made by ideal. On the front there is only one temperature control which goes from 1-6. The other controls include 2 buttons, one to turn of mains power, the other to turn the CH on/off. There are also buttons and an LCD display for programming it.

To be honest the thermostat doesn't seem to have much affect on the hot water wherever it is positioned.

Is it normal that you have to open up the tap quite a bit for the boiler to start. I understanding that the boiler will kick in when the water starts to flow through, but it just seems i need to open up the tap too much.

Also, i dont understand why i cant mix enough cold water in.

[ELVIS68]

What setting are you on ie 1-6?

[gasman]

Some of the older IDEAL boilers do not have a control on the front to change the Domestic Hot Water ( DHW )temperature. The control marked 1 - 6 is only to control the Central Heating temperature only. The DHW delivery temperature is controlled by a thermostatic mixer within the tank module, You have to pull off the lower door from its locating pegs and inside you should find a mixer valve right in the middle, with a twist control marked " min. 1 - 6. max " That you can adjust the to the required DHW delivery temperature. this should give you approx temperatures in Degree Celsius (*C) as below :-

Min - 30*C
1 - 34*C
2 - 39*C
3 - 43*C
4 - 48*C
5 - 52*C
6 - 56*C
7 - 61*C
Max - 65*C

You dont happen to know the exact model do you ???
i.e. Ideal - istor HE260 or Ideal Classic SE 12 etc.

[aurora83]

I do know the model, but not of the top of my head. I will let you know when I get home.

Thanks for the answers by the way!

[aurora83]

The boiler is a Ideal Response 80

There is a label on the front of the control pannel that reads "additional thermostat fitted", this must be the one you are talking about gasman.

I will pull the front pannel off and having a look when i get home.

[Steviegb]

The additional thermostat thats fitted is a safety thermostat. Nothing to do with your hot water.These boilers have a tendancy to burn a hole through the top of the heat exchanger. This thermostat will sense this and cut your boiler out altogether. (An after thought from ideal,whats new!)

[aurora83]

I just found a section in the manual that says what to do if the water temperature is not right. There is a release handle located somewhere near the pump, but i cant see this handle. It says to turn this handle to adjust the temperature of the DHW. There is a big screw on the front of the pump.

I think i understand. If you increase the flow, the the water doesnt heat up as much because it is moving through the boiler faster. Where as it will be hotter if it moves slower and has more time to heat up. Correct me if i'm wrong.

Does anyone have any idea where this handle might be?

[Steviegb]

If you look under your boiler , i think its the 2nd pipe from the left, (cold water mains to the boiler 15mm pipe) just before it disapears under the bottom grille , there will be a isolation ****. sometimes it has a little handle/lever that you can move to adjust the flow of water to it. If this lever /handle is missing you van use a small pair of pliers to turn it. It shoild have a groove in it indicating how far you have turned . you only have to turn it slightly as 1/4 of a turn turns it off altogrther.Dont turn it too much as you still need pressure to operate the flow switch which activates your boiler. 8-10 liters a minute is the average flow rate

[gucciman]

i might be missing something here but from the information in the question the problem seems to be with the incoming mains rather than the boiler i.e. when he turns on a cold tap alone he is getting a flow/pressure that is lower than the hot water delivery.
and would a thermostatic mixer valve be a solution for the shower?