With guidance from a local design person we remodeled an old tile shower.The plumber installed a two outlet half inch Grohe pressure balancing and mixing valve which provides user temperature control. The tub outlet is capped and the other outlet feeds a Grohe volume control above leading only to spray handle on a flexible cable on a bar (no fixed shower head).
After installation was complete, the plumber said he was surprised to be told by a Grohe USA rep that the downstream volume control had to come out because the pressure balancing valve would be damaged by any back pressure (for example shutting the volume control valve first). Is this typical for combined pressure balancing/mixing valves? It seems as if illustrations in the Grohe catalog and flyers show what effectively we have installed (mixing valve with volume control/stop downstream). The design person said she never heard of this and puts volume controls downstream of either pressure balancing or thermostatic mixing valves in most jobs (though not always Grohe).
The bathroom hasn’t been put into use but the pressure balancing valve bleeds a little water when shut off so it is necessary to close the volume control to avoid sending a couple gph down the drain. Presumably some backpressure is then inevitable with the volume control closed.
What are our options? I'm not looking forward to tearing out the tile.
Any advice welcome Part numbers available if that helps.
Thanks.
After installation was complete, the plumber said he was surprised to be told by a Grohe USA rep that the downstream volume control had to come out because the pressure balancing valve would be damaged by any back pressure (for example shutting the volume control valve first). Is this typical for combined pressure balancing/mixing valves? It seems as if illustrations in the Grohe catalog and flyers show what effectively we have installed (mixing valve with volume control/stop downstream). The design person said she never heard of this and puts volume controls downstream of either pressure balancing or thermostatic mixing valves in most jobs (though not always Grohe).
The bathroom hasn’t been put into use but the pressure balancing valve bleeds a little water when shut off so it is necessary to close the volume control to avoid sending a couple gph down the drain. Presumably some backpressure is then inevitable with the volume control closed.
What are our options? I'm not looking forward to tearing out the tile.
Any advice welcome Part numbers available if that helps.
Thanks.