heating advice

Piriz

Hi,

the expansion pipe from my hot water tank is dripping with increasing volume the past few months, the expansion valve is positioned awkwardly so the hot water tank would need to be removed to access the valve to replace it (assuming this is the solution). I replaced the expansion vessel myself as it was required.

I assume the cost for a plumber to remove the hot water tank and replace the valve alone would be expensive, 350euro if not higher? open to comment on this..

what I'm wondering is would it be better to get a new system entirely, because my gas boiler is approaching 25 years old, it's Ideal brand and hasn't been serviced in 2+ years. From what I can gather a new combi boiler will cost 2.5 -3k installed, and could save approximately 30% on gas bills per year (I paid 2,400euro in gas bills last 12 months so 30% savings here would be about 700euro, per year).

Also with a combi boiler I can remove the hot water tank altogether? giving back a bit of storage space would be helpful. correct me if I'm wrong..

so do you agree it would be better to spend more for a combi boiler ? and avoid spending a lot to just have the valve replaced when the rest of the system is inefficient and will need to be replaced in the coming years anyway? am I right? or what other way should I consider it?

thanks

whizbang

the expansion pipe from my hot water tank is dripping

do you mean the hot water cylinder thats typically in a hot press ? Where is the dripping pipe?

it may be a pressure relief valve?

Piriz

yea it's the pressure release valve, from the hot water cylinder, the overflow pipe goes to the garage..

Sleeper12

Can you post some photos. A picture speaks a thousand words. Sometimes

Piriz

top arrow is the location of the pressure release valve

bottom arrow is the location of the dripping pipe it goes through that wall to the garage..

thanks

10-10-20

I'm not sure whether that's a PRV or just a quarter-turn valve... We might need a better photo of that valve.

Piriz

17063490770948930083776409015209.jpg

I hope this helps...

Piriz

Screenshot_20240127_095305_Gallery.jpg

..

Piriz

I could access the valve with a pliers, I opened it and let the hot water flow out the pipe in the garage and closed the valve again but it's still dripping at a high volume, would fill a mug in less than 30 seconds.. so losing a lot of water each day, would be very difficult to access the valve to replace it, not a DIY job for sure, it begs the question, the cost of a plumber to replace the valve might be better spent towards a new efficient boiler install..

Lenar3556

You have a lot crammed into a small space there.

I am assuming this pressure relief valve is screwed directly onto an outlet from your unvented cylinder? It looks like that from the photo.

The valve itself may be at fault (and should be replaced in any case) but there may also be an underlying issue with the supply pressure to the cylinder or the expansion vessel mounted on top of it. Both would need to be checked, and I would probably replace the expansion vessel in any case.

The cylinder will likely need to be taken out to access that pressure relief valve. Might cost €500.

Incidentally you are best off not opening those valves manually by twisting the front - they have a habit of not sealing correctly afterwards, particularly if they are older.

In terms of upgrading the heating system, you could consider a combination boiler and do away with the cylinder altogether. There would be pros and cons to this option, but it is worth looking at.

Piriz

yea thanks, I have contacted two companies to get recommendations / quotes for new boiler install.. hopefully they get back to me and I can get sorted..

whizbang

Whats your mains water pressure like.. Is the filling loop turned off..?

Piriz

mains pressure is fine,

whats the filling loop?

I'd like to shut off water flow into the how water cylinder because at the rate its flowing out it activates the pump every 10mins and its annoying, could turn it back on once a day for showers until I get it all sorted, maybe this won't work

slystallone

https://www.boards.ie/discussion/comment/121683418#Comment_121683418

I have a filling loop where I have to top up the pressure every few weeks. I've never had this before in any house I've been in with similar setup. Is this a regular occurrence out there that people have to keep topping up the pressure on the filling loop?

10-10-20

https://www.boards.ie/discussion/comment/121804628#Comment_121804628

Yes, pretty much. Every month or so. Some systems are less often, some more.

Lenar3556

https://www.boards.ie/discussion/comment/121804628#Comment_121804628

No - You have water escaping from the system somewhere.

slystallone

https://www.boards.ie/discussion/comment/121805358#Comment_121805358

The fella who commented after you says different

slystallone

https://www.boards.ie/discussion/comment/121805448#Comment_121805448

A leak?

Lenar3556

https://www.boards.ie/discussion/comment/121805537#Comment_121805537

Yes, or an expansion issue which is causing water to be discharged via the pressure relief valve.

10-10-20

https://www.boards.ie/discussion/comment/121805534#Comment_121805534

He's a professional, that's the difference.

My own view is that all systems have some level of leaks, it's just a question of whether the rate of loss is acceptable or not and whether it's worth spending the time, effort and investment finding it. I've decided that mine is leaking in the concrete under the tiles, is a low rate of loss (from 1.5bar to 1.0bar in just over a month), and is manageable; so I won't chase it. I might try a leak sealer in the future, but it's not a priority.

slystallone

https://www.boards.ie/discussion/comment/121805931#Comment_121805931

Can you clarify what you mean by expansion issue.

Lenar3556

https://www.boards.ie/discussion/comment/121810648#Comment_121810648

Sealed heating systems need to have some means of providing for expansion when the fixed volume of water is heated. (When it’s heated it expands in volume and this has to go somewhere)

An expansion vessel is usually the way this is done, but these can fail or be undersized in the first instance. When this happens, the water pressure continues to rise when heated and eventually a safety release valve opens and discharges some of the water outside to help relieve excess pressure, and therefore a loss of water occurs.

A good test for expansion is to fill the system to 1.5 bar when cold and then start the boiler and run it up to normal temperature. The pressure shouldn’t rise above 2.5 bar at the very most. It will start to discharge water once it gets to about 3 bar.

slystallone

https://www.boards.ie/discussion/comment/121810674#Comment_121810674

What do the expansion vessels look like?

10-10-20

https://www.boards.ie/discussion/comment/121810742#Comment_121810742

Anything like these:

https://duckduckgo.com/?t=lm&q=expansion+vessel&iax=images&ia=images

But some of them are integrated into the back of the boiler where you can't see them.