Update - Thankyou all very much for taking the time to post your honest opinions - I'll be checking out your recommendations.
Most appreciated, Shona

Looking to replace my dad's boiler. Only had one quote so far which is based on a Ferroli boiler however when i research them online they are universally panned by almost everyone - clients and installers although I guess they are a source of work for the installers!! Fairly highly recommended seems to be Vaillent Ecotek but I think this is at the higher cost end of the scale.
Is there a boiler that has good reliability at a reasonable price or is it better to go with a big name like Vaillent or Worcester and pay more initially? My dad has a servicing contract with Scottish Gas so maintenance isn't an issue but all the same he doesn't want to be calling them out every 5 mins to repair it.
When I get quotes I want to make sure I'm comparing like with like and not getting a cheaper quote because it's based on a rubbish boiler.
Boiler is for a 3 bed house with one bathroom.

We have recently renovated our house and had a new boiler/central heating system installed and the boiler is always losing pressure. Once the boiler has been pressurised to around 1.5 bar it will run perfectly fine while it's on but once the thermostat switches it off it will lose pressure. We have had the boiler checked and there is no water in the boiler that shouldn't be there and no leaks from the pressure release outlet. This happens quite regularly and the boiler will often show 0 bar until re-pressurised!

I have checked all the rad valves and any pipe work I can see and there are no apparent leaks. There are no pipes under the ground floor and no leak patches on any ceilings. Any help would be much appreciated.

I have an old header tank system. I have moved a radiator, now the heating and hot water will not come on?

Do I have an air lock? and if so how do I solve this?

Cold water supply into the system?

I have just moved into a new build and the bath tap only every gets Luke warm and not hot enough to have a bath. All the other hot taps in the house produce extremely hot water but not the bath tap. I have tried turning down the flow and no matter what the flow, temperature still remains low. I have resorted to filling the bath with a pan from the sink as the tap in the sink is red hot!

The boiler is new and is a Worcester 34cdi green star classic combi boiler and is situated right next to the bathroom if this helps.

I've moved into a new flat that has a vaillant boiler. I set the wall controls so that the heating would only come on if it was below 22 degrees (which it hasn't been yet) but noticed that the boiler is constantly making a noise. It got so annoying that I decided to turn the wall thermostat controls to 'off' but it still does it. I assumed that it must be to do with the hot water instead of the heating however then noticed in the manual that I can actually change the boiler itself to 'heating off' so tried this and it now doesn't fire up, unless I'm running hot water...which is I assume what it should be doing.

Why does it constantly fire up when the heating setting is on even if the actual heating hasn't come on? At some point I'm going to need it but the constant on/off rumble noise is so annoying

Any help would be appreciated

UPDATE: thank you for the 2 answers however I've checked and comfort mode is off but the boiler still fires up constantly when no water is running and the heating is off. The only way to stop it is to turn the actual boiler to 'heating off'.

Thanks

Please help.
Can someone kindly explain what are the key indicators are that my combination boiler expansion vessel needs to be replaced?
If the vessel pressure is checked when the boiler is switched on and under pressure would it disperse water when a pump is attached and re-pressuring it with a bike pump?
What I have learned and understand so far is that there should be a release of air from the valve when activated when the boiler is switched on or off.
If the expansion vessel diaphragm is faulty when the air valve is engaged then water should/will come out?
However if the system is under pressure then my understanding is that of course water would come out of the air valve and the person doing the job is trying to con me into getting unnecessary work?
***Update***
Answers to your various comments - The boiler was checked with pressure in the boiler also when given the combustion receipt I compared with a previous receipt and quickly noticed that the device that has been used is out of date of its calibration so gave of incorrect readings. I showed the couple the door and did not pay. I believe that the boiler pressure continues to drop though very slowly and sometimes has gone into the anti frost 5°C area, there is pressure in the boiler though it isn't been driven over 3 bar 2.5bar max which I understand this is good?
It's just the drop in beyond normal pressure which I do not understand, will place a bag over the pipe to see if any water is trickling outside.
Many thanks in advance for your help.

Hi. My 4 year old boiler has stopped working. The display is blank. Had power and fuses checked all ok. Any ideas has to what the problem could be? Thank you.

The combi boiler was fine for a week. Then the radiators downstairs especially sitting room was very low on heat meaning heat is good when the heating is ON for 10 minutes ,then gradually goes down. I called the plumber who installed the boiler and he balanced all the radiators. But still heat wasn't proper to all the rooms.He took the pressure out of the radiators,power flushed too when he initially installed the system. The problem now is that the pressure gauge in the boiler often goes below 0 sometimes to red and heat in radiators comes down. I took the pressure out of the system by adjusting the valve in the boiler and it was fine for a day. Every day now the pressure goes to red or below 0. Also in the bedroom upsatirs where the pipes were taken below the carpet, there is a tapping noise and boiler vibrating sound whenever the boiler starts and also gurggling sound when water starts to flow.When I call the plumber, he isn't responding.I have spent thousands of pounds under the belief that heating issues will be resolved with this installation but all in vain. Why is there heat in raidiators when it is ON for 10 minutes and then heat gradually goes down in the sitting room radiatior?I am also worried about this noise upstairs. Can someone help and try to suggest something to resolve this issue?

Thanks
Sindy

Just moved house. There are microbore pipes to the radiators. I want to replace the boiler with a combi boiler, as there are just the two of us and heating a tank of water twice a day is a waste. I'd also like to install under floor heating in the kitchen, bathroom and en suite. The microbore is working well at the moment and we're in a very soft water area, but it's been suggested to me that microbore is unreliable in the long term. Should I replace it all while doing this other work? Thanks for any advice.