Lynx potterton 2 (CH issue resting & Noise)

[Simon08]

I know this boiler is old.

We had an issue with the boiler last year where it lost pressure, we had it serviced and a new pressure relief valve was replaced.

The HW function of the boiler is fine.

It is keeping its pressure.

When we have the CH on it sounds like an airplane taking off after 5 mins of this noise the reset light appears. If you here the noise and run the hot water it stops the noise but a few minutes later it happens again.

Sometimes the heating can be on 3 -4 hrs without this issue kicking in other times it can just be 5 minutes.

I hear the PCB board is a common fault with these but surely if this was the problem then there would be an issue with the hot water?

Just to add all the radiators get red hot.

Can anyone say what it may be?

Trying to find a decent engineer seems to be really hard.

I hope it is just a simple part to replace.

 

[Deleted member 105431]

get a new boiler, you're flogging a dead horse.

 

[Simon08]

Dangermouse thanks for the reply.

You dont think it is just a simple part that needs replacing then?

 

[tryitandsee]

By the sounds of it your pump is probably on the way out. It will be slowing down/sticking and not dispersing the heat quick enough.

The boiler is getting old now, but if a replacement pump keeps it going for a bit longer then that's what I would do.

Others say they are crap, I have a lynx electronic, which has been the best boiler for not being a problem.

 

[Simon08]

Thanks for the quick reply.

Is the pump and easy part to get hold of and can it be fitted yourself or do you have to be corgi registered.

 

[Deleted member 105431]

the pump you can change yourself but it may be an ntc fault (thermister), I take it the hw is fine? Do you have a system bypass?

 

[Simon08]

Yes the HW is fine it, i just this problem when the CH is on.

This subject is a bit new to me, what is a system bypass?

 

[Deleted member 105431]

Yes the HW is fine it, i just this problem when the CH is on.

This subject is a bit new to me, what is a system bypass?

you need a radiator without a trv fitted as a bypass.

 

[Simon08]

All the rads in the house have the valves on which you can turn off the raditor.

 

[Deleted member 105431]

All the rads in the house have the valves on which you can turn off the raditor.

if they all have trv's (thermostatic radiator valves) that could be the problem then. remove one of the thermostatic heads.

 

[Simon08]

Sorry Dangermouse, I have checked and the valves I have are just the standard ones which you can isolate the radiator not the Thermostatic ones.

Sorry.

I really appreciate all your help on this matter.

 

[Agile]

Simon, it may be difficult for you to understand but diagnosing faults on boilers is not that simple.

An old boiler like yours may have several partial faults, clogged pump, sensors out of tolerance, intermittent PCB or connector.

Having said that I dont think there is much of a problem with the pump as the flow switch is still activated. The diverter valve may not be fully returning to the CH position.

As it works on DHW there is no single simple fault with a part for you to change.

A boiler engineer has to check each part out carefully and use his skills to determine exactly what is causing each of the different problems.

Tony

 

[Simon08]

Thanks for all your replies.
I understand that diagnosing a fault on a boiler without seeing it isn’t simple at all.

I just thought with the symptoms I had it may point to something simple.

I will try to get an engineer to come and have a look, but trying to find a good one in our area seems tricky.

Thanks anyway.

 

[superdupergasman]

British Gas will do a fixed price repair on you boiler for £170 - £200
depending on your location

or you could go onto their maintenance scheme
with a breakdown included in the price for about £300 over the year.

The later is a better solution for an older boiler as it will get an anual check over and any breakdowns done for free over the years.

 

[snes]

Had similar probs with my Lynx 11 - system was not v. clean, divertor valve ball was not sealing properly and gave similar noise to your description. A new ball kit (not expensive) system clean and inhibit plus Magnaclean has prevented reoccurence.
Agile will howl justifiably at this homely unscientific advice - but it wont cost much to find out.
Good luck, apologies in advance to Tony