Systemate 2000 faults

Hi all.
I am looking for a little help.
I have a systemate 2000 installed in 2003 hence has done 13-14 years work. I moved into this house in 2013. It has two different issue develop in the last week or so.

1 when the tank calls for Hot water top up it also heats the radiators, so i think some of the valves either side of the pumps have jammed open.

2 the second issue a bit more serious, when the systemate calls for central heating, and the heating kicks in, it does on switch off, even when the thermostat for the house located in the hall hits temp the CH just keeps going, then when the timer tells it to turn off it keeps going,  then when i put the timer switch to off, it keeps going, I have to switch off the entire store to get it to stop. it also gets into sequence of start stop start stp every few seconds which i get around by turning on the emergency heating or hot water for a few seconds then back to boiler again. So i think the circuit board has a fault and needs replacing. As a result i cannot have heating on when no one is home or something will get too hot and go pop. . ....

Bearing in mind the age of the system and the faults i have and the cost i think i will incur as a result £300+ i am half thinking of replacing the system of something more modern, rather than repair a 14 year old system.

Has any one any advice replace or repair? and if replace what with. a newer gledhills 180 ltr st st? i got a quote from BG but it was a little steep.

It does sound like Main ACB trouble.
Can you read the fault codes?
Is there a display?
But with the age etc, might be better to change it.
Boiler same age?
If so cheapest option subject to survey would be a big combi boiler.
The Baxi Eco blue advance is well worth a look.
Should come with 10 year g/tee too. Still have to have a service every year.
Why I say big is ref the hot water flow rate.

Other than that.
You could have a Gledhill Boilermate BP unit. Cheaper, more parts to buy longer to fit.

Or

A Boilermate A class stainless unit Dearer less parts to buy, quicker to fit.

Or an unvented cylinder which will need a discharge pipe

Mike

Mike
I am looking at getting quotes for all the reasons you mentioned. yes a combi could work but yes i only get 13.5 l of hot water per min.
yes my current boiler is 13-14 seasons old (but working well)
I am looking at getting a replacement thermal store solution ideally as the house is set up for it (also solar panels on the roof down the line may benefit), i am looking for something that will last 25 years or so (ie 2 boilers) and is relatively simple and uncomplicated to maintain and understand. (unlike the systemate) any recommendations? i think the ss gledhills  180 ltr should do 25 years?
I was not aware of the need for a drain pipe, could that be plumbed into a drain from a sink of bath, or does it need external draining?
Again Thanks

Stu