Brown water from hot water taps

[WSB]

For those that saw my recent post enquiring about replacing my back boiler to something modern. Looks like this has now been brought forward.

Have started getting brown water coming from my hot water taps. All cold water in bathrooms and downstairs is fine.

I believe that the piping inside the hot water cylinder has perforated allowing the dirty radiator water to seep through.
Does that sound correct or could there be another explanation.

I should add that yesterday, I had the wall thermostat in the living room changed as the old one was going haywire.

Since then, the central heating has been much hotter but coincidentally this brown water issue has occurred.

Could it be that this now extra heat and pressure has burst the pipes in the cylinder.?
Alternately, the water in the cylinder heating up more and disturbing any sludge in the bottom of the cylinder?

Either way, a be cylinder and if I can get someone to do it, the entire boiler system but just wanted some ideas.

Thanks in advance

 

[Stuckinarut]

A room thermostat won’t cause the cylinder to heat up more. It’s either coincidence or something else. Have you checked the cold water storage cistern?

 

[WSB]

A room thermostat won’t cause the cylinder to heat up more. It’s either coincidence or something else. Have you checked the cold water storage cistern?

Thank you.
My understanding is that the pipes that feed the central heating are coiled inside the cylinder. Since we had the thermostat changed there is clearly a noticeable difference in radiator temp as expected.

The cold water is clear, so I'm guessing that the header tank in the loft must be ok. Or am I missing something.

 

[WSB]

Discovered the cause of the brown water.
The CH header tank was full of rusty water from expansion pipe due to old boiler, plus sediment.
When I had the CH drain valve seal fixed (due to leak) the heating engineer bunged the CH header tank.
Some water was lost when fixing the drain valve seal, so the mucky water from the CH header was drawn down.
As (I believe) the piping inside the cylinder is perforated, this seeped out into the main part of the cylinder.
Hence, the brown water through the hot water taps.

Clearly, the cylinder will need replacing which I'll get done as part of my boiler replacement but for now have cleaned out the CH header tank, so at least the water seeping into the cylinder is clean (ish).

Apparantly, the sentinal products that are in the CH system are non toxic, so will be ok for showers etc until how system is replaced.

 

[ChrisJP]

Operating the system for any length of time with CH circuit water continually escaping into your HW system will mean that the CH heating circuit is continually being topped up with fresh, oxygenated water via the CH header tank. This will not only dilute any inhibitor in the CH system but also introduce extra dissolved oxgen into the CH water. Both will markedly increase corrosion of all steel items (like radiators and parts of the boiler) in the system.
You really need to get the hot water cylinder (or at least the heating coil within it) replaced as soon as possible. Heating coils are normally wound into HW cylinders so there should be no need to replace the cylinder.

 

[WSB]

Operating the system for any length of time with CH circuit water continually escaping into your HW system will mean that the CH heating circuit is continually being topped up with fresh, oxygenated water via the CH header tank. This will not only dilute any inhibitor in the CH system but also introduce extra dissolved oxgen into the CH water. Both will markedly increase corrosion of all steel items (like radiators and parts of the boiler) in the system.
You really need to get the hot water cylinder (or at least the heating coil within it) replaced as soon as possible. Heating coils are normally wound into HW cylinders so there should be no need to replace the cylinder.

Great advice and info. Thank you.
Am planning on replacing boiler system and associated parts soon anyway.

 

[Elsa TLC]

If your coil is water is mixing with you hot water , there would more than likely be an Overflow dripping outside.

Because of water in both tanks will try to level up .

 

[WSB]

If your coil is water is mixing with you hot water , there would more than likely be an Overflow dripping outside.

Because of water in both tanks will try to level up .

In this case the water is pushing its way into the cold water tank, except the water in there is a bit warm now.
When that tank was full, it did overflow.

 

[Justin Passing]

Heating coils are normally wound into HW cylinders so there should be no need to replace the cylinder.

That is very much NOT normal.

Not the first time you're all wrong, is it.......

 

[Justin Passing]

@WSB look at the relative heights of the loft cisterns- assuming you have two.
Normally but not always, they're sitting on the floor, so the water level in the DCW (domestic cold water) cistern is higher than the heating water. Therefore you would get clean water into your heating. That's bad, and as ElsaTLC says you'd normally have an overflow from the c.heating header cistern, dripping.
That would NOT give you brown water.

If the heating cistern is raised (someties done) then you could get dirty water in your hot and low -pressure cold, tap water. It's unlikely to be that because it's not usually noticed, because of the relative volume. It would be in the hot as well as the cold water. You tend NOT to get an overfow quickly from the cold cistern, because the volume needed is quite high.

Another way you can get transfer (other than the perforated HW coil) is if the vents of the two systems are over the wrong cistern, or both over the one.

Have a look at your header tanks when you haven't used any water at all for a while, and see if the water is "coming up the ball" on the lower one.

If you have only one header tank you could have the old timer's problem, of a single feed system, using a cylinder called a Primatic (google it).. They rely on a bubble of air to keep the two waters separate. You have to fill them slowly then they're ok, mostly, but you can get a lot of water transfer when things are emptied. They had labels on when new, but a lot were lost. A lot of plumbers would never have heard of them, and been confused. They confuse anyone, they're so rare now.

There are some other possibles but I'll leave them out for now, except that some old systems still have iron pipes!.

 

[WSB]

@WSB look at the relative heights of the loft cisterns- assuming you have two.
Normally but not always, they're sitting on the floor, so the water level in the DCW (domestic cold water) cistern is higher than the heating water. Therefore you would get clean water into your heating. That's bad, and as ElsaTLC says you'd normally have an overflow from the c.heating header cistern, dripping.
That would NOT give you brown water.

If the heating cistern is raised (someties done) then you could get dirty water in your hot and low -pressure cold, tap water. It's unlikely to be that because it's not usually noticed, because of the relative volume. It would be in the hot as well as the cold water. You tend NOT to get an overfow quickly from the cold cistern, because the volume needed is quite high.

Another way you can get transfer (other than the perforated HW coil) is if the vents of the two systems are over the wrong cistern, or both over the one.

Have a look at your header tanks when you haven't used any water at all for a while, and see if the water is "coming up the ball" on the lower one.

If you have only one header tank you could have the old timer's problem, of a single feed system, using a cylinder called a Primatic (google it).. They rely on a bubble of air to keep the two waters separate. You have to fill them slowly then they're ok, mostly, but you can get a lot of water transfer when things are emptied. They had labels on when new, but a lot were lost. A lot of plumbers would never have heard of them, and been confused. They confuse anyone, they're so rare now.

There are some other possibles but I'll leave them out for now, except that some old systems still have iron pipes!.

Many thanks. Interesting reading.
The house was built in 1965 to give you an idea of pipe ages.
The CH header sits on a plank directly on top of the large DCW header tank.
That strikes me as strange and not a good idea. The expansion pipes are set up correctly.
The water in the DCW header is warm to the touch. I can only think hot water from the cylinder is somehow getting pushed back into the DCW header up the pipe that it normally feeds the cylinder with cold water.
Prior to me cleaning out the CH header tank, it was full of brown rusty water and sludge.
NB both ball valves are operating fine.

 

[Justin Passing]

Well it makess maintenance of the cold one tricky!

OK so it's not a Primatic.
If water as seems to suggest is getting through the HW cylinder coil, the level in the CW cistern should be rising, and if you shut off the supply to the CH one, that should empty.
It's late but I can't think of any other possibilities.
If you drain enough CH water, to lower than the HW cyl connections, (you can just turn the rads off one or both ends so they just hold their water), then undoing the lower union on the cyl should show an amount of clear water coming out.

Those 22mm pipes over the tops of the cisterns are vents, by the way. The water almost all expands back up the 15mm ones!

Cold water cisterns usually only get warm if the immersion heater is on and faulty, boiling the water over the vent. It can't come up by convection from the cold bottom of the cylinder..... Not a horizontal is it??
I'm suspicious there's something else.

 

[WSB]

Thanks. Certainly does make maintenance difficult. The CH header tank sits right above the cold water tank ball valve.
When I've woken up I'll take another look and go through your message on detail.
Things should all get resolved when I get the whole system and all tanks etc replaced. Got British gas bloke coming today.
Will most likely be gong for another conventional boiler.

 

[ChrisJP]

That is very much NOT normal.

Not the first time you're all wrong, is it.......

Well, I've fitted several heating coils into HW cylinders this way so I'm certainly not wrong. I don't intend to reply to any more of your rather rude comments.

 

[kidgreen61]

Well, I've fitted several heating coils into HW cylinders this way so I'm certainly not wrong. I don't intend to reply to any more of your rather rude comments.

I'd love to watch you do that