Does anyone have experience with thermostatic shower valve, particular Grohe
valve? I am trying to calibrate it but no luck. It either produces very hot
or very cold water, no in between. I am trying to figure out if the valve
does not work or I am doing something wrong.
Calibration *should* be easy; instructions are at
However, it sounds like there's something wrong with yours - you should have
a nice smooth transition from cold to hot. Some things to check:
1. Are both cold and hot water pipes and inlets clear of all debris?
2. Are cold and hot water pressures more or less the same (no kinked pipes
on one side or the other, or unusual drains on one side)?
3. Are both stops fully open?
4. Are the cold and hot water supplies connected to the correct sides?
5. Is the hot water supply at least 15 degrees F above the desired
Beyond these, it's possible the thermostatic valve itself is obstructed or
defective. However, I'd give Grohe a call before trying to take it apart.
We did get a defective Grohe volume control valve once, and once we were
able to convince them of that, they rushed out a replacement to us.
I followed these instructions but I still have strange results. Water is
either very hot or very cold regardless if I set handle to 100 degrees or 70
degrees. I am trying to figure out if the valve does not work I am doing
anything wrong. I have inverse hot and cold water connections to the valve.
Is there way to check if the valve works. The instructions say that
connection to the valve should not be soldered. So I use thread adapter that
I screwed into the valve. But the opposite side of the adapter I soldered to
the pipe. Of cause the valve body became hot when I soldered thread adapter
to the pipe. Can this damage the valve. However, I can't imagine other way
to attach a pipe to the valve. Any help and/or advise would be greatly
Are you saying you've reversed the hot and cold inlets? You don't want to do
Well, I know with some thermostatic cartridges, you can put them in hot
(>120 degree F) water and see if they "pop" but I don't know if the Grohe
does anything visible (haven't had any problems with ours).
I imagine you already know the answer here - it's a paraffin cartridge, and
it (and other parts) can certainly be damaged by excessive heat. I'd guess
it'd probably be ok up to around 180 degrees F, but any higher is certainly
a risk. And at the price of those cartridges (around $130), it's not a risk
I'd care to take.
Here are five different ways of handling it:
1. Wrap a damp rag around the body of the valve when soldering; should keep
it cool enough if you're quick with the torch.
2. Remove the cartridge and any other sensitive parts before soldering.
3. Use compression unions to connect to the water supply.
4. Use stainless mesh flexible supply connectors to make the hookups. I've
only personally seen these in 1/2" and smaller, but they're probably made
in 3/4" also.
5. (What I did) Solder long "legs" on the threaded adapters before screwing
them in to the valve. I used right-angle bends and soldered on approximately
3 foot lengths of pipe. When I attached these to the water supply, the
connections were so far from the valve that heat wasn't an issue. (I still
wrapped the rag around the valve for paranoia's sake.)
first of all the Grohe thermostatic valve that I have does allow reverse hot
and cold water installation. The manual clearly states this. It is not clear
for me however, what has to be turned 180 degrees for that.
What do you mean "pop" in very hot water? I still need some reliable way to
check if the valve is OK or not. The problem with soldering is that volume
valves can be disassembled before soldering, but thermostatic - not. At
least manual does not say anything about it, just not to solder pipes to
valves. I would really love to disassembling the valve to make sure it is
Ah, sounds like it would be good to figure that out.... The Grohe web site
has diagrams for all their valves - go to www.grohecatalog.com, enter your
part number, and check it out.
I just did that, and found for mine at least (an older model) they list a
normal and reverse thermostatic cartridge, which sure makes it sound like
it's a separate part to reverse hot and cold. (Or perhaps it's just to make
it turn the other way.) In our case, we moved the controls to the opposite
wall in redoing the shower, but flipped the pipes to make up for it.
Some thermostatic cartridges actually have a little piston that pops out
above a certain temperature, sort of like a turkey pop-up timer. But I
don't know if the Grohe ones are like that.
Check the Grohe site - the exploded diagrams also indicate what's needed
to take things apart. And I've already mentioned a bunch of ways to do
the soldering safely.
We put in a valve than senses the hot and cold water pressures but doesn't
care about the temperature. This works just fine: flush the toilet and the
shower valve maintains the same mix.
For most purposes, this is BETTER than a slow acting thermostat type valve.
I think you're confusing shower thermostatic valves with those intended
for other purposes. Shower valves that meet ASSE 1016 are *fast* acting,
at least in terms of human temperature perceptions.
Pressure-balancing valves are fine in their place, but don't have the flow
capacity to handle a multiple outlet setup like the original poster had.
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