Isolation valves on heating system

[Monty_jon]

I have two radiators in the kitchen and hall, but have just found 2 isolation valves under the floor where the piping drops down to feed them.

they are the cheap type 15mm with the screwdriver slot, the ones they sell at the DIY stores for water

Should a heating system have isolation valves on it?

 

[oldbutnotdead]

Not that type, no. They're not designed for continuous high temperature operation, they restrict the flow and the odds of them actually working successfully if you need to use them are low.
Usual reason for iso valves in a domestic radiator circuit is staged building (where, for instance, boiler and most rads are in and working but an extension is being planned or one or 2 rooms are being fully refurbed)- the lever operated ball valves designed for the job are fine and allow you to hook up the extras without draining down the whole system.

 

[Monty_jon]

Not that type, no. They're not designed for continuous high temperature operation, they restrict the flow and the odds of them actually working successfully if you need to use them are low.
Usual reason for iso valves in a domestic radiator circuit is staged building (where, for instance, boiler and most rads are in and working but an extension is being planned or one or 2 rooms are being fully refurbed)- the lever operated ball valves designed for the job are fine and allow you to hook up the extras without draining down the whole system.

That would explain it, the kitchen was not finished when the heating was installed by the previous owner. The kitchen had only been plastered just prior to my purchase

I guessed they wouldn't work but they have not leaked in 15 years so is it best just to leave them alone?

If they did start to leak I'm guessing it would be a dip rather than a total water loss?