Is my flat suitable for a Homeboost/Mainsboost?

[Ch_152]

Hello all.

I live in a low-rise block of flats, each flat has it's own metered supply. It's known that water pressure is not great in general, and especially in the upper floors (I am on the 2nd/3rd (top) floors). I have checked another flat on the top floor and theirs appears around the same as mine (so I don't think this is an internal pipework issue).

At the top (3rd) floor of my flat the toilet cistern takes a long time (>5 mins) to fill, and the electric shower will refuse to run at peak times occasionally.

Thames Water have measured ~1.7 bar at ground floor, and although didn't provide me a numerical flow rate the engineer suggested it was more than 20 - 25 L/m.

A plumber has measured 5-6 L/m and ~0.7bar static at my kitchen tap (2nd floor), and I have measured 3-4 L/m on the shower at 3rd floor.


There is not enough pressure for an accumulator (or space, or £££), so I was wondering if a Salamander Homeboost/ST Mainsboost type solution might be suitable?



As an aside, it strikes me as slightly crazy that TW are only obliged to provide 1.0 bar at the entrance to the building at ground floor. If that were the case, it literally wouldn't reach my CWS upstairs!


Thanks



Chris

 

[Madrab]

TW are only obliged to provide 1.0 bar at the entrance to the building at ground floor

I presume you have checked their documentation and confirmed it's not actually to your property?

0.7bar static, what does that drop to dynamic? It must be bad.

A homeboost could certainly help but you may have to have permission, as you may find it could draw from other residents making everyone else situation worse. A pumped accumulator may be an option.

 

[Ch_152]

I presume you have checked their documentation and confirmed it's not actually to your property?

0.7bar static, what does that drop to dynamic? It must be bad.

A homeboost could certainly help but you may have to have permission, as you may find it could draw from other residents making everyone else situation worse. A pumped accumulator may be an option.

Cheers for the reply.

I went through a bunch of calls to TW and one chap did say that should be to the bottom floor of my property (i.e 2nd floor of the building), but when asking others (and the site engineer), they said it was just to where it connects into my building at ground floor. I suppose this makes sense as TW won't be responsible for any nonsense that could be occurring in the pipework within my building. Have tried to google it to no avail.

I haven't been able to test it dynamic - but yes if I flush the toilet upstairs the shower is barely more than a trickle.

As there's separate metered supplies to each flat (have seen each separate supply at the manhole outside the property), I think the Homeboost shouldn't be an issue in that respect - but I will check with the freeholder/management company.


Pumped accumulator (and upgrading to an unvented HW cylinder) is obviously belt and braces, but it given I don't plan on living here much more than 2 or 3 years more I don't want to pour too much money into it.

 

[Madrab]

yeah - they'll probably state that they are responsible for the communication pipe to the boundary/mains tap, everything after that is a common supply and tha'll be the responsibility of all the house owners.

As far as I can find, TW are obligated to ensure the supply in their comms pipe is => 7M head which equates to 0.7bar

As there's separate metered supplies to each flat (have seen each separate supply at the manhole outside the property), I think the Homeboost shouldn't be an issue in that respect - but I will check with the freeholder/management company.

It may be - if that 0.7bar is dynamic then fine but as you suggest, if the flow/pressure drops even further @ peak times or if multiple outlets are used then the dynamic pressure must be a lot lower than that. If that's the case then if you draw more of that available water @ peak hours then it may very well affect others. I am surprised that if the mains is that bad that there isn't communal stored cold water in the property usually in the roof space.

If that isn't a long term location then no, there would be no benefit to dropping lots of money into it. for sure.

See what the responsible persons have to say.

 

[Ch_152]

Ahh yes I follow in relation to the dynamic pressure. I could do with getting some dynamic readings taken. Will buy a gauge and measure off the washing machine (which is by the kitchen tap).

I gather the measurement I need to take is the pressure with all taps closed, and then open the kitchen tap (and maybe run the shower too) and see what it drops to?


Yes, from talking to other residents that it has been a common and ongoing complaint - especially on the upper floor flats. Most of the flats (mine included) have stored CW and HW with a pump supplying the bathrooms.

My biggest issue is the electric shower that was installed at some point in time. Although I'd also welcome an improvement to the kitchen tap, toilet and refilling the CWS (which are all run from mains). Upgrading might also mean I could run potable water to the upstairs bathroom tap as a nice bonus.

 

[Johntheo5]

Ahh yes I follow in relation to the dynamic pressure. I could do with getting some dynamic readings taken. Will buy a gauge and measure off the washing machine (which is by the kitchen tap).

I gather the measurement I need to take is the pressure with all taps closed, and then open the kitchen tap (and maybe run the shower too) and see what it drops to?


Yes, from talking to other residents that it has been a common and ongoing complaint - especially on the upper floor flats. Most of the flats (mine included) have stored CW and HW with a pump supplying the bathrooms.

My biggest issue is the electric shower that was installed at some point in time. Although I'd also welcome an improvement to the kitchen tap, toilet and refilling the CWS (which are all run from mains). Upgrading might also mean I could run potable water to the upstairs bathroom tap as a nice bonus.

If you are happy with the electric shower performance of ~ 3.8/5.9LPM winter/summer you can install a pumped electric shower like the Triton T80SR (in the UK, T90SR over here), these are fed from the CWSC and have their own internal pump.

 

[Ch_152]

If you are happy with the electric shower performance of ~ 3.8/5.9LPM winter/summer you can install a pumped electric shower like the Triton T80SR (in the UK, T90SR over here), these are fed from the CWSC and have their own internal pump.

Hi mate. It was me that posted a thread on exactly that a couple months ago which you sent a few helpful replies in.

I was going to do that, but unfortunately the requirements for the shower state that the bottom of the tank needs to be at least 8 cm above the inlet to the shower. Unfortunately the bottom of my CWS is about 30cm below this and there's no room to move it up.

 

[Johntheo5]

Might have suggested it but feed the proposed pumped shower from the mains but via a pressure reducing valve set to 1 bar, it invalidates the warranty but works well.

Edit: I see I did mention it in your other thread.

 

[Ch_152]

Might have suggested it but feed the proposed pumped shower from the mains but via a pressure reducing valve set to 1 bar, it invalidates the warranty but works well.

Edit: I see I did mention it in your other thread.

Definitely won't need the pressure reducing valve given the pressure at that shower is less than 0.7 bar as it stands (but of course would install one anyway just in case!).

Is there no issue with the mains pressure potentially fluctuating during use (which wouldn't happen when fed from a CWS)?

 

[Johntheo5]

The T80SR, surprisingly for a pumped shower (fed from a CWSC) does, or appears to have, a flow stabilization valve so that will certainly help in a big way, the (ineternal) pump probably boosts the flow by 2.0bar so if the mains pressure was 0.7 bar and fell to 0.1bar. the flowrate will fall to 88% of the flow at 2.7bar, assuming a mains temp of 15c and a shower temp of 40C then a flowrate of 5.16LPM is required, this will fall to a flow of 4.54LPM at a mains pressure of 0.1bar and a showering temp of 43.4C, a increase of 3.4C, not outrageous, if you adjust the flowrate back to 5.16LPM to give the required 40C and the mains pressure then increases to 0.7bar then the temperature will fall to 37C, a reduction of 3.0C, I could live with that.

 

[Ch_152]

The T80SR, surprisingly for a pumped shower (fed from a CWSC) does, or appears to have, a flow stabilization valve so that will certainly help in a big way, the (ineternal) pump probably boosts the flow by 2.0bar so if the mains pressure was 0.7 bar and fell to 0.1bar. the flowrate will fall to 88% of the flow at 2.7bar, assuming a mains temp of 15c and a shower temp of 40C then a flowrate of 5.16LPM is required, this will fall to a flow of 4.54LPM at a mains pressure of 0.1bar and a showering temp of 43.4C, a increase of 3.4C, not outrageous, if you adjust the flowrate back to 5.16LPM to give the required 40C and the mains pressure then increases to 0.7bar then the temperature will fall to 37C, a reduction of 3.0C, I could live with that.

Interesting. Well that's all certainly better than what I have currently.

I guess it comes down to whether the Homeboost providing other benefits (toilet, CWS refill, drinking water upstairs) is worth the additional cost of installing (although the unit itself about the same price as a T80SR).

 

[Johntheo5]

The Salmander Homeboost and the Grundfos Homeboost 15/160 both seem to give 12LPM @ 1.6bar, don't know what the minimum inlet head is required to stop cavitation at that rate but imagine it would be ~ 0.2/0.3bar, both should be able to advise.

 

[Ch_152]

It may be - if that 0.7bar is dynamic then fine but as you suggest, if the flow/pressure drops even further @ peak times or if multiple outlets are used then the dynamic pressure must be a lot lower than that. If that's the case then if you draw more of that available water @ peak hours then it may very well affect others. I am surprised that if the mains is that bad that there isn't communal stored cold water in the property usually in the roof space.

Minor update, bought a pressure gauge and measured at the washing machine (next to kitchen tap downstairs):

~0.9 bar with nothing else open
~0.5 bar with kitchen tap open
~0.6/0.7 bar with upstairs shower running
~0.4 bar with shower running and kitchen tap open.

Noting that this was done at around 18:30, so pretty "peak".

 

[Johntheo5]

Minor update, bought a pressure gauge and measured at the washing machine (next to kitchen tap downstairs):

~0.9 bar with nothing else open
~0.5 bar with kitchen tap open
~0.6/0.7 bar with upstairs shower running
~0.4 bar with shower running and kitchen tap open.

Noting that this was done at around 18:30, so pretty "peak".

Can you turn the shower temperature setting to cold(est) and measure the flowrate and the pressure with this only runnng, then let it running, open the kitchen tap and measure this flowrate and remeasure the shower flowrate, note the pressure again, also note it immediately before beginning the test(s), static pressure.

 

[Ch_152]

Can you turn the shower temperature setting to cold(est) and measure the flowrate and the pressure with this only runnng, then let it running, open the kitchen tap and measure this flowrate and remeasure the shower flowrate, note the pressure again, also note it immediately before beginning the test(s), static pressure.

The only place I can measure the pressure is at the washing machine downstairs.


I did the flow tests, as follows, with the shower on "High" setting, with temperature set to coldest (this is the maximum flow the shower can give):

- Shower flow with kitchen tap off: 4.2 L/m (note that this is actually too hot for me to shower under, so I use the eco setting usually which has a flow rate of around 3 L/m)
- Shower flow with kitchen tap fully open: 2.6 L/m (in this test, the heating element didn't even turn on)
- Kitchen tap for context (shower off): 5.1 L/m

That any use without the pressure?!