Showers & Non-return valves

Zxcvbnm

Hmmmmmm. The PDF's for the Mira ones have lovely diagrams showing how to replace the internal NRV's.

keystone

Zxcvbnm wrote: »

Can't remember the make and model. It's a fairly standard non-condensing one.

If the mixer is set low or mid-way temperature doesn't generally fluctuate - it just doesn't get very hot.

From what I'm hearing - it sounds like ANOTHER broken shower valve - as these appliances shouldn't allow crossflow - but this one is just approaching it's second birthday - it's predecessor was around 3 years old. Is that normal? Two valves in 5 years? Am I just unlucky?

Methinks you may have an incompatibility issue between the shower and the boiler rather than a broken shower. The shower documentation will lay down the min spec of the boiler with which it will work. So it wil be interesting to compare the spec of the boiler with the shower docs when you get home to see if that gives us a clue.

If the mixer is set low or mid-way temperature doesn't generally fluctuate - it just doesn't get very hot.

Thanks.

(And is there no chance a £2 non return valve would fix(/bodge) this? )

An NRV would be a total bodge to overcome piping deficiencies in the type of system I described earlier which is (without information at that time) not what it turns out you actually have.

Cheers

Zxcvbnm

keystone wrote: »

Methinks you may have an incompatibility issue between the shower and the boiler rather than a broken shower. The shower documentation will lay down the min spec of the boiler with which it will work. So it wil be interesting to compare the spec of the boiler with the shower docs when you get home to see if that gives us a clue.

It's an Ideal Mini C28 apparently...

keystone wrote: »

An NRV would be a total bodge to overcome piping deficiencies in the type of system I described earlier which is (without information at that time) not what it turns out you actually have.

It works in my head. Probably just as well I'm not a plumber.

keystone

Zxcvbnm wrote: »

It's an Ideal Mini C28 apparently...

Literature confirmed that it is a modulating boiler and provides DHW at the correct flow rate for this shower. You should also check tht the boiler is providing DHW at the correct temperature differential as mantioned in the shower literature. Tweaking the DHW temp up or down a bit at the boiler can also sometimes make a difference. However, in the final analysis an NRV is looking like the solution in the HW supply for this shower but make sure the valve you fit is full bore.

It works in my head. Probably just as well I'm not a plumber.

Sorry if I was unclear. An NRV is a bodge IMHO where put in as an alternative to piping the shower correctly in the first place on a pumped gravity shower - you do not have this arrangement.

Cheers

Canucklehead

Hi,

Is there a significant difference between hot water pressure and cold?


GSR.

Zxcvbnm

Canucklehead wrote: »

Hi,
Is there a significant difference between hot water pressure and cold?

I don't think so. Both appear roughly similar.

Zxcvbnm

keystone wrote: »

Literature confirmed that it is a modulating boiler and provides DHW at the correct flow rate for this shower. You should also check tht the boiler is providing DHW at the correct temperature differential as mantioned in the shower literature. Tweaking the DHW temp up or down a bit at the boiler can also sometimes make a difference. However, in the final analysis an NRV is looking like the solution in the HW supply for this shower but make sure the valve you fit is full bore.

That's great thanks. I'll check out the temperature and see if I can affect it.

Otherwise if going down the NRV path. Should I be ok to cut the pipe (after turning off the water obviously) and slip a (NRV in there after the pipe has split to supply the bath taps?

None of the nrv's on ScrewFix specifiy "full bore" though some of the isolating valves do.

keystone

Zxcvbnm wrote: »

That's great thanks. I'll check out the temperature and see if I can affect it.

Kay.

Otherwise if going down the NRV path. Should I be ok to cut the pipe (after turning off the water obviously) and slip a (NRV in there after the pipe has split to supply the bath taps?

A guarded yes as I cant actually see what you are describing.

None of the nrv's on ScrewFix specifiy "full bore" though some of the isolating valves do.

You can get an iso valve which is full bore that includes a non-return element inside. You do not want to make any restrictions that would reduce flow rate as that may cause an imbalance at the shower valve. The alternative is a bog standard Screwfix one fitted on hot and cold. Then you have made the same change to both inputs. CHs question is one I should have asked but have assumed they are approximately the same anyway as both hot and cold are sourced from mains. But assumptions are sometimes dangerous.


Cheers

BTW just for clarification CHs question was related to pressure. Have you interpreted it to mean and answered it as flow rate?

Zxcvbnm

keystone wrote: »

A guarded yes as I cant actually see what you are describing.

Essentially I'm saying that I would fit the nrv on the hot feed approximately 1 - 1.5 metres from the actual shower unit but at a point where it was ONLY supplying the shower. (i.e. after it had split to supply the bath tap)

And, don't worry, I take full responsibility when it all goes wrong.

keystone wrote: »

You can get an iso valve which is full bore that includes a non-return element inside.

I will take a look for this as there is no iso valve on the shower (as far as I can see) so this would be two birds with one stone.

keystone wrote: »

BTW just for clarification CHs question was related to pressure. Have you interpreted it to mean and answered it as flow rate?

Hmmmm probably yes. I've no means to test this.

keystone

Zxcvbnm wrote: »

Essentially I'm saying that I would fit the nrv on the hot feed approximately 1 - 1.5 metres from the actual shower unit but at a point where it was ONLY supplying the shower. (i.e. after it had split to supply the bath tap)

That would be fine.

And, don't worry, I take full responsibility when it all goes wrong.

Oh don't worry I wasn't (worrying that is).

I will take a look for this as there is no iso valve on the shower (as far as I can see) so this would be two birds with one stone.

Sounds eminently sensible.

Cheers