Boilers... Hot water... What are best options

[rexehuk]

I'm currently redoing a town house, as part of this we're turning the main bathroom into a wet room with thermostatic shower (high pressure would be nice).

Currently, we have a Valiant ecoTEC Plus 418, with an indirect 117 litre cylinder. Both of these are located on the ground floor, part of a conventional system so header tank/expansion in the loft.

Our wet room will be on the 2nd floor, kind of straight line from the cylinder with slight offset. The total distance from cylinder to bathroom floor straight up is around 4.8M, adding another 2m if you consider the spout height in bathroom would be from ceiling or top of wall dependant on shower choice.

Now, with 117 litre cylinder we're expecting a short shower... and are worried about it providing 2 showers every morning lasting say 20 minutes a piece. Not only that, if we have guests it would be nice to have 4-5 showers in succession.

The only testing we've done thus far is flow, and we're achieving at the moment 10 litre/minute on hot and cold feeds independently. I thought that was fairly good, as it's pushing up 2 floors and from what I can tell no hot water/shower pump fitted. Is this likely however to deliver a nice powerful shower?

What options are open to us? All of the pipe work is currently exposed... but can the existing hot water cylinder be swapped out for something like a megaflow?

Any help would be much appreciated! Boiler systems still miff me, despite learning a ton by doing the house. Would be great to get the options on the table, as well as any concerns I have confirmed.

 

[rexehuk]

Your options can't be determined from the information provided.

On the face of it, 10L/min flow is absolutely insufficient for an unvented system and would deliver a shower akin to an electric shower, let alone if someone flushes a toilet or runs a tap elsewhere, though I'd like to know at what outlet this was measured (presume 2nd floor bath taps?). If you run hot and cold concurrently is the flow much higher? You need to measure the flow rates (including dynamic flow) at the garden tap / kitchen tap to rule out internal plumbing restrictions, which you can re-plumb in 22mm if necessary.

Given that the current boiler isn't a combi though, and the hot water cylinder is on the ground floor, how is the hot water to the current bathroom currently provided as you state there's no pump in situ? There's no gravity head for the hot in the bathroom on the 2nd floor so are you sure the current system is vented?

P.S. - absolutely nothing wrong with a 20 minute shower. This isn't 1940; people want their luxury showering experiences and I don't see why this is sniffed at.

Cheers for the reply!

Measured next to boiler/tank (we have a sink down there) and that's above 20L minute which I guess is good? Don't think I even had the tap on full whack.

On the hot water front... have wondered that myself. All we have off the tank is a grundfos pump, but pretty sure that's for the central heating? It's a UPS2 15-50/60. I assumed it was the header pressure from the drop pushing it out...

On the 20 minute shower front... well I like my showers as does partner and we don't have baths so. If I'm dropping that much money on a wet room with a roof light above my shower, then you bet I'm going to enjoy it.

 

[rexehuk]

This is our cylinder by the way

http://www.screwfix.com/p/rm-indire...mm/47140#product_additional_details_container

 

[rexehuk]

There must be another hot water cylinder in the loft. The grundfos is a central heating pump and the cylinder is a standard indirect ie vented. Either that or there's another water pump you can't see or hear delivering 10L/min to your 2nd floor!

Interesting theory. I will check again in the loft but 99% sure it's just the exp and header in there.

Thing is we required the house, so all the old circuits are toast. If they put a pump somewhere it would be dead by now, unless it's hidden downstream of the boiler circuit I've revived.

Think I'll get a plumber over to work out what's going on!

 

[rexehuk]

It does, you can either have one header tank or two. Two, one is for the expansion of the heating, the other is for the DHW. Ours had one which served as both.

Well yeah we have that configuration. 1 large header tank, and 1 small expansion tank.

I've bought a pressure gauge (thanks Prime) so should know shortly what my mains pressure is coming into the house. Luckily there's a tap fitted right above my stopcock, so we'll see what it's kicking out.

 

[rexehuk]

Static pressure isn't much use by its self, you want the dynamic pressure.
Measure the flow of a tap, leave it running and also measure the pressure. So you have something like 3 bar at 10lpm. Along with static pressure it helps to show how your incoming is able to cope with flow.

I'll give that a go tomorrow.

The good news (I guess?) is that outside on the tap I'm getting close to 3 bar pressure... so does that open up options of other systems being viable?

 

[rexehuk]

Had a plumber over today. Suggested we have two options, pressurised or moving to combi.

After seeing our flue which is about 5m in length he said best option is going for pressurised cylinder, as a replacement flue would add a fair cost.

Proposed he's going to run new feed from stop **** because they reduced down to 15mm for some reason. Said we have in excess of what's needed flow wise for the tank and decent pressure.

Just waiting for costs now, he seemed genuine and has good reviews on checkatrade. My only concern is him pressurising the heating, could blow some old joints as the work I've seen to date is flakey at best!

 

[rexehuk]

He checked our taps etc and confirmed all is good for the upgrade.

That is a serious install, are you running a swimming pool with the size of that pipework? Looks very sexy, copper is wonderful.

 

[rexehuk]

We've had two plumbers over now, not really sure where we stand.

Plumber one suggested removing cold water tank and expansion, replacing with unvented cylinder and pressurising the heating along with it. Also making sure we have a two way valve so we can have hot water and heating at same time.

Plumber two said pressure was fine on hot water, and recommended larger cold water storage and larger tank. In addition can fit a pump for the hot water feed for bathroom. However to fit a pump you need equal pressure from hot and cold feeds? So would put a new pipe run from the cold water tank in loft.

Two very different solutions to the same problem... The upside is I'll make them move the entire hot water tank, allowing me to make a brand new bathroom on ground floor, so that should cost offset the entire switchover.

What would you guys do?

 

[rexehuk]

After going from a combi to a cylinder. I would now always go with a cylinder.

How big is your house? How many people live there?

It's a 4 bedroom townhouse, only me and partner live there but renovating it with the view of resale at a family.

Combi is a no go if we have two bathrooms due to hot water delivery. Pretty sure we need to keep the system boiler, it's only a two year old valiant with a 6m+ flue which would have cost a fortune!

Really is just a question of should we go with pressurised or make our existing tank and cylinder larger.

In my head it's less work to ditch the tanks and switch than it is to take out a tank, fit a new tank and run pipework down 3 floors!

 

[rexehuk]

Got a guy lined up now, going with an unvented UVGOLD2 180l, moving the tank to new location about 1.5m from where it currently is (which enables a full second bathroom to be installed), new feed in 22mm from mains (probably about 5m+ run through garage wall/ceiling downstairs), removing our old water tank/exp from loft and sorting out our kitchen gas piping.

All in is charging 2.4k, which I think is incredibly reasonable. Have checked him out on checkatrade etc, seems to be well regarded.