Thermostatic Shower works once

[susielance]

My partner has installed a new Thermostatic shower for my daughter.

Gravity fed system with boiler new twin impellor salamanda shower pump at side of tank. Sussex flange etc all following instructions.
Cold water in header tank in loft.

The shower works fine Once Only and after it is turned off dribbles a bit (like emptying shower head or pipe)

If A second shower was needed say an hour/Day later the pump wont work unless bled from cold water pipe in loft, could this be an air lock, if so how do we clear it?

hope someone can help please.

Thank you
Kind regards

 

[picasso]

do the pipes from the pump to the shower go back up to the loft and then down to the shower?

 

[susielance]

do the pipes from the pump to the shower go back up to the loft and then down to the shower?

Yes they do.

 

[picasso]

do you know (roughly) what the distance is between the pipes at the highest point and the bottom cold water tank and what make and model of pump.

 

[susielance]

do you know (roughly) what the distance is between the pipes at the highest point and the bottom cold water tank and what make and model of pump.

Hi Picasso
not really sure what you are asking, there is at least a minimum of 2 metres from pump to cold tank. Airing cupboard on landing opposite bathroom, hot cylinder sits about eye level in cupboard, pump at side.

The pump is a salamanda RSP45 dual shower Positive head.

We had previous problems with back filling so fitted NRV on both hot & cold supply, this cured the problem but now we have this second problem of a one off shower.

Regards
Susan

 

[picasso]

I think your installation is negative head (because the pipes go back up into the loft) take out the nrv on the supply pipes they are not allowed,have a look at page 8 on the instructions, it shows how to change your pump to negative head,
(if this model lets you change it) and lastly follow the instructions about the air vents and nrv.

 

[susielance]

I think your installation is negative head (because the pipes go back up into the loft) take out the nrv on the supply pipes they are not allowed,have a look at page 8 on the instructions, it shows how to change your pump to negative head,
(if this model lets you change it) and lastly follow the instructions about the air vents and nrv.

Hi Picasso Thanks for helping.
The pipework is like so:

cold down from loft to pump back up and over and down to shower.
Hot from tank to pump up into loft and over and down to shower.
NRV are in loft pipework not on supply pipes. How is the backfeed stopped without NRVs? (getting confusing)

Are pumps specific to positive head or negative head, in other words... is it just the installation that signifys positive/negative OR the pump that determines weather the installation should be positive or negative.

Regards
Susan

 

[picasso]

The system is either positive or negative head, the nrv,s are fine in the discharge pipework but not in the supply (as you first said )the head is determined by the distance from the highest point in the pipework to the bottom of the cold water tank, you probably havent got enough flow to trigger the flow switches on the pump, is it possible to change your pump to negative head?

 

[susielance]

The system is either positive or negative head, the nrv,s are fine in the discharge pipework but not in the supply (as you first said )the head is determined by the distance from the highest point in the pipework to the bottom of the cold water tank, you probably havent got enough flow to trigger the flow switches on the pump, is it possible to change your pump to negative head?

Hiya
How Do I change it to negative head? Can I purchase a RCM (whats this stand for please) Negative head conversion kit (as suggested on page 2 fig 3 salamander instruction booklet) if so where from.

Relaying info from partner he speaks I type p.s. he is getting P**** off with this shower not working properly and costing more money on valves etc.

He thinks once it has worked and shut off it is not retaining its preasure for a second shower.

btw thanks for your quick responses

Susan

 

[picasso]

Have you fitted auto air vents in the high points of the pipework? I think you will have problems with the shower as (without seeing you system) it needs a negative head pump, sorry no idea what rcm stands for, I think you have a different set of instructions than I do (cant find rsp45).

 

[steve32]

it's the non return valves not opening
remove the nrv on the cold pipe you don't normally require one on the cold
remove the nrv on the hot and refit on hot supply from pump to shower above pump flex
salamander sell as a spare a nrv that screws direct onto the hot outlet of the pump
check there are not any nrv's in shower valve if there are remove them


Steve

 

[susielance]

Have you fitted auto air vents in the high points of the pipework? I think you will have problems with the shower as (without seeing you system) it needs a negative head pump, sorry no idea what rcm stands for, I think you have a different set of instructions than I do (cant find rsp45).

Hiya

Sound like we need a negative head pump. To fit the conversion kits will cost over £200 (need 2) Is it possible to locate the pump in the loft instead, would this work? or would it be cheeper to buy a new pump

Regards
Susan

 

[picasso]

3 options

1) move the cold water tank a lot higher

2)move the pipework so that its a lot lower than the cold water tank ie all the outlet pipework from pump stays as low as possible

3)buy a negative head pump

 

[susielance]

it's the non return valves not opening
remove the nrv on the cold pipe you don't normally require one on the cold
remove the nrv on the hot and refit on hot supply from pump to shower above pump flex
salamander sell as a spare a nrv that screws direct onto the hot outlet of the pump
check there are not any nrv's in shower valve if there are remove them


Steve

Thanks Steve will give some of your suggestions a try. Think we had it working ok before fitting NRVs but it was back filling the cold tank. The problems have occured after fitting the valves.

Regards
Susan

 

[seco services]

hows it backfilling if the cws is the highest point ?