Knackered Boiler?

[garry81]

I've currently got a Ravenheat 820/20 RSF which I acquired when I bought the house two years ago. I currently have several issues with it and am wondering whether it is worth paying for all the problems to be looked at an fixed or just save a bit more and replace it.

The first problem is that the heating is always losing pressure. When the system runs you can hear a drip hitting the bottom of the case every 5 seconds or so. Previous engineer we had look at it said the AAV was broken. Does this sound likely or could it be something more serious?

Secondly, the hot water is now playing up. Last summer the plate heat exchanger was scaled up and had to be unblocked. At the moment, every time you run hot water the boiler fires but water comes out so hot it burns your hand even though the hot water temperature is set to the lowest setting. The boiler also cuts out, the water runs cooler and then it fires up again. When the boiler runs cool you can hear a sort of noise similar to a kettle boiling.

I don't mind spending money getting it repaired although I'm wondering if this is like an old car which now requires lots of money chucking at it. I found the invoice which said it was installed in 1995.

Thanks in advance

 

[bengasman]

System rather dirty by the sound of it. Whatever else happens, that has to be solved.
FAQ will tell you how to flush if you want to do it yourself, or get somebody in to do it for you.

 

[mickyg]

I'm not always quick to suggest replacing boilers, but in your case I can't see any point in throwing money at this boiler. As ben has said it sounds like the system maybe suffering from corrosion which is contributing to the problems, no doubt due to constantly topping the boiler up with fresh oxygenated water to compensate the leak, a vicious circle really.
Get a new boiler and system flush and don't waste any money on this old beast would be my advice.

 

[Agile]

This sounds odd if an engineers visits and diagnoses problems to include a leaking AAV but never changes it !

You say the plate HE was cleaned last summer. That would indicate a dirty system!

I must be getting forgetful, as I dont even remember the Raven 820 having a plate HE.

Tony

 

[garry81]

Thanks for all the advice so far. I think it may be time to scrap it.

I have noticed that the water problem is more of a problem when having a shower in that the shower goes cold and then hot again (Mira Excel). If I run a bath or kitchen tap the boiling hot water temperature remains more constant although you can hear the boiler constantly refiring.

 

[bengasman]

Bear in mind that the dirt must come out of the system, preferably before the new one goes in. Corrosion is the number one killer of boilers, any make, any model, any size.
Have a magnaclean installed with the new one.

 

[Slugbabydotcom]

I do a lot of work for landlords who always prefer a boiler to be fixed than to be renewed. If I had yours in front of me with the information given I'd be looking to fix it.
Theres an outside chance that the drip you hear is a leaking heat exchanger.
Tony's right these dont have a plate heat exchanger.
Most of these boilers have stepped modulation so are not suitable for a shower.
You have had 14 years out of this boiler which is better than the current design lifespan of about 8 years
I couldnt give perfect advice without seeing the boiler. There may be other underlying faults. I reckon it could be fixed if you can find the right man to do it, but depending on your financial situation it might be best to move on and get a new boiler that can meet your demands.
I don't know what your finances are like but you may be eligible for a warmfront / staywarm grant

 

[Agile]

I must be getting forgetful, as I dont even remember the Raven 820 having a plate HE.
Tony

Tony's right, these dont have a plate heat exchanger.

Good, so its not senile dementure yet then!

Clearly the OP needs a competent engineer and not a cowboy who claims to clean a plate HE when the boiler does not have one.

Although the boiler could be repaired, after 14 years it is really time to seriously consider getting a new one. The design of the 820 does not give very good temperature control on hot water and the fully modulating current models are far better in this respect.

Tony

 

[garry81]

Thanks for all the advice. The previous engineers who have looked at it were ones found in the local rag. I have since been recommended a local guy so he is coming round tomorrow to give his verdict.