Forgive this off topic question. We have a kitchen faucet with a side spray attachment that is giving problems, it is about 12 years old. The manufacturer (Waterstone) has twice sent replacement parts under warranty, but the problem has not been solved. They have sent the diverter valve that fits in the main faucet just above the control lever and the inner parts of the side spray unit actuator button. Twice I have replaced these parts and still there is no water (except a few rare short bursts, so I know the hose is not plugged) coming out of the side spray when I push the button. Are there other areas that I should be looking for a problem? Thanks for any help.
Plumbing Question
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Re: Plumbing Question
#2
A few things that come to mind, and a letter that may encourage them to send an entire faucet replacement 
Subject: Ongoing Issue with Side Spray – Request for Further Assistance
Dear Waterstone Support,
Thank you again for your continued assistance in helping us resolve the issue with our kitchen faucet side spray. I appreciate the warranty support you've provided so far, including the replacement diverter valve and spray head internals.
Unfortunately, after replacing both components—twice—the problem still persists. The side spray fails to function consistently. Occasionally, there is a brief burst of water when the button is pressed, which confirms that the hose itself is not completely blocked. However, regular operation remains impossible.
To help isolate the problem, I have taken the following steps:
Replaced the diverter valve twice, as per your instructions.
Replaced the inner actuator components of the side spray twice.
Verified that the hose is not kinked or visibly damaged beneath the sink.
Observed that water does not consistently reach the spray head, even with all replacement parts installed.
Based on this, I suspect the issue may lie deeper in the faucet body—possibly mineral buildup in the diverter seat, a partial internal blockage, or a restriction in the spray hose or faucet housing itself. I’m also open to the possibility of a defect in the faucet casting that is preventing the diverter from functioning properly, despite replacing its components.
Given the age of the unit (about 12 years) and the troubleshooting efforts already undertaken, I would appreciate your guidance on what additional steps we might take to fully resolve this issue. If necessary, I am willing to send photos or videos showing the problem and the parts I’ve installed.
Please advise on how we should proceed. Thank you again for your support and for standing behind your products.
Sincerely,
[Your Full Name]
[Your Address, if relevant for shipping]
[Your Contact Info]
[Model # or Description of Faucet, if available]
Re: Plumbing Question
#3If you call a plumber 5'll git you 10 he/she'll say:
Rip it out and replace it with a straight connection faucet with an under-counter "T" to feed your spray directly with or without an above counter shut-off.
Diverter valves were popular in bathrooms, especially the "hi-tech" walk-in installations. Lots of problems with the diverters, so when possible they got changed out for a single temperature control feeding 2 cut-offs, 1 for tub spout/shower head and another for the hand or auxiliary spray.
i was fortunate in that the back of my shower's valve wall (sheet rock) making it easy to perform the alteration when the fancy diverter rig pooped the bed. 
Re: Plumbing Question
#4That's kind of a tough one without seeing it.
Really sounds to me like a malfunctioning diverter valve, and since that has been replaced, I'm betting it would have to be a design flaw. I'm assuming that when you push the button on the sprayer, that is supposed to actuate the diverter rather than a valve you turn to do so separate from the sprayer? I think the automatic diverter needs a minimum differential between the water pressure and the back pressure you get from the sprayer assembly. If your water pressure is on the low side that could cause something like this.
Back pressure is a funny thing, a little hard to understand intuitively. Basically too much friction in the branch line for the pressure of the system. Too much friction and you lose all the branch pressure. In this case perhaps the spring holding the diverter open to the branch is too strong for that back pressure and it just runs for a second then switches back to the main faucet path?
Bear in mind that I am speculating wildly on very little info, a good recipe for getting it wrong!