Problem with Shower

[kstandsteve]

I have fitted a new shower. This consists of an Aqualisa Axis Digital Shower complete with a monsoon 3 bar hp pump. The pump is located in the airing cupboard next to the hot water tank in the airing cupboard as stated in the pump instructions.

The hwc is a standard household size and is heated by my boiler (glow worm space saver 50-60F)

Anyway the new shower has been running fine all week but today has a problem. The shower pump keeps cutting out for a minute or so then fires up again. During this period the shower control flashes to indicate not at temperature.

Thinking about what could be the problem;-

1) Faulty pump
2) Faulty shower module

or maybe?

3) Insuficient hot water??

Would the latter cause this? Maybe the shower is taking too much hot water and the boiler cannot keep up??

One other point - my main central heating pump has been awfully noisy lately - This obviously pumps hot water from the boiler around the hwc to heat the water - maybe today the pump has started to fail causing a lack of hot water??

Thoughts appreciated.

Cheers

 

[seco services]

i'd be more with 3.

why did you choose to fit a seperate pump and not fit a pumped unit ?

 

[kstandsteve]

Yeah me too.

Just tried shower again and ran well. Deffo seems like a lack of hot water.

I got the shower brand new off a relative who never fitted it - this was a non pumped model. I spoke to Aqualisa who said just fit a separate pump so after taking alot of advice of here bought a monsson pump - so impressed with it its so quiet.

Anyway I double checked all the pump details with aqualisa before buying so thats why I am where I am

As I say the shower has worked fine all week until today.

So its either;-

a) Shower taking too much hot water for system to keep up
b) A problem with my hot water system

 

[seco services]

ok quite a few have been done with seperate pump.

these showers will pick up when the hot water temp supply is to low to the mixing valve. as you have already found out.

 

[kstandsteve]

Say for instance;-

Hot water cylinder = 110 litres

pump rating = 9 litres per min

say 50/50 hot /cold water then amount of hot water pumped = 4.5 litres per min

therefore it will take 110/4.5 = 24 minutes to empty the tank

Or is it not that simple?

 

[Whitespirit66]

If your CH pump is failing, that is a completely seperate issue to your shower pump problem. The CH pump moves heated water from the boiler through the coil in your cylinder, transfering this heat to the water in the tank. It wouldn't affect the flow of water from the cylinder.

How is the pump connected to the hot water supply? Does it have its own dedicated supply from the cylinder, via an Essex or Surrey flange?

 

[kstandsteve]

Appreciate that - thought tho if the main pump was not working properley then it wouldnt heat the cylinder up as quick therefore there would be a lack of hot water on demand.

The shower pump does have its own supply off the top of the hwc via a surrey flange.

 

[Whitespirit66]

When you say 'lack of hot water', do you mean that there is the amount of water being supplied that you would expect, but its not hot enough? Or, hot water is flowing, but not enough of it (in volume)?

 

[kstandsteve]

No the digital shower unit in the loft regulates the temperature. However the shower kept cutting out (see orig post) - this seems to be due to the shower unit receiving insufficient hot water to meet the required temperature setting and therefore cuts out.

So it seems either the flow wasnt good enough or the water temperature was not hot enough. The flow is via the 3 bar pump so I reckon its a lack of hot water thats doing it. ie as if I had run all the hot water off and the system needed time to heat more?

I have had 2 showers since and its been fine but seems that the system needs to be improved if I am to avoid this happening again.

 

[seco services]

kstandsteve you are correct in what your saying.
as i said if the water in the cylinder is to cold the unit will pick this up and
fail to meet the temp you require.

 

[kstandsteve]

How long do you think it would take to bring the hwc up to temp?

Just wondering as thats the time needed for the system to recuperate between showers!

If this time is too long then I will have to upgrade the system which I guess will mean replacing the hwc with a bigger unit or replacing the boiler.