How to tell which Valve needs replacing – Hot or Cold?

Leaking Tap

o Leaking Tap

Usually if your tap is dripping from the spout then you need to

Change the valve: Hot or Cold (or both) – if you have a Two Lever Tap

or Cartridge ( if you have a Single lever tap)

Which Valve is faulty?Hot or Cold?
The definitive way to check is to isolate each water feed in turn and thereby establish exactly which Valve (or both) is dripping.  The following tip is only where you are unable to do this so it is rudimentary and not exact.  Without removing the valves to see if there is any thing obvious on your valve to indicate that it is worn, you could run the hot water in your tap. Then turn it off and see if the drip continues to be warm or turns cold. If it turns cold then it is most likely the cold valve that is the problem. If it remains hot then it is most likely your hot valve.

A triflow tap has 3 valves , one for the hot side, one for the mains cold side and one for the filtered cold side. Usually the filtered cold valve and the mains cold valve are the same. If you have a filtered tap with 3 valve and you have narrowed it down to a problem on the cold side then it is far harder to distinguish which cold valve is at fault i.e. mains cold valve or filtered cold valve. What you could do is buy both valves and try the new one in both i.e. test it in one and if drip continues test it in the other one and see which ‘cold’ valve needs replacing. Remember that if you fit a new valve then it is ‘used’ and can’t be returned for a refund if not required.

A Cold Valve opens anti-clockwise and a Hot Valve opens clockwise

Valves with CO AND ACO Symbols 2 LEVER TAP

Valves with CO AND ACO Symbols 2 LEVER TAP

However, if you have a two lever tap and BOTH handles are horizontal when in the off position then you will, most likely, need a valve that opens Clockwise for the cold water i.e. the lever is turned inwards to turn on the cold water, which is actually a ‘hot’ valve. See this diagram here:

bridge lever valves with CO AND ACO Symbols

Bridge lever valves with CO AND ACO Symbols

Please note that if you have a PAIR of Pillar taps e.g. a separate Hot Tap and a separate COLD tap and BOTH your taps turn in the SAME direction ie. both turn anti-clockwise then you have the SAME valve in both the Hot and the Cold i.e a FR9246 Valve in the Hot and an FR9246 Valve in the Cold side.  If they turn in opposite directions ie. one clockwise and one anti-clockwise then you have  an FR9245 Hot valve in the Hot side and an FR9246 Cold Valve in the Cold side.  In other words both the Hot and Cold valves are the same but open in mirror directions so please select the valve you require according to how your taps work.

Single Lever Cartridge Example

Single Lever Cartridge Example

If you have a two lever ‘filterflow’ or ‘aquifier’ tap then the hot side has a valve and the cold side has a diverter cartridge for the cold and filtered cold.

Diverter Cartridge Example

Diverter Cartridge Example

Example of a Hot Valve

Example of a Hot Valve

Summary of useful guides:

7 easy steps to replace a valve
How to change a cartridge in a single lever tap

Our complete section of Guides / Plumbing Tips can be found in the Helpful Tips section. These have been written with the home DIY person in mind so we have tried to keep technical information to a minimum.

Posted in: Helpful Tips, How to identify which Valve you need, How to....

Leave a Comment (3) ↓


  1. Nic R May 23, 2017

    I used your tip of running the hot tap then turning it off and seeing whether the drip is hot or cold.. In my case it the drip was still hot, so I fitted a replacement hot valve. Unfortunately the drip still remains! Is it possible that the cold valve needs replacing as well, or might it be something else? thanks – I have a Franke Planar.

    • Alice May 24, 2017

      Hi Nic. Yes it could be that both valves need replacing OR when you installed the new valve you either over tightened it and damaged it or there is debris still left inside your tap that is causing the ongoing drip. You didn’t say if you tried the simple test again to see if the drip was hot or cold ? Here is a troubleshooting guide to assist you to rule out debris issues etc. New Valve leaking. I also just checked and you did order the 2307R version which has the larger seal than the later version so I can immediately rule out it being a valve issue (in some cases the later valve SP3547 does not work as effectively in Taps that had the original 2307R valve when manufactured).

      • Nic Rodgers May 25, 2017

        thanks Alice. I’ve had a look at that article, and can’t see anything obvious. So maybe I’ve over-tightened it, or maybe it’s the cold valve as well. I’ve just ordered a new cold valve so fingers crossed! thanks


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