Combi Boiler Flexicom cx 24kw

karlitob

Hi all,


We had a brand new central heating system installed during our renovation in Feb. Our boiler is the Combi Boiler Flexicom cx. About once a month, the pressure drops to 0 and we have no heat. I have to open the valve to increase pressure. I monitor the pressure fortnightly but the pressure drops happen out of the blue.

Is this normal? Should I contact our plumbers. Our plumbers originally said it was fine but its happening once a month and I never had to do it in our old house and our old boiler.

Just looking for some advice.

Thanks

shane0007

Yes you have a leak or expansion vessel issue.
Continuous refilling with fresh oxygenated water will lead to scale & rusting of the system internally.
Get them back.

corkgsxr

Imo topping it up every 6 months to a year is fine. Less isn't

Billy Bunting

What pressure are you topping upto ?

K.Flyer

karlitob wrote: »

...

Is this normal?
Should I contact our plumbers. Our plumbers originally said it was fine but its happening once a month and I never had to do it in our old house and our old boiler.

Just looking for some advice.

Thanks

The simple answer to your question is,
No this is not normal nor very good for your Gas Boiler and Heating System.
You have a leak and its not "Fine"!

The original installers should return, find and repair the problem. Don't be fobbed of with them saying this is normal and maybe wanting to install an automatic filling valve either.
More than likely you will also need to have the corrosion inhibitor replenished as some of the original inhibitor will have been lost and the remainder diluted.

karlitob

K.Flyer wrote: »

The simple answer to your question is,
No this is not normal nor very good for your Gas Boiler and Heating System.
You have a leak and its not "Fine"!

The original installers should return, find and repair the problem. Don't be fobbed of with them saying this is normal and maybe wanting to install an automatic filling valve either.
More than likely you will also need to have the corrosion inhibitor replenished as some of the original inhibitor will have been lost and the remainder diluted.

Thanks very much for your help guys. Appreciate it.

JohnnieK

Yep, a sealed system should NOT loose pressure if it's installed correctly and all is well with it.

karlitob

Billy Bunting wrote: »

What pressure are you topping upto ?

2 bar mainly.

shane0007

Should only be to between 1 and 1.5 bar. At 2.0 bar when cold, it could lift the pressure relief valve when the system gets hot.
Only refill when system is cold.

Billy Bunting

karlitob wrote: »

2 bar mainly.

Is that the pressure your plumber told you to top up to. :eek:

karlitob

Billy Bunting wrote: »

Is that the pressure your plumber told you to top up to. :eek:

yes - is that ok. in fact, he said that it'll find its own level. What level should I do. Do you think this is the cause of the problem?

Billy Bunting

As Shane as pointed out, you have been over pressurizing the system and could well now need to replace the pressure relefe valve.

Find its own level!!!

shane0007

karlitob wrote: »

yes - is that ok. in fact, he said that it'll find its own level.

Lol, that's a new one, finding its own level!

No, 2 bar is too high if that is the cold pressure. Set to about 1.25 bar. See how that is. If you need to drop the pressure, bleed it from a radiator. If pressure remains stable, that was your problem. If not, then as we previously described.

karlitob

Billy Bunting wrote: »

As Shane as pointed out, you have been over pressurizing the system and could well now need to replace the pressure relefe valve.

And the pressure relief valve - is there a poss thats now broken? Without sounding too stupid. What exactly is its job?

Should I still contact these guys or just wait and see? Would I see problems happening once a month or quicker?

shane0007

When they are lifted, they may not reseat and have a continuous drip, losing pressure from the system.

A pressure relief valve is an integral safety device to release pressure from the system should that pressure rise above 3.0 bar. Some are set at 2.5 bar but most are 3.0.

If you are setting system pressure to 2 bar when cold, it can rise by about a bar when hot.

Billy Bunting

A PRV is there to relieve high pressure, its not there to do it on a monthly basis, if you've been over pressirizing the system causing the PRV to activate, on a monthly basis, then it may well still give you a problem at correct operating pressure.

karlitob

shane0007 wrote: »

When they are lifted, they may not reseat and have a continuous drip, losing pressure from the system.

A pressure relief valve is an integral safety device to release pressure from the system should that pressure rise above 3.0 bar. Some are set at 2.5 bar but most are 3.0.

If you are setting system pressure to 2 bar when cold, it can rise by about a bar when hot.

Great. Ok - only raise to between 1 and 1.25.

Just went in to check the boiler - something weird is happening. The heat should not be on, its not on at the control panel. But the boiler sounds like its on - the digital gauge on the boiler says 2.9 bar. The manual guage on the valve says 2 and its shaking like mad as if its broken.

What the hell is going on?

shane0007

Is the system zoned? It could be pumping against a closed circuit.

karlitob

shane0007 wrote: »

Is the system zoned? It could be pumping against a closed circuit.

Yep its zoned. But all zones shouldnt be on now.

Billy Bunting

That and 2 bar pressure would keep ya busy.

shane0007

If boiler has pump over-run and the installer did not install an external automatic bypass valve, the pump will pump against a closed circuit.

Switch boiler off. Give the installer a call in the morning. Getting late and early start myself.

karlitob

shane0007 wrote: »

If boiler has pump over-run and the installer did not install an external automatic bypass valve, the pump will pump against a closed circuit.

Switch boiler off. Give the installer a call in the morning. Getting late and early start myself.

Thanks Shane - appreciate all your help.
G