I recently had a leaky TRV changed under a service contract. The engineer did not drain down the heating. Apparently he just plugged the vent pipe and boiler supply pipe in the header tank. Water did not flow out when he removed the old valve because air could not get in, and this was on a downstairs radiator with quite a head of water.
Is this common practice? I need to replace all my other ancient TRVs and hope to use the same technique.
Is this common practice? I need to replace all my other ancient TRVs and hope to use the same technique.