New gas boiler in outside utility room

A

aro-rat

Joined
5 Jun 2017
Messages
11
Reaction score
0
Country
United Kingdom
My first post here so take it easy :)

We are towards the end of our extension project, the last bit has been removing an attached garage from our 30's semi and building a detached utility room which is 6.5 mtrs away from the end of the new 6 meter extension.

We are looking to shift the current megaflow into the outside utility room and install a new gas boiler, although the old boiler is still working fine and we have had lots of parts replaced.

The new boiler & megaflow will be 12.5 mtrs away from where the old boiler is now, hot water will take a while to get into the house and longer to reach the 1st floor and loft bathrooms.

Question...

Has anyone done this sort of project, what are the negatives other than extra pipework, cost and time to get the hot water ?
 
Last edited:
aro-rat, good evening.

Given the distances proposed in what can be referred to as a "Dead leg" I must admit I have misgivings as regards the sheer distance between Boiler and taps.

If you Google "Dead Legs in water supplies" there is a load of information on there.

One source I located was

https://www.aecb.net/wp-content/uploads/2013/02/The_AECB_Water_Vol_2_V3.pdf

Page 20 is of particular Interest??

Bottom line is that there will be massive heat Loss between the Boiler and the Taps, and the Boiler and the Radiators??

Because of the above heat losses, there will be a significant increase in water used?

Bluntly if it were me, I would have a serious re-consideration?

Lets see what the board think??

Ken.
 
Put a secondary return in.

But as is always the case, this part of the job should have been planned from the beginning.

Now the poor plumber has to work miracles.
 
apologies for posting this in the wrong section.

Ken, thanks so much for information and the link, I am rethinking the options... interesting reading from page 20 and makes sense.

FiremanT, point noted... I agree with you, the 'Dead Leg' terminology is more apt to a leg of pipe that is redundant, i.e. the redundant hot water pipe to a washing machine from a 'T' which is no longer used. But the industry seems to be using 'dead leg' as terminology for a run of pipe where the water cools down. perhaps that should be called 'water lag' !! What is interesting is that a true dead leg can be breading ground for bacteria.

this explains true dead legs;

http://www.combico.co.uk/problems-with-dead-legs/
 
The Real Pin 5 said:
Put a secondary return in.

But as is always the case, this part of the job should have been planned from the beginning.

Now the poor plumber has to work miracles.
Click to expand...

The plumbing work hasn't started yet, my fear is the time required for hot water to reach taps, wastage of cold water to gain hot water and exactly how to insulate the pipework underground against frost and how to minimise heat loss for both hot water and CH. Yep I need to speak to our plumber in some detail as this could be a costly exercise.

Is a secondary return the same as a pump that keeps the hot water circulating (like in a hotel), could you help spell it out... my knowledge is limited to return / flow on rads. and whilst I am at it, do you think a megaflow will be able to send hot water to the loft via this run... 12.5mtrs to reach the where old megaflow was and then shoot the water vertically to a 30's semi-detached loft.

here are some boring pics, work in progress.

old garage demolished, new foundations underway
2017-07-26 07.50.56.jpg


6mtr extension built
2017-07-26 07.54.30.jpg


Reception blocked and being readied for new kitchen
2017-07-26 07.53.49.jpg


old utility room opened up to become part of new kitchen
2017-07-26 07.53.34.jpg
 
Last edited:
aro-rat said:
a secondary return the same as a pump that keeps the hot water circulating (like in a hotel
Click to expand...

Yes. We use the Grundfos Comfort pump.

aro-rat said:
do you think a megaflow will be able to send hot water to the loft via this run.
Click to expand...

Too many variables, but the size of the pipe work and quality of the insulation is key. As is the condition of the incoming water main.
 
aro-rat said:
my fear is the time required for hot water to reach taps,
Click to expand...

It also means a lot of water can be wasted until hot water reaches the tap.

It is worth finding space to fit the hot water cylinder ( Megflo ) as close to the taps as possible ( shortest runs for hot water ). This will mean long pipes for flow and return between boiler and cylinder but the water circulating in that loop is not wasted.
 
With the secondary return there will be little time for the hot water to reach the taps. Rarely done but a pipe thermostat on the pipework will greatly reduce the time the pump needs to run. Sometimes instead a timeclock is fitted to only run the pump when hot water is likely to be needed.

You seem to have a very small cylinder for a family house. I like to size them at 50 li plus 50 li per person.

Properly insulated pipework should not be any problem.

Tony
 
Do some schooly sums - for your loft basin hot tap you're going to waste something like 3litres of water which you also have to heat. Depending on pressure etc you might have to wait 20 seconds for hot to heat the pipes and to arrive and it'll cost you a few pence (order of 5) each time, though the house will absorb the heat while the pipe cools down again.
Secondary returns are small radiators too, but they save the wait. You can add up the cost of parts & labour.
You either pay up or put up!
 
When I stay in hotels, I must say I do just love the immediate hot water from the secondary return.

At home, I use the warm up flow time for the hot to clean my teeth!
 
The Real Pin 5 said:
Where is there any reference to the number of people?
Click to expand...

he made a Sherlock Holmes deduction as to why we may go to lengths for a solution which may not be required with just 2 people at the property...

Anyway the answer is 4, however the kids are finally taking showers when they get to the gym :)

145L megaflow has been okay but its on its limits with 4, 50L p/p would be a good estimation.
 
You must log in or register to reply here.
Back
Top