Expansion Vessel losing all pressure in hours?

[Cluelessnewby]

Hi All,

Bit clueless here, but wanted some advice if possible.

We had a new 200ltr unvented system installed recently. All seemed fine, however the CH kept turning off and rads going cold.

I checked the EV in the loft, and it's pressure gauge had dropped to 0. I opened the valves up and filled back up to 1.5bar (on advice of the fitting plumber). This got the rads going again, but two hours later it's back to no pressure/rads off?

When the rads came back on originally, I could hear them bubbling away (filling up?) quite loudly. I bled them, two released air...

The only thing I've done recently since the install is turn the gauge on the Worcester boiler up from 1/2 way to full.... could that be a problem?

Overflow seems fine, no water came out the EV when I checked...

Plumbed said air possibly escaping the system somewhere, or water leak in the ground floor pipes, but could try a sealing solution.

He's v.good, but is there anything obvious I should look for/try before rushing them back out? It seems a bit extreme the EV drops pressure in two hours?

Thanks,
CN

 

[Harvest Fields]

What size vessel is it? and how many radiators are there? Also the higher you set the temp on the boiler, the more expansion there will be in the radiators.

 

[Cluelessnewby]

What size vessel is it? and how many radiators are there? Also the higher you set the temp on the boiler, the more expansion there will be in the radiators.

Thank you for the reply!
I'll have to get up into the loft and have a look in the morning to see the size, i'm unsure myself.
There are only 7 radiators in the house. I've turned the boiler down now and also will turn the thermo down in the living room.

Could this possibly be a cause for draining the pressure?

 

[Welder]

Is the new UVC the only work you had done relating to the htg system?

 

[Cluelessnewby]

Is the new UVC the only work you had done relating to the htg system?

Hi, yes.
There were some other things associated with it, like a new pump as the old one was clogged up (that's set to max setting), 2 number 2 valves, moved some electrical work about (the control panel went from the tank on 1st floor to ground floor), but nothing else.
UVC was put in now in prep for a new bathroom strip out and install.

 

[Welder]

Do you mean the new pump is set to its highest speed?

 

[Cluelessnewby]

Do you mean the new pump is set to its highest speed?

Yeah. As the CH wasn't coming on, plumber wound it up to max setting,from 2 to 3

 

[Welder]

Where is the boiler now? When you look outside, there should be a discharge pipe for the boiler. Is the wall wet or stained below it? Once you've re pressurised, does the boiler pressure gauge rise a lot more - into the red or to say 3 or 4 bar?

 

[Welder]

Hmm. Pump up to 3 to get CH going!! Over to you HF end of my knowledge... but sounds somewhat odd...

 

[Cluelessnewby]

Where is the boiler now? When you look outside, there should be a discharge pipe for the boiler. Is the wall wet or stained below it? Once you've re pressurised, does the boiler pressure gauge rise a lot more - into the red or to say 3 or 4 bar?

Boiler is in the utility room. I'm not v.experienced with this sort of thing. I went outside hoping to see a pipe dripping or a wet wall, but the only thing I had in a protective case was a black pipe pointing up, not down as I'd expected.

I havent looked at the boiler in the utility room once i'd pressurised the EV.

 

[jtsplumbing]

All sounds very strange ? can you put up some photos ? and some of this black pipe !

 

[Cluelessnewby]

Hi @jtsplumbing - I've attached two of the black pipe that comes out of the boiler/utility room.
Hope it makes some sense to you, I have no idea with plumbing at all, so it's like trying to speak Dutch 😳

 

[king of pipes]

You need to get a engineer in bud to many things it could be . cheers kop

 

[Cluelessnewby]

You need to get a engineer in bud to many things it could be . cheers kop

I was worried that'd be the answer, but I think I'll have to.
The guy that fit the EV and UVC is back to install a complete bathroom next week, i'll get him round for a look before then...

 

[Harvest Fields]

I was worried that'd be the answer, but I think I'll have to.
The guy that fit the EV and UVC is back to install a complete bathroom next week, i'll get him round for a look before then...

Probably for the best mate

 

[Paul Styper]

Hi All,

Bit clueless here, but wanted some advice if possible.

We had a new 200ltr unvented system installed recently. All seemed fine, however the CH kept turning off and rads going cold.

I checked the EV in the loft, and it's pressure gauge had dropped to 0. I opened the valves up and filled back up to 1.5bar (on advice of the fitting plumber). This got the rads going again, but two hours later it's back to no pressure/rads off?

When the rads came back on originally, I could hear them bubbling away (filling up?) quite loudly. I bled them, two released air...

The only thing I've done recently since the install is turn the gauge on the Worcester boiler up from 1/2 way to full.. could that be a problem?

Overflow seems fine, no water came out the EV when I checked...

Plumbed said air possibly escaping the system somewhere, or water leak in the ground floor pipes, but could try a sealing solution.

He's v.good, but is there anything obvious I should look for/try before rushing them back out? It seems a bit extreme the EV drops pressure in two hours?

Thanks,
CN

Sounds like the diaphragm in the pressure vessel could be ruptured. What happens then is that there's nowhere for the expansion when the system heats up so it dumps the excess pressure through the pressure relief valve to outside. When the system cools down the pressure also goes down with it usually to zero thereby shutting down the boiler. The easiest way to check is to poke a small screwdriver in the schrader air valve (like a car tyre valve) on the expansion vessel and push it in. if water weeps out of it, the diaphragm has ruptured.

 

[dan_the_plumber]

If you press the pip down on the expansion vessel and water comes out, the expansion vessel is knackered.
If not, pump expansion vessel back up to system pressure (typically 1.0 bar)
The Shraeder air valve on the expansion is probably loosing air. You can buy a Shreader valve extension tube from city plumbing for £11.00. Stick that on, it's like replacing the valve effectively. Job done.
It is probably an engineer job though, since there are a few finaties, draining the boiker etc.

 

[Harvest Fields]

If you press the pip down on the expansion vessel and water comes out, the expansion vessel is knackered.
If not, pump expansion vessel back up to system pressure (typically 1.0 bar)
The Shraeder air valve on the expansion is probably loosing air. You can buy a Shreader valve extension tube from city plumbing for £11.00. Stick that on, it's like replacing the valve effectively. Job done.
It is probably an engineer job though, since there are a few finaties, draining the boiker etc.

Just because there is fluid inside the vessel. It does not necessarily mean the diaphragm has gone. Sometimes condensation builds up inside the vessel and just needs to be drained out.

 

[Cluelessnewby]

Hi All, just to update you following your comments, the plumber came back out, released air from the pump he'd installed, switched all bleed valves around to make it easier to bleed and took all air out of the system, recharged it all and added 3 tubs of sealant to the system. Appears to have done the trick thankfully!

 

[dan_the_plumber]

Just because there is fluid inside the vessel. It does not necessarily mean the diaphragm has gone. Sometimes condensation builds up inside the vessel and just needs to be drained out.

Never heard of that before. How does the moisture get into the air side of the vessel to begin with?