Search the forum,

Discuss Boiler keeps losing pressure in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net

Messages
14
Hi folks,

I assume this has been asked many a times, so I do apologise in advance. My boiler which is only 6 months old started to lose pressure in March. My plumber applied 2 bottles of Fernox F4 express sealer and it seemed to fix it. It has again started to lose pressure, not drastically, maybe 0.20 bar in 24 hours. I have applied 2 more bottles to the F4 express, I'm sure however a plumber would have done a better job with it. I'm not a DIY person by any stretch of the imagination. I then turned the heating on for 1 hour at approx. 22 degrees celsius to allow it to circulate. I then let it cool down and stuck the heating on again for 1 hours at approx. 15 degrees. It is still dropping every day by about 0.05-0.10 bar a night. There is def. a leak somewhere as I had the boiler checked over by Ideal and they said there was no fault with the boiler. I have recently extended and have laid down marble flooring all downstairs and the new pipework is running under the floor and there is no chance that I want to rip any of it out. I read somewhere but i can't find the page now, that it was possible to install a device which constantly kept the pressure at say 1.5 bar without the need to repressurise every few days. Does anyone know of this and would you recommend? Alternatively, other than ripping out the floor, what other options do I have?

Thanks,

Kash
 
1. Losing 0.1 bar a day is too much. Having to adjust the pressure every 6 months is acceptable.
2. Whenever you replenish the pressure your are letting fresh water into the system. This water contains dissolved oxygen which will eventually cause steel components (radiators) to rust from the inside out. So even if the "constant pressure" device exists (e.g. a pressure reducing valve set to 1.5 bar) using it is just disguising the symptoms and will damage your system over time.
3. I would suggest:
3a. Re-pressurise the system to 1.5 bar.
3b. Isolate the boiler flow and return pipes at their valves under the boiler.
3c. Do not run the boiler for a period of 24 hours.
3d. If the pressure still drops then the fault is within the boiler.
3e. Open the valves, and wait a further 24 hours. If the pressure then drops, the fault is within the system.
4. If the fault is in the boiler, get a decent engineer to fix it.
5. If the fault is in the system, then considering your floors I'd suggest a leak detection specialist to determine where the leak is.
6. Note re. isolating the boiler (3b. above). The valves used are often poor quality and may leak when operated. They would then need to be replaced, and are often ridiculously expensive for what they are.
 
1. Losing 0.1 bar a day is too much. Having to adjust the pressure every 6 months is acceptable.
2. Whenever you replenish the pressure your are letting fresh water into the system. This water contains dissolved oxygen which will eventually cause steel components (radiators) to rust from the inside out. So even if the "constant pressure" device exists (e.g. a pressure reducing valve set to 1.5 bar) using it is just disguising the symptoms and will damage your system over time.
3. I would suggest:
3a. Re-pressurise the system to 1.5 bar.
3b. Isolate the boiler flow and return pipes at their valves under the boiler.
3c. Do not run the boiler for a period of 24 hours.
3d. If the pressure still drops then the fault is within the boiler.
3e. Open the valves, and wait a further 24 hours. If the pressure then drops, the fault is within the system.
4. If the fault is in the boiler, get a decent engineer to fix it.
5. If the fault is in the system, then considering your floors I'd suggest a leak detection specialist to determine where the leak is.
6. Note re. isolating the boiler (3b. above). The valves used are often poor quality and may leak when operated. They would then need to be replaced, and are often ridiculously expensive for what they are.
Thank you for your prompt reply.

I am how the kids say these days a "noob" with all this; how would I isolate the boiler flow and return pipes at their valves? If I know how to do this, I can do the said tests. I have attached a photo of my valves in their current positions.
 

Attachments

  • Boiler middle.jpg
    Boiler middle.jpg
    367.6 KB · Views: 8
  • Boiler left side.jpg
    Boiler left side.jpg
    323.8 KB · Views: 8
  • Boiler right side.jpg
    Boiler right side.jpg
    325.5 KB · Views: 8
And just for my knowledge, how does a pressure reducing valve set to 1.5 bar work? Does it keep re-pressuring the system for you and maintains it at 1.5bar?
 
You say the boiler is 6 months old and started losing pressure around March time, when did you have the extension built, around March, or later?
 
The boiler was added as part of the extension. The extension finished in March. Boiler installed January.

Ah I see. That doesn't sound promising. Did the installer not pressure test the pipes before the floor was laid?
Everything steadyon says above is the correct approach.
 
Did it loose pressure/ did you notice before the floor went down ?
 
Did they screw anything to the floor ?
 
Over a timber or concrete floor ?
 
If they’ve gone straight over floor boards them tiles are going to come up anyway
 
So they screwed something on top of the floorboards ?
 
That’s going to fail due to flex
 
Due to movement the floor / screed will crack
 
What Shaun is saying is that floorboards are not suitable for screeding onto these are typically fixed at 600 mm centres into a joisted floor, there is to much flex and movement in those boards to accept a screed , these boards need either fixing securely cleaning down priming and over laid with Hardi backer cement type board laid with a flexible tile adhesive and screwed at 300 mm centres before priming and fitting the floor tile , or removing and replacing with a no more ply type flooring before tiling onto . Kop
 
Last edited:
Cut in some isolation valves on the flow and return pipes to the new extension. Isolate just that section and run the rest of the house as is. This will prove if there’s a leak on the new area.
 
Thats what I would do and certainly not keep pumping in leak sealer, find and repair the leak and do not keep masking the problem .
 
But isn’t that the case with any new floor which is screeded and not put down with floorboards?

you don’t screed floorboards / tile onto floorboards
 
Better toss this one in,I'm not saying for a minute that its the case on the op's floor but there are specialist screeds intended for use over timber floors.
Often involve d49 reinforcing and p p reinforced pumped screeds I've seen them used a number of times.
 
Hi all, thanks for the responses. So i isolated the valves last night, set to 1.5 bar and this morning 10 hours later it is still at 1.5 bar. I guess this means the problem is not in the boiler/system?

I also spoke to my tiler this morning and he does these jobs all the time and always applies the same process, so I am sure he has done the right thing here. Only last month he tiled a 400sqm car showroom in Liverpool and he used the exact same process as he did on mine.

I have spoken to a company which does thermal imaging and will look to get them out in the next few days to detect where the leak is, I will sadly then have to get my tiler back round to dig up that area, get the pipework fixed and retile over. The plumber at this company did mention it may be a faulty heat exchanger, but he said he'd come and take a look. I can't go back to the original company I used as the fella who owns it is going through a divorce and he will be dissolving the company 🙄
 
Hi all, thanks for the responses. So i isolated the valves last night, set to 1.5 bar and this morning 10 hours later it is still at 1.5 bar. I guess this means the problem is not in the boiler/system?

I also spoke to my tiler this morning and he does these jobs all the time and always applies the same process, so I am sure he has done the right thing here. Only last month he tiled a 400sqm car showroom in Liverpool and he used the exact same process as he did on mine.

I have spoken to a company which does thermal imaging and will look to get them out in the next few days to detect where the leak is, I will sadly then have to get my tiler back round to dig up that area, get the pipework fixed and retile over. The plumber at this company did mention it may be a faulty heat exchanger, but he said he'd come and take a look. I can't go back to the original company I used as the fella who owns it is going through a divorce and he will be dissolving the company 🙄

What valves did you isolate? Boiler valves or flow/return to just the new section?

If just the new section and you’ve run the system for 24/48h without pressure loss, you’ve got your answer and it’s not the heat exchanger. Funny thing is, I came across a leaking heat exchanger today.
 

Reply to Boiler keeps losing pressure in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net

Creating content since 2001. Untold Media.

OFFICIAL SPONSORS

OFFICIAL SPONSORS

Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock