Hot water cylinder waste pipe & toilet tank waste/overflow pipe both BLOCKED

greep

After I got the old water cylinder replaced with a new one, my plumber tested the waste/discharge pipe, to see if it is drainable.
This is the waste pipe connected to the hot water cylinder (there is a separate pipe connected to the sinks/toilet & it works fine).

It turned out that this pipe is blocked... i.e. does not drain water & the excess of water overflows through this pipe into the apartment...
It means that if there was some emergency (overheat water / pressure of more 4-5 bars), the safety mechanism in the cylinder would discharge the excess of water into the apartment...

He did some investigation as to where this pipe goes (the waste pipe from the cylinder), and discovered there are two of them in total, both of which are blocked.
1. Waste pipe coming out from the hot water cylinder
2. Waste/overflow pipe from inside the water tank in the toilet - when you pour more water in the toilet tank than usual, the excess of water does not come out through this pipe... - it means that if the mechanism that doses the amount of water within the toilet tank breaks for some reason, my apartment would be flooded, since the waste/overflow pipe is blocked...

He did some investigation & both pipes (hot water cylinder waste & toilet waste) come out of the apartment through small white pipes & go somewhere towards the outside of the apt.
In other words, they do not connect to the main waste pipe (where the sinks/toilet) are connected.
It is also impossible to check where the pipes go as it's behind the walls…

1. Does any of you might know why the two pipes do not connect to the main waste pipe in the apartment, but go some different way?
2. Also, where do they go/discharge the waste water, or rather where they are supposed to do it, as they seem to be blocked for me...?
3. Should this be fixed by a management company, as the problem seems to be outside of my apartment?

It looks like both pipes have been blocked for good while, not to say from the very beginning (fortunately, there has never been any emergency with hot cylinder/toilet tank).

The plumber suggested that if we cannot unblock the 2 pipes, the only solution is to connect the hot cylinder waste pipe to the toilet waste pipe & install a new water tank in the toilet, i.e. a newer model, which does release the excess of water down the toilet & not through a separate waste pipe.

Any ideas & especially on where the 2 blocked pipes are supposed to discharge water, and where they might be blocked (what could have blocked them)?

Thanks for your help!

JohnnieK

Those discharge pipe's are warning pipe's and are terminating somewhere outside the block. There's no point going into the main foul because you would not know when they are overflowing.

Under no circumstances should a discharge pipe from an unvented cylinder be connected to the foul drain. You could potentially get boiling water coming out of the cylinder in a fault state and it would compromise the joints causing leaks.

The discharge pipe should be copper for obvious reasons.

greep

JohnnieK wrote: »

Those discharge pipe's are warning pipe's and are terminating somewhere outside the block. There's no point going into the main foul because you would not know when they are overflowing.

Under no circumstances should a discharge pipe from an unvented cylinder be connected to the foul drain. You could potentially get boiling water coming out of the cylinder in a fault state and it would compromise the joints causing leaks.

The discharge pipe should be copper for obvious reasons.

Thanks Johnnie, that’s very helpful!

We’ve been looking for any discharge pipes coming out of the apt. block, but could not find any…
I’m on the 3rd floor - would the discharge pipes from all apartments be connected e.g. vertically & then the outlet is on the ground floor, outside the apt. block? I guess it would make sense, rather than having holes in the wall at each level (for each apt) & potentially water running down the walls… - how does it work, based on your own experience?

My discharge pipe is copper when comes out of the cylinder (1metre approx.), but then joins into a plastic pipe, which is part of the initial
installation.

One more silly question: When the Temp & Pressure valve kicks open, how much water does it discharge? Is it 1, 5,10,50 litres, or can be completely random amount?
My understanding of this mechanism is that it only discharges the amount of water, which is necessary to reduce the temp. within the cylinder to below 98 degree Celsius? Is it correct?

Many thanks again

JohnnieK

They normally have a 90oC lifting point, and that's under pressure so a lot of steam would be involved too. The volume is irrelevant really with those temps and pressure alotlittle water would fly out of it.

It depends really with regards to the discharge. I have seen some going into the main foul but more often they are outside of the apartment.

greep

JohnnieK wrote: »

They normally have a 90oC lifting point, and that's under pressure so a lot of steam would be involved too. The volume is irrelevant really with those temps and pressure alotlittle water would fly out of it.

It depends really with regards to the discharge. I have seen some going into the main foul but more often they are outside of the apartment.

Thanks again, Johnnie.

I've found some additional info online & thought some people might find it helpful

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If the water in the heater reaches a temperature of 210 degrees F, the T&P valve will open and release water until the water temperature is reduced. As water is removed through the T&P valve, cold water enters through the inlet and mixes with the water in the tank. When enough water has been mixed to reduce the temperature, the T&P valve will close. If temperature causes the release, there will likely be a lot of water released.

Most T&P valves are set to open at 150 psi. If the pressure in the tank reaches this level, the valve opens until the excess pressure is released. If pressure caused the release, you'll usually see about 1 cup of water per 10 gallons in the tank (per release).

http://diy.stackexchange.com/questions/25218/what-causes-a-water-heaters-relief-valve-to-discharge-water

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The very last one: If the discharge is outside the apt, would it usually be on the ground floor or at all levels?

Thank you

JohnnieK

Usually at all levels. Remember the overflow where your cylinder is was not originally put in for an unvented cylinder. Unvented cylinder discharge pipes should be brought to a safe terminating point usually at low level.

greep

JohnnieK wrote: »

Usually at all levels. Remember the overflow where your cylinder is was not originally put in for an unvented cylinder. Unvented cylinder discharge pipes should be brought to a safe terminating point usually at low level.

Not sure exactly what you mean, but the discharge pipe coming out of my cylinder goes down (0.5m) & then joins the plastic pipe & comes out of the apt. (not sure where the pipe terminates though)

K.Flyer

Most discharge / warning pipes in apartments if they are not plumbed into the overflow of the bath then they are usually brought down into the basement (car park) area somewhere.
Take a look around the basement for groupings of white pipes, usually with numbers on them.

JohnnieK

Is there a service shaft or boxing around the hot press/ bathroom where the plumber could access to take a look?

greep

Thanks guys,
I checked the shaft beside the apt (on the corridor) & these 2 pipes seem to be going towards the outside of the apt block (on the same level, i.e. not going down) – can’t see much though.
Also called a guy who looks after plumping in this apt complex & he confirmed that discharge pipes were connected to the overflow of bath.

Next steps are to get access to the pipes from under the bathtub to see what’s going on.

What do you think might be common reasons for clogged discharge pipes?
My ideas are:
- Discharge pipes not connected properly (& have never been)
- Discharge pipes are clogged due to sediment/dirt

If both (toilet tank overflow & discharge from hot water cylinder) are blocked, it suggests the blockage must be somewhere at the termination of the pipes (i.e. after the joint). Would you agree?

If so, what’s the best way to drain them?
- Drain And Waste Pipe Unblocker (like this one: http://www.amazon.co.uk/Kilrock-Drain-Waste-Pipe-Unblocker/dp/B000TAT2BY)
- Sink Plughole & Pipe Unblocker (liquid/gel)
- Drain Unblocker (wire) (like this one: http://www.clasohlson.com/uk/Drain-Unblocker/30-8666 ) - might be difficult, as there are two 90 degree bends on the way…
- Any other suggestions?

Thanks

K.Flyer

Best thing would be to get a wet vac onto the pipe and see can you pull the blockage out of it.
Acids can sometimes do more damage than good and blowing through with compressed air may blow weak connections apart.

greep

I got it sorted now

After removing the side wall of the bath, it turned out that the 2 discharge pipes (one from toilet tank & the other from the hot water cylinder) have never been connected to the bath overflow pipe...
They weren't even close... - a number of elements (connectors & pipes) had to be installed to join the two).
Also, the two pipes were blocked with some sort of plastic bags (rolled & put inside the pipes).
After a few days of sitting there, the water eventually started dripping very slowly down the wall - this could have caused serious problems over time.
However, it's nothing compared to what could have happened had there been a real emergency...
I wonder what an idiot did this installation in the first place...

Thanks again for your help!
I can see that boards.ie is a place to look for plumbers & not google

JohnnieK

greep wrote: »

I got it sorted now

After removing the side wall of the bath, it turned out that the 2 discharge pipes (one from toilet tank & the other from the hot water cylinder) have never been connected to the bath overflow pipe...
They weren't even close... - a number of elements (connectors & pipes) had to be installed to join the two).
Also, the two pipes were blocked with some sort of plastic bags (rolled & put inside the pipes).
After a few days of sitting there, the water eventually started dripping very slowly down the wall - this could have caused serious problems over time.
However, it's nothing compared to what could have happened had there been a real emergency...
I wonder what an idiot did this installation in the first place...

Thanks again for your help!
I can see that boards.ie is a place to look for plumbers & not google

And fair play to you for coming back and letting us know. There's nothing worse than a thread that's left in limbo.