New Boiler and effort to improve water pressure

[darrena]

We are replacing our current boiler which is an old glow worm boiler for a new Worcester condenser boiler.
Whilst the job is being done we have decided try and improve the house water pressure as our upstair hot water is awful. To date all engineers have suggested and unvented hot water tank however when the engineer came today to our 3rd quote he noted that we have a 22mm pipe to the stop cock and then there after all pipe work is 15mm, he suggested that using an unvented tank would not work and that we should use a pump in the airing cupboard however this would be noisy!
I have contacted the other two engineers and they have said that it would be preferential if we had a 22mm pipe to the tank but in their opinion we would still see a significant improvement and that the unvented tank is the right option.
Our house is a large 4 bed detached with 2 full sized bathrooms and a down stair toilet

I'm after peoples opinion on where we should proceed with the tank?

It may be possible to replace the 15mm pipe however we would need put the new pipe work in the wall and under a bedroom floor which would be very messy!

 

[darrena]

Bump

 

[muggles]

We are replacing our current boiler which is an old glow worm boiler for a new Worcester condenser boiler.

You've gone wrong already...you'll find precious few pro's on here recommending Worcester. I assume you've gone and believed the Which reports?

Whilst the job is being done we have decided try and improve the house water pressure as our upstairs hot water is awful. To date all engineers have suggested and unvented hot water tank however when the engineer came today to our 3rd quote he noted that we have a 22mm pipe to the stop cock and then there after all pipe work is 15mm, he suggested that using an unvented tank would not work and that we should use a pump in the airing cupboard however this would be noisy!
I have contacted the other two engineers and they have said that it would be preferential if we had a 22mm pipe to the tank but in their opinion we would still see a significant improvement and that the unvented tank is the right option.
Our house is a large 4 bed detached with 2 full sized bathrooms and a down stair toilet

I'm after peoples opinion on where we should proceed with the tank?

It may be possible to replace the 15mm pipe however we would need put the new pipe work in the wall and under a bedroom floor which would be very messy!

Before going unvented, you need to have your working pressure and flow rate measured. Has anyone who has come round so far actually done this for you? It may be possible to successfully run an unvented cylinder on 15mm, 22mm might be required, or your water main might provide insufficient flow rate at a sensible pressure to cope with the demand of running an unvented cylinder on any size pipework. Unless this is properly tested with a pressure gauge and flow cup, there is absolutely no way of knowing whether an unvented cylinder will work successfully in your house or not

 

[JohnD]

is the bath cold tap fed from the tank, or at mains pressure?

To get a rough idea of flow, fill a bucket at your kitchen cold tap (and the garden tap if you have one), time it, calculate how many litres per minute you get.

Anybody recommending an unvented cylinder ought to have tested the flow first. If your incoming pipe is 22mm copper (not plastic, iron or lead) it is likely to be quite good.

 

[darrena]

Hi
The incoming pipe to the stop cock is 22mm plastic. all other pipe work to the boiler and tanks upstairs are 15mm
British Gas did test the flow rate at the kitchen tap when they came and said it was ok and they were the ones that suggested the unvented system as the house is too big for a combi

I will test the flow rate and come back

 

[JohnD]

I haven't used 22mm plastic. 20mm blue plastic is a tiny bit bigger internal diameter than 15mm copper. 25mm blue is substantially bigger ID.

Is it grey or white, rather than blue?

 

[darrena]

its 25mm plastic pipe to the stop cock
I have also checked the flow rate and it 22 litres a minute. Is that ok?

 

[darrena]

also bath tap is mains fed

 

[muggles]

It's OK but by no means spectacular - performance might be acceptable at that but I'd certainly advise running 22mm all the way to the cylinder if you do go unvented

 

[darrena]

ok, I got 13 litres per minute from the cold tap in the bathroom sink

 

[simond]

I would recommend a Worcester. So would most people that have one, it seems, according to Which?

I'm an installer, by the way. I don't like repairing boilers, or irate calls in the middle of the night, so Worcester suit me, they just keep going and in the unlikely scenario they do go wrong, their no quibble support is just what everyone wants.

I have tried installing many esoteric boiler designs, and niche stuff - but at the end of the day, reliability and support are top of most customers lists. It is fun having an unusual car, but it's not usually such a joy having an unusual boiler, especially after it has a few years under it's belt and the installer is having second thoughts about whether it was so good after all.

If you have any doubt, look on this forum and see what they were raving about 7 years ago. You'd have ended up with a Keston or a Remeha Avanta.

 

[JohnHarrison]

Mains pressure systems take all from one pipe. If the pipe is not good enough an unvented cylinder or a combi will not perform too well in hot and cold water delivery, as all is going down one small pipe. If a cold outlet is opened when you are having a shower, the pressure will drop and most likely a hot slug of water makes it uncomfortable.

• Buy an Intergas 30/36 combi - 13 litres/minute flowrate.
• Run 22mm from stop cock to combi.
• Fit a 22mm full-bore stopcock.
• "Just before" the combi, tee off for the cold to the shower.
• Take the shower hot pipe directly from combi and no tees off this, giving the shower its own "dedicated" hot pipe.
• Take another hot pipe to all the other hot outlets directly off the combi; they can all be teed off this pipe.
• Tee off at main stopcock for kitchen tap.
• Keep the cold tank in the loft.
  
• Run 15 mm cold pipe to tank in loft (retain tank)
• Fit a flow regulator on the cold tank's cold supply These are combined flow regulators and isolation valves. This will not rob all the cold water flow and pressure when the ballcock valve opens up - set to 6 litre/minute. A 100 litre cold tank will refill in 16 mins. You have no need to refill the storage tank fast.
• Remove hot water cylinder.
• Run all cold outlets (except shower and kitchen) from the tank in the loft.
• Use the externally mixed mixers on kitchen and basins, that is the water is mixed as it drops from the tap. A little more difficult to find but available.

Then most of the mains water goes to the hot water via the combi. Cold water to baths, toilets, w/machine, d/washer, etc, do not affect the hot supply. As your cold water supply is not that good, you are now dividing and ruling. You are taking your cold supplies off two sources that do not impact on each other, stored cold water and directly from the mains, as the one, the mains, appears not to cope. It also release space by removing the hot water cylinder. This is a simple, reliable and effective solution giving great results.

This is by far the best solution in your case.

 

[JohnD]

An unvented cylinder will give unsurpassed hot water.

They are usually quite big, for example if you get a 250 litre one it will fill two hot baths and still have plenty for washing up. Meanwhile your boiler will be reheating it, so by the time the occupants have towelled off and brushed their teeth, it can be ready for another.

Notice what all the professionals who visited your home recommended.

If you measure the flow from your bath tap (which will be bigger than the basin tap) you may get more flow. However you can see that the 15mm pipe restricts it.

 

[Dan Robinson]

This is by far the best solution.

Is it f**k.

 

[JohnHarrison]

An unvented cylinder will give unsurpassed hot water.

A mains fed system depends on the flow and pressure down the one mains pipe. This man has not got a good flow through his mains pipe, it is severely limited. It is not enough to supply all hot and cold supplies effectively. He will get the usual drop in pressure at the shower when someone flushes a toilet or the washing machine kicks in. That will occur even installing an unvented cylinder. He needs stored water in a cold tank, as the cold mains pipe cannot deliver the whole house requirements. This cold tank is a buffer that can deliver the cold only outlets. It gets topped up slowly for further use. It also gives a reserve of water for the toilets if the mains is cut.

I assume he already has a cold tank in the loft. He is better keeping it and doing what I bullet pointed in the post above. If a washing machine cuts in, the shower is not affected. All flow must be prioritised for the shower. Using the Intergas good flow combi, he eliminates a bulky expensive cylinder with ugly pipes slapped all around it. It also costs to have the cylinder serviced each year. That is a boiler and unvented cylinder service charge each year.