unvented cylinder discharging

[Monkfish87]

I have an unvented cylinder, it is a range tribune he. I called a plumber to look, so far he has changed the temperature relief valve which is on the side of the cylinder and also tookthe expansion vessel down and checked. He said there was no pressure in the expansion and has reset it to 3bar.
All this work and water is still going through the tundish even when i am not heating water. When i turn my immersion on there is a loud hissing sound.
What should his next steps be as i dont want to keep paying him to change parts that arent required.

Untitled

• Monkfish87
• 1 Dec 2013
• 1

Untitled

• Monkfish87
• 1 Dec 2013
• 1

Untitled

• Monkfish87
• 1 Dec 2013
• 1

 

[PrenticeBoyofDerry]

Could be a thermostat problem.

 

[Blagard]

You have two relief valves, have you been able to identify which it is that is passing water?

Your plumber may have changed the wrong one. It is possible but unlikely the pressure on a relief valve is set too low.

The loud hissing on an immersion heater is a problem. You could disconnect each in turn to see which it is. If an immersion boils the water it creates a problem with both temperature and pressure. What did the plumber say about it?

 

[Monkfish87]

The plumber thinks that the problem may be with the pressure reducing valve off the mains set at 3 bar. He is pricing me up for this and the pressure valve which connects intoit. There has been no mention of issuses with the thermostats as they are boiling the water.
The cylinder bypasses water even when the cylinder is cold and there is no heating. The hissing comes when the thermostats are turned on and the water is heated there is also an increase in the amount of water going through the tundish.
Hope that made sense

 

[Blagard]

The mains PRV is set at a standard 3 bar - that should not be a problem and in any event the PRV you have is adjustable and can be serviced. You can even stick a gauge on it to check the downstream pressure.

You have not answered which of your two T&P relief valves are passing water. They both discharge into the same tundish and one of them is opening - Please answer Which one?

Have you identified yet which immersion is hissing?
What did the plumber say was the cause of the hissing? - this is the second time of asking!
Have you checked that the immersions are switching off via the thermostats?

If you can't answer simple questions how can you expect any help!

Edit: Ah well, you can lead a horse to water but......

 

[PrenticeBoyofDerry]

As I read it no water when water cold but when heated discharge at the tun-dish and boiler hissing.
Had new temp relief valve fitted, but still doing this.

*Cylinder stat kicks in at 65 degrees C
*Hi-Lim at 85
*TRV at 95

If the cylinder stat is not kicking in nor the hi-lim stat, I would say take a look at the stats.

 

[hazetimesfive]

All this work and water is still going through the tundish even when i am not heating water

 

[xr4x4]

I think the hissing is a red herring, immersions do create a faint hiss when heating water, I believe eps when cold.

When's the last time you stood next to the immersion when heating the water..!

 

[Blagard]

I think the hissing is a red herring, immersions do create a faint hiss when heating water, I believe eps when cold.

When i turn my immersion on there is a loud hissing.

"Loud" suggests something amiss. If not for that adjective I would tend to agree it is a red herring

But it seems the OP has had no response from the plumber or perhaps not even raised that issue with him.

I am actually beginning to wonder who the "plumber" is!

 

[PrenticeBoyofDerry]

All this work and water is still going through the tundish even when i am not heating water

Sorry, don't know how I missed that, I am sure it was not originally there!