Glow worm cxi pressure

[ErwinLoz]

Hi. I hope someone could help me. We got glow worm cxi boiler pressure dropping, topping the loop almost 24 to 26 hrs.Engineers changed Quite a few parts. Water heat exchanger.PRV.expansion vessel apparently working well. Leak detection done on the system after Engineer isolated the boiler and suggested its leak on pipes. Plumber done leak detection using a special gas on the system and found a small leak on one of the pipes of the radiator legs on the hallway and mended it but he said as the boiler loosing pressure since 1st week of November until last week ist week December, around 5 weeks he thinks that is not the cause of the pressure dropping.when he tested the boiler with the leak detection special gas..the boiler was beeping a lot showing more than 2 from his detection machine.he said the leak is in the boiler. Boiler engineer came and said main heat exchanger must be change. The boiler was left with 1.5 pressure and it only dropped to 1.4 after 5 days from Tuesday to Sunday. Boiler engineer came yesterdayTuesday, a week after he said to change the main heat exchanger.main heat exchanger changed yesterday and left with boiler pressure of 2 at 2pm. At 8pm when heating cooled down from heating being on from 2pm to 5pm.pressure dropped from 2 to 1.9 then heating on from 10pm to 1 am. When checked at 4am when heating cool down, pressure dropped to 1.8 is this normal. The engineer said that the pressure goes down when heating cools down. But since 2pm until 4am for 14 hrs and twice after heating was on and cools down it drops from 2 to 1.9 then 1.9 to 1.8
Is this normal or will this continue to drop and need to worry again. I asked the engineer before he changed the main heat exchanger that for the 1st time the boiler didn't loose much pressure for 5 days when he left to order the the main heat exchanger and plumber mended the small.leak on the radiator pipes. I asked him if the main heat exchanger still needs to be changed and he, he might as well change it. Pls help for answer.thanks

 

[Stuckinarut]

Sounds like it could be operating as normal, but just keep an eye on it. Water expands when it is heated.

 

[ErwinLoz]

Thanks Stuckinart. So far it kept on 1.7 pressure upto now. The only problem we noticed now is it looks like one of the radiator is with air because hot on bottom and cold on top but last week it was only cold on the left side(bleeding point) now it it is on the whole top area of the radiator. When the Engineer came and change the main heat water exchanger. I saw him sorting out the heat pump with screwdriver and was leaking as he needed lots of tissue paper. I hope that it is just a normal air trapped on radiator causing the air rather problem with heat pump. What are your thoughts?Many thanks for replying

 

[ErwinLoz]

Stuckinarut. As my previous message earlier. It is only 1 out of 9 radiators at home that seems to have air. The one in our bedroom which is opposite the boiler room. I hope it is not a big issue.

 

[Stuckinarut]

Ok, perhaps bleed the radiator and then top the pressure back up if required. Not a major issue, but need to get the air out.