Price Pfister shower valve

Is there an adjustment for the Price Pfister single handle shower valve other than the slotted disc? I can't get this valve to actuate the tankless hot water heater. The sink with separate valves works great - tons of hot water. But, when I turn on the shower (all the way to hot) the hot water heater does not fire up.

Please help!

There is likely a water temperature limit adjustment on the valve. This is so that you can't adjust the valve so hot you get scalded. It may need adjustment so you can get more hot in the mix.

For a showerhead, the feds limit the max flow to 2.5gpm. Depending on your incoming cold water temperature, you may never be able to get a warm shower...it may be hot or cold since you have not only the limits of the showerhead, but the flow sensor on the tankless that can interact so you won't have a continous adjustment if you can't get it to trigger. Also note, that if you are in an area where the winters are cold, or have a deep well, the incoming cold water can be really frigid. That will affect how hot the tankless can make the water, so you may have to readjust that limit (if it works for you) again in the winter, since you'll probably need nearly all hot because the cold will be sooo cold it will limit how hot it can get, and then is so cold you don't want much of it.

Another thing...all new shower valves typically have a pressure balance spool inside of them. If the tankless system has a flow restrictor, the spool may be stuck to one side, and not letting any hot in at all because the pressure is different between the hot and cold supply.

Good luck, and let us know how it goes.

Thanks for the quick response. I'm no plumber, that's for sure. But, I am pretty handy. It took me a while to figure it out but I finally got it. There was an obstruction in the hot water line. Once I got that it all came together. I had to turn all the dials back down so it wasn't scalding hot but now I have continuous hot water.

And, I learned a little more (like stay calm and be patient).

Tankless Heater No Hot Tub Water

jadnashua said:

There is likely a water temperature limit adjustment on the valve. This is so that you can't adjust the valve so hot you get scalded. It may need adjustment so you can get more hot in the mix.

For a showerhead, the feds limit the max flow to 2.5gpm. Depending on your incoming cold water temperature, you may never be able to get a warm shower...it may be hot or cold since you have not only the limits of the showerhead, but the flow sensor on the tankless that can interact so you won't have a continous adjustment if you can't get it to trigger. Also note, that if you are in an area where the winters are cold, or have a deep well, the incoming cold water can be really frigid. That will affect how hot the tankless can make the water, so you may have to readjust that limit (if it works for you) again in the winter, since you'll probably need nearly all hot because the cold will be sooo cold it will limit how hot it can get, and then is so cold you don't want much of it.

Another thing...all new shower valves typically have a pressure balance spool inside of them. If the tankless system has a flow restrictor, the spool may be stuck to one side, and not letting any hot in at all because the pressure is different between the hot and cold supply.

Good luck, and let us know how it goes.

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I know I am trailing onto someone else's older problem, but I have a similar problem. Installed a whole house electric tankless water heater. New tub/shower faucet, both PF and Moen, neither works for hot water in the tub, only the shower. The best the tub spouts lets out is lukewarm water with a horrible spraying all over the place. We have since reduced the main water flow pressure into the house and the water from the tub spout now gets warmer, just not hot enough for a comfortable bath. We have totally removed the anti-scald controls and this did not change anything.

The tankless water heater supplies extremely hot water throughout the house, EXCEPT to the tub spouts. Five different plumbers have all made different diagnoses, including insisting we change the valve from Price Pfister to Moen posi-temp. This was a waste of time and money.

Price Pfister sent us three different valves for their 8000 H series faucets, with no changes. They even admitted they had defective valves, but no amount of time or money has corrected this problem.

Would it be better to replace these faucets with the three handle versions (the ones with a separate hot, cold and shower diverter)? As the showers get hot now, it seems there is something really associated with the pressure, but the plumbers in our area do not seem interested in doing anything else to help correct this problem.

Both baths have all new tubs (in one we have already had to remove and replace a tub with a second one as the first one had a manufacturer defect), faucets and plumbing, as well as new backer board and tile. Obviously I would prefer not to tear out again, but I will if I can get water hot enough for bathing. This problem exists in both bathrooms with tub/shower combinations.

We basically feel we are paying for the best plumbers in town and getting their trainees without supervisory help. What would an experienced plumber do next?

Thanks for any help.

NortexP said:

What would an experienced plumber do next?

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Probably realize that they should never get involved with tankless water heaters.

I'm guessing that the flow from the tankless is far less than the flow on the cold water line, and the balancing spools in the faucets are restricting the flow for the sake of safety. It's a case of two separate technologies not working well together.

Every fixture has 2.5 gal per min flow rate,except the tub filler.
Your tankless may not be able to handle the demand.

I'll second that...depending on where you live, the incoming winter water temperature can be very close to freezing. Tankless systems can only raise the water temperature maybe 70-degrees or so. That will depend on how fast the flow is. Some valves do not have a volume control, so you get the full flow no matter what. that could be in the order of 6-7 gallons/minute. Few tankless systems can handle that if the incoming water is 33-degrees, especially if the heater is not very close to the tub and it cools off some more on the way there. If you could throttle the flow down to a trickle, it would be warmer and maybe even hot.

Do not confuse flow and pressure. Your problem (IMHO) is volume, not pressure...too much water passing by the hot plate too fast; it doesn't absorb enough heat. The solution is more heat (i.e., bigger unit), or less water/minute (a big pain when trying to fill a tub). Bet you have the same problem if you try to fill the washing machine with hot, or even the dishwasher.