Potterton Flamingo Rs50 - CH Causing Cut Out

[Paul_214]

Hi,

I'm hoping for some help with my home Boiler/CH System.

I have an old Potterton Rs50 and have had a problem these last few weeks with the CH. Boiler seems fine for HW only, but when the CH System is switched on too, it runs for a few (maybe 10) minutes then the pilot and main burner are extinguished with a "ping" noise, requiring a re-light.

System is a follows:

Gravity Fed HW (F&E tank in loft), immersion beneath, pumped CH. So when CH is active HW must also be on.

I get the impression from reading other threads with the same problem on here and other sites that the boiler is overheating when CH is added. Question is why I guess. I suspect air or similar in the system, but don't know how to get it out.

Steps:

• Thermocouple replaced fairly recently (Separate Matter, but just FYI).
• New boiler thermostat with probe: Replaced and probe in thermal pocket (in case stat was at fault causing overheat).
• Pump appears to be working because rads get hot, I have to free it up every autumn as it seizes over the summer with no use.
• Loud clunking noise from system when CH is on, think it's a combination of water boiling and gas of some kind in the system, can hear whooshing in the rads.
• Have bled rads, was a little air in one or two but not much. Noise still happens.
• Can work around the problem by turning boiler thermostat down, rads get hot enough, burner and pilot stay alight but this causes the problem that H/W is only warm and not hot.

Any help greatly appreciated!

Thanks

 

[ianmcd]

Go to the highest point of the system and open a bleed vent and see if you get a good flow of water, if you dont its probably a blocked cold feed

 

[Paul_214]

Thank you for your reply Ian,

By the highest point I'm guessing you mean the highest radiator, which would be the towel rail. Opened the vent, a moment (2 sec) of air then water firing out nicely.

I don't think there are any valves higher than that, not in loft as F&E is open vented. Couldn't see anything else.

 

[ianmcd]

Then sounds like your cold feed is not blocked, so most likely you have a restriction or blockage somewhere

 

[gas112]

flamingo does not have an overheat stat so overheating is not causing pilot to go out
boiler needs a service as its more than likely a dirty pilot injector causing your trouble causing flame to lift off from t/couple . thats providing t/couple is correct type and fitted correctly

 

[Paul_214]

flamingo does not have an overheat stat so overheating is not causing pilot to go out
boiler needs a service as its more than likely a dirty pilot injector causing your trouble causing flame to lift off from t/couple . thats providing t/couple is correct type and fitted correctly

Thanks, I will look in to getting a service. Will/Could this be what is also causing the main burner to extinguish at the same time?

 

[gas112]

main burner cant light without pilot being sensed

 

[FiremanT]

I get the impression from reading other threads with the same problem on here and other sites that the boiler is overheating when CH is added. Question is why I guess. I suspect air or similar in the system, but don't know how to get it out.

Air in rads is not an issue.

The boiler is as basic as they come.It has no idea s to whether you are demanding heat or HW or both. In fact, as a Gravity HW set up, it would be more likely to cut out - if there was an OH stat, which there isn't.

112 has pointed you in the right direction. The pilot extinguishing with heat on must be simply a matter of timing.

 

[jeff the gasman]

Could be vitiation due to burner being on for long periods or pilot drift.
A gas man will sort it.