Fill valve

Seaswimmer

Hi folks.

looking for some advice.

Our gas boiler Glowworm flexicom 18hx tripped out last night with f11 and f20 errors.

I noticed the gauge was at 0 bar so i reset the boiler and bled a few radiators. It stayed running but the pressure never increased.

I had a look at what I think is the fill valve in the hotpress. see attached pictures.

The red and black valves were fully open so i fiddled with the threaded spindle on top of the valve. I turned this clockwise and it seemed to increase the pressure to 1 bar. Now however the pressure is at 3 bar. The heating is running fine but I am not sure what state the vales and the spindle should be in?

i could bleed a radiator to lower the pressure but with the current valve configuration I am not sure if the system will top up/pressurise itself again.

Any help greatly appreciated

agusta

Close the red valve and black valve and then bleed a radiator untill the pressure is back down to 1 1/4 bar

Seaswimmer

agusta wrote: »

Close the red valve and black valve and then bleed a radiator untill the pressure is back down to 1 1/4 bar

thanks.

and do I open them again or leave them closed??

agusta

Leave them closed and monitor the pressure on the gauge for the next few days.your looking for between 1 and 1 1/4 bar pressure when the heating system is cold

Seaswimmer

what does the adjustable screw on the top do??

agusta

That unit is an automatic fill valve.If you had the red valve and the black valve open,the automatic fill valve can be used to top up the system.the screw adjusts the pressure on the automatic fill valve.
They really should not be used because if you had a leak in the system you may not know you had a leak.it would be better to keep the valves closed and monitor the pressure on the gauge

Seaswimmer

agusta wrote: »

That unit is an automatic fill valve.If you had the red valve and the black valve open,the automatic fill valve can be used to top up the system.the screw adjusts the pressure on the automatic fill valve.
They really should not be used because if you had a leak in the system you may not know you had a leak.it would be better to keep the valves closed and monitor the pressure on the gauge

thanks augusta for the extremely useful information.

A final question. Should the system keep up its pressure indefinitely or do all systems need topping up. Is falling pressure over time a sign of a leak or is it just something that happens.

agusta

Falling pressure is a sign of a leak or something wrong with the heating system.If this happens its better find and fix the problem.If you have to top up system once a year its ok.

Tom44

No point in checking pressure vessel ?

agusta

Tom44 wrote: »

No point in checking pressure vessel ? [/QUOte
Good point alright,but the pressure is now at 1 to 1 1/4 bar and i would think it is being monitored ,if the pressure does drop then maybe its a leak or a fault in the heating system,ie pressure vessel etc.The system more than likely just needed to be topped up

Seaswimmer

Tom44 wrote: »

No point in checking pressure vessel ?

our old system had a red pressure vessel in the hotpress.

Not sure where the new one is. Possibly in the attic above the hotpress as the new cyclinder takes up the entire hotpress.

What should one check for on a pressure vessel??

I haven't had a chance to bleed radiators yet to drop pressure so I will l do this tomorrow morning and monitor.

The pressure hasn't really dropped with the valves closed so I am assuming there is no leak anyway.

Its at just below 3 bar running and about 1.3 bar cold.

agusta

It should not be 3 bar running,Your may have a problem with your expansion vessel.you will have to take the pressure out of the system and then check the pressure in the vessel,you are looking for 1 bar pressure.the schrader valve on the vessel is identical to ones fitted on most tyres.
ps well done tom:)

agusta

You can also check the 1/2 inch copper pipe outside the property and see is it dripping a little when the heating is on.it would be situated on the outside wall behind the boiler

Seaswimmer

agusta wrote: »

It should not be 3 bar running,Your may have a problem with your expansion vessel.you will have to take the pressure out of the system and then check the pressure in the vessel,you are looking for 1 bar pressure.the schrader valve on the vessel is identical to ones fitted on most tyres.
ps well done tom:)

Would letting air out of the expansion vessel have the same effect as bleeding a radiator?

agusta

no,there are not related

Wearb

agusta wrote: »

no,there are not related

And could cause the pressure problems you mentioned.

Also the pressure valve mentioned by agusta is notorious for continuing to leak once activated.

Adding extra rads to a system with a previously closely sized expansion vessel would also cause similar problems.

Seaswimmer

at home today so did a bit more investigating.

Pressure drops right off to 0 bar when heating is off but runs at nearly 3 bar when on.

I found the expansion tank in the attic. Its fairly new so should be ok.

See attached picture. There is a schrader valve on it but no gauge.

My fill valves are still closed. I am not sure why the pressure fluctuates so much.

Wearb

Seaswimmer wrote: »

at home today so did a bit more investigating.

Pressure drops right off to 0 bar when heating is off but runs at nearly 3 bar when on.

I found the expansion tank in the attic. Its fairly new so should be ok.

See attached picture. There is a schrader valve on it but no gauge.

My fill valves are still closed. I am not sure why the pressure fluctuates so much.

That sort of fluctuation is usually caused by undersized (did you add any new rads) vessel, discharged vessel or blocked vessel.

You need to get it checked out. Not good to have it operating like that.

K.Flyer

The Flexicom HX (Heat Only) range can be very temperamental. It is designed primarily for open vented systems and doesn't have a pressure switch built in.
Common problems are caused by poor circulation issues, air circulating in the system etc.

Seaswimmer wrote: »

Pressure drops right off to 0 bar when heating is off but runs at nearly 3 bar when on.
I found the expansion tank in the attic. Its fairly new so should be ok..

As the HX is fitted to a sealed system and its ramping from 0 bar cold to 3 bar hot, this points to issues with the expansion vessel. Trying to read the label, it looks to be a 24 litre, sufficient for most systems.
The "pre-charge" air pressure in the vessel may be set incorrectly, this would explain the large pressure swings.
Only when the pre-charge is set correctly and the system pressure brought up to a nominal set point, e.g. 1.25 bar when cold, then you can start to see where the other issues may be as the pressure should not fluctuate too much from cold to hot.
Leaking pressure relief valve may need changing if its dripping as well.
As mentioned earlier auto filling valves cover up for leaks. The auto setting on yours also needs to be checked to ensure it is not the cause of the high pressure gain.
Make sure to shut the valve off by turning the black wheel under the valve clockwise.

jca

Is there air in the pressure vessel? Did you try depressing the centre of the Schrader valve to see what comes out? I had the very same symptoms as you and it turned out the pressure vessel was ruptured and full of water. If that's the case with you the vessel needs to be replaced urgently as there is no "spring" in the system. I have an automatic filling valve too but I leave it turned off and let in water as needed( about once every 6 month's)

K.Flyer

jca wrote: »

Is there air in the pressure vessel? Did you try depressing the centre of the Schrader valve to see what comes out? I had the very same symptoms as you and it turned out the pressure vessel was ruptured and full of water. If that's the case with you the vessel needs to be replaced urgently as there is no "spring" in the system. I have an automatic filling valve too but I leave it turned off and let in water as needed( about once every 6 month's)

The expansion vessel is one of the most neglected parts of a heating system during the service schedule.
Depressing the valve to check for air or water is only part of it. If the vessel is in serviceable condition, the pre-charge pressure needs to be checked and set using the correct methods.

jca

K.Flyer wrote: »

The expansion vessel is one of the most neglected parts of a heating system during the service schedule.
Depressing the valve to check for air or water is only part of it. If the vessel is in serviceable condition, the pre-charge pressure needs to be checked and set using the correct methods.

I understand that, checking it by just depressing the Schrader valve isn't scientific but it would tell if it was ruptured or not and hence the urgency required to fix it. A system filled to the neck with water using only the 3 bar pressure relief valve for expansion relief isn't safe, as you know. Since I got mine replaced I drain down some water so the gauge reads zero. I then check the pressure in the vessel using a tyre pressure gauge, it always creeps down a bit from year to year, I pump it back up to 1.5 bar and use that as as a baseline.

Seaswimmer

Thanks all.

so to check the expansion tank I can put a gauge on the Schrader valve and it should be 1.5 bar.

If over let air out?

If under pump to 1.5 Bar??

if water comes out its faulty??

Seaswimmer

Wearb wrote: »

That sort of fluctuation is usually caused by undersized (did you add any new rads) vessel, discharged vessel or blocked vessel.

You need to get it checked out. Not good to have it operating like that.

no new rads but new system in mid December.

New cyclinder, new expansion tank, zoned heating and lots of new plumbing.

Was fine up to last week.

Tom44

jca wrote: »

I understand that, checking it by just depressing the Schrader valve isn't scientific but it would tell if it was ruptured or not and hence the urgency required to fix it. A system filled to the neck with water using only the 3 bar pressure relief valve for expansion relief isn't safe, as you know. Since I got mine replaced I drain down some water so the gauge reads zero. I then check the pressure in the vessel using a tyre pressure gauge, it always creeps down a bit from year to year, I pump it back up to 1.5 bar and use that as as a baseline.

If pressure vessel need filling up with air, then water side has to be left open with hose on drain cock.
If not you cannot fill pressure vessel to it's full 100% volume with air.
Pressure is not an indication of a fully functional pressure vessel.



There's a reason God gave us plumbers & service engineer's.

jca

Tom44 wrote: »

If pressure vessel need filling up with air, then water side has to be left open with hose on drain cock.
If not you cannot fill pressure vessel to it's full 100% volume with air.
Pressure is not an indication of a fully functional pressure vessel.



There's a reason God gave us plumbers & service engineer's.

That's what I said, water pressure gauge reading zero, pump up pressure vessel to 1-1.5 bar. I don't know what God has to do with it, or are you being like the other plumbers, slash, service engineers on here...A smartass.

Tom44

jca wrote: »

That's what I said, water pressure gauge reading zero, pump up pressure vessel to 1-1.5 bar. I don't know what God has to do with it, or are you being like the other plumbers, slash, service engineers on here...A smartass.

Water pressure at zero.
But you can pump in 1/4 ltr of air and you'll get 1.5 bar air pressure.
But vessel will still be 95% full of water.
The point your missing is that the water side has to be OPEN for a reason.
That's what your missing.

No need for name calling, there's a reason there's experts in their chosen profession, no matter what that profession is.
They know more.

We can't share what took us 20+ years to learn just by a text post here, but we do try to help.

jca

Tom44 wrote: »

Water pressure at zero.
But you can pump in 1/4 ltr of air and you'll get 1.5 bar air pressure.
But vessel will still be 95% full of water.
The point your missing is that the water side has to be OPEN for a reason.
That's what your missing.

No need for name calling, there's a reason there's experts in their chosen profession, no matter what that profession is.
They know more.

We can't share what took us 20+ years to learn just by a text post here, but we do try to help.

In my particular setup the pressure vessel is up beside the copper cylinder, the highest point in the system bar the air valve which is slightly higher. Draining off any water will empty the pressure vessel straight away. The problem with the experts in the plumbing section is that they assume everyone else is stupid. Over in the car section, experts help people all the time without displaying this superior attitude, calling a spade a spade, a car is a lot more complex than the average home heating system.

K.Flyer

jca wrote: »

In my particular setup the pressure vessel is up beside the copper cylinder, the highest point in the system bar the air valve which is slightly higher. Draining off any water will empty the pressure vessel straight away. The problem with the experts in the plumbing section is that they assume everyone else is stupid. Over in the car section, experts help people all the time without displaying this superior attitude, calling a spade a spade, a car is a lot more complex than the average home heating system.

That's as may be, but, irrespective of whichever forum you care to frequent, if advice is wrong, then it is wrong.
The correct procedure for pre-charging an expansion vessel involves the pipework being "open" or, if possible, the vessel disconnected.
This is to allow all the water in the vessel to be fully displaced and to allow full expansion of the diaphragm to the correct pre-charge pressure.
The manufacturers give these instructions in their literature or on their web-sites.
Pumping air into an expansion vessel on a sealed heating system with no means for excess water to "run-off", is the incorrect method and will give you an incorrect pre-charge pressure reading.
Also, the pre-charge pressure should not be + or - 20% of the heating system pressure when Cold.

Tom44

jca wrote: »

In my particular setup the pressure vessel is up beside the copper cylinder, the highest point in the system bar the air valve which is slightly higher. Draining off any water will empty the pressure vessel straight away. The problem with the experts in the plumbing section is that they assume everyone else is stupid. Over in the car section, experts help people all the time without displaying this superior attitude, calling a spade a spade, a car is a lot more complex than the average home heating system.

Draining the water with a flat pressure vessel will NOT get the water out of the pressure vessel.
That's why it has to be left OPEN to expel 24ltr of water while pressure vessel is been pumped up.
Not doing it correctly is possible the biggest cause of expensive damage to heating system.
Were just trying to point out the correct way.


That's why it is better to actually call out a professional to your house.
Most good guy's will show the householder what he or she safely can do themselves.
Text information is not a perfect way to do this.

jca

Tom44 wrote: »

Draining the water with a flat pressure vessel will NOT get the water out of the pressure vessel.
That's why it has to be left OPEN to expel 24ltr of water while pressure vessel is been pumped up.
Not doing it correctly is possible the biggest cause of expensive damage to heating system.
Were just trying to point out the correct way.


That's why it is better to actually call out a professional to your house.
Most good guy's will show the householder what he or she safely can do themselves.
Text information is not a perfect way to do this.

When I had the exact symptoms that the op is having I called out a professional as I couldn't figure out what was happening. When talking to him on the phone the first thing he told me was to turn off the water at the filling valve and not to run the system. The first thing he did on arrival was depress the schrader valve on the vessel and water came out meaning it was doomed. I had three problems, The pressure vessel was ruptured, The PRV was dripping continuously having lifted and most importantly the pressure gauge was wildly inaccurate which certainly didn't help things. The filling valve also had a mind of its own but he advised me to leave it turned off and only add water to a cold system if it needed it after replacing the gauge obviously. I'm only trying to help the op from an ordinary person's perspective, I'm not some vice grip wielding ham fisted moron either.