Combi Boiler (Glow-worm HW Express 80) not always firing up?

[martyp]

Hi all,

My Hot Water Express 80 was in my house when I moved in in 2005. The house was built in 1991 and I haven't serviced it at all and I have no idea if it has been serviced at all.
It's been working great except for occasionally needing the pressure topping up.
Last week though when running the tap upstairs in the bathroom no hot water was coming out. I switched the boiler off for a minute then back on and after a minute hot water came out.
Tonight it played up again. The central heating had been on a fair bit today by the way. I turned the kitchen hot water tap on but the boiler didn't start up. I switched it off, checked the pressure was ok (about 1.5bar, I increased it to 2). Due to the difficulty in reaching the pressure valve thing I accidentally put the pressure up to 4...
I started the boiler up again and the pressure dropped to about 3.5 after about a minute. It seems ok now but I'm worried as to why it isn't 'triggering' when the hot tap is turned on...
Please can someone advise what it might be (in fairly basic terminology please as my knowledge of boilers is very minimal).

Much appreciated.

 

[muggles]

1.5 bar cold is plenty for the central heating, could be a sticky flow switch giving you trouble with the hot water, get the boiler serviced, should be done annually anyway.

 

[mickyg]

start saving, this is as old as your house! Needs replacing, its obsolette as far as the manufacturer is concerned

 

[martyp]

Thanks all, I might look into getting that part replaced. How can I reduce the pressure from 3.5 or would it go down naturally with that little downward pointing pipe outside the front of the house?
How much does it cost for an annual service roughly? I mean would it be like a car service or could it possibly be a huge bill as it hadn't been serviced for so long?
I would have to really save hard as I'm pretty much struggling financially as it is (as are so many) and it'd probably be a few years before I could save about £5k for a new boiler...