Kingfisher 2 50 CF Gas Manifold 402856

[Hottapplumbing]

Hello fellow Gas Engineers.

My Parents have an ancient Kingfisher 2 CF50 boiler, which I've tried to explain is time to update to a new model.
They are in their 80's so the thought of the disruption sends them into a spin.
I'm Gas Safe Registered based in Greenwich they live in Devon. The engineer they are currently using has recently replaced a thermocouple but the last time I visited it seems to me that the boiler no longer has the ability to modulate correctly.
The control setting is ineffective, turn the boiler dial to any setting and the boiler will just run at full rate.
As cylinder has no stat this causes the water to get incredibly hot (semi pumped system, gravity hot water, no two port diverter valve)
The Gas control valve Compsit 402856 G.C.N 391 745. is obsolete and no longer available( I couldn't find one).
I see that there is a gas valve available (SIT NOVA 402906) but the configuration is different, can the gas pipe work be updated to fit this. or can the existing Gas valve be stripped and repaired.
Ideally I'd like to rip the whole lot out and install a combi boiler:83:
Appreciate all advice.

Andrew H

 

[stevetheplumber]

if its running at full blast i would be looking at the boiler stat and not the gas valve there is no modulation on these boilers its on or of but if the stat was faulty it would be boiling over in the loft just turn the boiler stat down and see if it goes off at temperature hot water temp is set by how high you run the boiler stat

 

[Hottapplumbing]

Thanks Steve.
Will do as you suggest on next visit.
the burner does switch off but only if you have it on the lowest setting, almost off.
Even this according to my father is producing very hot water.

Regards
Andrew

 

[jtsplumbing]

Good chance its the Boiler stat, Think they were made by Ranco, could still be available

 

[Hottapplumbing]

Yes that is exactly what I've got on order.
cheers JTS..

 

[drip-dry]

You may well find it is just the thermostat control knob that is broken and not turning stat spindle...lack of basic boiler knowledge would suggest you get someone in who knows what they are doing...take it you have given them a co2 alarm..

 

[Hottapplumbing]

Thanks Drip-dick
will take that on board.

 

[dancinplumba]

Co2 alarm ?

 

[Hottapplumbing]

Ventilation is all good now I've given them the riot act about covering up some of the vents in winter.

Since they moved into the property in 2009 I've insisted on a CO2 alarm as they have a Gas fire as well as this antiquated boiler system. Have tried on many occasions to offer to update this but get the same reaction. Dons't help that my father has dementia.

 

[Dotty]

Thread moved.

 

[tamz]

The boiler doesn't modulate. It fires up at full rate then switches off with the stat. Stat temperatures are around 130ºF at min and 180ºF at max.
If it is gravity hw with no cylinder stat the hw temp is determined by the boiler stat so turn it much above min and the temperature at the taps will be above 60ºC.
You either control the hw temp with the boiler stat or you can fit a basic cylinder stat to it if you like which will give some control but when the heating is on the cyl stat won't work.
A C plan will give total control of the hw temp.
These are pretty bulletproof boilers and will run forever.
Btw the kingfisher 2 has a SDT that will cut the boiler off if it spills.

Another btw
If you don't fit a cyl stat think about tmv's at the taps