Halstead Finest Gold-- thermostat or temperature control knob ?

[2 cautious]

My 9 yr. old Halstead finest gold is reluctant to switch itself off after starting from cold , The pressure goes up to 3.5 ish , and I then turn off the electricity , allow the pressure to drop to 2.5 -- 3 ish, and then turn it back on and usually it then works ok.( sometimes I have to repeat this several times)

But in order for it to function as above I have had to reduce the temperature setting on the control knob on the front fascia (over the last few days) now down to 50% of max.

Could the problem be the main thermostat or the control knob --- or something else?

Thanks 2

 

[2 cautious]

Er! nobody!!!-- think I may have answered my own question, as have now had to turn the temp. control knob down to 25% in order for boiler to function " properly".

Would have liked to have had a reply from a "pro" -- in order for me to have had a better understanding of boilers / thermostats etc.

Bye for now
2

 

[Mbear]

Expansion vessel issue. Nowt to do with temp control

 

[tamz]

Where does the pressure sit when it is cold?

 

[2 cautious]

Mbear and Tanz

Thanks for reply, pressure sits at 1 ( or just under ) when cold.

Am now in nervous sweat , with this boiler the expansion vessel is right at the back, ie. "fixed to the wall" with all the pipe gubbins in front.
If ex. v. is the problem , any ideas for an easy fix-- there are no leaks anywhere.
Thanks

2

 

[Mbear]

The vessel needs pumped up, or it's burst and needs replaced or the pipe that connects the vessel to the heating manifold is choked, or the schreader valve is goosed

If its flat, repressurise it.
If the pipe choked, clean it.
if the schreader is goosed, replace schreader valve.
If the vessel Is burst internally, an external system vessel may be the best option. If u replace the Internal vessel this maybe unclude taking the boiler off the wall to do so.

 

[cdodds2004]

much easier to add a external vessel on these boilers they are a pig to change!

 

[2 cautious]

Thanks all-- I have`nt as yet carried out the checks as advised by Mbear, but if it seems that the vessel needs replacing, I will fit an external one.

The Halstead vessel is 7 litre capacity, Screwfix and Toolstation sell 8 litre and 12 litre vessels-- only £2 difference in price between the two sizes, I have read "do not be stingy with the size of replacement vessel"-- so should I fit the 12 litre or will the 8 litre be OK?

Thanks again

2

 

[Mbear]

How many rads?

Generally 8 litre should be fine though