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I recently went to a job on a newly installed combi boiler. Problems where that the boiler had lost a large amount of its pressure. The first thing i did was to check the pressure in the expansion vessel
When bleeding the upstairs rads there was a strong smell . I lit the "product" coming out of the bleed nipple in the upstairs rads and it turned out to be hydrogen
1.Now as i understand it hydrogen can be caused by either corrosion in the system or sludge (is this correct) y/n
2. My boss found a small leak on the system and explained that because the water contracts when it cools down it causes a vacuum and pulls air into the system.....He did say that i should completely forget about the hydrogen in the system and that the hydrogen is something thats not relavant. is it relevant and should i forget about it y/n
3. Is this creation of hydrogen only happening cause there is air in the system being pulled into the system via the leakin joint....y/n
4.or would hydrogen be caused without the introduction of air if the system y/n
5. as hydrogen is created do these gases increase the pressure and eventually force water out of the prv because as its generated the pressure increases . y/n
6. Is it more likely that a lack of inhibitor is the cause of this problem (i was told that the engineer did cleanse and put inhibitor in) y/n
7. Surely hydrogen is a sign that there is corrosion in the system or sludge which could lead to the premature demise of the boiler....Surely the cause should be rectified y/n
8. Does water that is lost in the system get replaced with an amount of air that takes up more space than the water (eventually operating prv) ...I thought the
air/hydrogen could be compressed much further than the water so the system would never over pressure in this way (because eventually u would get to a stage where there was little enough water in to operate pressure switch). Again on the baxi combi course i asked a question and was told that air in the system could force the system to become over pressurised temporarily and the prv to open and dump water
9.I also asked the question on baxi training course if a system over pressurised during operation would the prv operate and dump ALL the pressure contained in the boiler dropping the pressure to zero....the trainer said yes. My boss explained it differently and said what would happen was that the system would keep rising til the pressure got to 3.5 bar then dump the water til it got to 3.2 bar then stop there. Since when i got there the pressure was below 1/2 bar it could not have been a pressure issue but more so a leak on the system....Could anybody please clarify this point...who was right
10. Also if the boiler was overheating because of stat, THERMISTOR AND ot STAT failure then would also cause the boiler to dump water because water would boil and steam expands so quickly then in this instance you would expect the prv to open but this time dump a large amount of water out and when the system cools it would be well below the 3.2 you would see as described in the previously over pressure situation (ie hydrogen being produced in rads). y/n
again i have taken onboard and appreciate your comments. Hopefully this makes a much easier read and makes the question easier to answer. Ive got a head ache just trying to restructure it lol...and ive left loads off for another day
David
When bleeding the upstairs rads there was a strong smell . I lit the "product" coming out of the bleed nipple in the upstairs rads and it turned out to be hydrogen
1.Now as i understand it hydrogen can be caused by either corrosion in the system or sludge (is this correct) y/n
2. My boss found a small leak on the system and explained that because the water contracts when it cools down it causes a vacuum and pulls air into the system.....He did say that i should completely forget about the hydrogen in the system and that the hydrogen is something thats not relavant. is it relevant and should i forget about it y/n
3. Is this creation of hydrogen only happening cause there is air in the system being pulled into the system via the leakin joint....y/n
4.or would hydrogen be caused without the introduction of air if the system y/n
5. as hydrogen is created do these gases increase the pressure and eventually force water out of the prv because as its generated the pressure increases . y/n
6. Is it more likely that a lack of inhibitor is the cause of this problem (i was told that the engineer did cleanse and put inhibitor in) y/n
7. Surely hydrogen is a sign that there is corrosion in the system or sludge which could lead to the premature demise of the boiler....Surely the cause should be rectified y/n
8. Does water that is lost in the system get replaced with an amount of air that takes up more space than the water (eventually operating prv) ...I thought the
air/hydrogen could be compressed much further than the water so the system would never over pressure in this way (because eventually u would get to a stage where there was little enough water in to operate pressure switch). Again on the baxi combi course i asked a question and was told that air in the system could force the system to become over pressurised temporarily and the prv to open and dump water
9.I also asked the question on baxi training course if a system over pressurised during operation would the prv operate and dump ALL the pressure contained in the boiler dropping the pressure to zero....the trainer said yes. My boss explained it differently and said what would happen was that the system would keep rising til the pressure got to 3.5 bar then dump the water til it got to 3.2 bar then stop there. Since when i got there the pressure was below 1/2 bar it could not have been a pressure issue but more so a leak on the system....Could anybody please clarify this point...who was right
10. Also if the boiler was overheating because of stat, THERMISTOR AND ot STAT failure then would also cause the boiler to dump water because water would boil and steam expands so quickly then in this instance you would expect the prv to open but this time dump a large amount of water out and when the system cools it would be well below the 3.2 you would see as described in the previously over pressure situation (ie hydrogen being produced in rads). y/n
again i have taken onboard and appreciate your comments. Hopefully this makes a much easier read and makes the question easier to answer. Ive got a head ache just trying to restructure it lol...and ive left loads off for another day
David