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Gate valve problems

Rickadoo

Active member
Messages
141
Location
North east
Hi everyone,

Recently bought a 40:40 ro and I find that every time I turn the water on I have to readjust the gate valve to get the correct ratio. I would have thought that once set it should remain at a similar ratio, but no. I find that when I turn it back on there is often not enough waste and I have to readjust. Is this normal. I dont use a booster pump and I wondered if fluctuations in pressure, such as neighbour using washer, or missus going for a shower, would make difference. Normally get pressure of 60psi after the filters

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The reason it’s adjustable is for flushing as it should be flushed through before each fill , also you can alter the waist to pure depending where you are in the country as a lower tds will not need to put so much down the drain . A pre set Waist is also a common thing but it will use more water as most seam to be set to 50-50 

 
This sounds odd. Unless you're flushing every time you produce pure?
No. This is without flushing. I don’t touch the tap between fills. Then obviously I have to to readjust it to 50:50

The reason it’s adjustable is for flushing as it should be flushed through before each fill , also you can alter the waist to pure depending where you are in the country as a lower tds will not need to put so much down the drain . A pre set Waist is also a common thing but it will use more water as most seam to be set to 50-50 
Didn’t realise you could get preset wastes. I’m running mine at 50:50 anyway. 

 
Last edited by a moderator:
Hi everyone,
Recently bought a 40:40 ro and I find that every time I turn the water on I have to readjust the gate valve to get the correct ratio. I would have thought that once set it should remain at a similar ratio, but no. I find that when I turn it back on there is often not enough waste and I have to readjust. Is this normal. I dont use a booster pump and I wondered if fluctuations in pressure, such as neighbour using washer, or missus going for a shower, would make difference. Normally get pressure of 60psi after the filters
 
 
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You have kind of answered your own question rickadoo - all of the above will have an effect on your pressure. The only other thing to have any noticeable change is the water/air temperature. Most wont pay much attention to minor differences but the main indication is water pressure - if that changes so will your production rate


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You have kind of answered your own question rickadoo - all of the above will have an effect on your pressure. The only other thing to have any noticeable change is the water/air temperature. Most wont pay much attention to minor differences but the main indication is water pressure - if that changes so will your production rate
 
A change in the pressure shouldn't affect the ratio though should it? Perhaps @spruce or @doug atkinson could set this straight but I always figured if 10 litres per minute went through at 50/50 then 5 litres would be waste and if 20 litres went through then 10 would?

Also, how are measuring your ratio? I met a local lad who told me he made the mistake of measuring his waste per minute and compared it to what he knew his tap gave out, the amount of litres per minute from the tap wasn't accurate. Said he messed up his HF4 and had to buy another.

 
A change in the pressure shouldn't affect the ratio though should it? Perhaps @spruce or @doug atkinson could set this straight but I always figured if 10 litres per minute went through at 50/50 then 5 litres would be waste and if 20 litres went through then 10 would?

Also, how are measuring your ratio? I met a local lad who told me he made the mistake of measuring his waste per minute and compared it to what he knew his tap gave out, the amount of litres per minute from the tap wasn't accurate. Said he messed up his HF4 and had to buy another.


I watched my 4040 start up this morning. The water from the waste started off as a trickle and took time to start flowing into the drain as I would expect it to. The pure that goes into the tank also seems to start slowly. It isn't something that I've ever concerned myself with. The only thing I check from time to time is the quality of the pure being produced once the r/o has settled down. It may need a tweak of the gate valve either way to get the lowest output.

Water temperature has a lot to do with the performance of the r/o. During the summer I had to readjust the gate valve to get back to my 'sweet spot'. If my memory serves me I had to open the gate valve slightly. I thought at the time it didn't make sense as warmer water's viscosity changes and I would have thought that as its 'thinner' I would need to close the gate valve a bit.

 
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When filling I start by dumping everything then adjust the waist to pure ratio on every fill , this helps to flush out the ro s summer time need to dump a bit less than winter but you soon get to know when it’s right 

 
A change in the pressure shouldn't affect the ratio though should it? Perhaps @spruce or @doug atkinson could set this straight but I always figured if 10 litres per minute went through at 50/50 then 5 litres would be waste and if 20 litres went through then 10 would?

Also, how are measuring your ratio? I met a local lad who told me he made the mistake of measuring his waste per minute and compared it to what he knew his tap gave out, the amount of litres per minute from the tap wasn't accurate. Said he messed up his HF4 and had to buy another.
Measure my ratio by timing how long it takes to fill half a litre in a jug on both waste and then pure 

I watched my 4040 start up this morning. The water from the waste started off as a trickle and took time to start flowing into the drain as I would expect it to. The pure that goes into the tank also seems to start slowly. It isn't something that I've ever concerned myself with. The only thing I check from time to time is the quality of the pure being produced once the r/o has settled down. It may need a tweak of the gate valve either way to get the lowest output.

Water temperature has a lot to do with the performance of the r/o. During the summer I had to readjust the gate valve to get back to my 'sweet spot'. If my memory serves me I had to open the gate valve slightly. I thought at the time it didn't make sense as warmer water's viscosity changes and I would have thought that as its 'thinner' I would need to close the gate valve a bit.
Mine started off slowly but I went away and came back 10 mins later the waste was still slow and had to adjust. 

 
Measure my ratio by timing how long it takes to fill half a litre in a jug on both waste and then pure 

Mine started off slowly but I went away and came back 10 mins later the waste was still slow and had to adjust. 
I'm sorry but I honestly don't have an explanation for this. You would think that once a gate valve is set it should continue to allow the same amount of water through the opening. The only factors that would change the flow of water through a partially open valve would be water pressure and temperature of the water.

 
Weird stuff. Sounds like the valve doesn't hold its position properly then.

Can they creep when not under pressure?

Maybe try to set a mark where the handle is when the ratio is correct and see if it moves.

If not I'd change it.

 
Weird stuff. Sounds like the valve doesn't hold its position properly then.

Can they creep when not under pressure?

Maybe try to set a mark where the handle is when the ratio is correct and see if it moves.

If not I'd change it.


This is what I've done with my wheel handle.

I've been thinking about this today @Rickadoo. The paddle or gate is a wedge shaped piece of brass plate sliding in grooves that is raised and lowered on a male threaded shaft that is connected to the wheel handle. The paddle/gate incorporates a female thread. I have a feeling that if the control wheel is turned too far, the paddle can come off the male threaded shaft.

I would take the gate valve off and see if the paddle operates correctly without any 'play'. In other words, can the paddle be 'encouraged' to move open and closed without the wheel handle turning?

My thought is that if the paddle is loose it could drop closed when the pressure is off and when the system is repressurised the force of the water holds the gate/paddle in its dropped down closed position. I have a vague memory of this happening to a gate valve I was working with in my youth - some 50 or more years ago.

If this is the case then it can easily be reset. If not a replacement gate valve will be available from any plumbing outlet, B&Q, Wickes, etc.

TBH will you all, I hardly ever flush my r/o. My gate valve is only cracked open once every blue moon when I flush the system. The water going to waste always seems to be the same.

 
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Weird stuff. Sounds like the valve doesn't hold its position properly then.

Can they creep when not under pressure?

Maybe try to set a mark where the handle is when the ratio is correct and see if it moves.

If not I'd change it.
Thanks mate. Back to work this week. Tried your making a mark suggestion today. Will See what happens

This is what I've done with my wheel handle.

I've been thinking about this today @Rickadoo. The paddle or gate is a wedge shaped piece of brass plate sliding in grooves that is raised and lowered on a male threaded shaft that is connected to the wheel handle. The paddle/gate incorporates a female thread. I have a feeling that if the control wheel is turned too far, the paddle can come off the male threaded shaft.

I would take the gate valve off and see if the paddle operates correctly without any 'play'. In other words, can the paddle be 'encouraged' to move open and closed without the wheel handle turning?

My thought is that if the paddle is loose it could drop closed when the pressure is off and when the system is repressurised the force of the water holds the gate/paddle in its dropped down closed position. I have a vague memory of this happening to a gate valve I was working with in my youth - some 50 or more years ago.

If this is the case then it can easily be reset. If not a replacement gate valve will be available from any plumbing outlet, B&Q, Wickes, etc.

TBH will you all, I hardly ever flush my r/o. My gate valve is only cracked open once every blue moon when I flush the system. The water going to waste always seems to be the same.
Thanks for the suggestions mate, and for giving it your consideration. Will have a look at that if it continues. (Took 20 mins today just getting the pressure to around 55:45)?

 
Yes it does happen I presume it’s do with tap pressure fluctuating. I find this when testing membranes I’ll set the pressure gauge then come back an hour it sometimes changes.

Easy way to measure ratio is hold both waste and pure hose together and as long as the waste is flowing more than the pure you’re fine.

 

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