JELD-WEN do not recommend any components of the fire doorset are changed. If a component replacement is required throughout the life of the doorset, it is critical that the components exactly match those listed on the relevant fire certificates and data sheet for this specific doorset.
Changing the specification of any components will invalidate product certification, and warranties and present safety and performance risks in a fire.
Please contact ukwarranty@jeldwen.com if you require further help.