Water mains pressure in a very big house.

[somert8]

Hi all,first of all I am plumber,heating engineer etc, I am corgi registered,and amongst other certificates I own, I am registered for unvented cylinders.

I have done some quite large houses in my time but I have just been offered a chance to quote for a VERY large house,I have linked megaflo`s and I know about accumulators,the heating and hot water side is not a problem, the problem is the mains pressure.
Even a 32mm alk main may not suffice because of the length of runs in this house as well as running megaflo`s, I obviously can`t pump it,so I wondered what kind of solutions there may be out there, a breaker tank maybe? or do I have to tank everything(except for the sink tap,where it needs to be drinking water) and pump it that way. Any pointers to any designers out there I could contact would be great.

It has 4 en-suites,2 bathrooms,downstairs shower rooms and utilities etc.

Thanks in advance

 

[corgiman]

Thats a big question for a DIY site mate

are you not a member of the IPHE? if so there are some top boyos on there that will help


or on the combustion chamber at least

 

[simond]

If you knew what you were talking about you would;

- have the answer
- or given us the static pressure and flow rate readings for the property, without which no one can help

Are you sure you have done unvented This is simple stuff.

 

[doitall]

Break tank twin pump set is the only way.

 

[somert8]

If you knew what you were talking about you would;

- have the answer
- or given us the static pressure and flow rate readings for the property, without which no one can help

Are you sure you have done unvented This is simple stuff.

prat

 

[somert8]

Well it confirmed my worst thoughts,a load of so called experts telling diy`ers what not to do,like the man said if you don`t know what you are doing you should`nt be doing it,get somebody in.

 

[corgiman]

Well it confirmed my worst thoughts,a load of so called experts telling diy`ers what not to do,like the man said if you don`t know what you are doing you should`nt be doing it,get somebody in.

Jaysus mate

this is a site for DIYers not full on lads

why would we bore the harris of people who log in with answers to this long and techy question

what does joe average Diyer have to gain from this.

??

also being rude to people who know the answer to a question that you have asked (and dont know) is not the cleverest idea I have ever seen

 

[doitall]

Well said Corgiman

I have been installing large houses, hotels and the like for over 49 years, so do know a little about what is required.

Never mind

 

[corgiman]

I have seen some of your psts and pics DIA and if I had a question of this ilk I would be beating a path to your door

My point is that there are more professional forums that would gain a lot from a dicussion about aquestion like this and this lovely site aint one of them

 

[Agile]

If you knew what you were talking about you would;

- have the answer
- or given us the static pressure and flow rate readings for the property, without which no one can help

Are you sure you have done unvented This is simple stuff.

prat

You said that you have done some large houses.

If that were the case, which I am beginning to doubt, then you would know that the pressure and flow rate are the essential measurements before designing a system.

It also seems that you are not a member of the IPHE as their members are polite to people!

I dont think you deserve the help we could give you!

Tony

 

[corgiman]

It also seems that you are not a member of the IPHE as their members are polite to people!

I dont think you deserve the help we could give you!

Tony

I quite agree we Charters iphers are luvverly chaps and chapesses

 

[BigBurner]

It has 4 en-suites,2 bathrooms,downstairs shower rooms and utilities etc.

Thanks in advance[/quote]

That is:
7 showers
2 baths
kitchen
utility

Correct? What size boiler will be needed?

Divide and rule. Avoid pumps. Is there space for a loft tank(s)?

Showers - thermal store
Have the showers and kitchen taps (hot & cold) off the mains. Heat the showers via a direct thermal store heat bank, it may need two plate heat exchangers, which again divides and rules by splitting the showers.

Baths - vented cylinder
Have a cylinder off the tank and serves the rest of the DHW by gravity. So, a mains pressure thermal store for the showers and kitchen and all the rest of the DHW off a low pressure cylinder. Have a secondary circulation loop on each, depending on DHW runs of course.

CH - thermal store:
Have the CH off the vented thermal store heat bank too. Have the thermal store vented. Take the CH off the store via a plate heat exchanger to isolate the CH rads from the store (prevents sludge build up too) and have the CH rads pressurised. That is a pump from the store to a plate and another Smart pump(s) on the other side serving the rads. The store side pump acts as an injector pump into the CH loop(s). Zone up the CH - you have to with a large system anyway. Put TRVs on all rads and no room stats will be needed as the CH loops are hydraulically isolated from the boiler. The thermal store acts a CH buffer - this is very important.

Weather Compensator
Fit a stand alone weather compensator on the CH circuits. This can modulate a 3-way modulation valve before the CH plate heat X or switch in and out the injection pump to maintain return temperature set by the weather compensator. This guarantees very low return temperatures for high condensing efficiency.

Hybrid thermal store - does the lot
The same as above but eliminate the lower pressure cylinder and have all in one larger vented hybrid thermal store to do the lot. A hybrid thermal store has a DHW take off coil and a plate heat exchanger. The DHW takeoff coil replaces the vented cylinder and can be fed off the tank in the loft for the baths and the high pressure showers off the plate heat exchangers.

Boilers
The boiler(s) can be simple vented heating only boilers like the Glow Worms.

I would be tempted to go with the hybrid thermal store.

 

[ChrisR]

Well it confirmed my worst thoughts,a load of so called experts telling diy`ers what not to do,like the man said if you don`t know what you are doing you should`nt be doing it,get somebody in.

Nobody said anything of the sort.
You seem to be claiming experience and knowledge yet show lack of it!
Who's calling anyone an expert?

If your mains pressure is really too low then your only option is to use a break tank and pump set. All sorts of packages are available, which need careful investigation. Mains pressure is unpredictable, and often too low for exotic bathroom clobber to work at its best. Again if you can't economically upgrade the house's distribution pipework, pressure increase is your only option.

Pumps can give problems but they're a mature technology. Big pumps do make some noise, but in many larger houses they're not audible in the living accommodation. Smaller pumps aren't often a problem.
Look at Grundfos, Wilo etc, but also specialist companies who put rigs together to order.