2 port zone valve question...

[Ryster]

Hello,

quick question! I was asked to look at a problem with a hot water system today, however when I got there I found it to be an indirect cylinder that was doing the hot water and a worcester combi doing the heating.

I had a quick look round, checked the immersion for power and then noticed why the hot water was on, the two port zone valve coming from the heating pipework was manually set to open.

So my question is this: Is it ok for the valve to be set to open, obviously the hot water is only going to be on when the boiler is on, but as long as its safe Im not too bothered. Or, is the 2 port linked to the cylinder safety stat and need to be on auto?

As I dont have an unvented ticket and dont really deal with much domestic systems I just had a quick look, iif this isnt safe then I will get one of the other lads to go own tomorrow and deal with it. Or is it ok to leave it as it is, even though it may not be too efficient?


Thanks.

 

[SimonG]

If it's unvented then the 2 port should be auto as part of the unvented cylinders safety features.

 

[PlumbBobBob]

i agree if it's an unvented cylinder the two port should be set to auto maybe there is a problem with it so it was set to manual.

 

[Ryster]

i agree if it's an unvented cylinder the two port should be set to auto maybe there is a problem with it so it was set to manual.

This is what I thought, but my worry is if its on manual is there going to be a problem tonight, or should I be ok to get someone there tomorrow?

 

[SimonJohns]

it can cause problems

just for example, if the valve is manual open, there is no temperature control of the water it may scold or hurt someone

 

[Ryster]

it can cause problems

just for example, if the valve is manual open, there is no temperature control of the water it may scold or hurt someone

Nobody will be using it tonight so thats not a worry.

Is there a chance it could flash to steam, or cause the cylinder to blow off though?

 

[SimonJohns]

it could be possible that the tpv could blow ( if working correctly)

you shouldnt be working on this without ur ticket!

 

[mountainman]

You've not said if it's an invented cylinder or not yet.
Too many variables so this thread could become really overcomplicated.
If in doubt, shut the MV and use the immersion backup until someone more knowledgeable can attend.
If no backup immersion then don't worry, it's unlikely the family will suffer lasting trauma from a day or two without hot water.
MM

 

[Ryster]

You've not said if it's an invented cylinder or not yet.
Too many variables so this thread could become really overcomplicated.
If in doubt, shut the MV and use the immersion backup until someone more knowledgeable can attend.
If no backup immersion then don't worry, it's unlikely the family will suffer lasting trauma from a day or two without hot water.
MM

Its an unvented cylinder. Its an office building with 3 people working in it, so they wouldnt be too bothered about not having any hot water for a day or two.
Will shut it down tomorrow and get one of the lads with an unvented ticket to look at it.

it could be possible that the tpv could blow ( if working correctly)

you shouldnt be working on this without ur ticket!

Im not working on it, Im just interested to know what could happen and the reason behind why somebody has done what they have.

 

[SimonJohns]

Possible outcomes?

Do a search on you tube for water heater explosion

Lmao. And you will to

 

[mountainman]

Most likely reason for the MV being locked open is that the motor has packed up and the valve was opened to give temporary hot water.
The main problem is that the water would get too hot (as no temperature control) if the boiler 'stat is set above 60 deg or if it fails in the on position.
But of course we would hope that the boiler overheat would shut the boiler down before the cylinder TPV got even close to operating.
MM

 

[smileyplumber]

Possible outcomes?

Do a search on you tube for water heater explosion

Lmao. And you will to

I did and I did LMAO

people just dont get it do they I remember a case in Nottingham in the late 80's when some one reconected an old gas fire back boiler they found left in , what they didnt know was that the plumber/ builder had caped off the pipework , natrualy thermostat didnt work any longer and after a short while the boiler got above 100 deg c pipe ruptured all the water instantainiously turned to steam and "BANG" side of house missing and one fatality .