Sabre 24. Water pressure increasing ???

[Chris G]

Hello there

Hope someone out there can point me in the right direction. I have a Sabre 24 boiler that keeps increasing in water pressure up to the maximum 3bar causing water to drain out of the Safety Drain Valve.

I have tried reducing my incoming water pressure to see if that stops the water pressure incrasing to the 3bar and draining out the safety drain valve but that does not have any effect.

Any pearls of wisdom are welcome.

Cheers Chris

 

[PlumbBobBob]

sounds to me like the filling loop is passing.

oh and welcome to the forums

 

[SimonG]

Is the filling loop connected and passing, or could be a split plate heat exchanger allowing mains cold into heating water side.

 

[SimonG]

sounds to me like the filling loop is passing.

oh and welcome to the forums

Fastest finger first 🙂

 

[kay-jay]

Yep i agree. Ensure that the valve/s on the fill loop are completely isolated.

Sent from my GT-I9100 using Tapatalk 2

 

[Chris G]

I had the same thought (even if I did not know what it was called at the time) and I replaced the Lever arm ball valve in the Filling Loop with a new one. But unfortunatley it has not had any effect, the pressure is still peaking at 3bar and water is still draining out the safety drain valve.

Does that mean that I have a split plate heat exchanger allowing mains cold into heating water side?

 

[kay-jay]

If you are sure that its not the filling loop then yes. Pressure can only build as a result of water entering the system....

Sent from my GT-I9100 using Tapatalk 2

 

[mountainman]

If you are sure that its not the filling loop then yes. Pressure can only build as a result of water entering the system....

Sent from my GT-I9100 using Tapatalk 2

As a side issue Kay-Jay, is a split plate Hx common or a rarity as I personally have never yet encountered one.

 

[SimonG]

Only seen it once MM, I only caught it because the cust opened the hot water tap and the pressure gauge moved and my nose was right in front of it.

 

[dave1]

Expansion vessel could need recharging or replacing. Run the tap with the boiler switched off and see if the pressure still rises.

 

[Chris G]

Hi Dave1 - I did run the taps (H+C) with the boiler off and the pressure still increased.

 

[jtsplumbing]

Plate EX I had one on a Flexicom, can you here water going into boiler ? Turn of cold supply to boiler and see what happens !

 

[dave1]

Plate EX I had one on a Flexicom, can you here water going into boiler ? Turn of cold supply to boiler and see what happens !

I agree with this.

 

[Chris G]

Yes I can hear water gurgelling away after I drain the central heating and then run the taps.

also I drained all the water from the Central Heating to reduce the pressure to prevent any damage. I did not run any taps and obviously the heating is not on; thus the burner never fired up. After approx an hour the pressure just gently increases up to the 3bar. Furthermore I have removed the Filling Loop.... Then after the hour has passed I need to drain the Central Heating again.

 

[jtsplumbing]

So have you turn'd off the cold supply under the boiler ! leaveing rest of house connected, so that no mains water is going through boiler ??

 

[Chris G]

Hello again. Thanks to everyone for the advice / guidance.

I have fitted a new Heat Exchanger and the boiler working fine.

Cheers Chris