Boiler loosing pressure

Jeepers_Creepers

Please let us know.

And strike that original plumber off your Christmas card list. :-)  

southcoastrgi

Ok you possibly have two issues, 
1st, logic boilers are crap, they have a known issue with the main hex falling to pieces, also the sumps split, now Ideal won't accept responsibility for either of these things.

2nd, how is your system piped with regard to filling up the heating ? If as I suspect you are filling it with softened water that could be the issue if the hex is leaking & even if it was still under warranty it would be void, NO BOILER with a aluminium hex should be filled with softened water

Jeepers_Creepers

Ok, so that's quite depressing.

Jeepers_Creepers

Hang on - do the installation instructions actually outlaw the use of soft water to fill the system? And the installer set it up with a filling loop connected to the mains?

Well, I know who to blame...

Really, tho', that's just crazy. Is 'soft' water more acidic than condensate? Absolutely not.

Jeepers_Creepers

When I fitted my GlowWorm a good 16 years ago, I ran out of 22mm plastic 'overflow' pipe for the condensate so added a short piece of copper pipe as a temp measure to get the job done.

'Temp' became around 7 years - when I discovered that the whole lower side of the copper pipe had literally corroded away.

Kristoffs

Hi SouthCoastRGI,

The boiler does have the infamous sump crack but it isn’t leaking yet. 

Boiler is filled from the mains. It only shares a waste pipe with the softener. 

I’m going to rerun the test tonight to see if the boiler looses pressure when isolated as I’m not sure if the return value was letting by so I have closed the 2 at the magnet filter. 

The silly thing is I’m hoping it is the boiler as I really don’t want to trace a leak in the house!

Kristoffs

Update. 

Pressure held on the boiler over night at 2.5 bar. When releasing the valve the pressure dropped to 2 bar. So it seems it’s not the boiler. 

Next question for you kind people. 

My bathroom towel rails T off before the hot water cylinder so they run on the HW circuit instead of CH. It is always the towel rail that needs bleeding with the pressure loss. Does this indicate that the leak is somewhere on the HW ring? Either in the towel rail pipework or the heating coil? Or is just that the towel rail is the highest radiator?

How would I check the heating coil to rule that out?

Thanks again,

Kris

Jeepers_Creepers

First thing - why does your towel rail - any rad - need bleeding with the pressure loss? In theory, your system is still sealed and still pressurised to some degree, so air shouldn't be getting in there at all.

If a heating coil leaks inside the cylinder - it happens, but not very often at all - the usual symptom is the presence of the system water in your DHW - a chemical smell, slight discolouration, an oily appearance, that sort of thing. If it's bad, it'll push the hot contents slowly out the vent pipe and in to the CWS, or back-fill the CWS from below. A bad coil leak would have the CWS overflowing - you'd see it come out the overflow pipe outside. Mind you, it's hard for a sealed system to give that much leaking flow as its volume is limited.

Not sure how else you'd check for a coil leak - perhaps have a good look at your CWS content with a good torch? Is the DHW as clean as always? I think you'd have smelled the 'chemicals' in a shower when it surrounds you (assuming there are still chemicals left in your system...)

Sorry it's such an uncertain outcome, Kris. Can I ask - did you pressurise to 2.5bar last night and THEN shut off both CH valves?

There's a chance it's still the main-X as sometimes leaks only show themselves when hot and expanded.

Not sure what else to suggest - perhaps the engineer will have a detecting chemical they can add to the system and then see where it appears?

(I still don't understand why your system would need bleeding when it loses pressure. Yes, a tiny bit of dissolved air comes in with the top-up water, but that'll be teeny. Your system doesn't need bleeding at any other time?)

Kristoffs

I waited for the system to cool and pressurised to 2.5 bar then shut off the flow then shut off the return (by closing the 2 valves on the magnet filter). After 10 hours the system was still at 2.5 bar but when I opened the flow the pressure dropped to 2 bar. 

In terms of the bleeding. It is not a lot of air in the towel rail but if I leave it for a month the top rung will be warm rather than hot. I just assumed this was due to water escaping somewhere means air must be getting in. 

I am tempted to cancel Ideal coming out as they will only look at the boiler and charge me a £125 call out charge if nothing is wrong with the boiler. Instead I’ll get someone in that will look at everything (different from the original person). 

Jeepers_Creepers

*cough* - if you shut off the two valves on just the filter, all you've done is shut off the 'return'. The 'flow' from the boiler is still open.

The filter is installed on the return pipe only - it has two valves simply to stop the system water getting out from either direction when the filter is opened for cleaning (which should be done if it hasn't been checked for 6 months or so).

I'n guessing that the LH copper pipe in your pic - also 22mm - is the boiler FLOW, and this should have an isolating valve on it as it exits the boiler.