View Full Version : Question about plumbing a Riobel thermostatic valve - Help!

08-13-2011, 10:36 AM
I am installing a new bath/shower unit and am using a Riobel FI22LC thermostatic valve with shutoff. I am a little confused based on what the store told me and then now looking at the diagrams in the installation manual. My confusion is regarding the tub filler and showerhead copper line.

According to store, the left and right output is constant flow. This means I need a shutoff valve for each of these lines. I have this for the hand shower, which will be using the right side output. The left side output will remain capped.

My question is regarding the tub filler and shower head line. The store recommended (and sold me) a tub filler with diverter. They said to run one line using the top output (the one for the shower head) and run line the down to the tub filler. Just before the tub filler, I will put in a "T" and then run the copper back up to the shower head. They assure me when the tub filler diverter is open, the pressure will not be significant enough to allow any water from the shower head. Once the diverter is closed, the shower head would obviously be in operation.

I have attached a rough diagram below. I was originally going to use the left side output, however there would be constant flow on this side and I would need a shutoff valve for the tub filler instead of the diverter.

My questions are:
1) Did the store give me good advice? Will the showerhead be dripping when the tub filler is open?
2) Should I go back and get a tub filler without a diverter and then buy a separate shutoff valve and then use the left side output and have the top output for only the shower head? I will use the tub as a shower 90% of the time. I am thinking that once the temperature is set on the bottom valve I can simply open the top valve for the shower each time and avoid the tub filler unless my wife is having a bath.

Thank you in advance for your help. It's the first time I have done a shower/tub combo and want to make sure I am making the right decision!

08-13-2011, 02:10 PM
NO! NO! NO! A tee will NOT work. You need a "twin ell" designed for use with a diverter spout. The water from the valve goes into the "front" opening, the shower riser goes into the rear opening, and the spout, usually with a 3/4" thread, not a 1/2" one, goes into the front.

08-13-2011, 04:29 PM
Thank you for your advice. I searched for the twin ell and now understand. I will go to the local supply store on Monday and pick this up as well as review options for the 3/4" spout if needed.

Other than this, everything would be fine, I assume? I will try to run the lines back to the shower head as directly as possible.

Thank you again.

08-13-2011, 06:27 PM
It WILL be needed because the spout opening WILL be 3/4". Sometimes the spout and twin ell are avavilable as a set. It makes no difference HOW you route the shower line, OR the spout line, OR what kind of pipe you use, for that matter. This is one case where it is immaterial.

08-14-2011, 02:52 PM
Great, thank you again for your help. I will be heading to the supply store tomorrow and will buy the 3/4 filler and double ell.