Or, could your PRV be allowing some flow-by during the night or day when there's no-one running water, and it's allowing the pressure on the domestic side to creep up to the point it drips out the safety valve?

Since there are three 22mm pipes to hook up and the 15mm outflow you would probably otherwise need a 'union' to be able to make the connection to the tundish. My understanding is the pressure reducing valve ( 3 bar) is to maintain a level and balanced pressure for cold flow and thus level flow and equal pressure on hot water.

I presume this safety valve it in case the pressure on the domestic side increases too high for some reason? Unvented heating system has a caleffi pressure reducing valve, 3 bar with 6 bar safety release valve. These Caleffi inlet control groups are designed to control the pressure on the mains supply of an unvented hot water cylinder. This includes a specific connection for a balanced cold water take offs and a dedicated connection for an expansion vessel.

This multibloc is comprised of a pressure reducing valve, a pressure relief valve, and an internal check valve. You can change your choices at any time by visiting Cookie preferences, as described in the Cookie notice.

Comprising a pressure reducing valve, a pressure relief valve and check valve, fitted all together in a single inlet control multibloc valve.

uk/caleffi-altecnic-inlet-control-group-valve-unvented-3bar-22mm-109104007 220114 Caleffi Altecnic Inlet Control Group Valve Unvented 3Bar 22mm https://www. It incorporates pressure reducing valve, pressure relief valves, check valve, and filter in a single valve design.I would imagine the safety release valve same as the one on the actual hot water tank are there to act if pressure goes to high. Specially shaped diaphragm to give accurate pressure regulation in response to changes in downstream pressure. Caleffi is a decent make, I understand, but these fellows - well, the safety-release-valves - are prone to allowing a drip through after they've been activated.