Calling a plumber or Dave Yates

oilwizard

One of these that it has been working fine then all of a sudden this started to happen story.
I have a Delta shower diverter that I just replaced the packings to try to fix the problem but it didn't work. Here is what happens, If you turn the shower on hot and then pull the lever up to have the water come out of the shower head, you get a pulsating of water that if you let it go for more then a few seconds the pipes start to knock through the wall. But if you turn it on cold and start the shower then go to hot everything is fine. But then the kids flush the toilet or the wife decides to do the dishes and it happens again. But if when this happens and you turn the hot water on in the sink it stops it. Now, right above that bath is the second floor bath. that shower is fine but when the shower downstairs starts to pulsate it affects the sink upstairs. The kitchen sink and downstairs bath sink are fine to the best of my knowledge. I have a softball size expansion tank on the cold pipe going to the boiler, running a thankless coil. Do I need to install a larger expansion tank and if yes does it go on the hot or cold? Also is this the answer to the problem or is it something else.
Now this may be unrelated or not, but every once in a while, the downstairs toilet wont flush right. Its a low flow, nothing blocking it, if you dump a bucket of water in it, like from cleaning the fish tank, it goes right down, but flushing it all it does is swirll around but it doesn't flood. Any ideas?
Thanks,
Joe
aka: oilwizard

ScottMP

Hey Joe

Heres a few thoughts. My first one is that you have a preasure balance issue in the mixing valve. I am not sure if Delta has that or if your model has it. If so change the preasure balancing spool in the valve.

Also have you recently installed a compeditivly priced ballcock in a toilet ? Some of these cheap valves cannot handle the preasure and start to bounce around.

Its definatly a preasure problem since turning on another faucet relieves the high preasure and allows the valve ( culprit ) to balance out.

Scott

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Dave Yates (PAH)

agreed and I'd

get rid of that coil. Darned ungrateful thing. The nerve of being thankless after all you've done for it! You have a tempering valve no doubt & it should be listed as an ASSE 1017 device & installed with a thermal trap. Gotta protect the loved ones from a squirt of 210 degree F skin stripping scalds.

The ballcock pressure wobble thing is real - I've seen that first hand. I discovered that one day when the Tidy Bowl man was squeeking (as in The Fly "Help me" scene) "Surfs up dude". Makes for bodacious waves in the tank! Mansfield valves are the ones I've seen go crazy. Don't bother knocking when this toilets rocking! When the valve really gets going, the rocking of the tank water caused by the float ball being torqued up and down only aggravates the problem.

I've also seen this phenom occur with PRV's close to double check backflow preventers. Your pressure drop in the hot water side can be just the ticket to trigger this problem & yes, If that's only a softball sized expansion tank, it's too small. Get a thermal expansion tank at least 4 gallons in size, or larger. With a coil, you could use a smaller 2 gallon tank, but bigger really is better. New favorite you ask? Flow through style to avoid breeding bugs in stagnant water. Bout $20 buckeroos more, but the family (yours or mine) is worth spending the extra buckage.

And as pointed out, a thermostatic or thermostatic/pressure or pressure only valve can set up this pattern too if there's a point of reference in the system to bounce off of. Hydraulic slide I calls it. In my mind it looks like a Bongo board.

But in the end, I'm almost certain it will turn out to be Murph's fault!

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Online Sheriff \"Murph\"

thanks again dave...

i think?? joe check for some loose or missing bibb washers in some valves ,this sounds like two different problems, that delta must be a dinosaur if its one handle and you can start with hot side, take a couple hours to change to pressure balance, but with an unpredictable usage that may be the best route. that toilet flushing could be a multiple of evil happenings, but probaly not any thing to do with the shower. are all the valves fully open and functional, sometimes the pressure reducing valve will play games against a check ,i have not used the flo-threw type PAH is talking about, but if he says then it must be so!!

Al_3

water prob

A little bit embarresed to say that i have first hand knowledge of a possible culprit, if you have any stop, or stop and waste valves in the piping system,make sure that the arrow on the valve body is pointing in the right direction. wicked noisy, sounds like an ak-47 throughout the entire house as the water vibrates the washer in the valve.

oilwizard

Thanks

Thanks to all of you and your suggestions, I'll try them all.
Joe