Hot water through a Megaflo moosoon sealed vented system?

[tomtomato]

Hi,

I am buying a flat, and the home buyer survey just came back.

The surveyor states that "hot water is provided by a Sadia Megaflow Moonsoon sealed and vented system, providing hot water at mains pressure. There is an associated Sadia pump and expansion bottle. Pressure was low at time of inspection. Pump was turned off due to noise during the night. The bath and wash hand have fairly low water pressure without the pump pressure. The pump didn't operate immediately when switched on and therefore should be inspected. Water pressure in the kitchen sink was fine".

I was told initially by the seller that there is a pressure pump, but it's not really required and they disabled it. The flat is in a modern, high specification building built 7 years ago.

I am confused by all of this:

1) I can't find a cylinder called Megaflow Moonsoon vented. I can only find Sadia Megalo unvented, and a separate ST Moonsoon pump. Is he just confused?

2) Did they install a pump just for high shower pressure? I thought unvented systems were supposed to provide more pressure?

3) Should the pump start on demand? Is it just fine to turn it on and off (power switch), or is it likely to damage it? Is it more complicated than this to bypass the pump?

4) Should the pump make some noise during the night, even when unused? I am reading that ST pumps are supposed to be the quietest. I don't understand why the pump would work all the time.

5) If I had to replace the boiler and the pump, what would be a typical cost including installation. Is there a quiet, efficient better solution for high pressure (shower).

Sorry if I am asking obvious questions, but I am new to all of this.

Many thanks.
Tom

 

[plumbnuts]

Hi
Without knowing more details it appears that you have a Megaflow unvented hot water system providing hot water at 3.5bars to your hot taps and a Monsoon pump that is boosting the stored cold water from the storage tank.
Flow and pressure permitting, it would have been better to supply the cold water via the megaflow valve to give you balanced mains pressure cold water.
My advice would be to get a good plumber who is qualified in unvented systems (G3) to take a look prior to the purchase of the property.
Hope this helps?
Steve

 

[sooey]

It doesn't make sense though for someone to fit mains pressure hot water and not do the same for the cold.
If the pressure is good enough for the unvented cylinder it must be good enough to have no need of a pump on the cold side.
I wonder if the pump he refers to is a secondary circulation pump for the megaflo, which would be why it can be heard at night if it's not on a timer.

 

[tomtomato]

If the pressure is good enough for the unvented cylinder it must be good enough to have no need of a pump on the cold side.

From what I understand, hot water pressure is not good at the taps, unless the additional pump is used (but does not seem to work), cold water pressure is good. Therefore, I would seem that the heating cylinder is not providing enough pressure/pressure is lost?

The additional pump was installed when the flat was new, and I understand its purpose was to have more power for the shower.

 

[plumbnuts]

It's not about pressure more so flow. Unless the flat is enormous, it would be unlikely to have a bronze secondary circulating pump installed. I agree it would be pointless not using the balanced cold water supply available, but I still think that you have a pumped gravity cold water supply
Steve

 

[gordonspants]

Ah, the Megalow moosoon.
:taps side of nose knowingly:
Perfect for bungalows due to it's reduced height, but an absolute cow to fit.

 

[picasso]

the chances are you have a balanced hot and cold water supply from your cylinder, the pump will be installed before the cold water control set and will balance the supplies to the bath/shower ect,

The pump wont come on every time you switch a tap on as the expansion vessel acts like an accumulator, this is a good set up and sounds like a good solution to low pressure, there is no guarantee that the pressure at your kitchen tap will be the same at peak periods.

 

[tomtomato]

It's not about pressure more so flow. Unless the flat is enormous, it would be unlikely to have a bronze secondary circulating pump installed.

No, it's a small flat, one bedroom, on the second floor.

 

[tomtomato]

the chances are you have a balanced hot and cold water supply from your cylinder, the pump will be installed before the cold water control set and will balance the supplies to the bath/shower ect,

The pump wont come on every time you switch a tap on as the expansion vessel acts like an accumulator

So would it come on every few hours to accumulate pressure then? If so, could I just put a timer on the plug to disable it during the night, rather than disabling it completely if too noisy?

 

[picasso]

So would it come on every few hours to accumulate pressure then? If so, could I just put a timer on the plug to disable it during the night, rather than disabling it completely if too noisy?

yes you could put it on a timer, a dripping tap is the usual culprit as it loses pressure then the pump switches on to repressurise.