I have a GE GXWH20F home water filter. When the bypass valve is moved to filter position, there is no water flow. I have to put it in bypass to have water. Can this unit be cleaned

The technician is correct and you could take a water sample from a normal faucet and send it in to see how high the particulate and turbidity is. Then you can decide about a whole house filter. They can be expensive so get bids.

b> VALVE SETTING FUNCTIONS OF VALVE POSITIONS FLOW DIRECTION THROUGH VALVE FILTER PUMP - TOP - THROUGH FILTER - BOTTOM - RETURN For normal filtration and vacuuming pool through filter. BACKWASH b> PUMP - BOTTOM - THROUGH FILTER - TOP - WASTE For reversing flow for cleaning filter. RINSE b> PUMP - TOP - THROUGH FILTER - BOTTOM - WASTE For initial start-up cleaning, plus resetting filter bed after backwashing. WASTE b> PUMP - WASTE For vacuuming directly to waste, lowering pool level/draining pool. CLOSED b> NO CIRCULATION PAST PUMP PORT For shutting off all flow to filter and pool. RECIRCULATE b> PUMP - RETURN For bypassing filter, but circulating pool water. May be plumbed for "off-system" pool water access. Ideal for Jet-Air® fittings. WINTER b> VALVE NOT IN USE
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try switiching the ice maker with the water valve solenoid

This is usually caused by the water inlet valve not opening all the way or it got clogged up. The valve assembly will need to be replaced, don;t try cleaning it out it will likely cause a clog further up the tube. They are usually pretty inexpensive and easy to replace. Here is a link that should help http://appliancehelponline.com/referwaterinlet.html

Sounds like you have a bad water intake valve

Disconnect the water line where it comes out of the water inlet valve and see how the flow is when you try the dispenser. Disconntct the water line at the bottom of the freezer door where it goes into the door. If it flows good here it may be freezing in the door. Open the door till it thaws.
If it's good at the inlet valve and slow at the door, some models have a way to put a plug in and bypass the filter.

It might be that you have a restriction at the water supply line serving the fridge. Check it for good flow (have bucket and towels handy!) If supply line is good, then move onto the fridge to check the water inlet valve(s). as newer models have 2 or 3 inlet valves, a main water valve for the entire unit, and possibly one each for the ice maker and water dispenser past the main inlet valve (solinoid).

You can check these by simply shutting off the main supply to the fridge from the house water line 1st, and then removing each water line from the supply side of the fridge and seeing if you have water flow from the house to the valve side. If you do, then reconnect the lines to the fridge valves and see if you can get water flowing to the other side of the solinoid/valve when you have someone try to get a glass of water from the water dispenser, etc.

It is possible that there is an obstruction in the lines, by not very likely. Normally it is a failed water valve(s) (solinoid) that causes low flow or complete loss of flow, especially if you've changed the fridge water filter or replaced it with the "cap" which eliminates filtering of the water.

It is that you'll likely have to replace at least one, maybe more, of the fridge inlet water valves. If you have the time, try to zero in on the failed one by bypassing each, one at a time, until you get water flow. That way, you'll only have to purchase just the replacement valve needed to get things working again.

There is a water solenoid valve that controls water flow. The valve will be near where the water line connects to the unit. You will need a voltmeter to test the valve; put the voltmeter on the two leads on the valve, and then start a cycle. If the valve is getting 120 volts, but not turning on, then the valve is bad and needs replacement

The red button is a pressure relieve valve. If the system is leaking from the valve, try pushing the valve up from the underside of the cap where the valve is located. If this does not work the housing needs to be replaced. You do not have to replace this with a name brand like GE. All you need to do is make sure the housing that you are purchasing is the same size.

Example of Replacement Filter Housing: http://www.freshwatersystems.com/c-107-filter-housings.aspx

FreshWaterSystems.com: The Water Super Store: 1-877-335-3339

If you used a self piercing saddle valve to hook up to the water supply it is probably the source of your problem. These should never be used. You need to install a drill in type which will increase the water flow and probably never clog.