New Grohe cartridge - poor flow/pressure - whazzup?

[Bruce Brugler]

Cartridge on our Grohe shower broke (stripped gear). Opened it up and replaced with new cartridge 47-157-000 that fit perfectly. The old one didn't have a part number but this was the only one that I could find that looked right. It has little tabs on each side to hold it in place.

Shower now works but pressure and flow are very low. I opened again and checked for obstructions (none) and if I'd fully turned the water back on (far as I can tell you just turn the valves 90 degrees so the slot is perpendicular to the flow to close then parallel to open - they are fine). Same problem.

Any ideas? thanks

 

[Jeff H Young]

remove shower head does water come out normal? plugged? turn off stops remove cartridge, open stops does water blast out? hold a rag or bucket in front of it. if none of this helps put old one back in and try it. look everything over look for debris are you sure stops are open all the way most are 1/4 turn not sure if all are

 

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[Bruce Brugler]

remove shower head does water come out normal? plugged? turn off stops remove cartridge, open stops does water blast out? hold a rag or bucket in front of it. if none of this helps put old one back in and try it. look everything over look for debris are you sure stops are open all the way most are 1/4 turn not sure if all are

Thanks - water flow from the bath spigot is fairly anemic as well as the shower spout with the head removed. I removed the cartridge - yes water blasts out each stop. Sadly I threw out the old cartridge. No debris evident in new one. Played with stops and they do appear to be 1/4 turn and are fully open.

I'm wondering if the cartridge has been altered to meet newer low-flow specs? The shower does work but it's not nearly as strong as with the old cartridge.

 

[Jeff H Young]

Im guessing its a pressure ballancing cartridge but it should work as good as original did. tub and shower valves One of my pet peeves about modern shower and tub valves is many of them are slow on tub filling. Only other thing I can tell you is time how long it takes to fill 5 gallon bucket and check water pressure then check with grohe . at leas youll have accurate info as opposed to saying slow or kinda slow. I cant imagine cartridge is differant Did you see anything differant about it at all?
I would really blast the water through with cartridge removed to be sure nothing was stuck

 

[Bruce Brugler]

Im guessing its a pressure ballancing cartridge but it should work as good as original did. tub and shower valves One of my pet peeves about modern shower and tub valves is many of them are slow on tub filling. Only other thing I can tell you is time how long it takes to fill 5 gallon bucket and check water pressure then check with grohe . at leas youll have accurate info as opposed to saying slow or kinda slow. I cant imagine cartridge is differant Did you see anything differant about it at all?
I would really blast the water through with cartridge removed to be sure nothing was stuck

Yes it's pressure balanced. Fill rate thru tub spout is 2 GPM. Cartridge looked identical to the old one, neither had a part number listed.

 

[Jeff H Young]

2 gpm not good at all any idea of your pressure? Dont know what to tell you other than contact grohe.
You say it flowed well befor . I find other brands like delta are horrible on filling a tub. My old house from 1955 with 2 handel price phister would blast but youd get a scald when showering if someone ran another fixture. Sorry Cant help more

 

[Bruce Brugler]

I contacted Grohe... they replied quickly and suggested I check the two pressure-compensating check valves, one on each side of the cartridge. Turns out one was broken! Got a pair on order, should solve the problem.