Potterton 28 odd behaviour?

[kevins]

Hi All. As this is quite an old boiler ‐ I'm hoping there are many people familiar with this issue.

The boiler works normally for hours (hot water and/or radiators).

Then, it appears to be resetting itself every few seconds. This may only be a problem for radiators?

Hot Water and radiator set to max. Temperature display LEDS shows water reaching about 60%. Then a loud relay clicks, the temperature leds go off and just the far right one lights (central heating fault). In less than 1 second, the temperature LEDS come back on and the relay clicks.

Although the LEDS show a fault for less than a second, there can be 2 to 5 seconds between the loud relay click.

Is this a common known issue? There are no error codes to read, it is only in the fault state for half a second.

All advice greafully received.

 

[kevins]

Are there two temperature sensors? One regulating the water temp and one to "trip out" the system if it goes over temp?

 

[ShaunCorbs]

Yes

But might be pcb

 

[kevins]

OK.
I left the unit shutdown for a couple of days.
Today, I used hot water for around 20 mins before it shut down. The fault light indicates central heating fault but central heating was not selected (only hot water).

Should I still start by changing the pcb?

 

[ShaunCorbs]

I’m guessing heating over temp ?

 

[kevins]

I’m guessing heating over temp

 

[kevins]

After the boiler has been off for 48hrs. It goes to fault mode on central heating at 30 degrees after 20 seconds

 

[kevins]

But I can run hot water slowly for 20 mins

 

[kevins]

Boiler rumbles more than it used to

 

[cjg]

when was it last serviced, when you say rumbles does it sound like water swishing.

 

[kevins]

Never serviced (to the best of my knowledge). Just safety checked annually.

sounds like a noisy kettle, not a swishing sound. I'm expecting a heat exchanger issue, but due to the age of the boiler, I want to replace the whole thing.

My house, not a rental.

I would have it serviced, but I've never had much luck finding good engineers. The ones I've met at other properties believe "if it ain't broke, don't fix it" Their service amounts to blowing some dust out and checking for complete combustion.

Now I have a demonstrable fault, it may be worth placing a service call (greasing up and bending over etc etc) but this is probably just money down the drain, better to request a new boiler install?

On this occasion, the money I've saved on servicing will almost pay for a new boiler

I will pay for a service contract on the new boiler. I was hoping to put off the installation for six months until I had installed new rads and filter.

Many thanks for all the help.

K

 

[kevins]

I'm thinking heat exchanger because the pulling mains water (for hot water) keeps it running whilst recycling the warm radiator water does not.

due to age of boiler, I don't want to invest in an engineer call and a new exchanger when other faults must be waiting to surface.

 

[ShaunCorbs]

Change the boiler as anything is just putting good money into bad if your looking to change soon