geyser problems - some advice needed please

[SilverNodashi]

I need some advice on a geyser please.

My mom's house has a 5year old kwikot 150L geyer, which we thought packed up last week. There was no water coming through any of the host water taps.

So I went there and decided to open up the geyser to see what's wrong. It's a horizontal one with the cold inlet at the bottom and warm outlet at the top. I opened the "bleeder" (is that what it's called) valve to let out the water and at first it ran very slowly. With all the hot water taps open. The inlet was shut-off. Just to see if we got enough water coming in, I opened the inlet's feed and there was a strong flow of water. So the problem should either be inside the geyser or the pipes. After some time of flushing, the water suddenly came out much faster, like it was getting air through from the taps in the house. After completely flushing the geyser I took off the big round plate where the heater element and thermostat is on and there's no build-up inside, as I expected it to be. The element and geyser walls look pretty much brand new. I couldn't see as far as the hot water outlet due to the angle of the geyser and the limit space in the roof.

But now my mom tells me the hot water is running slower and slower again. There's a copper pipe (looks like 16mm) connected to the hot water outlet, and then into the house's old galvanized pipe, attached to a T-piece Most of the pipes in the roof look fine, but there's something wrong.

My mom did mention that there's some small black stones coming from the hot water pipes, but it's been doing that for quite some time now. And they're tiny, about the size of sugar.

Is it possible to flush the system with something? Or what else can I do?

[AndyD]

Sounds to me like either the washer on the shut-off tap is causing problems or the PRV (pressure regulating valve) is malfunctioning/blocked. A new PRV should be around R300.00 and a new tap washer and jumper kit should be around R40.00.

[SilverNodashi]

I highly doubt that 6 washers could be a problem here

And the PRV is very new.

Like I said, as soon as I emptied the geyser and re-filled it, it worked fine, for a week now (last Saturday) so I suspect lime build-up in the pipes, which are probably 20years old now. Is there a way to flush it out?

[AndyD]

Build-up in the pipes is unlikely unless you live in a notoriously high lime-scale area, even then it's rare, scale tends to build up where the flow rate is slower such as in the cylinder itself. This would have been evident when you removed the element and looked inside. Also scale blockage of pipes would give constant symptoms of slow water flow, not intermittent symptoms.

Sometimes the washer in the shut-off tap comes free from the brass jumper it should be fixed to and it floats loose and causes the water flow to slow and stop intermittently. My primary suspect would still be the shut-off tap followed by the prv as a close second.

[SilverNodashi]

Build-up in the pipes is unlikely unless you live in a notoriously high lime-scale area, even then it's rare, scale tends to build up where the flow rate is slower such as in the cylinder itself. This would have been evident when you removed the element and looked inside. Also scale blockage of pipes would give constant symptoms of slow water flow, not intermittent symptoms.

Well, the problem only started now, so I can't rule-out lime buildup yet.

Sometimes the washer in the shut-off tap comes free from the brass jumper it should be fixed to and it floats loose and causes the water flow to slow and stop intermittently. My primary suspect would still be the shut-off tap followed by the prv as a close second.

I'm not a plumber-by-trade. Would you mind explaining this in a bit more detail to me?

There's an inlet pipe, with a "bleeder valve" (if you can call it that) which I used to empty the geyser. This is on the bottom left hand side of the geyser (Kwikot 150L), then hot water outlet is on top, right hand side) which connects directly to a brass pipe (looks new) and has the pressure valve in. My mom says it did "leak out" a bit last year, in the beginning a bit, but not much. From the pressure valve it goes straight to the house's water pipes.

So, all in all, there's 3 things connected to the geyser - the inlet tap + non-return valve and the pressure release valve. It looks like a cross, with a red knob on the bottom and a black one on top, with a pipe going out the roof, next to the black knob.

I know the geyser was put in 5 years ago, and I suspect the pressure valve as well. But I put the non-return valve in last year, when I worked on a pipes in the garden and noticed hot water coming through. This stopped since I put the non-return valve in.

[AndyD]

I'm getting confused Rudi, something doesn't sound Kosher. The PRV should be on the cold water inlet pipework between the stop tap and the geyser cylinder itself.
Does your installation look remotely like the picture below? If it does then somebody's cut a massive hole in the side of her cylinder which is no laughing matter, it will take an enormous amount of Pratleys to fix it. Seriously, if it doesn't maybe you can attach a couple of Polaroids.

[SilverNodashi]

Hi Andy,

I'm going there tomorrow to see what's going on.

From what I remember, it looks similar to the pic, but doesn't have 2 pipes on the right side, only the top one. And yes, maybe the PRV is on the cold water pipe, but I can't remember.

[Dave A]

I'd also suggest double checking those "black stones" to try to identify what it might be. I've had a disintegrating washer on the tap that stops the cold water supply to my geyser produce something similar, but it did feel distinctly rubbery. Perhaps some rubber seal or valve component in the system is playing up. They tend to expand before they start falling apart...

Sidenote: seems the electricians outnumber the plumbers on TFSA by quite a wide margin

[AndyD]

Sidenote: seems the electricians outnumber the plumbers on TFSA by quite a wide margin

Yeah, I noticed that as well. I work with lots of commercial pump control systems and know enough about plumbing to be dangerous...but a plumber I'm not.

[SilverNodashi]

I'd also suggest double checking those "black stones" to try to identify what it might be. I've had a disintegrating washer on the tap that stops the cold water supply to my geyser produce something similar, but it did feel distinctly rubbery. Perhaps some rubber seal or valve component in the system is playing up. They tend to expand before they start falling apart...

The stones are brittle, like charcoal but not rubber.

Ok, so I took out the pressure release valve, on the inlet pipe, and there was quite a bit of small stones in there which I cleaned out. The stones were significantly different than the black ones in the hot water pipe. They were generally light brown, darn brown and white, but no black stones. I never saw these stones come out of the hot water pipes though.

But, before I took it off, the inlet's water pressure was very strong so I don't think the stones made much difference. Right now the water on the hot water pipes are running full force again. So I don't know if this actually fixed the problem, or not. And I don't see anything in-line of the hot water pipes which could cause problems. From the geyser, the hot water pipe goes to a T-piece. The left side goes to the kitchen - this pipe is a new-ish copper pipe, which I guess was put-in 5 years ago with the geyser. The right side of the T-piece goes to another T-piece, which goes down to the first bathroom, and then right again to the 2nd bathroom.

[Justloadit]

The biggest problem with blocked pipes is usually gunk stuck in the the filters that are usually part of certain parts iin the plumbing line. Usually there is a strain filter before a pressure valve, non return valve, mixers, and also at the end of many taps. They usually have a screw type of end, which is part of an aerator. There is usually a wire mesh here and with time clogs up with stones and debris, and causes the type of flow no flow problems one encounters. Check these before stripping all the pipes.

[wynn]

Sounds to me like you are getting an airlock in the pipework from the geyser to the hot taps.

best way forward is to take the shower head off block the shower outlet off with one hand and a damp towel then open the cold water tap a little and slowly open the hot tap so that the cold water runs back up the hot water line and pushes the air back into the geyser.
Once the air is in the geyser the air relief/vaccuum breaker valve should do the rest.

The other thing that concerns me is the mention of galvanised pipe, it is notorius for scaling up and sometimes is so narrow and tortuous that a loose bit of dirt or scale the size of a match head can cause a blockage.

[SilverNodashi]

hi everyone. I just want to give some feedback. Since cleaning out all the pipes, the geyser didn't give anymore problems again. And it's been just over a month since my mom had the problems. So in this case it seems like the inlet was simply not supplying quick enough to keep the geyser pressurized enough to make it work properly - or something like that?