2 minutes for tap water to come up to temperature in a new build?

ksousauk

Hi, my in-laws have purchased a new build property (a bungalow).

Ever since they moved in, it has taken nearly two minutes for their tap water to come up to 50 degrees. They've had two private plumbers tell them that it should come up to 50 degrees within one minute in order for it to be legally safe. We raised this with their builders and they came back and said this standard (reaching 50 degrees within one minute) is actually something that only applies to commercial premises (including private lets).

I don't know how to verify whether or not this is the case and any help would be greatly appreciated.

Thank you!

Bendy_House

Presumably this is a combi boiler? Most/all have what's called a 'pre-heat- setting, where the boiler will fire up for s few seconds every while in order to keep the boiler hot and ready to deliver DHW. So that had to be the first thing to check.

Mind you, I'd be astonished if this has already been looked at since it's so obvious.

Make and model of boiler? And do they have the instructions for it?

casper_gutman

Bendy_House said:

Presumably this is a combi boiler? Most/all have what's called a 'pre-heat- setting, where the boiler will fire up for s few seconds every while in order to keep the boiler hot and ready to deliver DHW. So that had to be the first thing to check.

Mind you, I'd be astonished if this has already been looked at since it's so obvious.

Make and model of boiler? And do they have the instructions for it?

I was gonna say something similar. Won't bother now.

Sebi_895

Is this the same issue for all the taps?

coffeehound

I read something about the Building Regs now requiring mixing valves at some outlets to prevent water temps exceeding 48 C. It might have just been bath taps, or maybe wash basins, too.

A product that was mentioned here a few weeks back was the 'combisave' valve which claims to reduce wasted water and reduce the waiting time for water.  Seems legit though not sure how much it might save

https://teddingtonheating.com/combisave/

Northern_Wanderer

I don't have a "pre-heat" and yes, it can take a while to get hot water out of the tap.

Soot2006

I turned the hot water down to 56 following some energy/money saving advice and now it takes the hot water quite a while to come out proper hot. When it turned to the max 65 I think, it was much quicker.

daveyjp

Is the boiler correctly sized for the mains pressure?

grumbler

daveyjp said:

Is the boiler correctly sized for the mains pressure?

What do you mean? AFAIK, the size (power) of the boiler depends on the size of the property, not on the pressure.

Pipe size does matter and can be smaller for the mains pressure.

The time needed for hot water to reach a tap depends on the flow, the distance to the tap and the pipe diameter. 10m of 15mm pipe have almost 2L volume.  For this purpose it makes more sense to measure the volume of the cold water, not the time.

macman

Hot water from a combi, or from a hot tank? Or another form of hot water supply, such as an immersion? How far away from the tap is the boiler or hot tank?
Impossible to answer your question without the most basic info about the hot water system.

Doozergirl

Bendy_House said:

Presumably this is a combi boiler? Most/all have what's called a 'pre-heat- setting, where the boiler will fire up for s few seconds every while in order to keep the boiler hot and ready to deliver DHW. So that had to be the first thing to check.

Mind you, I'd be astonished if this has already been looked at since it's so obvious.

Make and model of boiler? And do they have the instructions for it?

I had the same issue and read about it on here! 

Combi boiler was in Eco mode and wasn't pre-heating.