Can/should I switch hot water systems?

Jeepers_Creepers

Grundfos, for one, don't recommend loft installs. I'd assumed this was for 'what if it bursts?' reasons, but now that I know of one that's in use (in a shed on a flat roof over a flat), the noise could well be another issue - the owner finds it annoying.

If I were you, if I possibly could, I'd fit it in the garage or other outhouse. It's only two pipes.

nicw_3

Funnily enough, the British Gas guy told me they won't install unvented tanks in lofts in case they leak. The guy thought it was stupid, given so many people have giant cold water storage tanks in their lofts, but that's the policy.

Wish I'd had your advice when we moved our current pump to the loft from the airing cupboard - not particularly keen to have another one up there, to be honest. We'll have to look at it properly once we have a better idea of what we're doing!

Section62

nicw_3 said:

We've just had the heating engineer round, who said it's probably at least £2k worth of work and quite a big job. He also thinks that while the flow might improve significantly, it's unlikely the pressure will make enough of a difference.

Is he the person who might be in line to pick up the job of installing something else? If so, beware of bias in what he is telling you.

Digging a trench to lay a replacement supply pipe is considered a labouring job.  A heating engineer might not consider that kind of work to be their thing, instead preferring to install wizzy equipment indoors.  You can't blame them because digging trenches outside in the rain or hot weather is much harder work, with the hassle of reinstating everything to look tidy.  Plus you'd be paying heating engineer rates for a labouring job, unless he also employs labourers (more hassle).

Before committing to anything I'd get other quotes for replacing the supply pipe. Without details it is difficult to say whether £2k is reasonable, but one well-known website suggests an average of £400 to £600 for replacement from meter to house by a private plumber. (sounds a bit on the low side to me though)

Does the water company's £250 contribution involve using their contractor?  If so, it would be worth getting a no-obligation quote from them as a comparison.

In any event, if the supply pipe is defective to the point it is proven to be affecting the flow and pressure, then there is also a risk of the pipe leaking, which would mean the water you are paying for is vanishing into the ground, or your foundations.  Getting rid of leaking supply pipes is one reason why water companies offer incentives like £250 towards the cost of replacement.


For me the next step would be confirming whether or not the supply pipe is defective, and if it is, get it replaced.  Then you can assess whether or not you need to spend money on pumps or accumulators as well.

Jeepers is spot on that a 'passive' solution would be best.... also because you won't have any additional ongoing energy costs, no kind of pressure pump is cheap to run.

nicw_3

@Section62 Thank you, it sounds like you may be right.

I just spoke to someone at a company that does moling to replace water mains (much less digging), and he said as a really rough estimate without seeing the house, we might be looking at around £950 worst case scenario (could be more like £700 if it's more straightfroward).

We'll have to wait on the measurements from the water company (which we can't get for a couple of weeks) to find out if the difference at the road is enough to make it worth replacing the pipe but at least now we have a different set of numbers if so. We've also got someone else coming round later for another quote so we'll see what he thinks as well.

Section62

nicw_3 said:

I just spoke to someone at a company that does moling to replace water mains (much less digging), and he said as a really rough estimate without seeing the house, we might be looking at around £950 worst case scenario (could be more like £700 if it's more straightfroward).

Those figures sound a lot more realistic.  Depending on the surface type and local labour rates you might still find if cheaper to have it trenched rather than moled.  Moling companies can charge more for the job because it saves the disruption and cost of digging and reinstatement.  There's a capital cost on the equipment, and customers are willing to pay a premium.  (Its the same principle as 'drain jetting' companies being able to get away with charging a 4-figure sum to clear a blockage that most householders could do themselves with a £20 set of drain rods)

If the area you need to go through is concrete, newish tarmac, resin, or block paving then moling may be the best option - either due to the effort needed to dig through it, or the difficulty in doing a good reinstatement job.  But if it is grass or flowerbeds etc then digging could be cheaper.

If you want to share a picture of the area between the meter and the house then you'll either get confirmation or else other suggestions from people here.

nicw_3 said:

We'll have to wait on the measurements from the water company (which we can't get for a couple of weeks) to find out if the difference at the road is enough to make it worth replacing the pipe but at least now we have a different set of numbers if so. We've also got someone else coming round later for another quote so we'll see what he thinks as well.

Just to emphasise the point, if there is reason for doubt about the condition of the pipe then replacing it is something to consider even if it won't make a significant difference to the flow and pressure.

With the house being built in 1880 the full range of possible supply pipe materials are a possibility - including lead as Jeepers says, but also iron/steel which are more vulnerable to corrosion and deposits of debris.  If it hasn't been replaced in the plastic era then it is likely due for replacement soon.

nicw_3

Section62 said:

If the area you need to go through is concrete, newish tarmac, resin, or block paving then moling may be the best option - either due to the effort needed to dig through it, or the difficulty in doing a good reinstatement job.  But if it is grass or flowerbeds etc then digging could be cheaper.

If you want to share a picture of the area between the meter and the house then you'll either get confirmation or else other suggestions from people here.

Interesting! Photos of the whole thing would be too much but I've made a terrible diagram 

When the watermain was put in it would have gone straight alongside the house, but in the 80s someone built the garage extension so I assume that's now in the way? If you were going to have to go around it, there's the drive (not new or good condition) and an area to the side that's mostly just dirt. In the garden there are paving slabs laid but for about a foot between the house and the slabs it's dirt covered in gravel - don't know if that's enough room? Judging by the swarm of ants I just found coming out from between the slabs, just dirt beneath those. So maybe not quite so much trouble to dig?

Jeepers_Creepers

nicw_3 said:

Section62 said:

If the area you need to go through is concrete, newish tarmac, resin, or block paving then moling may be the best option - either due to the effort needed to dig through it, or the difficulty in doing a good reinstatement job.  But if it is grass or flowerbeds etc then digging could be cheaper.

If you want to share a picture of the area between the meter and the house then you'll either get confirmation or else other suggestions from people here.

Interesting! Photos of the whole thing would be too much but I've made a terrible diagram 

When the watermain was put in it would have gone straight alongside the house, but in the 80s someone built the garage extension so I assume that's now in the way? If you were going to have to go around it, there's the drive (not new or good condition) and an area to the side that's mostly just dirt. In the garden there are paving slabs laid but for about a foot between the house and the slabs it's dirt covered in gravel - don't know if that's enough room? Judging by the swarm of ants I just found coming out from between the slabs, just dirt beneath those. So maybe not quite so much trouble to dig?

Does your house have a void under the floor? If so, then surely take the new pipe in to the house at a point to the left of the tarmac drive?

From there, under the floor - well insulated - to the connecting point.

We are talking digging a trench through 'mostly dirt' for a distance of ten feet? If so, that would be cool. I fear it ain't like that, tho'...

nicw_3

@Jeepers_Creepers Oh hadn't thought about to left, there's a bit more tarmac that way but peters out into dirt. Some options for the watermain guy to look at I guess should we go that route!

New heating guy has just been round (a friend of a family member who did their work). He measured 12L/min and 3 bar static pressure, 2 bar dynamic (the guy this morning took my word on what water company had given us, didn't do a measurement; British Gas guy on Monday did a flow test but didn't mention pressure). Seems to think an unvented system, with pipes upgraded from 15mm to 22mm would work, with the option of an accumulator (he recommended starting with that and then retrofitting a pump to one after if we found it inadequate).

Jeepers_Creepers

nicw_3 said:

@Jeepers_Creepers Oh hadn't thought about to left, there's a bit more tarmac that way but peters out into dirt. Some options for the watermain guy to look at I guess should we go that route!

New heating guy has just been round (a friend of a family member who did their work). He measured 12L/min and 3 bar static pressure, 2 bar dynamic (the guy this morning took my word on what water company had given us, didn't do a measurement; British Gas guy on Monday did a flow test but didn't mention pressure). Seems to think an unvented system, with pipes upgraded from 15mm to 22mm would work, with the option of an accumulator (he recommended starting with that and then retrofitting a pump to one after if we found it inadequate).

Do you have a void under your floor?

Anyhoo, in situations where you have very good pressure but poor flow, it's possible to use a non-pumped accumulator. There's a Challis model, for example, which has a diaphragm inside it with sealed air on one side and water is allowed in t'other. As water comes in - slowish, in this case, but at 3 bar - it fills the water side and compresses the dia against the air which is squished right down. The tank is therefore storing water at 3 bar pressure, and this will then provide a very good flow - until the tank is exhausted.

Actually, since you cannot (you ain't allowed to) pump mains water at a greater rate than 12lpm in any case, if you do have 12lpm at 3 bar, then the pump would be rather redundant - on a Challis at least.

So, what the guy says about a passive accumulator - with the option of adding a pump if needed - sounds sensible. Essentially, tho', as part of your research you need to CONFIRM 100% what P&F you have, and use this info to ask Challis, Grund, Sala etc what they recommend. They are usually very good at replying.

For all sorts of reasons, tho' - many more outlined by S62 - if you can (and you can...) replace the incoming pipe, then you should really do so.

Sooo, treat yourself to a https://www.screwfix.com/p/roughneck-trench-head-trenching-shovel-4/57424

Section62

nicw_3 said:

When the watermain was put in it would have gone straight alongside the house, but in the 80s someone built the garage extension so I assume that's now in the way? If you were going to have to go around it, there's the drive (not new or good condition) and an area to the side that's mostly just dirt. In the garden there are paving slabs laid but for about a foot between the house and the slabs it's dirt covered in gravel - don't know if that's enough room? Judging by the swarm of ants I just found coming out from between the slabs, just dirt beneath those. So maybe not quite so much trouble to dig?

The garage was likely just built over the top of the water supply pipe... could be part of the problem now?

Moling on a direct line is unlikely to be an option because of the unknown of the garage foundations.  It could be possible to mole under the driveway to an intermediate pit, and from there to the house in order to go around the garage, but at what cost? There are also moles with quite good steering capabilities, but again cost is an issue.

Moving the water meter to the other side of the driveway would simplify the supply pipe route, but again £££.

If you have a void under the floor then Jeeper's way is the easiest.

Failing that, explore whether you can follow the edge of the drive up to the garage and bring the supply pipe up into that and find a route through the garage into the right part of the house. It is possible that you don't need to go all the way to the existing point of entry if you can hook into the cold water system somewhere else in the house.  The feasibility of this depends on how solid the garage floor is, and what the local bylaws are regarding supply pipes and stoptaps inside garages.