Insanely hot water, noisy boiler, noisy rads

[stubags]

Hello,
I have three problems with my central heating system and I don't know if they're connected as I know nothing about plumbing.
I have a Ferroli combi boiler, which was fitted, with the whole radiator system, just under 2 years ago.
Here's the problems in no particular order.

1. No matter what you set the hot water temp to on the boiler, the hot water that comes out of the tap invariably ends up scaldingly hot. Even when the water temp's set to the lowest setting, it can still strip the skin of your hands
2. Every night (when the CH has been on a while) the most incredible whooshing, dive-bombing, shaking-the-house-to-the-foundations-juddering-to-a-halt noise comes from the boiler maybe two or three times a night.
3. And every so often, any one of the upstairs radiators suddenly decides to do a tractor engine impression which can be stopped by just turning the radiator knob.

I have bled some of the radiators on numerous occasions, and sometimes got a lot of air out, but often this seems to bring on problem number 2 with a vengeance.
Can anyone give me any clues as to what I should do?

 

[COG]

Cant be specific about your boiler as ive never seen that model,but. the nose from your radiator is 95% a faulty thermostatic rad valve, either installed the wrong way around (most have a directional arrow on the body pointing in the direction of flow) or just bust. the noise from the boiler sound as if its overheating from a sudden restriction poss a stalling pump. if you have a dhw temp dial then you should have a dhw thermister poss faulty.sound as if you need .a good eng

 

[corgiman]

1. No matter what you set the hot water temp to on the boiler, the hot water that comes out of the tap invariably ends up scaldingly hot. Even when the water temp's set to the lowest setting, it can still strip the skin of your hands

Not really sure about this problem maybe the high limit stat is now faulty, need an enginner to confirm this

2. Every night (when the CH has been on a while) the most incredible whooshing, dive-bombing, shaking-the-house-to-the-foundations-juddering-to-a-halt noise comes from the boiler maybe two or three times a night.

sounds like the boiler is over heating and the nosie you here is the water boiling in the appliance, might be the boiler needs urgent de-scaling or (now i have read a bit mopre carefully) that your system need topping up (what does the pressure guage read>?)

3. And every so often, any one of the upstairs radiators suddenly decides to do a tractor engine impression which can be stopped by just turning the radiator knob.

This is more that likely because you have a thermostatic rad valve, does it have a knob with numbers on it?, and it has been installed the wrong way around.

all these problems can be sorted but not in a DIY job, in my opinion

 

[stubags]

thanks guys - i think i'll definitely get an engineer in to have a look at it then.