help please! problems with a combi boiler!

suze1310

hi i am wanting some free advice please.
we have just moved into our own home and have never had a boiler before and we are having trouble with it. the previous owners turned off the boiler before they left and we switched it back on.
its a combi boiler and it runs the shower too.
the problems we are having are
1. the hot water is on the maximum temp on the boiler but i can still put my hand under the water so its not getting very hot.
2. the shower is going hot and cold and the boiler is firing up and shutting down everytime the water goes cold, however it worked perfectly fine the first night we both got showers!! i wondering if i have done something to the boiler coz i was fiddling with it to try and get the radiators to work coz there is a temp thingy on the wall that i didnt know how to work!
we are rather skint as well so cant afford to call out british gas etc for it to be something stupid i have done and any advice on how to fix this problem would be greatly appreicated!!
thank you!! xx

Cardew

When showering the boiler should be running all the time.

If the boiler is shutting down, it will normally be because the water it is heating has reached the set temperature. So it sounds like the water it is heating is restricted in getting to the shower.

Does your combi have a setting where you heat a small tank in the boiler itself?

If you haven't got an instruction manual, you can get the model number and see if you can find one on the internet. If it worked the first night it does sound like 'finger trouble'.

macman

Possible diverter valve problem?
Would be helpful if you gave the make and model.
And what is a 'temp thingy' (room 'stat, programmer)?

joop1977

Could be div valve or dirt in the plate heat exchanger

gas4you

Plate heat exchanger blocked on the system side will be the cause of the hot/cold scenario.

Luke warm water may be caused by this, but could well be a stuck diverter valve or simply you are running the hot tap too fast.

terrierlady

in our old house my husband usally ran the water tasp too fast which resulted in luke warm water always worked fine for me but then it didnt and was diverter valve, so mayb either.Good luck lets hope its the first reply running the water too fast...

Eco-Installer

Definately gas safe registered plumber needed!

Cardew

If the water was running too fast the boiler wouldnt be shutting down, it would be running all the time!

the shower is going hot and cold and the boiler is firing up and shutting down

gas4you

Plate HE then.