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Discuss New boiler location and ultimate setup recommendation please in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net

Thanks anyone for reading

Looking for peoples views of best setup, location and any points to consider that I don’t mention please

2000 built home, 4 bed, family bathroom, en-suite, downstairs toilet, radiators

Currently set up with gravity fed system. Showers are a terrible. Want to rip out everything and start over, without Compromising at any point. Aim is never to feel a change in temp or velocity of water, up to 2 showers run simultaneously

Leaning towards unvented cylinder, new boiler, 22mm new cold supply, accumilator.

Guesstimate my flow rate to currently be 12ltrs per minute using kitchen sink test. So that’s why I would install new supply. Not sure about pressure. Probably ok. But not amazing. So I’ve read a accumulator helps that.

Been offered by first plumber 42kw combi. But I’ve read that doesn’t matter what the boiler is capable of. Unless you can get succifiant water coming in. You can’t run 2 decent power showers simultaneous. So ruling out combis unless I missed anything on this

Would ideally like to move boiler and unvented to loft. A full unvented setup is massive and a complete eyesore. Would be prepared to fully board and insulate roof. But I keep reading frost will affect boiler even with frost free. Not sure how cold Loft will get once insulated. But without a radiator up there. I would speculate it won’t be much above freezing most of winter. So this puts me off. Any comments positive or negative on this. Or fixes

If I go with loft I read this:
Gas, water, and electrical isolation points should be provided outside of the roof space so boiler can be isolated without gaining access to roof space. Lag pipes. Especially the “condescending pipe” ?
Anything else anyone can add please

Also running a new 22mm water supply up the side of the house to loft. Will this mean I’m going to loose a ton of pressure? Really wanting to avoid pumps. They noisy and one broke down on me in year. So have little confidence in something with that many moving parts. So if I do loose pressure something to help with this. I believe accumulator is the answer

Other questions
Is g3 certified the same as gas safe or are they different qualifications

Probably will change radiotors. Will there be change in pressure in the central heating with the new setup. How likely is any of my pipe work connections gonna give way with new pressure and need accessing and sealing

Any other factors and considerations? Please

There is a option to put it all in an internal garage. But this means I would use a ton of useable space and take away the option to convert the garage in the future. Without garage heating, I can’t see it being much warmer than the loft.

current cylinder is in a airing cupboard on floor one. But I don’t think you’d get a Unvented in there

cheers
 
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You already well informed compared to some whom ask this question. I think your first action is to accurately test your incoming water for
1. volume. 2. Pressure.....they are separate but inter related. Test at a reliable place like an outside tap. Not at a tap with reducers or fancy airation inserts Test at specific times. Sunday morning 7am when demand is least
Weekday morning 7.30am and NOT in school holidays when the demand peaks.
Then we will know what you are dealing with. Where are you because some areas are diabolical. the suppy crawls out of the main. centralheatking
 

gmartine

Gas Engineer
The system you want is right but where to locate it?

Convert the loft and stick it in the garage, it's an almighty faff to do a loft install plus folks despite the actual risk of failure tend not to like the thought of many hundreds of litres of hot water residing above their heads. Temperature shouldn't be an issue for either if everything is insulated (even the boiler) and you need G3 qualified engineer to install an unvented cylinder.
 
The system you want is right but where to locate it?

Convert the loft and stick it in the garage, it's an almighty faff to do a loft install plus folks despite the actual risk of failure tend not to like the thought of many hundreds of litres of hot water residing above their heads. Temperature shouldn't be an issue for either if everything is insulated (even the boiler) and you need G3 qualified engineer to install an unvented cylinder.
In the garage all day long wack a honeywell frost stat in the coldest corner near the door
off you go....get two quotes loft or garage its obvious which one will be cheaper and thats the best location ...centralheatking
 
Loft or garage, combi or unvented?? Everyone you ask will have a slightly different perspective. Only you can choose.

The only point I would be (very) uncomfortable with is running the 22mm mains supply to the loft externally to the property.

If you opt to go down the (pumped ?) accumulator route - I would not consider installing that in the attic.

If you go for the loft installation, the area must be properly prepared with good access and support for the UV tank. Without teaching you to suck eggs - the limiting factor is (in my experience) hatch size and overhead clearance to get a decent UV tank into place.
 
I saw that regarding mains supply water externally thats is a no no and would cost extra gas to bring it up to hot water temp, then it freezes ...bin that idea right away chking
 
OK, I'm not a plumber but was in your exact situation last year. 3x bathrooms, downstairs toilet in a large victorian semi, gravity-fed. Also 15mm mains feed, 13 litres per min at garden tap with 3bar.

Like you I considered a large combi, but having spoken to people who had actually had this done, it wouldn't sustain 2 high flow showers simultaneously, which was my requirement.

I did a lot of research and decided for an unvented cylinder and an accumulator until I could upgrade the mains feed (it's under the front driveway which I'm planning to redo in a couple of years). In the end, had the unvented cylinder fitted while waiting for the accumulator to come into stock (it was on 3 weeks order). The flow and pressure was so good out of the unvented cylinder I ended up cancelling the accumulator order and haven't yet upgraded the mains supply to 22 or 28mm. I don't really need to upgrade it but will end up doing so when the drive is being done as it would be a shame not to.

Guess what I'm saying is have an unvented cylinder fitted and see if you are happy. If not, upgrade your mains feed. If still not happy, add an accumulator. You might end up saving some cash.
 

EvilDrPorkChop

Gas Engineer
Advent Win
Another vote for the garage too. If your cylinder leaks in future then I wouldn't want it leaking through my ceiling, at least in the garage it can do little damage. Also from a maintenance point of view of servicing etc it's a lot easier. And you notice things when they go wrong, when it's tucked away in the loft you'd only know there's a problem when something starts leaking or something stops working!

I'd bet it's easier getting a new water main to the garage too than the loft..
 

gmartine

Gas Engineer
If temperature is a real concern for either boiler location especially if the system is going to be off at critical times and for long periods you can always use an antifreeze protector like Alphi 11, pricey to dose a large system at the right levels but that is relative.
 
In the garage all day long wack a honeywell frost stat in the coldest corner near the door
off you go....get two quotes loft or garage its obvious which one will be cheaper and thats the best location ...centralheatking
So no one likes the loft placement:)
I get the reasons why having big heavy equipment is better on a lower level and closer to the feeds etc. It just meant when I converted the garage. I had nothing in the way.
This is my house.
picture 1 is the old boiler position on the wall in the utility room I want to get rid of
Picture 2 the red is the other side of the wall the boiler is on. The blue is where I’m considering now positioning a new boiler. Far enough away from the wall so it can be knocked down with having to move it again
I have this tiny utility room. The wall backs on to the internal garage. So my idea was to get rid of the wall in the future and make the garage living space. I didn’t want to use a large portion of the garage new living space already used for the boiler and unvented and potentially accumulator. But maybe if he can fit the unvented in the airing cupboard upstairs. It would be as bad. Anyone know what minimum size what be for a cupboard to fit standard unvented. Including pipe work etc.
Post automatically merged:

Loft or garage, combi or unvented?? Everyone you ask will have a slightly different perspective. Only you can choose.

The only point I would be (very) uncomfortable with is running the 22mm mains supply to the loft externally to the property.

If you opt to go down the (pumped ?) accumulator route - I would not consider installing that in the attic.

If you go for the loft installation, the area must be properly prepared with good access and support for the UV tank. Without teaching you to suck eggs - the limiting factor is (in my experience) hatch size and overhead clearance to get a decent UV tank into place.
I had organised a quote from instaloft to look at the loft. Was thinking to strengthen joists. Make a bigger hatch. Completely board. And insulated the roof rafters. Before I put any plumbing stuff up there.Good point about running a pipe externally up the side of the house. I wouldn’t have considered that. It’s amazing what some plumbers will recommend just so they can do the easiest way for them. And not what’s best. Which is why I’m researching and using this forum. Thanks
Post automatically merged:

OK, I'm not a plumber but was in your exact situation last year. 3x bathrooms, downstairs toilet in a large victorian semi, gravity-fed. Also 15mm mains feed, 13 litres per min at garden tap with 3bar.

Like you I considered a large combi, but having spoken to people who had actually had this done, it wouldn't sustain 2 high flow showers simultaneously, which was my requirement.

I did a lot of research and decided for an unvented cylinder and an accumulator until I could upgrade the mains feed (it's under the front driveway which I'm planning to redo in a couple of years). In the end, had the unvented cylinder fitted while waiting for the accumulator to come into stock (it was on 3 weeks order). The flow and pressure was so good out of the unvented cylinder I ended up cancelling the accumulator order and haven't yet upgraded the mains supply to 22 or 28mm. I don't really need to upgrade it but will end up doing so when the drive is being done as it would be a shame not to.

Guess what I'm saying is have an unvented cylinder fitted and see if you are happy. If not, upgrade your mains feed. If still not happy, add an accumulator. You might end up saving some cash.
Thanks. Gives me some hope everything will be ok. Tho I don’t want to retro fit Equipment if I can try and work out the problems before they arise. I don’t believe my original plumber was on about digging up my drive. Just taking the feed from where it comes in the house And running 22mm pipe from there. Again I’m not sure on this. Tho he didn’t mention new connection to the outside main. Which I believe can be a good solution but costly

got a new plumber comin sat hopefully hel have some ideas
 

Attachments

Last edited:
I think you know the way fwds now, let us know the final plan...ohh now you
have to choose which boiler ...thats a good one ...plenty of advice on PF regarding
which Manu which model and then which components ...these boys really do know
their stuff...no % driven sales people on here just hard advice based on practical
experience...I have my opinion in this area but will hold back
have a good weekend
 

ShaunCorbs

Staff member
S. Mod
Plumber
Gas Engineer
Min space I would say would be a meter by 800mm deep for a standard 600mm dia unvented

Pressure and flow is key with an unvented setup

Min spec would be 2.5 bar and 15lpm just for one outlet open

If you want multiple 4bar and 25lpm minimum

Right now down to the brass tacks

If you don’t have the flow eg 15lpm etc you can install an accumulator but this would need to be sized correctly allowing for the 50% rule so potentially around 400-600l accumulators

You can try and ask the water board to see if they could up your flow and install a new main of it isn’t a 25mm blue plastic one

If you don’t have the pressure then only option is a pump as you can’t pump directly from the mains have a look at the dab easy sys
 
Just had my second boiler guy come round.

He was most keen like my first plumber to put in a combi. Less to go wrong and cheaper was his words. Checked and He is g3 qualified.

He didn’t check my flow rate or pressure. Am now considering buying a pressure gauge myself off amazon. But he said from running the kitchen tap flow rate looks “ pretty good”, whilst waggling a finger under it. So not that that means much.

To be honest I’m comin around to the combi option. It means compromising on multiple showering but it’s positives is it doesn’t occupy much space. I don’t like the idea of turning a liveable area of my home into a pumping station. And I can’t fit the cylinder in my airing cupboard.

Plus then Getting a uv cylinder alone doesn’t guarantee me multiple hot water use without the flow rate coming in and would take up such a large part of my garage. It would be more negative to have a sacrifice of useable floor space over the occasional que to use shower. No one likes the loft idea and I feel like if it was a good idea. Houses would be built with all the stuff in the loft in the first place. It’s such a wasted of area.

If I get a combi. If I go a large as poss, 42kw and get a 22mm feed from the first point In the house (I think it’s under the sink). Is this going to give the best shower In terms of power type shower? I’m guessing as with this system, flow rate is going to affect how much you’ll notice if someone does the washing up whilst someone else is showering ???
 
If I go back to your first post, you believe that your incomming flow rate is around 15 litres per minute. Any Combi fitted should be sized to that flow rate. A 42kw Combi requires a much higher flow rate than that.

You have clearly set out what your requirements are - you need a decent heating engineer to design a system to deliver them and give you some guarantees.

A Combi solution (without an accumulator) winot address the fundamental issue that you have - low flow.


At the moment, with the route you are following, the likely outcome is that the showers won’t perform significantly better than they do now.

I would also talk to your neighbours as to how they have addressed and resolved this issue.

Apologies, but I have seen it so many times - systems ripped out, an enormous Combi on the kitchen wall - and the shower still trickles.

As the previous poster succinctly said - pumping the shower from a vented hot water tank will at least show some imorovement.
 
If I go back to your first post, you believe that your incomming flow rate is around 15 litres per minute. Any Combi fitted should be sized to that flow rate. A 42kw Combi requires a much higher flow rate than that.

You have clearly set out what your requirements are - you need a decent heating engineer to design a system to deliver them and give you some guarantees.

A Combi solution (without an accumulator) winot address the fundamental issue that you have - low flow.


At the moment, with the route you are following, the likely outcome is that the showers won’t perform significantly better than they do now.

I would also talk to your neighbours as to how they have addressed and resolved this issue.

Apologies, but I have seen it so many times - systems ripped out, an enormous Combi on the kitchen wall - and the shower still trickles.

As the previous poster succinctly said - pumping the shower from a vented hot water tank will at least show some imorovement.
The other dynamic to consider is ...you install pump assistance to achieve desired rate from your combi then as you are legitimately taking your neighbours water they go and get
similar pumps installed and you are all back to square one. I watched a whole cul de sac in
Hightown go this way we did our fair share. Stored water is the best way it can build up overnight for the morning onslaught and recover during the day. Then in the summer you will be laughing when your neighbours cant even suck it out of the main
centralheatking
 

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