Over 3 mins to get hot water in kitchen - is this normal?

[LCV]

Hi,

My family have just moved back in from a house renovation just before the Easter bank holiday. When I turned on the tap in the kitchen to wash up and it takes over 3 mins before the water was hot enough to wash up. I had a large kitchen sink put in and I managed to fill that up with cold water which I had to then drain away to replace it with the hot water. It would have been faster (and used less water) if I had boiled the kettle for the hot water. I now wash my hands with cold water after I have used the toilet because it takes so long and as a family so much water is wasted while we wait for it to be hot enough to bathe and shower.

I feel concerned. Is this normal? Before the renovation I did not have to wait long to get hot water to all my taps.

We had a Vaillant system boiler with a 250L indirect hot water cylinder put in. The previous combi boiler was moved from the kitchen to the Utility room. The kitchen is at the front of the house while the Utility room is at the back of the house on the same floor. The previous house was over 3 floors with 2 bathrooms and a loft conversion has taken it to 4 floors and 3 bathrooms. We were told that we would have to wait up to a minute to get hot water in the loft which we said we were fine with but it is actually a lot longer than that and we certainly did not expect the rest of the house to be affected in this way.

I will go back to the plumber to discuss but wanted to get your views and advice first. I am really hoping the problem is to do with a setting on the boiler.

Thanks!

 

[SimonG]

:leaving:

 

[LCV]

This posting started off with the question whether 3+minutes was normal to get hot water in the kitchen. I thought it could be to do with a setting on the boiler. I did not even connect it to the circulating ring because that, in my mind, was in relation to getting hot water in the loft so why would my kitchen be affected.

 

[ShaunCorbs]

This posting started off with the question whether 3+minutes was normal to get hot water in the kitchen. I thought it could be to do with a setting on the boiler. I did not even connect it to the circulating ring because that, in my mind, was in relation to getting hot water in the loft so why would my kitchen be affected.

the longer the run the more cold water you have to draw off before fresh hot water from the cylinder is used, the pipe might not be lagged/ insulated

with a secondary return the cold water in the pipe is sent back to the cylinder and fresh hot water is put in its place

in simple terms

 

[LCV]

Thanks for explaining Shaun.

What I can't get my head round is why it takes such a long time to get hot water in the kitchen. I know the boiler has been moved from the kitchen to the Utility room but when the boiler was in the kitchen I didn't have to wait over 3 minutes to get hot water in the Utility room. The wait was more like 40seconds. My husband thinks the hot water must go to the loft first before coming back down to the kitchen in order to take that long rather than straight from the Utility room to the kitchen...

Hopefully it will all be resolved and this will be a story I will tell to my children when they are older about the dramas involved with renovation projects.

 

[ShaunCorbs]

Thanks for explaining Shaun.

What I can't get my head round is why it takes such a long time to get hot water in the kitchen. I know the boiler has been moved from the kitchen to the Utility room but when the boiler was in the kitchen I didn't have to wait over 3 minutes to get hot water in the Utility room. The wait was more like 40seconds. My husband thinks the hot water must go to the loft first before coming back down to the kitchen in order to take that long rather than straight from the Utility room to the kitchen...

Hopefully it will all be resolved and this will be a story I will tell to my children when they are older about the dramas involved with renovation projects.

from the boiler to the kitchen distance wise? and very unlikely it will go upstairs first and then back down to the kitchen

 

[LCV]

It is around 8 meters away, is that big? The kitchen and living room is open plan so one room. The Utility room is next to the living room, so across the living room to get to the kitchen sink.

 

[ShaunCorbs]

It is around 8 meters away, is that big? The kitchen and living room is open plan so one room. The Utility room is next to the living room, so across the living room to get to the kitchen sink.

depending on run you could have 10-12m maybe 15m if theres things in the way of pipework esp if its un- insulated yes

at a rough guess 0.2L per m of 15mm or 0.35L for 22mm

worst case 22mm estimated at 15m 5.25L

 

[LCV]

Sorry this doesn't mean anything to me. How does this translate timewise? Are you saying 3+mins is normal then because of the distance? If so, why didn't I have an issue with the time to hot water in the Utility room when the boiler was in the kitchen?

 

[ShaunCorbs]

Sorry this doesn't mean anything to me. How does this translate timewise? Are you saying 3+mins is normal then because of the distance? If so, why didn't I have an issue with the time to hot water in the Utility room when the boiler was in the kitchen?

depends on factors length and run of pipework is it insulated etc, but building reg/water regs state you must have hot water within 30 seconds

"government guidance recommends that when opening a hot water tap, or other outlet, the water should reach 50°C within 30 seconds." to stop wastage of water

 

[LCV]

Do you know which section of building regs your quote came from so that I can refer to it. It does say it is only a recommendation though.

I had instructed private building control for my renovation project but the surveyor for some reason is not replying to my e-mails about this issue as I had asked him first whether 3+mins was normal before posting here.

 

[ShaunCorbs]

Do you know which section of building regs your quote came from so that I can refer to it. It does say it is only a recommendation though.

I had instructed private building control for my renovation project but the surveyor for some reason is not replying to my e-mails about this issue as I had asked him first whether 3+mins was normal before posting here.

3.7 g3

"Pipework should be designed and installed in such a way as to minimise the transfer time between the hot water storage system and hot water outlets."

also

4.4.1

"In small systems, with normal tap running times and a maximum delay of 30 seconds for the hot water to reach the outlet, the pipes would be subjected to sufficient temperature to kill Legionella (or inhibit growth) without the need of secondary circulation."

but something is wrong

 

[LCV]

Thank you Shaun. I presume my house despite being on 4 floors is still classified as a small system.

 

[ShaunCorbs]

Thank you Shaun. I presume my house despite being on 4 floors is still classified as a small system.

yes was from my commercial book

could you measure how much water is drawn off before it becomes hot please?

 

[ShaunCorbs]

if my math is right a bristan kitchen/ any tap has a flow rate of about 10-15 lpm (estimated)

so take it at 10 and you dont have hot water for about 3 mins

thats 30L does that sound about right (ballpark)

 

[LCV]

I can fill my kitchen sink to the top before it gets hot. Would the measurement of my sink be sufficient?

 

[ShaunCorbs]

I can fill my kitchen sink to the top before it gets hot. Would the measurement of my sink be sufficient?

need to know how many l your sink holds you could try with 1 or 2 L bottle of pop and see how many it takes before you get hot water

 

[LCV]

Do you feel like there is something else wrong aside from not having the secondary return? I don't know why but something is not sitting right with the length of time the taps in my house is taking. My neighbour across the road lives in a very similar house but his combi boiler is located on the 3rd floor and he doesn't have to wait minutes to get hot water to his kitchen.

Actually, just thinking about this a bit more. I have another neighbour who lives in an identical house (these are new houses 11 years old on a new street so all the houses are built the same size and layout). He had a loft conversion but did not change his combi boiler. I am going to ask him to time how long it takes to get hot water in his loft.

 

[LCV]

Ah okay. I will do that tomorrow and post back. Thanks you so much and goodnight.

 

[ShaunCorbs]

Do you feel like there is something else wrong aside from not having the secondary return? I don't know why but something is not sitting right with the length of time the taps in my house is taking. My neighbour across the road lives in a very similar house but his combi boiler is located on the 3rd floor and he doesn't have to wait minutes to get hot water to his kitchen.

Actually, just thinking about this a bit more. I have another neighbour who lives in an identical house (these are new houses 11 years old on a new street so all the houses are built the same size and layout). He had a loft conversion but did not change his combi boiler. I am going to ask him to time how long it takes to get hot water in his loft.

like i have said before factors on a few things like pipe runs/ length, is it insulated, dia of pipe work etc

tbh i would of put a secondary return in anyway as while your doing the lot its one extra pipe that can matter

and good night

 

[LCV]

Oh okay. I understand. It is difficult to make a real assessment without all the relevant information.

 

[gastec]

What size is the incoming water mains?

 

[LCV]

Hi Shaun - test done at 3:40pm. Time taken to get hot water is 2mins 40 seconds. 10.8 litres.
Does the time of day make a difference? Also, I had to stop and start as I only have one empty 2L plastic bottle, i.e. once the bottle was full I turned off the tap, emptied the bottle and refilled. Do not know if this affects the results in anyway.

 

[LCV]

Hi Gastec - sorry I don't know and I wouldn't be sure of which pipe to measure.

The house is 11 years old. Your question has made me think whether the location of the water mains could be causing the time lag. I think my mains water pipe is at the front of the house. The Utility room where the boiler and cylinder is located is at the back of the house.

 

[Riley]

Hi Shaun - test done at 3:40pm. Time taken to get hot water is 2mins 40 seconds. 10.8 litres.
Does the time of day make a difference? Also, I had to stop and start as I only have one empty 2L plastic bottle, i.e. once the bottle was full I turned off the tap, emptied the bottle and refilled. Do not know if this affects the results in anyway.

those results sound ridiculous that's under 5 L a minute. My naff gravity hot water at home will do 10 L a minute easily. It sounds to me like you have a bigger problem there Also stopping in between each 2 L is going to make a mess of the results. maybe get a couple of 5 L buckets from the hardware store

 

[Riley]

Hi Gastec - sorry I don't know and I wouldn't be sure of which pipe to measure.

The house is 11 years old. Your question has made me think whether the location of the water mains could be causing the time lag. I think my mains water pipe is at the front of the house. The Utility room where the boiler and cylinder is located is at the back of the house.

Why do you think it's causing an issue ?? Were you given the option to upgrade your mains if necessary The correct operation of an unvented cylinder is very dependent on the flow and pressure of water. Do you know where your stopcock is if so take a photo of it to include the pipe entering and exiting it

 

[LCV]

if my math is right a bristan kitchen/ any tap has a flow rate of about 10-15 lpm (estimated)

so take it at 10 and you dont have hot water for about 3 mins

thats 30L does that sound about right (ballpark)

Just rereading this comment. Wow, 30L, that is a lot. I thought filling over five 2L bottles before I got hot water was bad but okay my situation is not as bad as this. When I wash up I don't turn on the tap at full blast otherwise the water would spray everywhere. Generally I turn on the tap, wait for the water to become hot and when it is hot I increase the flow. In the test I had it a bit higher than medium flow.

 

[ShaunCorbs]

those results sound ridiculous that's under 5 L a minute. My naff gravity hot water at home will do 10 L a minute easily. It sounds to me like you have a bigger problem there Also stopping in between each 2 L is going to make a mess of the results. maybe get a couple of 5 L buckets from the hardware store

Won't harm that much tbh will give you a rough Idea
And agree somewhere there is a problem, maybe a half closed valve or rubbish in a strainer etc

Would need a G3 eng to check those tbh

 

[rpm]

Oh okay. I understand. It is difficult to make a real assessment without all the relevant information.

More like impossible I`d say !

 

[LCV]

those results sound ridiculous that's under 5 L a minute. My naff gravity hot water at home will do 10 L a minute easily. It sounds to me like you have a bigger problem there Also stopping in between each 2 L is going to make a mess of the results. maybe get a couple of 5 L buckets from the hardware store

Hi Riley - I see, shall I redo the test but turn on the water at full blast? I need to get the bucket first.

 

[Riley]

I think the simple answer here is LCV needs to get another engineer in to take a look there is a number of things here that don't add up and over the Internet it's Nigh on impossible for us to work out with a massive degree of accuracy