Crosswater 2006 model thermostatic shower valve - temperature issue resolved

10 Jan 2022
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United Kingdom
Hi everyone,

I've recently has temperature control issues with a Crosswater 2006 model thermostatic shower valve. I believe Crosswater changed the valve design in 2007 and finding information on the 2006 model was difficult so I thought I'd post some info here in case it's helpful to others. I've also had issues with a second Cosswater valve at another property so I've noted that below as well

The attached IMG_6982 shows the shower valve with 3 dials / 2 outlets, the duct tape is temporary water proofing until I'm satisfied the valve is adjusted properly and the face plate can be more permanently waterproofed to the tiles.

The key point to note on the faceplate are the two fixing screws (chrome dome head cover caps) which are to the upper right and lower left of the central temperature dial. This gives away that it's a pre 2007 valve behind. The 2007 models onward don't appear to have the visible fixings or the fixings aren't arranged diagonally like this.

The problems were;
  • Property A - 3 dial / 2 outlet valve - has worked fine for many years, in the last month the shower temperature became gradually more tepid. Initially thought the boiler might not be delivering hot water, turning up the boiler water output temp had some effect but it could not produce a hot shower. Had the boiler serviced and this didn't resolve the issue. Removed and changed the thermostatic valve without improvement. Turned off the cold water supply feeding the boiler (effectively turning off the hot water supply) and opened the hot tap on my kitchen sink which flowed albeit slowly. This indicated cold water was being fed into the hot water pipework somwhere in the house and the thermostatic valve is the most likely point. Removed and cleaned the two non return valves using limescale remover and a toothbrush. They were not obviously dirty nor had obvious limescale but having played with the valves the spring is weak and the valve design means it doesn't seat properly on closure. Cleaning the NRV's resolved the issue in my case. For context this property has cold water supply direct from main without a tank and hot water supply direct from Combi boiler (no tank).
  • Property B - 2 dial / 1 outlet valve - temperature and flow control issues. Water temperature was tepid and didn't change with adjustment of the thermostatic dial. I changed the thermostatic cartridge and cleaned both non return valves without success. The issue turned out to be a pump in the water supply to that property. The incoming cold water supply fed into a loft tank then a pump. The pump would kick in when a tap was opened so until that happened there was little pressure in the water supply to the shower valve, which it did not like. Once the pump was removed the shower valve worked as expected. This property also has cold water supply direct from main without a tank and Hot water suppler direct from Combi boiler (no tank).
Other photos / videos attached
IMG_6970 - shows the 3 dial / 2 outlet valve with faceplate removed. For both shower valves I found the installer had tiled over the non return valves, which are positioned perpendicular to the control dials. The centre of each NRV is 50mm up / down from the centreline of the dials and I used a 38mm diamond hole cutter to expose the NRV's. You can see the pencil outline of the faceplate will cover the new holes.
IMG_6908 - shows the thermostatic cartridge, which is brass / copper construction NOT plastic.
IMG_6794 - shows the Non return valve, mine didn't have the wire filter around the outside.

This site has the only diagram I could find for the 2006 model valve and lists the various parts.

In both cases above the thermostatic cartridge was not the problem and they're expensive to replace so I suggest pay attention to the NRV's first, remove and give a thorough clean and descale, then consider if water supply pressure might be an issue.


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Noted but it comes across as a very long question. Maybe better posted under “your projects”?


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