Old house with 15mm pipes. Failed to replace boiler due to piping sizing. How messy is this going to be?

[Scruti]

Hi, I live in an old Victorian terraced house 2bed/1bath with a 23-30y Vaillant Turbomax 242 E combi boiler that came with the house when we moved in 3 years ago.

We booked a boiler replacement through an online service for today. The new boiler is a Worcester 4000 30kw (I plan to do a loft conversion with an ensuite in the coming years, hence the 30kw).
The installer arrived this morning, looked at the boiler and noticed that the piping is 15mm. Then he checked the gas meter (installed in the cupboard under the stairs) and told me that I was f*ed with the gas pipe sizing.

He says that he could install the boiler, which probably would work, but that the piping is inadequate and that he could risk his licence if something goes wrong. And that to upgrade the piping, he would have to open/break our kitchen slate flooring and raise our living room solid wood flooring.
The piping upgrade cost is included in the agreed price, but I naively assumed that it would only require changing a section of pipe reaching the boiler, not destroying our flooring, to replace the whole pipe from the gas meter. He clearly wasn't up for the job either.

He recommended installing a 24kw Ideal boiler instead, as that could be done with the current piping and would be good enough even if we get an ensuite extra bathroom (I doubt so). I didn't want to take any uninformed decision, so I decided to hold for a couple of days, get opinions, talk with the provider and discuss the options.

We plan to reform in the oncoming years to convert the loft into a bedroom with an ensuite. We may redo the kitchen (probably changing the slate flooring then), and we would also have to change the position/size of the radiators in the living room as the current radiator is undersized, poorly placed and not enough for the room size.

Given this, I understand that the reform when moving radiators and changing the kitchen flooring would be the perfect time to upgrade the gas pipes, but this reform may happen in 1-3 years (if so).

What would be the most sensitive way to approach this?

So far, I see a few options:

A) Install a cheaper & smaller 24kw boiler that will work with 15mm piping. Upgrade the gas piping as part of the future house reform.
B) Upgrade the piping now with a new boiler (I have no idea how messy this will be, besides what the installer told me today).
C) Don't do anything at the moment, and pray for the Vaillant to keep going and replace the whole system during a reform.
D) It is 2023, time to install a heat pump instead (Very hesitant about this due to the poor insulation on the old Victorian house).

At the moment, I think A is the way to go, but I want to get second opinions before deciding, and there may be options or issues I may not have considered.

Thanks!

 

[Deleted member 267285]

I certainly wouldn’t recommend a heat pump, as this may cause you more disruption than the gas pipe upgrade. Unless you’re planning to use both the bathroom and en-suite at the same time, then a 24Kw boiler should give you enough hot water delivery. If you do want the upgrade of boiler, then wait until you’re ready to upgrade every else, or obtain a 2nd opinion on the gas route and see if it can be done without ruining the existing floors.

 

[Fred Blogs]

Better still find a plumber who is gas safe and upgrade the 15 mm to 22mm. That's what happened when I had my boiler changed a few years ago.

 

[Madrab]

Where is the gas meter in relation to the boiler - distance/location? Depending on that answer, unless it is really close then even a 24Kw boiler might not be happy on a 15mm supply, any other gas appliances in the house?

A heat pump would probably be a much larger installation compared to a new boiler and lot more expensive.

What prompted you to consider replacing the current boiler? Most key parts are still available and if it comes to biggies then a decision could be made then. Why a 30Kw, do you have a vast number of big rads as the boiler you have just now is a ~30Kw but is probably well oversized. Only other benefit to that is the increase in DHW output but as suggested, with a combi, using more than one HW outlet at a time is pretty pointless anyway.

 

[roguetrader]

If you had used a recommended local tradesman rather than an online shot in the dark, this may have been raised earlier saving everyone a bit of time.
Not a dig, just saying.

 

[Scruti]

Where is the gas meter in relation to the boiler - distance/location? Depending on that answer, unless it is really close then even a 24Kw boiler might not be happy on a 15mm supply, any other gas appliances in the house?

The gas meter is in the cupboard under the stairs. It is around 5.5-6meters distance to the boiler.
Other gas appliances are the kitchen cooker (both oven and hobs use gas) and a gas fireplace in the living room (that we barely use).

A heat pump would probably be a much larger installation compared to a new boiler and lot more expensive.

Noted.

What prompted you to consider replacing the current boiler? Most key parts are still available and if it comes to biggies then a decision could be made then. Why a 30Kw, do you have a vast number of big rads as the boiler you have just now is a ~30Kw but is probably well oversized. Only other benefit to that is the increase in DHW output but as suggested, with a combi, using more than one HW outlet at a time is pretty pointless anyway.

We decided to replace it due to its age to avoid letting it die in the middle of winter. So wanted to be proactive given its age.
It has a couple of annoying issues, but nothing serious: tap water temperature control doesn't seem to work, and the filling loop with a worn-out screw head is quite nightmarish to operate (I recon I could get this changed independently of the boiler). If I try to fill the bathtub, it struggles to produce hot water (for showers, it is perfectly ok).

The 30Kw was based on the current seven rads and our plans to add an extra bathroom with an ensuite. We thought that if our current 29Kw boiler struggles with the bathtub, we should go for 30Kw. But maybe I'm completely wrong here.

We don't plan to take two showers simultaneously, but it is not uncommon that I do the dishes while my wife is taking a shower (that is OK at the moment as we have enough hot water output for minimally notice it).

Given your questions and previous answers, it seems the smartest thing to do now may be... nothing? Hold on the current boiler while it works and only replace it when strictly necessary or when upgrading the whole piping with a future reform.

 

[Scruti]

If you had used a recommended local tradesman rather than an online shot in the dark, this may have been raised earlier saving everyone a bit of time.
Not a dig, just saying.

Fair enough, got too focused on a cheap online quote and good review without considering how important is to have someone take a look given the house is 130 years old and reformed in the 80s.

 

[roguetrader]

Fair enough, got too focused on a cheap online quote and good review without considering how important is to have someone take a look given the house is 130 years old and reformed in the 80s.

As mentioned, not a dig and understand why people do it this way. But, you can't really price a job without physically looking at it.
All that happens is you get a middle man who wants a cut and an installer who has to get done a quick as he can to make any money.

 

[cdbe]

Gas pipe can go pretty much anywhere (eg up and across ceiling) and boxed or painted to blend in, or get a small boiler and stick an unvented in your loft if you convert it.

 

[Madrab]

I suppose the next question would be, how does the current gas supply handle the current boiler. You may find that if there was a gas safety check performed on the boiler that the current supply wouldn't pass.

If you took a straight 15mm pipe from the meter to your boiler @ 2.79 m3 peak usage - then that gas pipe wouldn't be large enough to satisfy the boiler properly, never mind if anything else is on it at the same time, especially with a cooker that has a gas hob and oven and then there's the fire.

Have you never had any of the gas appliances serviced/checked? Can I recommend you get a local gas safe registered bod in to give your whole system a good look over.

 

[Scruti]

Oh God...

The boiler was serviced by BG engineer ( and passed all the checks) late 2019 and we got the document in 2020 (moved in just before COVID lockdown hit) as part of the purchase enquiries.
There is some note about the gas meter seal being broken and the handle being in the wrong way, but nothing major.

I am definitely going to bring someone who give a good look to the whole system. Thanks for the comments .

 

[Madrab]

At the end of the day as long as it all works just now then no need to worry but certainly get someone in to give it a good look over and ensure you get good and proper advice.