Why can't you put a shower pump on a megaflow?

[xaerocool]

Hi

I've been reading many forms about megaflow and all of them say you can't put a shower pump after a megaflow or a combi boiler but I can't find a single one that says why not? I'm sure there's a very valid reason and this is more just because i'm curious what it is.

Many thanks

Xaero,

 

[seco services]

megaflo, combi's are mains pressure systems so don't need a pump.
it's also illegal to pump mains pressure.

 

[greemyamochop]

Ive pumped megaflos before now quite a few times, it depends on circumstances

 

[DP]

Why would anyone want to pump the output from this type of cylinder other than for use as secondary return

 

[seco services]

Why would anyone want to pump the output from this type of cylinder other than for use as secondary return

probably a lash up install.

 

[greemyamochop]

aye, nobody checked water pressure pre installation is the favourite

 

[Happyplumber]

You may require an accumalator or grundfos complete homebooster pump,but this is for mains in ,not on the output side


why would you want to pump a mains pressure hot water,whats the exact problem you having?

 

[corgiman]

aye, nobody checked water pressure pre installation is the favourite

so you have been whcking a pump on it??

are you putting a break tank on it?

 

[corgiman]

aye, nobody checked water pressure pre installation is the favourite

so you have been whacking a pump on it??

are you putting a break tank on it?

 

[greemyamochop]

aye, nobody checked water pressure pre installation is the favourite

so you have been whacking a pump on it??

are you putting a break tank on it?

Normally a break tank and a Grundfos CRIE or an MQ depending on the job really but prefer the CRIE, you?

 

[xaerocool]

Hi Guys

Thanks for all the responses.

We just got a megaflow tank put in last week. Prior to to this we have a pumped system gravity system. From talking to everyone with a combi the pressure was never very good on showers. So we had a thermostatic shower valve which was being fed by a shower pump. The pressure was good.

Now with the new boiler and megaflow the pressure in the taps is better however the shower sucks - in a word.

So I'm trying to work out how to improve the pressure. The plumber that installed the system just simply said there was nothing that could be done.

What is a break tank? Is this like a cold storage tank but for the hotwater and then you can put a pump behind this? Besides being illegal is there any technical reason why you can't put a shower pump on a megaflow along with the cold as it was before?

Many thanks again in advance.

 

[transam]

You need to refer back to Happyplumber's post ref accumulater & the grundfoss pump system .

Basically an acumulater is a way of storing main's water via an external expansion vessel , it work's on kinetic energy (water) a pumped system is a way of storing water in a tank & useing a pump ? pressure to boost the inlet of the cylinder I must admit I have never used the pumped set up only the accumulater but from what I have heard on here they are better !you other alternative is run a new main's supply into the hose a shower pump is not designed for the purpose to which you intend to put it ! do not confuse pressure & flowrate !

 

[greemyamochop]

What shower valve do you have?

It seems odd that the shower is the only outlet which has poor pressure

Are there any inline strainers fitted before the shower? They come with most showers they look like a long brass fitting with a nut on the top?

 

[xaerocool]

thanks again for the follow up.

The shower is a Grohe thermostatic shower. The pressure varies in the house - sometimes its super powerful and sometimes its normal but less notable. Any reason why there is not consistent pressure even when no other outlets are open?

There are no strainers fitted before the shower no.

How does one measure flowrate and pressure?

Many thanks

Guru

 

[transam]

Flowrate = litre's of water per minute , timeing device (stopwhatch ?) & a jug or bucket time how long it take's to fill than a simple mathematical calc will give you your flowrate !!!

Pressure 2 type's standing pressure = water pressure whemn no demand is being made e.g all outlet's (tap's) closed & running pressure when an outlet is open you meed a pressure gauge & the relevant fitting's for it , plumber's merchant's ect your interest ie flowrate & running pressure !!