Device ID please

[DIYspanner]

I had a look in the HW tank cupboard at a house today where I'm going to fit a bath tap/shower mixer set. I'd need to isolate the HW at the tank and CW at the main stop.

I presume the red Grundfos device is a HW pump to increase pressure.?

I'm mystified by the white plastic body device which has a cable feed. Can someone clue me in please?

 

[Elkato531]

Central heating pump and motorised mid position valve. You shouldn't have any dealings with either if you're only changing taps.

 

[HERTS P&D]

Are you doing this for a customer or to help a friend out?

Andy

 

[DIYspanner]

Are you doing this for a customer or to help a friend out?

Its my nephew's house. The tap set is an easy off with the old and on with the new. So long as I can isolate the HW, the CW off at the main stop.

Then of course, there's the shower rail/curtain to fit.

 

[HERTS P&D]

Tell your nephew to get a plumber in.

Andy

 

[JohnD]

I had a look in the HW tank cupboard at a house today where I'm going to fit a bath tap/shower mixer set. I'd need to isolate the HW at the tank and CW at the main stop.

You appear to be describing a house with mismatched hot and cold water pressures, so it will be unsuitable for a mixer shower and most mixer taps

(Especially ceramic ones with a joystick)

It could be done by running a new cold water supply pipe to the loft tank, but the pressure will be insufficient for a shower so you will need a shower pump, connected by a competent electrician..

It is not as easy as you hoped.

 

[DIYspanner]

Tap/shower fitted and yes, its performance is rather poor due to gravity fed HW. Will look to getting a HW pump fitted.

One aspect that bemuses me. Why are HW Pumps only rated up to 65° C ? ....... not particularly hot?

 

[pcaouolte]

65° C ? ....... not particularly hot

Hot enough to hospitalise you with serious scalds if you shower under it or bathe in it.

 

[Madrab]

Why are HW Pumps only rated up to 65° C

The max temp of HW coming out of an open vent cylinder is normally ~ 60Deg (55deg @ the tap), there's absolutely no need for it to be any hotter. Mixed HW at the outlet that's greater than 44deg can poses a scalding risk, especially with the young and elderly.

Therefore the pump's hardware (seals/construction materials/motor/etc) is designed to cope with temps slightly over that limit, even then it can probably deal with temps hotter than that but for warranty and lifespan consideration then the limit is 65deg. Any hotter and the components (ergo the pump) would probably have to be more expensive to deal with the greater extremes and still have a reasonable lifespan.

 

[JohnD]

Will look to getting a HW pump fitted.

hot and cold must be the same pressure.

You can achieve this by running a new cold supply pipe from the loft tank, and using a shower pump for both the hot and the cold shower supplies.

 

[fixitflav]

Central heating pump and motorised mid position valve. You shouldn't have any dealings with either if you're only changing taps.

Unless the photo is upside down, I believe the installation, actuator below valve, is incorrect.