Low Pressure Alpha 240P

[Thomasba]

Apologies for this if it's ben answered before but a search for similar came up with hundreds of replies.
I have an Alpha 240p Combi and the water pressure for the hot this morning was too low to fire up the boiler. The cold water pressure is high and the pressure gauge on the front increases if I open the fill loop tap under the boiler.
Over the past 6 months I have had 5 different BG engineers round all for no Hot water who have either done nothing in 1 case changed the Fan in another, the diaphragm in another and pressure switch in another, and cleaned some bits in another.
I'm on the BG HomeCare 200 scheme and I know I can call these guy's out time and time again and it doesn't cost me anymore, but is there something I can ask them to do to get the problem fixed once and for all? The Boiler is now about 10 years old and has been service annually ever since. but this business with the hot water is really beginning to hack me off. I've mentioned the difference in pressure to them all but they don't seem to be interested. I'll stop whining now and leave it up to you guys' (The experts)!

 

[Gasguru]

If the water flow rate is poor from the hot taps it would appear the inlet filter/flow restrictor is blocked. Does the hot water demand light come on?

The pressure gauge on the front of the boiler should be around 1 Bar (ie in the green section) when the radiators are cold.

These boilers are better made than most and have many years life left in them.

 

[gas4you]

As gasguru says or if inlet is clear I would suspect the plate heat exchanger scaled up and need cleaning, or in my case I would replace.

 

[Thomasba]

Well the flow rate is about 5lts per min and that's with the Hot Water working and at 8pm in the evening, I'll try and remember to measure it in the morning which is when I had the problem. It was definately slower this morning though. Is 5lts per min high or should it be better?
The pressure gauge on the front is in the green

 

[Gasguru]

5 lites/min is very low - the flowrate should be much higher - call out BG again.

 

[gas4you]

I think the manufacturers state around 9 or 10 litres /min for this model, that is the norm for a 24Kw combi