Combi boiler/central hearing issue

[justin72]

Hi,

We've had 5 new radiators fitted, and have an existing towel rail. Currenlty we're having issues with the pressure dropping in the boiler. To summarise the last 24 hours:

• We had a BAXI engineer come out and service the Combi boiler. He replaced a couple of valves and confirmed that everything works as expected with the boiler.
• I bled all of the radiators and towel rail (which did have a lot of air in them), and re-pressurised the boiler. Turned the boiler on and the heating worked fine, however, the pressure started dropping. I re-pressurised during the day and bled the radiators twice more.
• This morning, the boiler did not start, as there was no pressure at all. I have checked every radiator and towel rail this morning and none have air, they all have water as soon as I turn the key.

Could there be a leak somewhere in the system? I am not sure, as if there was I would have expected more air in the system this morning. Not sure I can blame the boiler as it has been serviced in last 48 hours. The radiators do not have valves fitted, as the company initially gave us valves that were incorrectly sized. They are, however, working fine when I re-pressurise and turn the boiler on. The entire system worked fine until the BAXI engineer attended on Friday night, so am at a total loss at to what could be wrong.

Any advice would be very welcome.

Many thanks, Justin

 

[IDCHAPPY]

I've never in 20 years, seen radiators fitted without valves...
A system only looses pressure through loosing water, it must going somewhere

 

[IDCHAPPY]

Top it up to 1 bar on the pressure gauge and then stick the heating on and see what the pressure gauge does

 

[justin72]

Hi IDCHAPPY, Thanks for replying to me. The valves I was referring to are trv valves that control the flow to the radiator. These have been removed as they were the wrong size and we're waiting to fit the correct ones. The radiator is connected to the pipes by a valve (I probably was not clear on this as i am not an expert).

I re-pressurised and turned the system on. The display is showing the pressure is falling below 1. I have checked teh overflow outside and I cannot see any water, so assume that there must be a leak under the floorboards/ Does this sound correct?

 

[oil gasman]

snap, I can't remember the last time I saw rads without valves, must look horrible with male irons in them

surely that would fail due to the requirements of having trvs in bedrooms ?

along with the inability to balance the system up


id chappy I know where u going with this one with regards to the pressure gauge dial,lol

 

[IDCHAPPY]

So the pressure gauge doesn't rise the 3bar?
If not then yeah, there a problem somewhere, still worth checking the boiler by closing the isolation valves under it, pressure drops then it's a boiler issue, stays the same then it's the system.

 

[Crinkmeister]

You don't have to lose much water for the pressure to drop. I'd be thinking of checking very carefully where the new rads were fitted, or anywhere else where pipework might have been disturbed. Is it easy to get the floorboards up near the new rads? What valves did Baxi dude change - valves on your rads or inside boiler?

 

[justin72]

We had trv valves but they were faulty - when we first fitted the radiators they were lsoing heat - turned out the valves were falty as they kept pressing down(?) which meant the rads could not hold heat. They have now been removed and we are waiting for their replacements. The second we removed the trv valves the rads heated up no problem. They initially did extensive work looking for a leak in the system as they could not figure out why the radiators were not holding the heat and the boiler was losing pressure. We have just had herringbone parquet laid so it is not easy to look at the new pipe work or pipe work aorund the radiators (It is around the boiler). We have had people out to the boiler who insist there is no leak relating to the boiler.

Once the valves were removed from the rads teh system appeared to eb fine- until one week later when the water started to lose heat- we then had the boiler person out who changed some of the parts (something that diverts the water from rads to water and the part that heats the water?). This has solved the water heat problem - but now the boiler loses pressure at an alarming rate!

 

[oil gasman]

hi

is ur boiler a 105 e by any chance or a newer model

so ur waiting for an engineer to come back and fit the trvs back onto ur radiators

hope this doesn't come across as rude but are u topping the system up when cold, do u do it with the boiler off, ie no demand for heating and hot water , plus the pump is not going

if u top the boiler up to around 1-1.5 bar , whilst there is no demand , ie no hot taps opened and the CH turned off and that everything is vented correctly see how long it takes for the pressure to drop

if it does u will have to get the engineer to isolate the boiler for u , so u can see if it's the boiler or system that has the leak

if he works through the system stage by stage can hopefully intentify the leak

hopefully it's not under the floor where u can no longer get to the pipes

please let us know how u get on but seems as though u may have to get the engineer back

u say u checked the relief pipe outside, may be a good idea to put a small container under the pipe or maybe a plastic bag attatched with an elastic band so that when the ch is on can see if it starts to leak

as as sometimes what can happen u top the system up then after a while it discharges outside , but by the time u look at the pipe it's empty giving u the impression it's not leaking from there

see how u get on

gary