Vacu Flush still an issue

[tonyiiiafl]

I had mentioned that my forward vacu flush unit was cycling on and off too frequently. The aft unit is perfect and holds vacuum for weeks at a time when away from the boat. I saw a pin hole in a hose, and also noticed that the duck bill adaptors ere missing, only allowing for one duck bill on each side. I bought the rebuild kit, new bellows, duck bills, adaptors and new nipples and o rings. I installed it all today along with the hose from the pump to the Y valve. Since I was adding the adaptors, I had to move the pump forward a few inches to accommodate them and cut some of the tank to pump hose off so all would fit. So I tested the unit.....yep, still coming on and cycling too often, say every 20 minutes. It flushes fine, and holds water in the bowl. I must point out that the PO had a stripped screw that hods the pump top to the housing. I was thinking of drilling out and tapping with a 3/16” machine screw or seeing is I can find the next size up self tapping screw to get more bite. OH yes, and a Hail Mary as I put it in. Silicone grease was used on all o rings also.

I am thinking TWO issues perhaps :
1) Can the fittings be tightened too tight for the duck bill valves? I placed each vale perpendicular to the other one.

2) I see that the angle of the hose to the Y valve is at a tough angle. Almost like a strain on the fittings.

I have ordered a 45 degree fitting to reduce the angle, and also a sweeping 90 degree fitting to ease any stress on that may preclude a good seal.

Where else may I have overlooked?

[Midnightsun]

Have you tried tightening the clamps? They do not stay perfectly tight forever and this is why they actually make self tightening clamps. https://www.alibaba.com/product-detail/ ... 06922.html

I really think this may be the issue. You could get some real clamps however you do need to get the right size as they are rather limited in adjustment. https://www.amazon.com/HPS-Marine-Stainless-Steel-T-Bolt/dp/B07PWB469F/ref=sr_1_10?dchild=1&keywords=hose+t+clamps+1-1%2F2%22&qid=1598794096&sr=8-10

[bud37]

Source of the post I am thinking TWO issues perhaps :
1) Can the fittings be tightened too tight for the duck bill valves? I placed each vale perpendicular to the other one.

It is possible to over tighten fittings, the same goes for hose clamps....properly fitted hoses should only require secure clamping, nothing excess. You have new fittings and hose so all should be well. The section of the system under vacuum can be tested at a suspect fitting with shaving cream, look for it to get sucked in.

Remember you have disturbed things here that maybe were ok previous....also nowadays new fittings have surprisingly ill fitting ( sealing ) threads, leading to unexpected leakage.

[tonyiiiafl]

That is what I was thinking I may have over tightened the fittings and distorted the duck bills. Like I said, I added the adaptors, so there are 2 on each side now. The shaving cream is a GREAT idea! Back to it on Thursday and going to have a go at it again.

[Viper]

It's common to twist the valves and distort them when you tighten the fitting against them. To help prevent that, spread a little dish soap on the valve flange and the surface of the fitting that mates with the valve. That will help prevent the two from sticking/grabbing each other while you tighten the fitting.

[tonyiiiafl]

I believe hat is what happened. They got distorted. On it!

[tonyiiiafl]

I think I propound the issue. I redid my work using soap so I did not distort the fittings. Then I just TOUCHED the pressure switch and it wont stop pumping at all. I am going to replace the pressure switch. It is also very sloppy when you push it down towards the tank. Stay tuned.

[bud37]

Have close look at the pressure switch as there is may be an adjustment screw.......you are talking about the one on the end of the white football shaped tank...right.

[tonyiiiafl]

yes, that switch. I saw the adjustment wheel. When I turned it the pump now runs continuously and never shuts off. That’s why I am thinking it may be a seal inside. At least it looks like an easy replacement with no you know what to drain out!

[Viper]

You shouldn't try to adjust those as you can cause other issues. Replace it if it's not working properly ($$)