Boiler Pressure Q

TheDriver

I have an ideal s30ie gas boiler, about 2 and half years old. Sealed system, 3 zones. I topped it up a month ago to 1.2 bar cold, rose to 1.5 when hot.
Heating system works fine, no issues.
However I'm noticing that the cold pressure dropped steadily throughout the month (ie after heating off for the night). When it was particularly cold outside (ie freezing outside), it dropped more.its now down to 0.5 bar cold but when it's running, it maintains a steady 1.2-1.3bar no matter if it was 1.0 cold or 0.8 cold or 0.5 cold.
When it turns on, the pump pushes it up to 0.7 and then within 10 mins she's running at 1.2-1.3.
Should I be concerned or just top it up and forget about it?
Any advice is appreciated. I'd happily call my plumber but don't want to be bothering him if it's a thing of nothing.

TheDriver

It's not dropped to 0.4 when cold but still operating 1.2-1.3 hot. No issues with heat.

Lenar3556

You can try topping it up again, but if it persists the cause needs to be identified and corrected, and you will likely need a plumber.

There may be a leak, or possibly a defective expansion vessel. I would rule out the latter first as it is likely to be the easier fix!

TheDriver

Thanks for the reply. Topped it up to 1.2 cold and I'll monitor it over the coming week or two.

As an aside, I thought the hot pressure would always drop in line with the cold pressure reading but the fact the hot pressure is staying steady would indicate a boiler internal pressure issue?

Wearb

Locate the pipe that has the pressure relief valve and see if there is any water dripping from it as the boiler comes up to temperature.

TheDriver

Wearb wrote: »

Locate the pipe that has the pressure relief valve and see if there is any water dripping from it as the boiler comes up to temperature.

Is that the white plastic pipe or the the brass pipe beside of it, both come out of the boiler and both go into a drain pipe?
The plastic condensate pipe drips a lot straight away as it heats up

Wearb

TheDriver wrote: »

Is that the condensate pipe or the the brass pipe beside of it (both go into a drain pipe?
The plastic condensate pipe drips a lot straight away as it heats up

Plastic one should drip, mostly.



It's the copper (brass) one.

TheDriver

Plastic one is dripping mad fast. Nothing from the copper one.
I've topped up to 1.2 cold, rises to 1.5-1.6 hot. (she was 0.4 cold, rising to 1.3 hot).

Thank you for your replies by the way.

K.Flyer

Plastic pipe is condensate discharge, nothing to worry about there unless it is still dripping when then boiler has been off for a while.
How often are you topping up the system pressure from <0.5 bar to over 1.25 bar?
When was the boiler last serviced?

pinkfloyd34

I have the very same problem, got the plumber in to check it, gas boiler over 12 years old, plumber did say something about the vessel and would be nearly 200 to replace but he said that will be the start of problems and you could end up pouring hundreds into it as other stuff will no go, so he advised just to keep topping up the pressure in it and get what you can out of it until it packs in completely, but I'd be lucky to get this winter out of it, that was last March he was in so its still going strong so far

TheDriver

K.Flyer wrote: »

Plastic pipe is condensate discharge, nothing to worry about there unless it is still dripping when then boiler has been off for a while.
How often are you topping up the system pressure from <0.5 bar to over 1.25 bar?
When was the boiler last serviced?

Boiler was serviced start of Oct, 2 years old.
I topped it up at start of Dec when I noticed cold pressure had dropped. Topped up again tonight so 5 weeks approx.

Lenar3556

pinkfloyd34 wrote: »

I have the very same problem, got the plumber in to check it, gas boiler over 12 years old, plumber did say something about the vessel and would be nearly 200 to replace but he said that will be the start of problems and you could end up pouring hundreds into it as other stuff will no go, so he advised just to keep topping up the pressure in it and get what you can out of it until it packs in completely, but I'd be lucky to get this winter out of it, that was last March he was in so its still going strong so far

Unless you were planning on replacing the whole heating system anyway - Thats not great advice he gave you. The source of the problem needs to be identified and resolved, otherwise you will end up with a whole range of problems.

An expansion vessel is under €30 (a bit more if it’s a within a system boiler) and pretty easy to replace. It should be immediately apparent on inspection if it needs to be replaced or not.

K.Flyer

TheDriver wrote: »

Boiler was serviced start of Oct, 2 years old.
I topped it up at start of Dec when I noticed cold pressure had dropped. Topped up again tonight so 5 weeks approx.

Ok, you shouldn't need to be topping it up that frequently, one or twice a year would be acceptable.
Plus regular filling of heating systems will start to do harm by introducing fresh water you will start to create sludge in the system.
Large variances from not running cold temp to fully hot is usually indicative of an issue with the expansion vessel, but loss of pressure from vessel issues usually cause dripping from the small copper pipe outside.
If no water is dripping from the narrow copper pipe outside there may be a leak issue elsewhere.
From my experience the expansion vessel is quite often neglected during boiler servicing, so I would suggest discussing it with the Registered Gas Installer that you use to service the appliance.

TheDriver

K.Flyer wrote: »

Ok, you shouldn't need to be topping it up that frequently, one or twice a year would be acceptable.
Plus regular filling of heating systems will start to do harm by introducing fresh water you will start to create sludge in the system.
Large variances from not running cold temp to fully hot is usually indicative of an issue with the expansion vessel, but loss of pressure from vessel issues usually cause dripping from the small copper pipe outside.
If no water is dripping from the narrow copper pipe outside there may be a leak issue elsewhere.
From my experience the expansion vessel is quite often neglected during boiler servicing, so I would suggest discussing it with the Registered Gas Installer that you use to service the appliance.

Thanks for all the replies. I had checked everywhere for a leak over the past month but tonight, I pulled out bags of clothes at the base of the hot press and a motorised valve for upstairs has been leaking quite a bit for a while, grand big wet patch up there. Obvious where my water loss is and I'd say a few litres have gone with a bit every day but thankfully easily fixed. I'm assuming this is my boiler Pressure issue. Plumber calling tomorrow.

K.Flyer

TheDriver wrote: »

Thanks for all the replies. I had checked everywhere for a leak over the past month but tonight, I pulled out bags of clothes at the base of the hot press and a motorised valve for upstairs has been leaking quite a bit for a while, grand big wet patch up there. Obvious where my water loss is and I'd say a few litres have gone with a bit every day but thankfully easily fixed. I'm assuming this is my boiler Pressure issue. Plumber calling tomorrow.

Yes, that explains pressure loss, great that you found it.
When it's repaired just monitor the difference between cold temperatures and full hot temperature. There shouldn't really be any more than 0.5 bar difference.

TheDriver

Update, motorised valve needs replacing.

Wearb

TheDriver wrote: »

Update, motorised valve needs replacing.

When you have it drained down, be sure to check the expansion vessel.

TheDriver

Wearb wrote: »

When you have it drained down, be sure to check the expansion vessel.

My RGI always seems a thorough guy and looks after the system annually, he usually does the inhibitor and filters etc so I'll assume he'll give it a once over. Theres an expansion yoke in the way which he put in 2 years ago when he installed this boiler so he'll have to remove it to get at the valve.

TheDriver

As an update, finally got it fixed. Replaced the piece of pipe connected to the motorised valve and the motorised valve itself (excuse my use of probably very non plumbing terminology).
He said it was well goosed, peeing out water.
Hopefully that's the issue solved.

Thank you to all your help and advice.