Groco K pressure problem

[TVD1247]

Requesting any advice here... desperate... bought groco k head repair kit- have assembled and dismantled 3 times... can't see what I've done wrong. After installed, The flapper plate gasket doesn't seem to be flapping down when trying to pump out. Pressure then builds up within seconds while mumping until you cannot move the hand pump anymore.
Thank you for any help!!!

[delmag]

sounds like there may be some sort of blockage on the downstream side. is there a valve that needs to be opened?

[Pendragon35]

I have a Groco K also...I agree with the person above who suggested you look at the downstream side, especially the joker valve.

[TVD1247]

Thanks so much for answering.. we put the compressor to the hose a couple days ago and we had bubbling at the hull- so it seems to not be blocked... 😖 However it did take a bit of time (and a lot of pressure) before the bubbling occurred...

[TVD1247]

The compressor was put on the down stream hose... joker and entire apparatus was rebuilt today with repair kit, again...! We can check the downstream once more I suppose

[wsmurdoch]

Flapper plate gasket? What part are you talking about?

https://www.groco.net/media/file/file/k/-/k-series.pdf

Nos. 5-11 or No.26?

Does the problem occur when the footpedal is pressed? ...or not depressed?

Is the joker valve installed backwards?

[TVD1247]

Thanks for answering... sorry my terms are not so precise! I am referring to part numbers 5-11... as far as the foot pedal goes- when not depressed, after 3/4 pumps, the pressure builds and the head pumping blocks (meaning the pressure is so strong that you cannot hand pump anymore). Joker valve was replaced today, correctly. Thank you...

[Pendragon35]

Be glad you can't pump. My wife had a similar problem that resulted in a geyser coming up!

Is the vented loop working? Is the holdingding tank empty?

[wsmurdoch]

Press on part No. 6 with your finger. It should easily go down then come back up when released.

If that is the case, I'd suspect a plug in the discharge line, closed valve in the discharge line, or a completely full holding tank.

From step 8 in the overhaul proceedure, "You can test the unit by connecting a hose to the inlet and dropping the other end into a bucket of water and pumping." That would be with the outlet hose disconnected from the joker valve discharge (No.38). That separates the toilet from the boat's piping and would let you know if the toilet was the problem.

[delmag]

you could disconnect the hose from wherever it goes, after leaving the toilet, and try pumping into a bucket. that will tell you if it is the toilet or something downstream. to be COMPLETELY certain, you would have to eliminate the hose.

[TVD1247]

Thank you all... I've tested the unit- the toilet isn't the problem, and holding tank is not full. I must have a blockage in the downstream...

[TVD1247]

Part nr 6 goes easily down with the finger by the way

[Smokeys Kitchen]

I have a Groco also and have noticed that if the user forgets to open the seawater inlet the pump gets stiff after one throw and will not work. Opening the inlet releases the water to come in

I do not know your set up, but I have essentially 2 valves controlling the seawater flow. A regular bronze through hull under the sink cabinet that we leave open most of the time and a small bronze feed valve adjacent to the toilet that we open and close with normal use. Both need to be open for use.

[James R]

it sounds like you have an incorrectly set pedal # 37 you can adjust this by removing the raw water inlet fitting#24 and loosing the set screw #22 then set depressing the pedal #37 and tightening the set screw. then let the pedal back up reassemble and give it a try.

You can do this with out having to take the head apart if you can get to the back of the head.

Hope it helps

[TVD1247]

Much gratitude to all your replies... learning a lot everyday.
turns out after blood sweat and tears this afternoon, that our discharge hose has been chipping away from the inside. Vacuumed out many small pieces today after taking it apart at one end. Trying to get the hose out is the next challenge. It seems to be stuck (maybe a T junction) in a blind spot of about a foot, under the bath tub unit.